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BDS Stage 1 > Neurobiology > Flashcards

Neurobiology Flashcards

1
Q

What are the basic divisions of the nervous system?

A

Central Nervous System
Peripheral Nervous System
Enteric Nervous System

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2
Q

What can the CNS be divided into?

A

Brain and Spinal Cord

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3
Q

What can the PNS be divided into?

A

Sensory Nervous System and Motor Nervous System

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4
Q

What can the motor nervous system be divided into?

A

The autonomic or somatic nervous system

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5
Q

What can the autonomic nervous system be divided into?

A

Sympathetic

Parasympathetic

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6
Q

What is grey matter composed of?

A

Neuronal cell bodies and dendrites
Astroglia
Microglia

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7
Q

What are astroglia?

A

Support cells that are responsible for maintaining intracellular ion levels.

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8
Q

What is white matter composed of?

A

Myelinated axons
Oligodendroglia
Microglia

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9
Q

What are microglia?

A

Act as macrophages of the nervous system

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10
Q

What does ipsilateral mean?

A

Same side

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11
Q

What does contralateral mean?

A

Opposite side

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12
Q

What are afferent fibres?

A

sensory fibres travelling to the brain

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13
Q

What are efferent fibres?

A

motor fibres travelling from the CNS

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14
Q

What does the frontal lobe do?

A

Involved with thinking and problem solving

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15
Q

What is the parietal lobe associated with?

A

Interpreting signal:
Touch,
taste,
smell,

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16
Q

What is the occipital lobe associated with?

A

Vison

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17
Q

What is the temporal lobe associated with?

A

Memory

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18
Q

Roughly how much space of the brain is associated with head and neck?

A

Roughly 1/2

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19
Q

What is cranial nerve IX?

A

Abducens

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20
Q

What is cranial nerve IV?

A

Trochlear

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21
Q

What is cranial nerve I?

A

Oculomotor

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22
Q

What is cranial nerve VIII?

A

Vestibulocochlear

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23
Q

Where is pain mostly transmitted through in the head and neck?

A

The trigeminal (CN V)

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24
Q

What are A-beta fibres?

A

Present in the tooth sensitive to light tough and proprioception

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25
Q

What are A-delta fibres?

A

Present in the teeth responsive to noxious stimuli, with short sharp pain

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26
Q

What are C-fibres?

A

Unmyelinated fibres in the teeth responsible for dull aching or burning pain

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27
Q

What is the clinical relevance of C-fibre pain?

A

The pain signals inflammation of the whole tooth meaning extraction or root canal treatment is necessary.

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28
Q

What is bells palsy?

A

Sudden paralysis of facial muscles

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29
Q

What are the characteristics of bells palsy?

A

Unilateral,

Normally improves over time but might never fully recover

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30
Q

What are the visible differences between a stroke and bells palsy?

A

Stroke doesn’t tend to affect the forehead.

Bells Palsy only affects the face.

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31
Q

What cranial nerve sits on the parotid gland?

A

VII (Facial)

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32
Q

What do we have to be careful of when placing an inferior alveolar nerve block?

A

Reaching the parotid gland as that could cause partial facial paralysis

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33
Q

How do we know we haven’t reached the parotid gland?

A

Can feel bone (mandible)

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34
Q

What is iatrogenic damage?

A

Damage caused by a healthcare professional

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35
Q

What is Frey’s syndrome?

A

following trauma or surgery, when thinking about food or drink, sweating will occur over skin of the neck.

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36
Q

Why does Frey’s syndrome occur?

A

The parasympathetic axons left behind from surgery ‘need something to do’ so infiltrate the skin on the neck

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37
Q

What is peripheral sensitisation?

A

Inflamed peripheral receptors can gave increased responsiveness or respond to lower thresholds

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38
Q

What can peripheral sensitisation lead to?

A

Stimulation can be more intense and can lead to referred pain

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39
Q

What is central sensitisation?

A

When CNS receives prolonged stimulus of pain it can become sensitised

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40
Q

What can central sensitisation lead to?

A

Non painful signals being amplified so the patient feels pain

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41
Q

What is neuralgia?

A

Pain in the distribution of a nerve due to damage in the nerve and the neuroplastic changes following.

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42
Q

What is the most common form of neuralgia?

A

Trigeminal (about 90%)

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43
Q

What is trigeminal neuralgia?

A
  • Affects CN V
  • Short Sharp Pain
  • Triggered by Touch
  • ## Usually unilateral and isolated to one division
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44
Q

What is localised non-odontogenic pain?

A

Must be present for 3 months or more ad 8 hours a day

Can be diagnosed by process of removal

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45
Q

When can non-odontogenic pain occur?

A

Following extraction or endodontics, (roughly 1.6% of cases)

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46
Q

How does dementia affect dentistry?

A

Patients might not be able to give proper consent

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47
Q

How does parkinson’s affect dentistry?

A

Motor skills in the hand will be affected therefore oral hygiene might not be carried out properly

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48
Q

What are analgesics?

A

pain relieving drugs (i.e paracetamol, codeine, ibuprofen )

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49
Q

What are microglial cells?

A

Immune cells of the brain

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50
Q

What are oligodendrocytes?

A

There are the myelinating cells of the CNS. They secrete myelin that wraps around the neurones.

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51
Q

What is the cerebellum involved in?

A

Remembers complex motor movements

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52
Q

What is the gyrus?

A

‘The hump’ of a fold

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53
Q

What is the sulcus?

A

‘The valley’ of a fold

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54
Q

What is the importance of gyri and sulci?

A

They increase surface area meaning more brain cells are present.

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55
Q

Where is the frontal pole?

A

The most anterior part of the frontal lobe

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56
Q

What is the frontal pole responsible for?

A

Personality

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57
Q

How many separate frontal gyri are there?

A

3

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58
Q

What are the 3 frontal gyri?

A
  • Superior
  • Middle
  • Inferior
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59
Q

Where is the angular gyrus located?

A

On the angle between the temporal, parietal and occipital lobe

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60
Q

How many divisions of the temporal lobe are there?

A

3

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61
Q

What role does the superior temporal lobe has?

A

Audio roles

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62
Q

What borders the pre-central gyrus?

A

The pre-central sulcus (anteriorly) and the central sulcus (Posteriorly)

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63
Q

What borders the post-central gyrus?

A

The central sulcus (anteriorly) and post central sulcus (Posteriorly)

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64
Q

What are the two types of cerebral cortex?

A

Primary

Association

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65
Q

What does the association cortex deal with?

A

more complex aspects of sensory and motor function, such as planning and predicting.

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66
Q

What separates the parietal and occipital lobe?

A

The parietal-occipital sulcus

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67
Q

What does the thalamus do?

A

Relay centre for sensory information.

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68
Q

What is the main role of the hypothalamus?

A

Homeostatic control, linked to the the pituitary gland.

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69
Q

What is the pons?

A

Bridge between the brain and the spinal cord.

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70
Q

What is the corpus callosum?

A

Big white matter tract that connects the two hemispheres of the brain.

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71
Q

What is the longitudinal fissure?

A

Runs right down the middle of the brain separating the two hemispheres.

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72
Q

What is Spina bifida?

A

The formation of the bones in the spine are disrupted, following the failure of neural tubes to close.

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73
Q

How do you identify neural tube defects in pregnancy?

A

Screen for Alpha-fetoprotein levels. Will be high.

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74
Q

What do haematopoetic stem cells form in the brain?

A

Microglial Cells?

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75
Q

What do embryonic CNS stem cells differentiate to?

A
  • Glial Progenitor

- Neuronal Progenitor

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76
Q

Which secondary embryonic vesicle goes on to develop into the pons and the cerebellum?

A

Metencephalon

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77
Q

Which two arteries enter the cranium to supply the brain?

A

Verterbral and Internal carotid

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78
Q

Where do the vertebral and internal carotid artery join?

A

Circle of willis

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79
Q

What do the two vertebral arteries join to form?

A

Basilar artery

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80
Q

What branches off the vertebral artery?

A
  • Ant. Spinal Artery.
  • Post. Spinal Artery
  • Posterior Inferior Cerebellar artery
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81
Q

Where does the basilar artery form?

A

Pontomedullary Junction

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82
Q

What are the two terminal branches of the basilar artery?

A

Anterior Inferior Cerebellar Artery

Superior Cerebellar Artery

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83
Q

Where does the basilar artery split?

A

Ponto-midbrain junction

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84
Q

Posterior Cerebral Artery

A
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85
Q

What is the ophthalmic artery a branch of?

A

The Internal Carotid Artery (ICA)

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86
Q

What is the most important branch of the ophthalmic artery?

A

Central Retinal artery

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87
Q

What is the Posterior Communicating artery?

A

A branch of ICA that rises just before the ICA terminates.

Joins the first part of the posterior cerebral artery

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88
Q

What is the anterior choroidal artery?

A

A branch of ICA that supplies the choroid plexus

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89
Q

What does the choroid plexus form?

A

Cerebral Spinal Fluid

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90
Q

What junction do the endothelia cells in the blood brain barrier have?

A

Tight Junction

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91
Q

What do astrocytes do in the blood brain barrier?

A

Modulate the function of endothelium cells and ensure correct nutrients are collected

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92
Q

Why do we have the circle of willis?

A

Allows blockage of some vessels while still allowing circulation of blood in the brain

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93
Q

Which arteries mainly supply the cortex?

A

Posterior cerebral
Middle cerebral
Anterior Cerebral

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94
Q

How does the middle of the brain get its blood supply?

A

Perforating branches of the middle cerebral artery.

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95
Q

Which artery mostly supplies the lateral surface of the brain?

A

Middle cerebral artery

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96
Q

What forms the cavities in the brain?

A

The neural tube

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97
Q

What makes the cerebrospinal fluid?

A 
Choroid Plexus (70%)
Ependymal cells (30%)
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98
Q

What does the CSF do?

A

Gets rid of waste products.
Provides cushioning for brain.
Allows brain to ‘float’
Stable ionic environment for CNS

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99
Q

What ventricles are there in the brain?

A 
Lateral ventricles (1 in each hemisphere)
Third Ventricle (in centre)
Fourth Ventricle (in centre)
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100
Q

What joins the 3rd and 4th ventricle?

A

Cerebral Aqueduct

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101
Q

What joins the Lateral ventricle with the 3rd ventricle

A

Intraventricular Fo. (of munro)

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102
Q

Where does the CSF flow start?

A

Lateral ventricles (by choroid plexus)

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103
Q

Where does the CSF enter the sub arachnoid space?

A

The Median aperture

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104
Q

What % of strokes are due to blockages?

A

Around 85%

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105
Q

What % of strokes are due to bleeds?

A

Around 15%

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106
Q

Where do you find berry aneurisms in the circle of willis?

A

Anterior Communicating arteru (40%)
Middle cerebral artery (34%)
Joining of Posterior Communicating Artery and ICA (20%)
Branching of Basilar Artery (4%)

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107
Q

What is TACS?

A

Total Arterial Circulation Stroke

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108
Q

What can TACS cause?

A

Inattention
Visual Deficits
Right hemiparesis (Paralysis)
Dysphasia (if on dominant side)

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109
Q

What is sensory neglect?

A

Often damage in the right hemisphere, association somatosensory lobes in the parietal region. Leads to ignorance of items on the opposite side of the body.

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110
Q

What is locked in syndrome?

A

Damage to the basilar artery prevents blood supply to the brainstem. This causes paralysis of nearly all voluntary muscles in the body. Except eye movements. EEG is normal indicating normal brain function.

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111
Q

What is hemiplegia?

A

paralysis on one side of the body

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112
Q

What is aphasia?

A

Impairment of language

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113
Q

What are the effects or posterior cerebral artery stroke?

A

Affects the occipital lobe- vision

Also damage to visual association cortex

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114
Q

What is the rate of proliferation during foetal development?

A

Around 250,000 per minute

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115
Q

What is the diameter of a neurone cell body?

A

4 to 100 microns

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116
Q

What is a soma (cell body)?

A

It houses the cell nucleus and is responsible for cell metabolic maintenance

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117
Q

What is the function of dendrites?

A

Receive and process information from other neurones (via synapses)

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118
Q

What is the definition of a ganglion?

A

Group of neurone cell bodies in the peripheral nervous system

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119
Q

What is the equivalent of a ganglion in the CNS?

A

A nucleus

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120
Q

Where do you find nerve tracts or pathways?

A

In the CNS was bundles of nerves

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121
Q

What is the function of a neurone related to?

A

The shape
The neurotransmitters used
The ways it reacts to other neurones

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122
Q

What defines a multipolar neurone?

A

They have many processes emanating fro the cell body

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123
Q

What are motoneurons?

A

They carry signals from the spinal chord to the periphery

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124
Q

What are bipolar sensory neurones?

A

They account for 0.9% of neurones and have two axons.

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125
Q

How do bipolar sensory neurones work?

A

One axon communicates with a sense organ, one communicates with the CNS

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126
Q

What percentage of brain cells are glial cells?

A

90%

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127
Q

What are glial cells?

A

Nerve cells that do not carry nerve impulses

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128
Q

What are the functions of glial cells?

A

Digest parts of dead neurones.
Manufacture myelin.
Provide Physical and nutritional support.

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129
Q

What different types of glial cells are there?

A

Astrocytes
Oligodendrocytes
Schwann Cells
Microglia

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130
Q

What do astrocytes do?

A

They help regulate extracellular ionic concentrations.

They also form the scar tissue in the CNS

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131
Q

What do oligodendrocytes do?

A

They form myelin around several axons for electrical insulation in the CNS

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132
Q

What do Schwann cells do?

A

They form myelin in the PNS

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133
Q

What do microglia do?

A

They clean up dead tissue

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134
Q

What is the point of origin of an axon?

A

the axon hillock

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135
Q

Do dendrites taper with distance?

A

YES

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136
Q

Do axons taper with distance?

A

NO

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137
Q

Why do neurones have dendrites?

A

To receive and process information from other cells making synaptic contacts with them

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138
Q

What are spines on dendrites?

A

Small mushroom appendages on the dendrites

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139
Q

How many synapses does a typical neurone have?

A

Between 1,000 and 10,000

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140
Q

What is the cerebellar purkinje cell?

A

It integrates tens of thousands of inputs in the cerebellum and integrates the signals.

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141
Q

How are purkinje cells arranged in the cerebellum?

A

They have a molecular layer with millions of parallel fibres passing through the sheet

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142
Q

What is myelin made up of?

A

70-80% lipids, 30-30% proteins

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143
Q

What types of connections can you have with axons and postsynaptic cells?

A

Axodendritic
Axoaxonic
Axosomatic

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144
Q

How does a cell gain it’s resting potential?

A

The ability of the membrane to allow different ions in and out of the cell in a selective manner.

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145
Q

What is Nernst potential?

A

It is used to calculate the exact V generated by a specific ion

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146
Q

What happens when Vm = Vnernst

A

There is no net flow of that ion across the membrane

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147
Q

Which ion will have the highlights Vnernst

A

The ion with the highest permeability

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148
Q

What channels are found in neuronal membranes?

A

Leak K+ Channels (always open)

Na+ and Cl- channels

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149
Q

Which ion has the highest influence on the resting membrane potential?

A

K+

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150
Q

What does the Goldman equation do?

A

Combines the nearnst equation for all ions and takes permeabilities into consideration

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151
Q

What is passive propagation?

A

Membrane properties that do not change during electric signalling

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152
Q

What is active propagation?

A

These are triggered by changes in Membrane potential. Allowing signals to be passed efficiently over long distances.

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153
Q

What does a large diameter of axon do to the signal?

A

Increases the distance the current will propagate

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154
Q

What does myelin on an axon do?

A

It increases signal propagation

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155
Q

What are the voltage gated Na+ channels like under resting conditions?

A

70% of the internal gates are open

External gates are closed

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156
Q

What are the voltage gated K+ gates like under resting conditions?

A

They are closed

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157
Q

What happens when Vm decreases to threshold?

A

External Na+ channels start opening, this further reduced Vm. Example of positive feedback mechanism.

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158
Q

What prevents further depolarisation of the membrane?

A

The internal Na+ channels inactivate

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159
Q

When do V-gated K+ channels open?

A

They slowly open after threshold depolarisation to speed up the depolarisation process

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160
Q

What causes the undershoot of an action potential?

A

The delay of closing V-gated K+ channels.

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161
Q

What is the Absolute Refractory Period?

A

When a second AP cannot be produced

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162
Q

What is the Relative refractory period?

A

APs can only be generated with increased threshold, or reduced amplitude.

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163
Q

Why does the AP travel ‘forward’?

A

As on one side the Na+ are in a closed state ready to be open. The other side the Na+ channels are in an inactive state.

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164
Q

What is saltatory conduction?

A

The process of the signal ‘jumping’ from one node of ranvier to another in myelinated axons.

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165
Q

What are the characteristics of electrical synapses?

A

They are fast,

No chemical transduction

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166
Q

Where are electrical synapses found?

A

Gap synapses in cardiac muscle cells and epithelial cells

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167
Q

What are the characteristics of chemical synapses?

A

Use a chemical substance as an intermediate to convert electrical signals in presynaptic cell into postsynaptic cell..

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168
Q

What are gap junctions?

A

Protein pores that bride the gap between two cells

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169
Q

What makes up the pore in gap junctions?

A

6 subunits of connexin

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170
Q

What is the distance between membranes in an electrical synapse?

A

3.5nm

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171
Q

Is there a delay in transmission with chemical synapse?

A

Yes, about 1-5 msec

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172
Q

What direction do signals pass in chemical synapses?

A

Unidirectional (one way)

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173
Q

What identifies a neurotransmitter?

A

It mimics normal transmission when applied to postsynaptic membrane.
Manufactured and released from presynaptic cell.

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174
Q

What are Ionotropic receptors?

A

Directly linked to ion channels

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175
Q

What are metabotropic receptors?

A

G-protein-coupled receptors that use a second messenger

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176
Q

What would you find at a chemical synapse?

A 
Synaptic vesicles
Receptors
Synaptic Cleft
Secretory Granules
Mitochondria
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177
Q

What forms the presynaptic element?

A

The axon terminal

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178
Q

What is the 1st step of synaptic transmission?

A

The AP is propagated in the presynaptic neurone

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179
Q

What is the 2nd step of synaptic transmission?

A

Ca2+ enters the synaptic knob through V-Gated channels

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180
Q

What is the 3rd step of synaptic transmission?

A

Release of neurotransmitter into the synaptic cleft by exocytosis

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181
Q

What is the 4th step of synaptic transmission?

A

Binding of neurotransmitter to postsynaptic receptor

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182
Q

What is the 5th step of synaptic transmission?

A

Opening of ion channels or activation of G-Protein secondary messengers.

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183
Q

What is the importance of recycling neurotransmitters?

A

If they remained in the synaptic cleft there would be uncontrolled signalling

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184
Q

How do vesicles dock with the membrane of the terminal?

A

SNARE proteins that trigger exocytosis in the presence of Ca2+

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185
Q

What are the main differences of AP and EPSP

A
  • EPSP only reaches threshold
  • EPSP is decremental
  • EPSP is much longer (15-20 msec)
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186
Q

What does EPSP stand for?

A

Excitatoty Post-Synaptic Potential

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187
Q

Why do you get temporal summation in EPSP’s

A

As the time taken for a single EPSP takes much longer the signals adduct at high frequency to each other reaching the threshold.

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188
Q

Why is temporal summation in EPSP’s important?

A

Otherwise the EPSP would decrement. This allows for an AP to be generated

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189
Q

What is spatial summation?

A

This is when signals come in from different inputs. This ‘collects’ the signals together allowing for threshold to be met for AP

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190
Q

What does IPSP stand for?

A

Inhibitory Post-synaptic potential?

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191
Q

What does IPSP do?

A

It causes hyperpolarisation of post-synaptic neurones

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192
Q

What is the importance of IPSP’s

A

It makes it much harder to generate an AP as you are further away from threshold.

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193
Q

What is a first order neurone?

A

The first axons until the first synapse

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194
Q

What is a second order neurone?

A

Neurones from 1st synapse to the 2nd synapse (normally in thalamus)

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195
Q

What is a third order neurone?

A

From 2nd synapse to the final destination

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196
Q

What are afferent nerves?

A

Towards CNS
Group of nerve fibres
Various sensory modalities

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197
Q

What are efferent nerves?

A

Away from CNS

Motor nerve fibres to effector organs

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198
Q

What are the general properties of motor neurones?

A

Cell body in spinal cord
Fast
Myelinated

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199
Q

What are the general properties of sensory neurones?

A

Cell body in dorsal root ganglion
Different types have different speeds
Myelinated and Unmyelinated

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200
Q

How do you classify peripheral nerves?

A

Two methods

Letter System: for sensory and motor

Roman numeral system: for sensory only

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201
Q

What do Ia (Aα) fibres do?

A

Sensory from Muscle Spindle to CNS

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202
Q

What do Ib (Aα) fibres do?

A

Golgi tendon organ to CNS

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203
Q

What do II (Aβ) fibres do?

A

Muscle spindle, touch, pressure to CNS

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204
Q

What do III fibres (Aδ) do?

A

Pain, pressure, temperature to CNS

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205
Q

What do IV fibres (C) do?

A

Pain, touch, temperature to CNS

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206
Q

What do B fibres do?

A

Part of ANS towards effector organ. Preganglionic

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207
Q

What do C fibres do?

A

Part of ANS to effector organ. Post ganglionic

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208
Q

What do Aα fibres do?

A

Transmits signals from CNS to skeletal muscle

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209
Q

What do Aγ fibres do?

A

Transmits signals from CNS to Muscle spindle

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210
Q

Whats the difference between B and C fibres in parasympathetic ANS.

A

B fibres are longer than C fibres

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211
Q

Whats the difference between B and C fibres in sympathetic ANS.

A

B fibres are shorter than C fibres

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212
Q

What are golgi tendon organs?

A

A sensory receptor organ that senses changes in muscle tension.

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213
Q

How can you tell if a fibre is sensory/motor based on its name?

A

If it is roman numerals it is sensory only.

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214
Q

What does sensation mean?

A

Conscious/subconscious awareness of external environment

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215
Q

What does perception mean?

A

Interpretation of sensation

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216
Q

What is the definition of pain?

A

Unpleasant felling caused by stimulus of nociceptive receptors following tissue injury

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217
Q

What is acute pain?

A

Short term

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218
Q

What is chronic pain?

A

Long term

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219
Q

What is somatic pain?

A

Body

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220
Q

What is visceral pain?

A

Thorax/Abdomen

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221
Q

What two phases of pain do we have?

A

Sharp, instant pain

Dull, throbbing pain

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222
Q

What are pain receptors called?

A

Nociceptors

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223
Q

Where are nociceptors found?

A

Skin, muscle, joint.

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224
Q

What are the two types of pain fibres?

A

A-delta and C-Fibres

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225
Q

What is the difference between A-delta and C-Fibres

A

Aδ are myelinated, therefore conduct speed fast. Pain type is sharp and fast.

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226
Q

What is Rexed’s Laminae?

A

Found in dorsal horn of grey matter. They are where pain receptors synapse.

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227
Q

Where do C-fibres synapse in rexed’s laminae?

A

Mainly towards the top

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228
Q

Where do Aδ fibres synapse in rexed’s laminae?

A

In different laminae

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229
Q

What is specific about peripheral sensitisation?

A

They have a high threshold, meaning they respond to noxious stimuli.
They become sensitised reducing likelihood of further damage.

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230
Q

What importance of amygdala?

A

Key centre of brain for anxiety, pain, and worry.

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231
Q

How does referred pain work?

A

It is due to convergence of sensory input on second order neurones

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232
Q

How does the CSF flow through the brain ?

A

in the ventricular system
lateral ventricles
third ventricles via the interventricular foramen
4th ventricles via the cerebralaqueduct

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233
Q

How does CSF leave the 4th ventricle ?

A

via the median and lateral apertures

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234
Q

Where is CSF made ?

A

in the lateral and 3rd ventricles

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235
Q

What is the touch pathway ?

A

dorsal column medial lemniscus

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236
Q

Where do the first order neurones synapse in DCML?

A

in the cuneate or gracile nuclei in the medulla

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237
Q

What is the pain pathway ?

A

anterolateral system

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238
Q

Where do the first order neurones synapse in the anterolateral system ?

A

in the dorsal horn of the spinal chord

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239
Q

Where does the DCML dessucate ?

A

in the medulla

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240
Q

Where does the anterolateral system dessucate ?

A

in the spinal chord

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241
Q

What are the fibres that conduct pain ?

A

A-delta and C fibres

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242
Q

What is the centrifugal pathway ?

A

the pathway that inhibits ascending sensory pathways via release of chemicals that inhibit interneurones

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243
Q

Describe the centrifugal pathway ?

A

sensory information from the thalamus and the amygdala passes to the sensory cortex,
passes to the periventricular nucleus of the hypothalamus
passes to the periaqueductal grey matter
to the raphe nucleus and the locus coereleus
to the spinal chord

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244
Q

What are the vesicle fusion proteins ?

A

Synaptobrevin - joins to the vesicle (V-snare)
Syntaxin - T-snare - join to the terminal
SNAP 25 - T-snare

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245
Q

What is the axon hillock ?

A

the last place in the cell body where the action potentials are generated before passing to the axon

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246
Q

Explain the gated theory of pain ?

A

A-delta and C fibres (pain) enter the dorsal root and synapse in various laminae.
The 2nd order neurones can pass to the anterolateral system via interneurones
rubbing the site of pain triggers the A-alpha and the A-beta fibres which have collateral branches that act on the interneurones - this inhibits the ascneding pain pathway.

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247
Q

Explain saltatory conduction ?

A

positive ions move under the myelin
trigger the sodium channels to open
positive ions move to the negative area
triggers the threshold
opening of voltage gated sodium channels
AP
the outside becomes negative and the negative ions move backwards and the sodium moves forward under the myelin

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248
Q

What do the 2 vetebral arteries converge to form ?

A

basillar artery

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249
Q

What are the branches of the vertebral artery ?

A

anterior and posterior spinal arteries
posterior inferior cerebellar artery
medullary branches

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250
Q

What does the basillar artery extend across ?

A

pons

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251
Q

Where does the basilalr artery form ?

A

at the ponto-medullary junctions

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252
Q

Where does the basillar artery end ?

A

ponto-midbrain junction

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253
Q

What does the basillar artery divide into ?

A

superior cerebellar arteries
posterior cerebral arteries
anterior inferior cerebellar artery
pontine arteries

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254
Q

What does the posterior cerebral artery do ?

A

supply the posterior parts of the temporal and occipital lobes

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255
Q

What arises from the posterior cerebral arteries ?

A

small perforating arteries to supply deep brain structures

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256
Q

What are the branches of the internal carotid arteries ?

A 
opthalmic artery 
posterior communicating artery 
anterior choroidal artery 
anterior and middle cerebral arteries 
anterior communicating artery
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257
Q

What does the opthalmic artery do ?

A

passes through the optic canal to supply the eye

a branch of this is the central retinal artery

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258
Q

What does the anterior choroidal artery do ?

A

supplies the choroid plexus of the lateral ventricle

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259
Q

What are the features of the blood brain barrier ?

A

astrocytes
endothelial cells
tight junctions

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260
Q

What do the astrocytes do in the blood brain barrier ?

A

form a barrier around the endothelial cells

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261
Q

Where does the middle cerebral artery supply ?

A

most lateral aspects of the brain

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262
Q

What does the anterior cerebral artery supply ?

A

most superior aspects laterally

most medial aspect

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263
Q

What does the posterior cerebral artery supply ?

A

most of the posterior aspect - occipital and temporal lobes

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264
Q

What is unique about the dural venous sinuses ?T

A

They dont contain valves

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265
Q

What are the deep cerebral veins ?

A

great cerebral vein of galen

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266
Q

What does the great cerebral vein of galen do ?

A

lies beneath the corpus callosum

continuous with the straight sinus

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267
Q

What are the superficial veins ?

A

the superficial middle cerebral vein - runs along the lateral fissure and empties into the cavernous sinus

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268
Q

What does the superior sagittal sinus receive blood from ?

A

superior cerebrak veins

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269
Q

What lies within the tentorium cerebelli ?

A

straight sinus

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270
Q

How is the confluence formed and where is it ?

A

meeting of the straight sinus and the superior sagittal sinus and is adjacent to the internal occipital protuberance

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271
Q

Where does blood flow from the confuence ?

A

transverse sinus

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272
Q

Where does the transverse sinus drain into ?

A

sigmoid sinus

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273
Q

What does the cavernous sinus drain into and where does it receive blood from ?

A

receives blood from the middle cerebral vein

drains into the internal jugular vein via the inferior petrosal sinus

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274
Q

How are the ventricles formed ?

A

from the neural tube which forms cavities

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275
Q

What do the ventricles contain ?

A

CSF

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276
Q

What produces the CSF ?

A 
choroid plexus (in the 3rd and 4th ventricles)
ependymal cells (line the ventricles - 30%)
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277
Q

How does the CSF get rid of waste products ?

A

placing them in the bloodstream

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278
Q

Where is the 4th ventricle located ?

A

above the medulla

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279
Q

What is lateral to the 4th ventricle ?

A

lateral aperture (luschka)

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280
Q

What is medial to the 4th ventricle ?

A

median aperture (magendie)

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281
Q

What does the 4th ventricle extend rostrally as ?

A

cerebral aqueduct

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282
Q

What is the flow of CSF through the ventricles ?

A

lateral ventricle
to the 3rd ventricle via the interventricular foramen
to the 4th ventricle via the cerebral aqueduct
subarachnoid space via the median and lateral apertures

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283
Q

How is CSF absorbed into the blood stream ?

A

in the superior sagittal sinus via the arachnoid villi

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284
Q

What are the roles of the CSF ?

A

allows the brain to float - reduce traction on nerves and blood vessels
protective cushioning
removes waste metabolites
provides stable environment for the CNS

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285
Q

What is the composition of the CSF ?

A

small amounts of protein
glucose
ions- calcium , potassium , NaCl and Mg

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286
Q

85% of stroke is due to what ?

A

ischaemia - blockage

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287
Q

What is ischaemia ?

A

restriction in blood supply to the tissue causing a shortage of oxygen needed for cellular metabolism

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288
Q

What causes ischaemia ?

A

artheroma (arterial wall degeneration)

blood clot

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289
Q

15% of stroke is due to what ?

A

a bleed - haemorrhage

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290
Q

What are aneurysms ?

A

bulgings that can cause bleeds

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291
Q

Where are berry aneurysms located ?

A

occur at a point where the cerebral artery departs from the circle of willis

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292
Q

What is total anterior circulation stroke ?

A

affects the main artery to one hemisphere

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293
Q

What can left total anterior circualtion stroke lead to ?

A

right hemiparesis - weakness on the right side

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294
Q

What is lacunar syndrome ?

A

damage to the perforating arteries - deep brain structures affected

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295
Q

What is sensory neglect ?

A

failure to be aware of one side of space
affects the somatosensory association cortex
middle and cerebral artery affected

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296
Q

What is locked in syndrome ?

A

basillar artery affected
cant communicate to the rest of the body as ascending/descneding pathways are gone
aware but cant move

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297
Q

What does posterior cerebral artery stroke affect ?

A

occipital lobe and the primary visual cortex

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298
Q

Where is the calcerine sulcus ?

A

perpendicualr to the parieto-occcipital sulcus

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299
Q

Where is the 4th ventricle located ?

A

in the cerebellum

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300
Q

Where is the 3rd ventricle located ?

A

in the midbrain

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301
Q

What structures form the wall of the 3rd ventricle ?

A

thalamus

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302
Q

Which artery supplies the primary motor cortex ?

A

middle cerebral artery

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303
Q

Which artery supplies the primary motor cortex medially ?

A

anterior cerebral artery

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304
Q

Which artery supplies the primary auditory cortex ?

A

middle cerebral artery

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305
Q

Which artery supplies the primary somatosensory cortex ?

A

middle cerebral artery

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306
Q

Which artery supplies the primary visual cortex medially ?

A

posterior cerebral artery

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307
Q

What supplies wernickes area ?

A

middle cerebral artery

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308
Q

What supplies brocas area ?

A

middle cerebral artery

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309
Q

What are 1st order neurones ?

A

conduct impulses from receptors to the spinal chord or brainstem where they synapse

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310
Q

What are 2nd order neurones ?

A

synapse in the thalamus (from the brainstem or the spinal chord)

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311
Q

What are 3rd order neurones ?

A

they synapse in the cortex from the thalamus

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312
Q

Where are the cell bodies of motor neurones located ?

A

in the spinal chord

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313
Q

Where do motor neurones usually synapse ?

A

muscle

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314
Q

Where are the cell bodies of sensory neurones ?

A

dorsal root ganglion

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315
Q

Where do sensory neurones usually synapase ?

A

brain stem or the spinal chord

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316
Q

Are motor neurones myelinated or unmyelinated ?

A

myelinated - fast

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317
Q

Are sensory neurones myelinated or unmyelinated ?

A

both

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318
Q

What are the 2 classification systems for peripheral nerves ?

A

letter system and the roman numeral system

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319
Q

What does the letter system show ?

A

both sensory and motor

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320
Q

What does the roman numeral system show ?

A

only sensory

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321
Q

What are the different types of fibres in the letter system ?

A 
A-alpha
A-beta 
A-gamma
A-delta 
B
C
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322
Q

What are the function of A-alpha fibres ?

A

alpha motoneurones , muscle spindle , golgi tendon organs , touch

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323
Q

What is the role of A-beta fibres ?

A

touch
kinesthesia
muscle spindle

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324
Q

What is the role of A-gamma fibres ?

A

4-8 micrometres

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325
Q

What is the function of A-gamma fibres ?

A

touch , pressure , gamma-motoneurones

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326
Q

What is the function of A-delta fibres ?

A

pain , crude touch , pressure and temperatures

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327
Q

What is the function of B fibres ?

A

preganglionic autonomic

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328
Q

What is the funcntion of C fibres ?

A

pain, touch , pressure , temperature

postganglionic autonomic

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329
Q

What are the fibres in the Roman numeral system ?

A 
1a
1b
II
III
IV
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330
Q

What is the role of 1a fibres ?

A

muscle spindle and primary endings

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331
Q

What is the role of 1b fibres ?

A

golgi tendon organs

332
Q

What is the role of type II fibres ?

A

touch
kinesthesia
muscle spindle
secondary endings

333
Q

What is the fucntion of type III fibres ?

A

fast pain , crude touch , pressure , temperature

334
Q

What is the role of type IV fibres ?

A

slow pain , touch , pressure and temperature

335
Q

What is the equivalent of A-alpha fibres ?

A

1a and 1b fibres

336
Q

What is the equivalent of type II fibres ?

A

A-beta

337
Q

What is the equivalent of A-delta fibres ?

A

type III

338
Q

What is the equivalent of C fibres ?

A

type IV

339
Q

What are the sensory fibres ?

A 
1a
1b 
II 
III 
IV 
A-alpha 
A-beta 
A-delta
340
Q

What are the motor fibres ?

A

B
C
A-alpha
A-gamma

341
Q

What do sensory nerves do ?

A

convert their stimuli into action potentials

342
Q

What are the somatic general senses ?

A

touch , temperature , proprioception and pain

343
Q

What are the visceral general senses ?

A

conditions of the internal organs

344
Q

What are the special senses ?

A

smell / taste / hearing / equilibrium and balance

345
Q

How can sensory receptors be classified ?

A

microscopic features
receptor location
type of stimulus detected

346
Q

What types of receptors with microscopic features ?

A

free nerve endings
encapsulated nerve endings
separate cells

347
Q

What types of receptors are based on their location ?

A

exteroreceptors
intereceptors
proprioceptors

348
Q

What are the type of receptors based on stimulus ?

A 
mechanoreceptors 
thermoceptors 
nociceptors
chemoreceptors 
photoreceptors 
osmoreceptors
349
Q

What is the fine touch pathway ?

A

dorsal column medial lemniscus

350
Q

Describe the dorsal column medial lemniscus ?

A

Ascends in the dorsal column as the 1st order neurone on the ipsilateral side
synapses in the medulla in either the gracile or cuneate nuclei - decussate in the medulla
ascends to the thalamus as second order neurone via the medial lemniscus
ascend as third order neurones to the post central gyrus

351
Q

What is the pathway for pain and crude touch ?

A

anterolateral system

352
Q

Describe the anterolateral system ?

A

1st order neurones synapse in the dorsal horn of the grey matter
second order neurones decussate in the spinal chord
and ascend to the thalamus to synapse
3rd order neurones ascend to primary somatosensory cortex.

353
Q

What is the trigeminothalamic tract ?

A

detects fine touch , pressure , vibration and proprioception

354
Q

Describe the trigeminothalamic tract ?

A

Sensory neurones enter the pons through the trigeminal ganglion
1st order neurones synapse in trigeminal brainstem complex
2nd order neurones ascend to synapse in thalamus (venral posterior medial nucleus)
3rd order neurones ascend to sensory cortex in post central gyrus

355
Q

Describe the pain and temperature system for the trigeminothalamic tract ?

A

Sensory neurones enter the pons through the trigeminal ganglion
small myelinated and unmyelinated axons descend the medulla
synapse in the spinotrigeminal complex
2nd order descend and ascnedd to the thalamus and synapse in the ventral posterior medial nucleus
ascend to primary somatosensory cortex

356
Q

What are the 2 types of pain ?

A

sharp instant pain

dull throbbing pain

357
Q

What are pain receptors called ?

A

nociceptors

358
Q

What fibres do pain receptors activate ?

A

A-delta and C fibres

359
Q

What pain type do A-dleta fibres respond to ?

A

sharp and past

360
Q

What pain do C fibres respond to ?

A

dull, slow ache

361
Q

What are the stimuli for A-delta ?

A

mechanical stimulation

painful hot and cold

362
Q

What are the stimuli for C-fibres ?

A

substances released from damaged tissues

363
Q

Which laminae do A-delta fibres synapse in ?

A

1 and 5

364
Q

Which laminae do C fibres synapse in ?

A

1 and 2

365
Q

Where do type II and III fibres synapse ?

A

substantia gelatinosa

366
Q

Where do type IV-VI fibres synapse ?

A

nucleus proprius

367
Q

What type of threshold do nociceptors have and why ?

A

high
to trigger pain and discriminate from touch
allows a response only to noxious stimuli

368
Q

When do nociceptors become more sensitive ?

A

threshold is lowered - previous damage means non-noxious stimuli cause pain
responsiveness increased - nociceptor damage leads to increased sensitivity

369
Q

What is the role of peripheral sensitisation ?

A

protective role - reduces the likelihood of damage

370
Q

How does peripheral sensitisation occur ?

A

when chemicals from damage and inflammation act on nociceptors reducing the threshold for the firing of Action potentials

371
Q

Examples of chemicals that can reduce the threshold of nociceptors ?

A

ATP
histamine
serotonin

372
Q

What is the role of neutrophils in peripheral sensitisation ?

A

release cytokines which act on nociceptors making them more sensitised

373
Q

What does central sensitisation mean ?

A

a sensitised CNS means that pain pathways are more sensitive

374
Q

How does central sensitisation occur ?

A

alter the synaptic strength between neurones

stronger synapses mean more sensitivity

375
Q

Where does central sensitisation occur ?

A

spinal chord - lamina I and V
thalamus
amydala
anterior cingualte cortex

376
Q

How does central sensitisation alter synaptic strength ?

A 
increased activity of the synapse 
increased use of AMPA and NMDA receptors 
increased intracellular calcium 
activates second messenger system 
TFs activated 
upregulation of proteins 
more receptors on membrane 
more sensitive to neurotransmitter 
lower levels of stimulus cause pain
377
Q

What is the gated theory of pain ?

A

non painful input can close the nerve gates to painful input preventing sensation travelling to the CNS

378
Q

What is the role of collateral branches in the gated theory of pain ?

A

act on interneurones to feedback on pain pathways to inhibit ascending pain pathways

379
Q

What do different sensory modalities do ?

A

interact to modify pain input to the CNS

380
Q

in which areas are pain perceived ?

A

thalmaus - ventral posterior medial/lateral nucleus
primary somatosensory cortex - has a discriminative component
hypothalamus
lymbic system

381
Q

What is referred pain and how does it happen ?

A

feeling pain away from the area of damage

due to convergence of sensory input of 2nd order neurones

382
Q

What does the periaqueductal grey matter do ?

A

receives signals from hypothalamus , amygdala and cortex

383
Q

What does the locus coereleus do ?

A

secrete noradrenaline

384
Q

What does the raphe nucleus do ?

A

release serotonin

385
Q

What is the centrifugal pathway ?

A

the descending system which acts to reduce the response to pain

386
Q

Describe the centrifugal pathway ?

A

sensory cortex , frontal and limbic cortex receives sensory info
periventricular nucleus of hypothalamus - OPIOIDS
periaqueductal grey - SEROTONIN
raphe nucleus/locus coerelus
spinal chord - ENDORPHINS

387
Q

What does the raphe nucleus do ?

A

inhibits ascending pathways by interneurons in the centrifugal pathway

388
Q

What is usually released at the synapse between the interneurones and the centrifugal pathway ?

A

GABA

an inhibitory neurotransmitter which controls the centrifugal pathway

389
Q

What do opioids do ?

A

inhibit the internerones and stop the inhibition of the descending pathway

390
Q

What is a motor unit ?

A

made up of the motor neuron and the skeletal muscle fibres innervated by the motor axon terminals

391
Q

Why do motor units differ in size ?

A

depending on the grading of movement

392
Q

What do alpha motoneurones do ?

A

activate skeletal muscle fibres

they are under descneding control

393
Q

What do gamma motoneurones do ?

A

activate intrafusal fibres within the muscle spindle

394
Q

What does the muscle spindle do ?

A

brings back information via 1a afferents about the degree of muscle stretch

395
Q

Damage to a lower motoneurone causes what ?

A

flaccid paralysis

396
Q

Damage to a upper motoneurone causes what ?

A

spastic paralysis

397
Q

What is the myotatic stretch reflex ?

A

muscle contraction in response to stretching within the muscle

398
Q

What does excitatory input come through in the myotatic reflex ?

A

1a afferents

399
Q

Information from the 1a afferents causes what ?

A

excitation of the flexor

400
Q

A stretch in the muscle spindle has what effect on the extensor ?

A

a stretch in the muscle spindle is fed forward to the alpha motoneurone which inhibits the extensor via inhibitory interneurones

401
Q

Describe the myotatic reflex ?

A 
change in muscle length 
muscle spindle stretched 
1a afferents activated 
alpha motoneurones activated 
muscle contracts - flexor is excited whilst the extensor is inhibited
402
Q

What is the muscle spindle ?

A

length controlled by gamma-motoneurone
1a afferents signal change in muscle length
stimulates muscle contraction

403
Q

What is the golgi tendon organ ?

A

found in tendons
sends signals to the spinal chord via 1b afferents to signal change in tension
inhibit muscle contraction

404
Q

What is the inverse stretch or inverse myotatic reflex ?

A

stretch of a tendon leads to inhibition of the muscle nut activation of the antgonistic muscle

405
Q

In the myotatic reflex stretch of a tendon leads to ?

A

activation of 1b afferents via the golgi tendon organ

406
Q

Is the inverse reflex faster or slower than the normal reflex ?

A

slower as it involves another synapse bteween the 1b afferents and the motoneurone - normally the 1a afferents go straight to the motoneurone

407
Q

How do 1b afferents work ?

A

through inhibitory interneurones

408
Q

An increase in muscle length leads to what ?

A

both the stretch and tendon reflexes being activated- they have opposite effects

409
Q

What is the purpose of the tendon relfex ?

A

to dampen dwn the stretch reflex and prevent excessivve muscle contraction

410
Q

What is the purpose of the stretch reflex ?

A

to increase muscle contraction

411
Q

What is the cross extensor reflex ?

A

a withdrawal reflex

412
Q

What happens in the cross extensor reflex ?

A

flexors in the withdrawing limb contract
extensors relax
in the stationary limb flexors relax and extensors contract

413
Q

How is the cross extensor reflex coordinated ?

A

reciprocal inhibition of flexors and extensors via interneurones act to coordinate both sides in routine movements

414
Q

What is the stimulus in the cross extensor reflex and how is it detected ?

A

temeprature or pain from group III afferents

415
Q

What is the central pattern generator ?

A

neuronal circuits that produce rhythmic motor patterns

they generate alternate activities for routine movements

416
Q

Where are central pattern generators located ?

A

brainstem or spinal chord

417
Q

What is an example of an activity regulated by the central pattern generator ?

A

breathing and swallowing

418
Q

What are the types of sensory receptors in the skin ?

A

merkel cells
meisners corpuscles
pacinian corpuscles
ruffini corpuscles

419
Q

What are merkel cells ?

A 
slow adapting receptors near border of the epidermis 
respond to touch and pressure 
large myelinated axons 
uncapsulated 
A-beta fibres are parent fibres
420
Q

What are meissners corpuscles ?

A

in the dermal papillae of skin
rapidly adapting
touch
A-beta fibres are parent fibres

421
Q

What are pacinian corpuscles ?

A

occur in the skin and deep tissues
rapidly adapting
respond to vibration mainly and pressure
A-beta fibres

422
Q

What are ruffini corpuscles ?

A

slow adapting mechanoreceptors
dermis of the skin
respond to touch and stretch
A-beta parent fibres

423
Q

What are hair follicle receptors ?

A

sensation- motion and direction

Fibre type - II

424
Q

What are mesissners corpuscles ? (C)

A

Sensation- Tap and futter (5-40 Hz)
Fibre type - II
RF- small

425
Q

What are pacinian corpuscles ? (C)

A

Sensation- Vibration
FIbre type - II
Receptive field- large

426
Q

What are merkel cells ? (C)

A

Sensation- pressure
Fibre type- II
RF- small

427
Q

What are ruffini corpuscles ? (C)

A

Sensation - skin and stretch
Fibre type - II
RF- large

428
Q

What are free nerve endings ?

A

Sensation- nociception

Fibre type- III and C

429
Q

Skin receptors generally have which type of threshold ?

A

low

except for nociceptors which have a high threshold

430
Q

What is sensory transduction ?

A

conversion of sensory stimuli from one form to another

431
Q

Describe the process of signal transduction in the pacinian corpuscle ?

A

they are sensitive to changes in mechanical pressure
pressure on the skin changes the shape of the pacinian corpuscle
This alters the shape of pressure sensitive sodium channels
leads to depolarisation as sodium moves in however no AP is generated until the threshold is reached - this is the generator potential

432
Q

Sensory receptors generate what type of action potentials ?

A

tonic - steady and constant firing

433
Q

Coding of sensory information occurs due to ?

A

changes in the firing rates (increase/decrease)
Duration of time action potentials last for
Activation of different parts of receptive fields

434
Q

What are rapidly adapting receptors ?

A

they respond to the application and removal of a stimulus

fail to respond to a maintained stimulus

435
Q

What are examples of rapidly adapting receptors ?

A

meissners corpuscles
hair follicle recpetors
pacinian corpuscles

436
Q

What are slow adapting receptors ?

A

Encode stimulus intensity
Active for the duration of the maintained stimulus
increase their tonic firing rate if the stimulus intensity increases

437
Q

What are examples of slow adapting receptors ?

A

merkel cells
hair follicle receptors
ruffini corpuscles

438
Q

What are receptive fields ?

A

space occupied by a sensory receptor that can elicit the response to a stimulus

439
Q

The size of the receptive field determines what ?

A

the discriminatory nature of the stimulus

440
Q

The finger tips have what type of receptive fields ?

A

small and numerous - highly discriminatory response

441
Q

The back has what type of receptive fields ?

A

large and sparse receptive fields - low discrimination

442
Q

What is convergence ?

A

one postsynaptic neurone receives a convergent input from a number of postsynaptic neurones

443
Q

What is divergence ?

A

An individual neurone can make many divergent connections to a number of postsynpatic neurones

444
Q

Where are divergence and convergence seen?

A

sensory pathways

445
Q

What is the purpose of convergence and divergence ?

A

can lead to one sensory modality altering the other like in the Gated theory of pain
multisensory processing

446
Q

In sensitive areas what do receptive fields do ?

A

they overlap

447
Q

What happens upon stimulation of the centre of the field ?

A

the lateral aspects can also be stimulated

448
Q

Which neurone will have the strongest and weakest response ?

A

strongest - middle neurone

weakest - middle neurone

449
Q

What happens to the lateral neurones ?

A

they are inhibited by interneurones from the middle neurone

450
Q

What does the brain receive in lateral inhibition ?

A

info from the middle neurone to provide a more accurate and discriminative input

451
Q

The primary somatosensory cortex is the site of termination of what ?

A

thalamocortical pathway

452
Q

The primary somatosensory cortex contains what ?

A

a topographical map of senses that is proportional to the amount of sensory information

453
Q

What are Brodmans areas 1,2 and 3 ?

A

in the post ccentral gyrus - compartmentalisation based on different functions

454
Q

What is area 3b ?

A

primary somatosensory corte

455
Q

What is area 3a ?

A

proprioception

456
Q

What is area 1 and 3b ?

A

cutaneous stimuli

457
Q

What is area 2 ?

A

tactile proprioception - size and shape

458
Q

How is the post central gyrus organised ?

A

columnar organisation

459
Q

What does columnar organisation of the post central gyrus allow for ?

A

allows for exact info from body areas to be extracted

as well as the processing of information from nearby modalities

460
Q

Where is the secondary somatosensory cortex located ?

A

towards the end of the post ccentral gyrus

superior aspect is the lateral sulcus

461
Q

What are the higher order functions of the secondary somatosensory cortex ?

A

sensorimotor integration
integration from 2 bodily halves - bilateral
attention , learning and memory

462
Q

Where is the association cortex for the primary somatosensory cortex located ?

A

posterior parietal cortex

463
Q

What is the role of the posterior parietal cortex ?

A

integrates sensory information and allows recognition of objects by touch

464
Q

What does the lateral corticospinal tract control ?

A

voluntary control of distal musculature

465
Q

What does the anterior corticospinal tract control ?

A

voluntary control of proximal musculature

466
Q

Where do the reticulospinal tracts originate and terminate ?

A

from the pontine and medullary reticular formation to the spinal chord

467
Q

What is the role of the reticulospinal tract ?

A

regulates flexor reflexes and initiates patterned activity

eg. locomotion and swallowing

468
Q

Where do the tectospinal tracts run from ?

A

the tectum in the midbrain to mainly the cervical region of the spinal chord

469
Q

What is the role of the tectospinal tracts ?

A

orientation to auditory and visual stimuli

controle head movements in response to visual stimuli

470
Q

Where do the vestibulospinal tracts run from ?

A

from the vestibular nucleus to the spinal chord

471
Q

What does the lateral vestibulosponal tract do ?

A

antigravity muscles for balance

472
Q

What do the medial vestibulospinal tracts do ?

A

regulate head movements

473
Q

What are upper motor neurones ?

A

found in the cerebral cortex and brainstem

carry information to lower motor neurones directly or indirectly

474
Q

How can UMN project directly onto LMN ?

A

corticospinal or corticobulbar tracts

475
Q

Damage to the direct pathways causes what ?

A

babinskis sign
paralysis
paresis of fine skilled movements
segmental (local) relfexes are unaffected

476
Q

What are the indirect pathways that UMN can project onto LMN ?

A

from brainstem nuclei to LMN (rest of the pathways)

477
Q

What is the role of the indirect pathways of projection ?

A

they integrate supporting musculature during voluntary movements
facilitate spinal reflexes to do with balance , posture and equilibrium

478
Q

Where does the lateral corticospinal tract decussate ?

A

at the medulla-spinal chord junction - innervates the LMN on the opposite side

479
Q

Where does the anterior corticospinal tract decussate ?

A

at the segmental level in the spinal chord

480
Q

Where is the internal capsule located ?

A

between the basal ganglia and the thalamus

481
Q

What passes through the internal capsule ?

A

corticospinal and corticobulbar fibres

482
Q

How is the internal capsule organised ?

A

it is segmented to receive fibres for different limbs and parts of the face

483
Q

What type of stroke affects the internal capsule ?

A

lacunar stroke - this can take out the corticobulbar and corticopinal fibres

484
Q

What does the tectum consist of ?

A

superior and inferior calliculus - located in the midbrain

485
Q

What is the role of rubrospinal tracts ?

A

excite flexor activity and inhibit extensor activity

486
Q

What is the reticular formation ?

A

collection of neurones and nuclei not in a specific nucleus or pathway

487
Q

What does the reticular formation contain ?

A

many nuclei and fibres that travel to the cortex and release neuromodulators such as serotonin , acetylcholine and noradrenaline

488
Q

What does the reticular formation do ?

A 
regulation of cranial nerve activity 
slow pain conduction and modualtion 
voluntary movements 
regulation of ANS activity 
distribution of monoaminergic and cholinergic ascending pathways
respiration 
sleep 
CEREBRAL CORTICAL AROUSAL
489
Q

Where does the reticular formation spread from ?

A

from the pons to the spinal chord

490
Q

What is the vestibular nucleus ilnked to and what does this mean ?

A

to the cerebellum - controls same side

491
Q

What does the lateral vestibulospinal tract do ?

A

assist postural adjustments

492
Q

What does the medial vestibulospinal tract do ?

A

assist in head position

493
Q

What is babinskis sign ?

A

shows an upper motor neurone lesion leading to
damage to descending corticospinal pathways
stroking of the foot sole causes an abnormal fanning of the toes when normally they would move downwards.

494
Q

What is the early neural tube surrounded by ?

A

alar and basal laminae

495
Q

What does the alar lamina develop into ?

A

dorsal horn - sensory - lateral

496
Q

What does the basal lamina develop into ?

A

ventral horn - alpha motoneurones - medial

497
Q

What are the afferent components of CN fibres ?

A

general somatic afferent
special visceral afferent
special somatic afferent
general visceral afferent

498
Q

What are the efferent components of CN fibres ?

A

special visceral efferent
general somatic efferent
general visceral efferent (autonomic)

499
Q

What are the function of general somatic afferents ?

A

general sensation from skin joints and bone

500
Q

What are the function of special visceral afferents ?

A

taste and visceral sense

501
Q

What is the function of special somatic afferents ?

A

vision hearing and balance

502
Q

What is the function of special visceral efferents ?

A

skeletal muscle from the pharyngeal arches - muscles of facial expression and mastication

503
Q

What is the role of general somatic efferent ?

A

skeleta muscle from the somites

504
Q

What is the role of general visceral efferent ?

A

smooth muscle and glands - parasympathetic

505
Q

Which cranial nerves join to the brainstem ?

A

oculomotor - hypoglossal

506
Q

Which cranial nerves join to the diencephalon ?

A

olfactory and optic

507
Q

Where do motor cranial nerves attach ?

A

more medially

508
Q

What are the sensory only cranial nerves ?

A

olfactory
optic
vestibulocochlear

509
Q

What are the motor only cranial nerves ?

A 
oculomotor 
trochlear 
abducens 
accessory 
hypoglossal
510
Q

What are the sensory and motor neurones ?

A

vagus
glossopharyngeal
facial
trigeminal

511
Q

Which cranial nerves contain parasympathetic preganglionic fibres ?

A

vagus , facial , oculomotor and glossopharyngeal

512
Q

What are the general somatic motor nuclei ?

A

nucleus of the oculomotor
nucleus of the trochlear
nucleus of the abuducens
nucleus of the hypoglossal

513
Q

Where is the nucleus of the oculomotor ?

A

midbrain

514
Q

Where is the nucleus of the trochlear ?

A

midbrain

515
Q

Where is the nucleus of the abducens ?

A

pons

516
Q

Where is the nucleus of the hypoglossal ?

A

medulla

517
Q

What is the function of the nucleus of the oculomotor ?

A

superior , inferior and medial rectus
inferior oblique
levator palpebrae superioris

518
Q

What is the function of the nucleus of the trochlear ?

A

superior oblique

519
Q

What is the function of the nucleus of the abducens ?

A

lateral rectus

520
Q

What is the function of the nucleus of the hypoglossal ?

A

muscles of the tongue

521
Q

What type of fibres emerge from general somatic motor nuclei ?

A

general sensory efferents

522
Q

What type of fibres emerge from special visceral motor nuclei ?

A

special visceral efferents

523
Q

What are the special visceral motor nuclei ?

A

motor nucleus of V
nucleus of the facial nerve
nucleus ambiguus

524
Q

Where is the motor nucleus of V ?

A

pons

525
Q

Where is the nucleus of the facial nerve ?

A

pons

526
Q

Where is the nucleus of ambiguus ?

A

medulla

IX X XI

527
Q

What is the function of the motor nucleus of V ?

A

muscles of mastication
tensor tympani / tensor veli palatini
mylohyoid
anterior belly of digastric

528
Q

What is the function of the nucleus of the facial nerve ?

A

muscles of facial expression
posterior belly of digastric
stylohyoid
stapedius

529
Q

What is the role of the nucleus ambiguus ?

A

skeletal muscles of the pharynx , larynx and soft palate

530
Q

What fibres emerge from the general visceral motor nuclei ?

A

general visceral efferents - parasympathetic

531
Q

What are the general visceral motor nuclei ?

A

edinger- westphal nucleus
superior salivatory nucleus
inferior salivatory nucleus
dorsal nucleus of X

532
Q

Where can you find the edinger-westphal nucleus ?

A

midbrain

533
Q

Where can you find the superior salivatory nucleus ?

A

pons

534
Q

Where can you find the inferior salivatory nucleus ?

A

medulla

535
Q

Where can you find the dorsal nucleus of X ?

A

medulla

536
Q

What is the function of the edinger-westphal nucleus ?

A

sphincter pupillae

ciliary muscle

537
Q

What is the function of the superior salivatory nucleus ?

A

submandibular , sublingual and lacrimal glands

538
Q

What is the function of the inferior salivatory nucleus ?

A

parotid gland

539
Q

What is the function of the dorsal nucleus of X ?

A

cervical , thoracic and abdominal viscera

540
Q

What are the fibres from the visceral sensory nuclei ?

A

general visceral afferent

somatic visceral afferent

541
Q

What are the visceral sensory nuclei ?

A

nucleus of the solitary tract - facial , glossopharyngeal and Vagus

542
Q

Where can you find the nucleus of the solitary tract ?

A

medulla

543
Q

What is the function of the nucleus of the solitary tract ?

A

taste and visceral sensation

544
Q

Where does the vagus provide taste ?

A

from the epiglottis

545
Q

What are the fibres from general somatic sensory nuclei ?

A

general sensory afferent

546
Q

What are the general somatic sensory nuclei ?

A

mesencephalic nucleus of V
chief sensory nucleus of V
Spinal nucleus of V

547
Q

Where can you find the mesencephalic nucleus of V ?

A

pons-midbrain

548
Q

Where can you find the chief sensory nucleus of V ?

A

pons

549
Q

Where can you find the spinal nucleus of V ?

A

pons to C3

550
Q

What is the function of the mesencephalic nucleus of V ?

A

proprioception

551
Q

What is the function of the chief sensory nucleus of V ?

A

fine touch on the face

552
Q

What is the role of the spinal nucleus of V ?

A

pain and temperature from the face

553
Q

Where do corticobulbar fibres run from ?

A

cortex to the cranial nerve nuclei

554
Q

What is the innervation of lower motor neurones ?

A

cranial nerve nuclei

555
Q

What is the innervation of V and VII ?

A

bilateral projections from the primary motor cortex - upper face

556
Q

What is the innervation of VII - lower face ?

A

contralateral

557
Q

What is the innervation of XI ?

A

ipsilateral from PMC

558
Q

What is the innervation of II , IVand VI ?

A

contralateral innervation from frontal and parietal eye fields

559
Q

What is the innervation of XII ?

A

bilateral from PMC except for genioglossus - contralteral

560
Q

Where does the trigeminal carry pain afferent run from ?

A

face, nose , orbit , meninges and muscles of mastication

561
Q

Where does the facial nerve carry pain afferents from ?

A

ear and the canal

562
Q

Where does the vagus nerve carry pain afferents from ?

A

meninges , ear canal and the larynx

563
Q

Where does the glossopharyngeal carry pain afferents from ?

A

posterior tongue and pharynx

564
Q

Where do the cervical spinal nerves carry pain afferents from ?

A

neck , meninges in the psoterior cranial fossa

565
Q

Where are the sensory neurone cell bodies of the trigeminal found ?

A

in the trigeminal ganglion

566
Q

Where are the proprioception cell bodies of the trigeminal found ?

A

mesencephalic nucleus of V

567
Q

What does the spinal nucleus of V receive information about ?

A

firm touch , pain and temperature from skin of the face , oral and nasal cavities and palate

568
Q

What does the main nucleus of V receive information from ?

A

fine touch from skin of face , oral cavity and palate

569
Q

What information does the mesencephalic nucleus of V receive ?

A

proprioception from muscles of head

570
Q

Where are the sensory neurone cell bodies ?

A

geniculate ganglion

571
Q

Where do the general somatic afferents in the facial nerve come from ?

A

skin of the ear , ext.auditory meatus to spinal nucleus of V in medulla

572
Q

Where are the sensory neurone cell bodies of the vestibulocochlear nerve ?

A

vestibular and spiral ganglia

573
Q

Where are the somatic sensory neurone cell bodies of the glossopharyngeal nerve ?

A

superior ganglion

574
Q

Where are the visceral sensory neurone cell bodies ?

A

petrosal ganglion

575
Q

Where does the glossopharyngeal bring general somatic afferents from ?

A

firm touch , pain and temperature from posterior third of the tongue , oropharynx , nasal cavity and paranasal sinuses to the spinal nucleus of V

576
Q

Where are the somatic sensory neurone cell bodies of the vagus ?

A

jugualr ganglion

577
Q

Where are the visceral sensory neurone cell bodies of the Vagus ?

A

nodose ganglion

578
Q

Where does the vagus carry general somatic afferentss from ?

A

firm touch , pain and temperature from the ear and external auditory meatus and mucous membrane of the larynx to the spinal nucleus of the V

579
Q

What is the plexus of Raschkow ?

A

a central plexus in the pulp of the tooth - pain from teeth is mediated through this

580
Q

What type of pain do A-fibres transmit ?

A

rapid and sharp pain

belong to the myelinated group

581
Q

What can A-fibres end branches to ?

A

odontoblastic processes located on the periphery of the pulp and dnetinal tubules

582
Q

Where are A-fibres located ?

A

on the periphery of the pulp

583
Q

What may trigger pain sensation in the teeth ?

A

fluid movement in the dentinal tubules

584
Q

What type of pain is conducted by C-fibres ?

A

dull aching pain

585
Q

Are C-fibres myelinated or unmyelinated ?

A

unmyelinated

586
Q

Where do C-fibres terminate ?

A

in the pulp proper as free nerve endings or branches around blood vessels

587
Q

What is the route of A and C fibres ?

A

run in the branches of V2 and V3 and then terminate in the spinal nucleus of V - passing to the thalamus and cortex

588
Q

Where is pain associated with emotional distress processed ?

A

anterior cingulate cortex

589
Q

Where is the periaqueductal grey matter located ?

A

around the cerebral aqueduct in the tegmentum of the midbrain

590
Q

What does the periaqueductal grey matter do ?

A

plays a role in the descending modulation of pain

591
Q

What neurones are found in the periaqueductal grey ?

A

enkephalin releasing neurones

592
Q

What do enkephalin releasing neurones do ?

A

suppress pain

593
Q

What is released from the raphe nuclei ?

A

serotonin

594
Q

What does serotonin do ?

A

descends to the dorsal horn of the spinal chord where it forms excitatory connections with inhibitory interneurones in laminae II

595
Q

When activated what do the interneurones do ?

A

release enkephalin

binds to opioid receptros - descending pain modualtion

596
Q

What is the corneal reflex ?

A

touch cornea with a cotton wisp which elicits the bilateral blink reflex

597
Q

What is the pathway of the corneal reflex ?

A

sensory input from V1 - spinal nucleus of V - facial motor nucleus - orbicualris oculi

598
Q

What is the gag reflex ?

A

touching the back of the oropharynx elicits brief elevation of the paate and brief constriction of the pharyngeal constrictors

599
Q

What is the pathway of the gag reflex ?

A

sensory input from the glossopharyngeal - nucleus of solitary tract - nucleus ambiguus - vagus to the pharyngeal constrictors

600
Q

What is the jaw jerk reflex ?

A

tapping on the chin leads to contraction of masseter and jaw closing

601
Q

What type of reflex is the jaw-jerk reflex ?

A

monosynaptic

602
Q

What is the pathway of the jaw-jerk reflex ?

A

afferent fibres from muscle spindle - mesencephalic nucleus of V - motor nucleus of V as efferents to masseter

603
Q

What is the jaw unloading reflex ?

A

chewing against resistance builds up tension in the PDL
unloading of stretch inhibits masseter
golgi tendon organ detects level of stretch in PDL , pressure is released and inihbits contraction of masseter

604
Q

Which 3 cortices can pain pathways synapse in ?

A

insular cortex
somatosensory cortex
anterior cingulate cortex

605
Q

What is the spinal nucleus of V continuous with ?

A

dorsal horn of the spinal chord

606
Q

Where is the primary visual cortex ?

A

occipital lobe - either side of the calcarine sulcus

607
Q

Where does light first hit ?

A

retinal ganglion cells

608
Q

How do impulses tavel from the retina to the bvrain ?

A

sensory neurones

609
Q

What does the retina consist of ?

A

pigmented epithelium

rods and cones

610
Q

Where are the cones situated ?

A

fovea

611
Q

Where are the rods sitted ?

A

peripheries

612
Q

How do the rods synapse ?

A

many rods synapse on one bipolar sensory neurone - more sensitive to lower light

613
Q

How do cones synapse ?

A

cones synapse on one bipolar neurone providing higher resolution

614
Q

What are the membraneous discs ?

A

thye contain proteins that respond to light - rods contain rhodopsin and cones contain photopsin

615
Q

What is the disinhibition of bipolar neuroness ?

A

light hits photoreceptors leading to hyperpolarisation which stops the release of neurotransmitter

616
Q

Where does the optic nerve travel ?

A

through the optic canal

617
Q

What is the pathway of the optic nerve ?

A

passes through the optic tract and the optic chiasm to the thalamus

618
Q

Where in the thalamus does the optic nerve pass to ?

A

lateral geniculate nucleus

619
Q

Alternatively where does the optic nerve pass to ?

A

superior calliculus

620
Q

What are the 4 cranial nerve nuclei that control the movements of the eye ?

A

edinger- westphal nucleus
oculomotor nucleus
abducens nucleus
trochlear nucleus

621
Q

What does the edinger westphal nucleus supply ?

A

ciliary muscle and the iris muscle

622
Q

What is the papillary light reflex ?

A

light shone in one eye - contraction of both pupils - direct light reflex
contraction if the pupil oppsote leads to consensual light reflex

623
Q

What is the accomodation relfex ?

A

focus on the incoming object leads to pupillary constriction- convergence of eyes as eyes focus on the near object

624
Q

What is the pathway of the pupillary light reflex ?

A

light comes into the retina and the retinal gnaglion cells
travel via the optic tract to the lateral geniculate nucleus and the superior colliculi
bilateral innervation of the edinger westphal nucleus
output to the pupil and ciliary nucleus - contraction of the pupils

625
Q

What is the pathway of the accomodation relfex ?

A

information travels tothe primary visual cortex

bilateral innervation of the oculomtor (eye muscles) and edinger westphal nucleus (eye focus)

626
Q

Where is the primary auditory cortex located ?

A

in the superior tempora; gyrus

627
Q

How are action potentials triggered in the ear ?

A

pressure waves in the ear are conducted through the inner and middle ear
vibrations are caused in the tympanic membrane
generates waves of fluid on the cochlear
triggers hair cells to move
opens mechanically gated ion channels
triggers action potentials

628
Q

What does the cochlear consist of ?

A 
semi circular canals 
utricle 
sacculae 
ampullae 
cochlea nerve
629
Q

What is the organ odf corti ?

A

between the scala vestibuli and the scala tympani

has a tectoriul and basilar membrane

630
Q

What does the sensory ganglion contain ?

A

sensory cell bodies of the cochlea nerve

631
Q

What does the sound on the tympanic membrane cause ?

A

sound hits the ossicles and causes vibration of the endolymph in the cochlea
generates vibrations in the basilar membrane
rubs in the tectorial membrane
moves the hair cells on the organ of corti
opens up channels and triggers APs.

632
Q

What is the action of stapees ?

A

vibrates on the oval window

633
Q

What is the helicotrema ?

A

a gap at the end of the unravelled cochlea allows fluid to move constantly

634
Q

High frequency sounds are picked up by what ?

A

proximal end of the cochlea

635
Q

Low frequency sounds are picked up by what ?

A

distal end of the cochlea

636
Q

Which hair cells are sensory ?

A

95% of inner hair cells

637
Q

What is the role of the outer hair cells ?

A

receive efferents from the superior olive

modulate basilar membrane motions

638
Q

What are sterocilia ?

A

organ of corti hair cells

639
Q

What are present on hair cells ?

A

potassium ion channels - linked mechanically

640
Q

Moving hair cells side to side causes what ?

A

physically opens the potassium channels and triggetrs voltage sensitive calcium channels - calcium cascade - vesicle movement and fusion with the presynaptic membrane

641
Q

Desribe the auditory pathway ?

A

1st order neurones from receptors in the organ of corti , fibres synapse in the cochlear nuclei
2nd order neurones travel to the medial geniculate nucleus of the thalamus via the superior olivary nucleus and the inferior colliculus
3rd order neurones travel to the superior temporal gyrus in a bilateral pathway

642
Q

Describe the auditory stream ?

A 
primary auditory cortex
association auditory cortex
wernickes area
arcuate fasciculus 
brocas area
motor cortices
643
Q

Where is brocas speech area located ?

A

in the frontal lobe

644
Q

What are the roles of the auditory cortrex ?

A

processing of sound
receives information from the medial geniculate nucleus
tonotopic representation of frequencies- different parts of the cortex pick up different f requencies

645
Q

What is the vestibular system concerned with ?

A

balance

646
Q

What is the vestibular system ?

A

semi circular canals are fluid filled - bulges are called ampullae
hair cells are located at the ampullae
endolymph inside the semi circular canals moves via inertia
triggers hair cell movement
nerve cells are triggered

647
Q

What are otolith organs ?

A

ear stones

648
Q

What are the ear stones ?

A

utricle and the saccule

649
Q

What is the sensory epithelium of the ear stones called ?

A

macula

650
Q

What do the ear stones do ?

A

sense tilt and linear head motions

respond to gravity and linear acceleration

651
Q

Where are the otolith organs ?

A

in a gelatinous mucous on top of hair cells

652
Q

What are the otolith organs made of ?

A

CaCo3 deposits

653
Q

What is the effect on the otolith organs of moving backwards ?

A

gravity pulls stones backwards and this pulls on the hair cells triggering a response

654
Q

Describe the vestibuLar pathway ?

A

information from the ampullae , utricle and saccule goes to the vestibualr nucleus
from here pathways go to the cortex (III, IC,VI) , spinal chord (vestibulospinal tract and cerebelllum (balance)
to enter the cortices the pathway is the medial longitudinal fasciculus

655
Q

performance of voluntary movements requires ?

A

job/task identification
planning for the activity
execution of the task and job

656
Q

What are the 3 levels of motor control ?

A

motor areas of thee cerebral cortex
brainsntem
spinal chord

657
Q

What are the roles of the motor areas of the cerebral cortex ?

A

issue sequential and parallel commands
change intensities of different patterns
modify timing

658
Q

What are the roles of the brainstem ?

A

maintain axial tone for standing

659
Q

What are the roles of the spinal chord ?

A

programmed , local pattern of muscle movement

location of complex pattern of rhythmical and reciprocal motion

660
Q

What are the cortices of the brain related to motor control ?

A

posterior parietal cortex

primary motor cortex

661
Q

What is the role of the posterior parietal cortex /

A

association and representation

initiation , planning and thought of activities

662
Q

What is the role of the primary motor cortex ?

A

corticospinal and corticobulbar fibres arise from here

663
Q

What are the 2 loops from the posterior parietal cortrex ?

A

1 to basal ganglia

1 to pontine nuclei and the cerebellum

664
Q

Describe the basal ganglia loop for planning , carrying out and modulating activities ?

A

from the posterior parietal cortex to the basla ganglia

back through the thalamus to the pre motor cortex to the supplementary motor cortex and to the primary motor cortex

665
Q

What do the basal ganglia store ?

A

patterned movements are stored , responsible for initiation and planning of movement

666
Q

Describe the pontine nuclei loop for planning , carrying out and modulating movement ?

A

fibres from the posterior parietal cortex to the pontine nuclei to the cerebellar hemispheres through the deep cerebellar nuclei to the thalamus
from the thalamus to the pre motor cprtex , supplemnetary motor cortex and the primary motor cortexx

667
Q

What does the cerebellum do in modifying movements ?

A

it looks at intended movement and the current position of the muscles and decides which muscles to move

668
Q

What does the cerebellum receive input from ?

A

the inferior olive- proprioception information from muscles

669
Q

What arises from the primary motor cortex ?

A

corticospinal and corticobulbar fibres that travel in the internal capsule

670
Q

What does the paramedian midbrain reticular formation do ?

A

regulates walking

671
Q

What do the pontine reticulospinal pathways do ?

A

control extensor lower motoneurones

672
Q

What do medullary reticulospinal pathways do ?

A

control flexor lower motoneurones

673
Q

What does the posterior parietal cortex produce ?

A

produces internal models of movement prior to the involvement of the premotor and motor cortices

674
Q

What do the prefrontal areas do ?

A

decisions here are made about what action to take
integrates info
concerned with personality , reasoning and conscience

675
Q

`What does the premotor area do ?

A

controls axial and proximal limb muscles in the initial phases of orientating the body and arm to a target

676
Q

What does the supplemnetary motro area do ?

A

execute stages of complex movements based on past experiences

677
Q

What side of the body does the cerebellum control ?

A

ipsilateral side

678
Q

What does the cerebellum consist of ?

A

vermis - central
folia - folds
flocularnodular lobe
deep cerebellar nuclie

679
Q

What are the 4 deep cerebellar nuc,ei from lateral to medial ?

A 
dentate nucleus 
emboliform nucleus 
globose nucleus 
fastigial nucleus
interposed nucleus - some individuals have this - emboliform and globose
680
Q

What are the 3 functional parts of the cerebellum ?

A

vestibulocerebellum
spinocerebellum
neocerebellum

681
Q

What is the vestibulocerebellum ?

A

flocculo-nodular lobe and part of the vermis

682
Q

What is the function of the vestibulocerebellum ?

A

posture and balance
input from the vestibular nucleus and the dorsal spinocerebellar tract
output to the vestibular nucleus

683
Q

What is the spinocerebellum ?

A

vermis and the fastigial nucleus and the intermidiate part or cerebellar hemisphere , globose and emoboliform nuclei

684
Q

What is the function of the spinocerebellum ?

A

updating ongoing movements
input from the primary motor cortex via pontine nuclei, DSCT, ASCT and olivary nucleus
output to red nucleus

685
Q

What is the neocerebellum ?

A

lateral part of the hemisphere and the dnetate nucleus

686
Q

What is the role of the neocerebellum ?

A

initiation and planning of movements , motor learning
inout from the posterior parietal cortex , inferioe olivary nuclue s
output to the premotor cortedx , supplemnetary moor area via the thalamus

687
Q

What is the route for planning and prediction in the cerebellum ?

A

from the cerebral cortex to the dentate nucleus via corticopontine fibres back to the thalamus to the cerebral cortex

688
Q

What is the route for modification of ongoing movement ?

A

from the inferior olivary nucleus to the interposed nucleus to the red nucleus and the rubrospinal tract

689
Q

What is the input and output of the olivary nucleus ?

A

output as climbing fibres to opposite cerebellum

input from cortex and spinal chord

690
Q

What is the role of the olivary nucleus ?

A

plays a role in movement inititation and motor learning

691
Q

How is a lesion in the vestibulocerebellum presented ?

A

staggering gat

692
Q

How is a lesion in the spinocerebellum presented ?

A

ataxia

693
Q

How is a lesion in the corticocerebellum presented ?

A

slow movement onset

694
Q

What are the basal ganglia ?

A 
caudate nucleus 
putamen 
globus pallidus 
subthalamic nucleus 
substantia nigra
695
Q

What is the circuit of the basal ganglia ?

A

output from cortical areas involved in planning and execution of movement to the basal ganglia
output from the basal ganglia to motorrelay areas of the thalamus (ventral anterior and ventral lateral nuclei of the thalamus)

696
Q

How do the basal ganglia act ?

A

act ispilaterally

697
Q

What do basal ganglia tend to do ?

A

inhibit movements therefore lesions produce unwanted movements

698
Q

What are the 2 circuits through the basal ganaglia ?

A

putamen ciruit- putamen - globus pallidus to the thalamus and the cortex

699
Q

What is the role of the putamen circuit ?

A

subconscious execution of learned patterns of movement

700
Q

What is the caudate circuit ?

A

cognitive planning of movement - feedback to cortex

701
Q

What does the substamtia nigra do ?

A

releases dopamine into the putamen circuit which acts on D1 and D2 receptors

702
Q

Describe the direct pathway ?

A

cells with D1 receptors are excited by dopamine released from the substantia nigra
release of dopamine increases inhibition of the globus pallidus
releases tonic inhibiion of the thalamus causing cortical excitation
increases movement and cortical activity

703
Q

Which pathway is normally inhibited ?

A

indirect pathway

704
Q

Describe the indirect pathway ?

A

cells with D2 receptors are inhibited by dopamine
increases inhibition of the globus pallidus
decreases inhibition of the sub thalamic nucleus
increases excitation of globus pallidus
increases inhibition of thalamus
reduces thalamic excitation of cortex
reduces cortical motor activity

705
Q

What are hypokinetic disorders ?

A

insufficient direct pathway output

excess indirect pathway output

706
Q

What are hyperkinetic disorders ?

A

excess directy pathway ouput

insuufficient indirect pathway output

707
Q

How is chewing iniitated ?

A

by voluntary movement

followed by a period of reflex activity

708
Q

What do CPGS do in mastication ?

A

generate masticatory rhythms - alternative action of jaw openers and closers

709
Q

Where are the CPGs for mastication ?

A

in the pontine reticular nucleus

710
Q

How is chewing modulated ?

A

feedback from peripheral receptors

711
Q

Describe the process of mastication ?

A

food is taken in and rhythmic mastication is imitiated
receptors in the oral cavity monitor hardness
assess whether the food is fir for swallowing
adjust the activity if muscles by feedback to motor neurones , CPG and cerebllum
when bolus is appropriate swallowing is initiated

712
Q

Describe the control of mastication ?

A

CPG in the pontine RF
activate s the pre motro neurones and the trigmeinal motro nucleus
sneds rhythmical signals to the maticatory muscles
sensroy signals feedback about the bolus to the RF and the trigeminal motro neucleus

713
Q

Which receptors control masticatory force ?

A

periodontal ligament receptors

714
Q

What do periodontal ligament receptors do ?

A

inhibit neurones in the trigmeinal motro nucleus via inihbitory interneurones

715
Q

What is the limbic system ?

A

neuronal cicitry that controls emotional behabviour and motivational drivees

716
Q

What does the anteiror conguakte gyrus do ?

A

emotional aspect of pain

717
Q

Where is the hippocampus and what does it do ?

A

medial aspect of the temporal lobe and is involved in memory formation

718
Q

What is the hypothalamus and what does it do ?

A

major part of the limbic system and controls internal body conditions - vegetative behavior and endocrine fucntions

719
Q

What are the outputs of the thalamus ?

A

to the braisntem RF
anterior thalamus and the limbic portion of teh cerebral cortex
hypothalamic infindibulum - pituitary glands

720
Q

What are the functions of the thalamus ?

A

sexual behaviour
endocrine function
homeostasis

721
Q

What does the hypothalamus do in terms of endocrine function ?

A

neuroendocrine cells reelase hormones that act in the pituitary gland and this releases more hormones

722
Q

Which part of teh hypothalamus is to do with sexdual behaviour in fmelaes ?

A

ventromedial hypothalamus

723
Q

Which part of the hypothalamus is to do with sexual behaviour in males ?

A

preoptic region

724
Q

How does the hypothtlmaus carry out temperature reguaktion ?

A

temeprature sensitive neurones in the preoptic area measure the core body temeprature of teh blood
reduced brain/blood barrier in the hypothalamus
repsonse- horemone production
activation of teh ANS
behavioural response

725
Q

Which area of the hypothalmaus creates a thirst sensation ?

A

laterla hypothalamic area

726
Q

Which nucleus of the hypothalamus controsl the excretion fo water into urine ?

A

supraoptic nucleus

727
Q

Which ara regualtes hunger in the hypothalamus ?

A

lateral hypothalamic area

728
Q

Which area of the hypothalamus creates a desire for food ?

A

satiety centre in the ventromedial nucleus

729
Q

What area of the hypothalamus carries out GI activity ?

A

mammillary bodies

730
Q

What is the orexigenic response ?

A

response to low glucose and the need to eat more food

731
Q

What is the anorexigenic response ?

A

high nutrients - stop eating food like GI stretch , circadian rhythms

732
Q

What does GI stretch do ?

A

inihibits te orexigenic response and excites the anorexigenic response

733
Q

What are circadain rhythms ?

A

endodogenous entrainsble 24 hour rhythmicity

734
Q

What nucleus are circadian rhythms controlled by ?

A

suprachiasmatic nuclei

735
Q

Where is the amygdala located ?

A

below the hypothakmaus and i the inferior portion of the laterla ventricvle

736
Q

What ae the fucntions of teh amygdala ?

A

emotional letrning and memeorty
fear and fear cinditioning
reward

737
Q

What does activation of the amygdala lead to ?

A

indices fea anxiety and violence

738
Q

What does deactivation of the amygdala lead to ?

A

incapable pof fear

739
Q

How is the amygdala involved in emotional learning and memory ?

A

amygdala assesses the emotional significance of inputs

much more likely to remember something with emotional significance

740
Q

How is thye amygdala involved in fear and fear conditioning ?

A

amygdala and the medial temporal lobe are invollved in the mediating , acquisition and storage of fear and memory

741
Q

What is the reward system for ?

A

liking and positive reinforcement

742
Q

What are the important structures in the reward system ?

A 
ventral tegmental area - origin 
amygdala 
nucleus accumbens 
hippocampus 
prefrontal cortex
743
Q

What is the reticular formation ?

A

a complex group of neurones and nuclei in the brainstem

744
Q

What are the afferent inouts to the RF ?

A

spinal chord
cranial nerves
cerebellum
forebrain

745
Q

What are the efferent ouputs of the RF ?

A

spinal chord and cortex

746
Q

What are the fucntiomns of the RF ?

A 
sleep and consciousness 
somatic motor cintrol - CPGs
cardiovascular control 
pain modulation 
habituation
747
Q

What are the 4 nuclei of the reticualr acting syste, ?

A

locus coereleus
raphe nucleus
ventral tegmental area
basal forebrain - nucleus of meynert

748
Q

Where are the dopaminergic pathways of the RF ?

A

VTA - mesocorticolimbic pathway

and substantia nigra - dopamine to basal ganglia

749
Q

Where are the serotonergic pathways ?

A

raphe nuclei and the nucleus raphe magnus
ascending pathways to the cortex
descending pathways to the spinal chiord - pain modulation

750
Q

Where are the noradrenergic pathways ?

A

locus coereleus

751
Q

Where are the cholinergic pathways ?

A

basal forebrain and nucleus of meynert

to the hippocampus

752
Q

When does rapid eye movement sleep occur ?

A

JUST BEFORE WE WAKE UP

753
Q

Wehre is rapid eye movement sleep regulated ?

A

pontine RF

754
Q

What is needed to prevent the acting out of ndreams ?

A

connections between the pontine RF and the spinal chord

755
Q

What nuclei are involved in sleep ?

A

Arpahe nuclei

dorsolaterla pontine RF

756
Q

What are the motor effects if the reticular formation ?

A

meduallry reticulospinal tract - laterla

pontine reticulospinal tract- medial

757
Q

What is the function of the pontine RT ?

A

enhances antigravity muscles and reflexes of the soinal chord
helps maintain a standing posture by resisting the effects of gravity

758
Q

What is the function of the medullary RT ?

A

liberates the antigravity muscles from reflex control

759
Q

What is the collective fucntion of the reticulospinal fibres ?

A

modualte muscle tone
regualte psoture
participate in automatic reflexes involving extensor musculature

760
Q

What are CPG s?

A

trigger the correct enets at the right time

2 processes occur and they interact sequentially

761
Q

What are the repsiratory CPGs ?.

A

pontine respiratory group

medullary respiratory group - DRG and VRG and the pre botzinger complex

762
Q

What is the paccemaker theory of CPGs ?

A

self activating fibres that trigger events

763
Q

What is the network theory of CPGs ?

A

VRG made of inspiratory and expiratory neurones

reciprocal imnhibition

764
Q

What is the embonuic serivation of the CNS ?

A

ectoderm

765
Q

What is the name of the process which i the formation of the central nervous system ?

A

neuralation

766
Q

What happens to the ectoderm ?

A

it thickens to forms the nerual plate
folds to fomrs the neural folds
apices of the folds - nerual crests
neural folds fuse to fomr the cavity - which emains inc ointact with the amniotic flkuid - through the cranial and caudal neuropores

767
Q

What ar ethe neural crest deruvatives ?

A 
odontoblasts 
adrenal medulla 
aprafollicular cells of the thmus gland 
autonomic ganglia 
melanoytes
768
Q

What is spina bifida ?

A

failure of fusion of caudal neurpores

769
Q

What in anencephaly ?

A

failure of fusion of cephalic neuropores

770
Q

What is teh development of CNS cells ?

A

embryonic CNS stem cell
neural progenitor
glial progenitor
glial progemitor ito astrocyte and oligodendrocyte progenitor

771
Q

Where is teh pre motor cortex ?

A

anteiror to the primary motor cortex in the postewrior parts of the frontal gytur

772
Q

Where is the prefrontal cortex ?

A

most extensive regions of the frontal lobe

773
Q

Where is the somatosensory association cortex ?

A

superiuor and inferior parital lobules

774
Q

Where is the primary visual cortex ?

A

medial aspects of the occipital lobes

775
Q

Where is brocass area ?

A

inferior frontal gyrus

motor speech area

776
Q

Whrer is wernickes ares ?

A

Superior temporal gyrus

speech comprehension area

777
Q

Where do the vertebral arteires fuse to fomr the basillar arteyr ?

A

ponto medullary junction

778
Q

What are the branches of the veretbelra arteires ?

A

anterior and posterior spina arteries

posterior inferior cerebellar artery

779
Q

Where does the basillar artery run from ?

A

from the ponto-medulalry junction to the ponto-midbrain junction

780
Q

What are the branche sof the basillar arteyr ?

A

superior cerebellar
anterior inferior cerebellatr
posteriuor cerebral

781
Q

What are the branches of the interbal carotid arteyr >/

A 
opthalmic artery 
posterior communicating artery 
anterior choridal arery 
anterior and middle crebral arteires 
anterior commumicati g rteyr
782
Q

What are the 3 primary brain vesicles that from after 5 weeks ?

A

prosencephalon
mesencephalon
rhomoencephalon

783
Q

What does the prosencephalon divide into ?

A

telencephalon

diencephalon

784
Q

What does the mesencephalon divide into ?

A

no dividsion - jut the midbrain

785
Q

What does the rhomencephalon ddivide into ?

A

metencephalon

myelencephaoon

786
Q

What does the telencephalon form ?

A

cerebral hemipsheres

787
Q

What does the diecneohalon form ?

A

thalamus

788
Q

What does the metencephalon form

A

pons and the cerebellum

789
Q

What does the myelencephalon fomr ?

A

meduall oblangata

790
Q

Where doe sthe CSF gfo from the 4th ventricle ?

A

to the subarachnoid apce via the median and laterla apertures

791
Q

How is CSF absorbed into the blood stream ?

A

by the superior agittal swinus through th eubarachnoid villi

792
Q

Which artery supplies blood to the retina and the cranial dura ?

A

opthalmic arteyr

793
Q

How does a bipolar sensory neurone work ?

A

one axon attaches to the sensory organ the opther to the CNS

794
Q

What are the examp[les of the rapidly adpting receptros ?

A

meissners corpuscles
pacinian corpsusles
hair follice recptors

795
Q

What are examples of the slow adapting receptors ?

A

merkel cells
ruffini corpuscles
some hair follice receptors

796
Q

Are reticulospinal tracts bilateral or unilateral ?

A

bilaterla

797
Q

What is the nucleus of the thalamus in the DCML ?

A

ventral posterior lateral nucleus

798
Q

Main output from the basal ganglia is from where ?

A

globus pallidus

799
Q

What are the nuclei of the thalamus related to motor relay and basal ganglia ?

A

Ventral anterior

Ventral lateral

800
Q

What are the receptor organs responsdibl;e for detecting vibrations in the basialr membrane ?

A

organ of corti and the ampullae

801
Q

What are sensory projections on the hair cells known as ?

A

sterocilia

802
Q

What are the receptor organs responsible ofr snesing baalnnce ?

A

ampullae

803
Q

Where are the ampullae located ?

A

in the semi circular canals of the cochlea

804
Q

Which nuclei in the brainstem does the ouput from the vestibular nucleus go to ?

A

nucleus of oculomotr , trochlear and abducens

805
Q

What are the outputs of the supplementary motor cortex ?

A

primary motor cortex
reticular formation
cortocspinal and corticobulbar

806
Q

Which area of the brain is responsible for making an internal model of move,ent when assessing movements ?

A

posterior parietal cortex

807
Q

Which nuclei are responsible for adaptation of movement in response to external stimuli ?

A

red nucleus

olivary nucleus

808
Q

In huntingtons disease which of the basal ganglia are effected /

A

globus pallidus

809
Q

Which of the hypothalamic nuclei are responsible for thirst ?

A

laterla hypothalamic nucleus

810
Q

Which of the nuceli are responsible for conbtrol of water excretion ?

A

supra optic nuclei

811
Q

Where is the satiety centre which controls hunger ?

A

ventromedial nuclei

812
Q

What are the 5 structures responsible for the reward system ?

A 
ventral tegmental area
nucleus accumbens
hippocampus 
amygdala 
pre frontal cortex
813
Q

What are thee nuclei of the reticular formation and what do thy release ?

A

nucleus of meynert- acetylcholine
nucleus raphe magnus/raphe nuckeus- serotonin
ventral tegmental area- dopmaine
locus coerleus- noradrenaline

814
Q

What are the fucntion sof teh reticular formation ?

A 
CVS control 
pain modulation 
habituation 
cpg- skeletal muscle control 
Sleep
815
Q

What happens during rapid eye movement sleep ?

A

paralysis of voluntary mucle and active brain

816
Q

What happens during non rapid eye movemnt sleppe ?

A

lowering of body temeratir
movement of muscles
lowering of heartr rate

817
Q

How can you identify a ruffini corpuscle ?

A

highly branched

818
Q

How can you identify a pacinian corpuscle ?

A

round

819
Q

How can you identify merkel cells ?

A

individual cells

820
Q

How can you identify a meissner corpuscle ?

A

bunch of cells

821
Q

How can you identify hair follicle receptors ?

A

around the hair

822
Q

What are the structural components of the cerebellum ?

A

vermis
intermdiate zone
cerebellar hemispheres
floculonodular lobe

823
Q

What are the functional components of cerebellum ?

A

spinocerebellum
vestibulocerebellum
neocerebellum

824
Q

What is the vestibulocerebellum ?

A

floculonodular lobe

posture and balance

825
Q

What is the neocerebellum ?

A

posterior lobe

planning of movement

826
Q

What is the spinocerebellum ?

A

anterior lobe

monitoring of ongoing movements

BDS Stage 1 (39 decks)

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