Neurobiology Flashcards
What are the basic divisions of the nervous system?
Central Nervous System
Peripheral Nervous System
Enteric Nervous System
What can the CNS be divided into?
Brain and Spinal Cord
What can the PNS be divided into?
Sensory Nervous System and Motor Nervous System
What can the motor nervous system be divided into?
The autonomic or somatic nervous system
What can the autonomic nervous system be divided into?
Sympathetic
Parasympathetic
What is grey matter composed of?
Neuronal cell bodies and dendrites
Astroglia
Microglia
What are astroglia?
Support cells that are responsible for maintaining intracellular ion levels.
What is white matter composed of?
Myelinated axons
Oligodendroglia
Microglia
What are microglia?
Act as macrophages of the nervous system
What does ipsilateral mean?
Same side
What does contralateral mean?
Opposite side
What are afferent fibres?
sensory fibres travelling to the brain
What are efferent fibres?
motor fibres travelling from the CNS
What does the frontal lobe do?
Involved with thinking and problem solving
What is the parietal lobe associated with?
Interpreting signal:
Touch,
taste,
smell,
What is the occipital lobe associated with?
Vison
What is the temporal lobe associated with?
Memory
Roughly how much space of the brain is associated with head and neck?
Roughly 1/2
What is cranial nerve IX?
Abducens
What is cranial nerve IV?
Trochlear
What is cranial nerve I?
Oculomotor
What is cranial nerve VIII?
Vestibulocochlear
Where is pain mostly transmitted through in the head and neck?
The trigeminal (CN V)
What are A-beta fibres?
Present in the tooth sensitive to light tough and proprioception
What are A-delta fibres?
Present in the teeth responsive to noxious stimuli, with short sharp pain
What are C-fibres?
Unmyelinated fibres in the teeth responsible for dull aching or burning pain
What is the clinical relevance of C-fibre pain?
The pain signals inflammation of the whole tooth meaning extraction or root canal treatment is necessary.
What is bells palsy?
Sudden paralysis of facial muscles
What are the characteristics of bells palsy?
Unilateral,
Normally improves over time but might never fully recover
What are the visible differences between a stroke and bells palsy?
Stroke doesn’t tend to affect the forehead.
Bells Palsy only affects the face.
What cranial nerve sits on the parotid gland?
VII (Facial)
What do we have to be careful of when placing an inferior alveolar nerve block?
Reaching the parotid gland as that could cause partial facial paralysis
How do we know we haven’t reached the parotid gland?
Can feel bone (mandible)
What is iatrogenic damage?
Damage caused by a healthcare professional
What is Frey’s syndrome?
following trauma or surgery, when thinking about food or drink, sweating will occur over skin of the neck.
Why does Frey’s syndrome occur?
The parasympathetic axons left behind from surgery ‘need something to do’ so infiltrate the skin on the neck
What is peripheral sensitisation?
Inflamed peripheral receptors can gave increased responsiveness or respond to lower thresholds
What can peripheral sensitisation lead to?
Stimulation can be more intense and can lead to referred pain
What is central sensitisation?
When CNS receives prolonged stimulus of pain it can become sensitised
What can central sensitisation lead to?
Non painful signals being amplified so the patient feels pain
What is neuralgia?
Pain in the distribution of a nerve due to damage in the nerve and the neuroplastic changes following.
What is the most common form of neuralgia?
Trigeminal (about 90%)
What is trigeminal neuralgia?
- Affects CN V
- Short Sharp Pain
- Triggered by Touch
- ## Usually unilateral and isolated to one division
What is localised non-odontogenic pain?
Must be present for 3 months or more ad 8 hours a day
Can be diagnosed by process of removal
When can non-odontogenic pain occur?
Following extraction or endodontics, (roughly 1.6% of cases)
How does dementia affect dentistry?
Patients might not be able to give proper consent
How does parkinson’s affect dentistry?
Motor skills in the hand will be affected therefore oral hygiene might not be carried out properly
What are analgesics?
pain relieving drugs (i.e paracetamol, codeine, ibuprofen )
What are microglial cells?
Immune cells of the brain
What are oligodendrocytes?
There are the myelinating cells of the CNS. They secrete myelin that wraps around the neurones.
What is the cerebellum involved in?
Remembers complex motor movements
What is the gyrus?
‘The hump’ of a fold
What is the sulcus?
‘The valley’ of a fold
What is the importance of gyri and sulci?
They increase surface area meaning more brain cells are present.
Where is the frontal pole?
The most anterior part of the frontal lobe
What is the frontal pole responsible for?
Personality
How many separate frontal gyri are there?
3
What are the 3 frontal gyri?
- Superior
- Middle
- Inferior
Where is the angular gyrus located?
On the angle between the temporal, parietal and occipital lobe
How many divisions of the temporal lobe are there?
3
What role does the superior temporal lobe has?
Audio roles
What borders the pre-central gyrus?
The pre-central sulcus (anteriorly) and the central sulcus (Posteriorly)
What borders the post-central gyrus?
The central sulcus (anteriorly) and post central sulcus (Posteriorly)
What are the two types of cerebral cortex?
Primary
Association
What does the association cortex deal with?
more complex aspects of sensory and motor function, such as planning and predicting.
What separates the parietal and occipital lobe?
The parietal-occipital sulcus
What does the thalamus do?
Relay centre for sensory information.
What is the main role of the hypothalamus?
Homeostatic control, linked to the the pituitary gland.
What is the pons?
Bridge between the brain and the spinal cord.
What is the corpus callosum?
Big white matter tract that connects the two hemispheres of the brain.
What is the longitudinal fissure?
Runs right down the middle of the brain separating the two hemispheres.
What is Spina bifida?
The formation of the bones in the spine are disrupted, following the failure of neural tubes to close.
How do you identify neural tube defects in pregnancy?
Screen for Alpha-fetoprotein levels. Will be high.
What do haematopoetic stem cells form in the brain?
Microglial Cells?
What do embryonic CNS stem cells differentiate to?
- Glial Progenitor
- Neuronal Progenitor
Which secondary embryonic vesicle goes on to develop into the pons and the cerebellum?
Metencephalon
Which two arteries enter the cranium to supply the brain?
Verterbral and Internal carotid
Where do the vertebral and internal carotid artery join?
Circle of willis
What do the two vertebral arteries join to form?
Basilar artery
What branches off the vertebral artery?
- Ant. Spinal Artery.
- Post. Spinal Artery
- Posterior Inferior Cerebellar artery
Where does the basilar artery form?
Pontomedullary Junction
What are the two terminal branches of the basilar artery?
Anterior Inferior Cerebellar Artery
Superior Cerebellar Artery
Where does the basilar artery split?
Ponto-midbrain junction
Posterior Cerebral Artery
What is the ophthalmic artery a branch of?
The Internal Carotid Artery (ICA)
What is the most important branch of the ophthalmic artery?
Central Retinal artery
What is the Posterior Communicating artery?
A branch of ICA that rises just before the ICA terminates.
Joins the first part of the posterior cerebral artery
What is the anterior choroidal artery?
A branch of ICA that supplies the choroid plexus
What does the choroid plexus form?
Cerebral Spinal Fluid
What junction do the endothelia cells in the blood brain barrier have?
Tight Junction
What do astrocytes do in the blood brain barrier?
Modulate the function of endothelium cells and ensure correct nutrients are collected
Why do we have the circle of willis?
Allows blockage of some vessels while still allowing circulation of blood in the brain
Which arteries mainly supply the cortex?
Posterior cerebral
Middle cerebral
Anterior Cerebral
How does the middle of the brain get its blood supply?
Perforating branches of the middle cerebral artery.
Which artery mostly supplies the lateral surface of the brain?
Middle cerebral artery
What forms the cavities in the brain?
The neural tube
What makes the cerebrospinal fluid?
Choroid Plexus (70%) Ependymal cells (30%)
What does the CSF do?
Gets rid of waste products.
Provides cushioning for brain.
Allows brain to ‘float’
Stable ionic environment for CNS
What ventricles are there in the brain?
Lateral ventricles (1 in each hemisphere) Third Ventricle (in centre) Fourth Ventricle (in centre)
What joins the 3rd and 4th ventricle?
Cerebral Aqueduct
What joins the Lateral ventricle with the 3rd ventricle
Intraventricular Fo. (of munro)
Where does the CSF flow start?
Lateral ventricles (by choroid plexus)
Where does the CSF enter the sub arachnoid space?
The Median aperture
What % of strokes are due to blockages?
Around 85%
What % of strokes are due to bleeds?
Around 15%
Where do you find berry aneurisms in the circle of willis?
Anterior Communicating arteru (40%)
Middle cerebral artery (34%)
Joining of Posterior Communicating Artery and ICA (20%)
Branching of Basilar Artery (4%)
What is TACS?
Total Arterial Circulation Stroke
What can TACS cause?
Inattention
Visual Deficits
Right hemiparesis (Paralysis)
Dysphasia (if on dominant side)
What is sensory neglect?
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.
What is locked in syndrome?
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.
What is hemiplegia?
paralysis on one side of the body
What is aphasia?
Impairment of language
What are the effects or posterior cerebral artery stroke?
Affects the occipital lobe- vision
Also damage to visual association cortex
What is the rate of proliferation during foetal development?
Around 250,000 per minute
What is the diameter of a neurone cell body?
4 to 100 microns
What is a soma (cell body)?
It houses the cell nucleus and is responsible for cell metabolic maintenance
What is the function of dendrites?
Receive and process information from other neurones (via synapses)
What is the definition of a ganglion?
Group of neurone cell bodies in the peripheral nervous system
What is the equivalent of a ganglion in the CNS?
A nucleus
Where do you find nerve tracts or pathways?
In the CNS was bundles of nerves
What is the function of a neurone related to?
The shape
The neurotransmitters used
The ways it reacts to other neurones
What defines a multipolar neurone?
They have many processes emanating fro the cell body
What are motoneurons?
They carry signals from the spinal chord to the periphery
What are bipolar sensory neurones?
They account for 0.9% of neurones and have two axons.
How do bipolar sensory neurones work?
One axon communicates with a sense organ, one communicates with the CNS
What percentage of brain cells are glial cells?
90%
What are glial cells?
Nerve cells that do not carry nerve impulses
What are the functions of glial cells?
Digest parts of dead neurones.
Manufacture myelin.
Provide Physical and nutritional support.
What different types of glial cells are there?
Astrocytes
Oligodendrocytes
Schwann Cells
Microglia
What do astrocytes do?
They help regulate extracellular ionic concentrations.
They also form the scar tissue in the CNS
What do oligodendrocytes do?
They form myelin around several axons for electrical insulation in the CNS
What do Schwann cells do?
They form myelin in the PNS
What do microglia do?
They clean up dead tissue
What is the point of origin of an axon?
the axon hillock
Do dendrites taper with distance?
YES
Do axons taper with distance?
NO
Why do neurones have dendrites?
To receive and process information from other cells making synaptic contacts with them
What are spines on dendrites?
Small mushroom appendages on the dendrites
How many synapses does a typical neurone have?
Between 1,000 and 10,000
What is the cerebellar purkinje cell?
It integrates tens of thousands of inputs in the cerebellum and integrates the signals.
How are purkinje cells arranged in the cerebellum?
They have a molecular layer with millions of parallel fibres passing through the sheet
What is myelin made up of?
70-80% lipids, 30-30% proteins
What types of connections can you have with axons and postsynaptic cells?
Axodendritic
Axoaxonic
Axosomatic
How does a cell gain it’s resting potential?
The ability of the membrane to allow different ions in and out of the cell in a selective manner.
What is Nernst potential?
It is used to calculate the exact V generated by a specific ion
What happens when Vm = Vnernst
There is no net flow of that ion across the membrane
Which ion will have the highlights Vnernst
The ion with the highest permeability
What channels are found in neuronal membranes?
Leak K+ Channels (always open)
Na+ and Cl- channels
Which ion has the highest influence on the resting membrane potential?
K+
What does the Goldman equation do?
Combines the nearnst equation for all ions and takes permeabilities into consideration
What is passive propagation?
Membrane properties that do not change during electric signalling
What is active propagation?
These are triggered by changes in Membrane potential. Allowing signals to be passed efficiently over long distances.
What does a large diameter of axon do to the signal?
Increases the distance the current will propagate
What does myelin on an axon do?
It increases signal propagation
What are the voltage gated Na+ channels like under resting conditions?
70% of the internal gates are open
External gates are closed
What are the voltage gated K+ gates like under resting conditions?
They are closed
What happens when Vm decreases to threshold?
External Na+ channels start opening, this further reduced Vm. Example of positive feedback mechanism.
What prevents further depolarisation of the membrane?
The internal Na+ channels inactivate
When do V-gated K+ channels open?
They slowly open after threshold depolarisation to speed up the depolarisation process
What causes the undershoot of an action potential?
The delay of closing V-gated K+ channels.
What is the Absolute Refractory Period?
When a second AP cannot be produced
What is the Relative refractory period?
APs can only be generated with increased threshold, or reduced amplitude.
Why does the AP travel ‘forward’?
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.
What is saltatory conduction?
The process of the signal ‘jumping’ from one node of ranvier to another in myelinated axons.
What are the characteristics of electrical synapses?
They are fast,
No chemical transduction
Where are electrical synapses found?
Gap synapses in cardiac muscle cells and epithelial cells
What are the characteristics of chemical synapses?
Use a chemical substance as an intermediate to convert electrical signals in presynaptic cell into postsynaptic cell..
What are gap junctions?
Protein pores that bride the gap between two cells
What makes up the pore in gap junctions?
6 subunits of connexin
What is the distance between membranes in an electrical synapse?
3.5nm
Is there a delay in transmission with chemical synapse?
Yes, about 1-5 msec
What direction do signals pass in chemical synapses?
Unidirectional (one way)
What identifies a neurotransmitter?
It mimics normal transmission when applied to postsynaptic membrane.
Manufactured and released from presynaptic cell.
What are Ionotropic receptors?
Directly linked to ion channels
What are metabotropic receptors?
G-protein-coupled receptors that use a second messenger
What would you find at a chemical synapse?
Synaptic vesicles Receptors Synaptic Cleft Secretory Granules Mitochondria
What forms the presynaptic element?
The axon terminal
What is the 1st step of synaptic transmission?
The AP is propagated in the presynaptic neurone
What is the 2nd step of synaptic transmission?
Ca2+ enters the synaptic knob through V-Gated channels
What is the 3rd step of synaptic transmission?
Release of neurotransmitter into the synaptic cleft by exocytosis
What is the 4th step of synaptic transmission?
Binding of neurotransmitter to postsynaptic receptor
What is the 5th step of synaptic transmission?
Opening of ion channels or activation of G-Protein secondary messengers.
What is the importance of recycling neurotransmitters?
If they remained in the synaptic cleft there would be uncontrolled signalling
How do vesicles dock with the membrane of the terminal?
SNARE proteins that trigger exocytosis in the presence of Ca2+
What are the main differences of AP and EPSP
- EPSP only reaches threshold
- EPSP is decremental
- EPSP is much longer (15-20 msec)
What does EPSP stand for?
Excitatoty Post-Synaptic Potential
Why do you get temporal summation in EPSP’s
As the time taken for a single EPSP takes much longer the signals adduct at high frequency to each other reaching the threshold.
Why is temporal summation in EPSP’s important?
Otherwise the EPSP would decrement. This allows for an AP to be generated
What is spatial summation?
This is when signals come in from different inputs. This ‘collects’ the signals together allowing for threshold to be met for AP
What does IPSP stand for?
Inhibitory Post-synaptic potential?
What does IPSP do?
It causes hyperpolarisation of post-synaptic neurones
What is the importance of IPSP’s
It makes it much harder to generate an AP as you are further away from threshold.
What is a first order neurone?
The first axons until the first synapse
What is a second order neurone?
Neurones from 1st synapse to the 2nd synapse (normally in thalamus)
What is a third order neurone?
From 2nd synapse to the final destination
What are afferent nerves?
Towards CNS
Group of nerve fibres
Various sensory modalities
What are efferent nerves?
Away from CNS
Motor nerve fibres to effector organs
What are the general properties of motor neurones?
Cell body in spinal cord
Fast
Myelinated
What are the general properties of sensory neurones?
Cell body in dorsal root ganglion
Different types have different speeds
Myelinated and Unmyelinated
How do you classify peripheral nerves?
Two methods
Letter System: for sensory and motor
Roman numeral system: for sensory only
What do Ia (Aα) fibres do?
Sensory from Muscle Spindle to CNS
What do Ib (Aα) fibres do?
Golgi tendon organ to CNS
What do II (Aβ) fibres do?
Muscle spindle, touch, pressure to CNS
What do III fibres (Aδ) do?
Pain, pressure, temperature to CNS
What do IV fibres (C) do?
Pain, touch, temperature to CNS
What do B fibres do?
Part of ANS towards effector organ. Preganglionic
What do C fibres do?
Part of ANS to effector organ. Post ganglionic
What do Aα fibres do?
Transmits signals from CNS to skeletal muscle
What do Aγ fibres do?
Transmits signals from CNS to Muscle spindle
Whats the difference between B and C fibres in parasympathetic ANS.
B fibres are longer than C fibres
Whats the difference between B and C fibres in sympathetic ANS.
B fibres are shorter than C fibres
What are golgi tendon organs?
A sensory receptor organ that senses changes in muscle tension.
How can you tell if a fibre is sensory/motor based on its name?
If it is roman numerals it is sensory only.
What does sensation mean?
Conscious/subconscious awareness of external environment
What does perception mean?
Interpretation of sensation
What is the definition of pain?
Unpleasant felling caused by stimulus of nociceptive receptors following tissue injury
What is acute pain?
Short term
What is chronic pain?
Long term
What is somatic pain?
Body
What is visceral pain?
Thorax/Abdomen
What two phases of pain do we have?
Sharp, instant pain
Dull, throbbing pain
What are pain receptors called?
Nociceptors
Where are nociceptors found?
Skin, muscle, joint.
What are the two types of pain fibres?
A-delta and C-Fibres
What is the difference between A-delta and C-Fibres
Aδ are myelinated, therefore conduct speed fast. Pain type is sharp and fast.
What is Rexed’s Laminae?
Found in dorsal horn of grey matter. They are where pain receptors synapse.
Where do C-fibres synapse in rexed’s laminae?
Mainly towards the top
Where do Aδ fibres synapse in rexed’s laminae?
In different laminae
What is specific about peripheral sensitisation?
They have a high threshold, meaning they respond to noxious stimuli.
They become sensitised reducing likelihood of further damage.
What importance of amygdala?
Key centre of brain for anxiety, pain, and worry.
How does referred pain work?
It is due to convergence of sensory input on second order neurones
How does the CSF flow through the brain ?
in the ventricular system
lateral ventricles
third ventricles via the interventricular foramen
4th ventricles via the cerebralaqueduct
How does CSF leave the 4th ventricle ?
via the median and lateral apertures
Where is CSF made ?
in the lateral and 3rd ventricles
What is the touch pathway ?
dorsal column medial lemniscus
Where do the first order neurones synapse in DCML?
in the cuneate or gracile nuclei in the medulla
What is the pain pathway ?
anterolateral system
Where do the first order neurones synapse in the anterolateral system ?
in the dorsal horn of the spinal chord
Where does the DCML dessucate ?
in the medulla
Where does the anterolateral system dessucate ?
in the spinal chord
What are the fibres that conduct pain ?
A-delta and C fibres
What is the centrifugal pathway ?
the pathway that inhibits ascending sensory pathways via release of chemicals that inhibit interneurones
Describe the centrifugal pathway ?
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
What are the vesicle fusion proteins ?
Synaptobrevin - joins to the vesicle (V-snare)
Syntaxin - T-snare - join to the terminal
SNAP 25 - T-snare
What is the axon hillock ?
the last place in the cell body where the action potentials are generated before passing to the axon
Explain the gated theory of pain ?
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.
Explain saltatory conduction ?
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
What do the 2 vetebral arteries converge to form ?
basillar artery
What are the branches of the vertebral artery ?
anterior and posterior spinal arteries
posterior inferior cerebellar artery
medullary branches
What does the basillar artery extend across ?
pons
Where does the basilalr artery form ?
at the ponto-medullary junctions
Where does the basillar artery end ?
ponto-midbrain junction
What does the basillar artery divide into ?
superior cerebellar arteries
posterior cerebral arteries
anterior inferior cerebellar artery
pontine arteries
What does the posterior cerebral artery do ?
supply the posterior parts of the temporal and occipital lobes
What arises from the posterior cerebral arteries ?
small perforating arteries to supply deep brain structures
What are the branches of the internal carotid arteries ?
opthalmic artery posterior communicating artery anterior choroidal artery anterior and middle cerebral arteries anterior communicating artery
What does the opthalmic artery do ?
passes through the optic canal to supply the eye
a branch of this is the central retinal artery
What does the anterior choroidal artery do ?
supplies the choroid plexus of the lateral ventricle
What are the features of the blood brain barrier ?
astrocytes
endothelial cells
tight junctions
What do the astrocytes do in the blood brain barrier ?
form a barrier around the endothelial cells
Where does the middle cerebral artery supply ?
most lateral aspects of the brain
What does the anterior cerebral artery supply ?
most superior aspects laterally
most medial aspect
What does the posterior cerebral artery supply ?
most of the posterior aspect - occipital and temporal lobes
What is unique about the dural venous sinuses ?T
They dont contain valves
What are the deep cerebral veins ?
great cerebral vein of galen
What does the great cerebral vein of galen do ?
lies beneath the corpus callosum
continuous with the straight sinus
What are the superficial veins ?
the superficial middle cerebral vein - runs along the lateral fissure and empties into the cavernous sinus
What does the superior sagittal sinus receive blood from ?
superior cerebrak veins
What lies within the tentorium cerebelli ?
straight sinus
How is the confluence formed and where is it ?
meeting of the straight sinus and the superior sagittal sinus and is adjacent to the internal occipital protuberance
Where does blood flow from the confuence ?
transverse sinus
Where does the transverse sinus drain into ?
sigmoid sinus
What does the cavernous sinus drain into and where does it receive blood from ?
receives blood from the middle cerebral vein
drains into the internal jugular vein via the inferior petrosal sinus
How are the ventricles formed ?
from the neural tube which forms cavities
What do the ventricles contain ?
CSF
What produces the CSF ?
choroid plexus (in the 3rd and 4th ventricles) ependymal cells (line the ventricles - 30%)
How does the CSF get rid of waste products ?
placing them in the bloodstream
Where is the 4th ventricle located ?
above the medulla
What is lateral to the 4th ventricle ?
lateral aperture (luschka)
What is medial to the 4th ventricle ?
median aperture (magendie)
What does the 4th ventricle extend rostrally as ?
cerebral aqueduct
What is the flow of CSF through the ventricles ?
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
How is CSF absorbed into the blood stream ?
in the superior sagittal sinus via the arachnoid villi
What are the roles of the CSF ?
allows the brain to float - reduce traction on nerves and blood vessels
protective cushioning
removes waste metabolites
provides stable environment for the CNS
What is the composition of the CSF ?
small amounts of protein
glucose
ions- calcium , potassium , NaCl and Mg
85% of stroke is due to what ?
ischaemia - blockage
What is ischaemia ?
restriction in blood supply to the tissue causing a shortage of oxygen needed for cellular metabolism
What causes ischaemia ?
artheroma (arterial wall degeneration)
blood clot
15% of stroke is due to what ?
a bleed - haemorrhage
What are aneurysms ?
bulgings that can cause bleeds
Where are berry aneurysms located ?
occur at a point where the cerebral artery departs from the circle of willis
What is total anterior circulation stroke ?
affects the main artery to one hemisphere
What can left total anterior circualtion stroke lead to ?
right hemiparesis - weakness on the right side
What is lacunar syndrome ?
damage to the perforating arteries - deep brain structures affected
What is sensory neglect ?
failure to be aware of one side of space
affects the somatosensory association cortex
middle and cerebral artery affected
What is locked in syndrome ?
basillar artery affected
cant communicate to the rest of the body as ascending/descneding pathways are gone
aware but cant move
What does posterior cerebral artery stroke affect ?
occipital lobe and the primary visual cortex
Where is the calcerine sulcus ?
perpendicualr to the parieto-occcipital sulcus
Where is the 4th ventricle located ?
in the cerebellum
Where is the 3rd ventricle located ?
in the midbrain
What structures form the wall of the 3rd ventricle ?
thalamus
Which artery supplies the primary motor cortex ?
middle cerebral artery
Which artery supplies the primary motor cortex medially ?
anterior cerebral artery
Which artery supplies the primary auditory cortex ?
middle cerebral artery
Which artery supplies the primary somatosensory cortex ?
middle cerebral artery
Which artery supplies the primary visual cortex medially ?
posterior cerebral artery
What supplies wernickes area ?
middle cerebral artery
What supplies brocas area ?
middle cerebral artery
What are 1st order neurones ?
conduct impulses from receptors to the spinal chord or brainstem where they synapse
What are 2nd order neurones ?
synapse in the thalamus (from the brainstem or the spinal chord)
What are 3rd order neurones ?
they synapse in the cortex from the thalamus
Where are the cell bodies of motor neurones located ?
in the spinal chord
Where do motor neurones usually synapse ?
muscle
Where are the cell bodies of sensory neurones ?
dorsal root ganglion
Where do sensory neurones usually synapase ?
brain stem or the spinal chord
Are motor neurones myelinated or unmyelinated ?
myelinated - fast
Are sensory neurones myelinated or unmyelinated ?
both
What are the 2 classification systems for peripheral nerves ?
letter system and the roman numeral system
What does the letter system show ?
both sensory and motor
What does the roman numeral system show ?
only sensory
What are the different types of fibres in the letter system ?
A-alpha A-beta A-gamma A-delta B C
What are the function of A-alpha fibres ?
alpha motoneurones , muscle spindle , golgi tendon organs , touch
What is the role of A-beta fibres ?
touch
kinesthesia
muscle spindle
What is the role of A-gamma fibres ?
4-8 micrometres
What is the function of A-gamma fibres ?
touch , pressure , gamma-motoneurones
What is the function of A-delta fibres ?
pain , crude touch , pressure and temperatures
What is the function of B fibres ?
preganglionic autonomic
What is the funcntion of C fibres ?
pain, touch , pressure , temperature
postganglionic autonomic
What are the fibres in the Roman numeral system ?
1a 1b II III IV
What is the role of 1a fibres ?
muscle spindle and primary endings
What is the role of 1b fibres ?
golgi tendon organs
What is the role of type II fibres ?
touch
kinesthesia
muscle spindle
secondary endings
What is the fucntion of type III fibres ?
fast pain , crude touch , pressure , temperature
What is the role of type IV fibres ?
slow pain , touch , pressure and temperature
What is the equivalent of A-alpha fibres ?
1a and 1b fibres
What is the equivalent of type II fibres ?
A-beta
What is the equivalent of A-delta fibres ?
type III
What is the equivalent of C fibres ?
type IV
What are the sensory fibres ?
1a 1b II III IV A-alpha A-beta A-delta
What are the motor fibres ?
B
C
A-alpha
A-gamma
What do sensory nerves do ?
convert their stimuli into action potentials
What are the somatic general senses ?
touch , temperature , proprioception and pain
What are the visceral general senses ?
conditions of the internal organs
What are the special senses ?
smell / taste / hearing / equilibrium and balance
How can sensory receptors be classified ?
microscopic features
receptor location
type of stimulus detected
What types of receptors with microscopic features ?
free nerve endings
encapsulated nerve endings
separate cells
What types of receptors are based on their location ?
exteroreceptors
intereceptors
proprioceptors
What are the type of receptors based on stimulus ?
mechanoreceptors thermoceptors nociceptors chemoreceptors photoreceptors osmoreceptors
What is the fine touch pathway ?
dorsal column medial lemniscus
Describe the dorsal column medial lemniscus ?
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
What is the pathway for pain and crude touch ?
anterolateral system
Describe the anterolateral system ?
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.
What is the trigeminothalamic tract ?
detects fine touch , pressure , vibration and proprioception
Describe the trigeminothalamic tract ?
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
Describe the pain and temperature system for the trigeminothalamic tract ?
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
What are the 2 types of pain ?
sharp instant pain
dull throbbing pain
What are pain receptors called ?
nociceptors
What fibres do pain receptors activate ?
A-delta and C fibres
What pain type do A-dleta fibres respond to ?
sharp and past
What pain do C fibres respond to ?
dull, slow ache
What are the stimuli for A-delta ?
mechanical stimulation
painful hot and cold
What are the stimuli for C-fibres ?
substances released from damaged tissues
Which laminae do A-delta fibres synapse in ?
1 and 5
Which laminae do C fibres synapse in ?
1 and 2
Where do type II and III fibres synapse ?
substantia gelatinosa
Where do type IV-VI fibres synapse ?
nucleus proprius
What type of threshold do nociceptors have and why ?
high
to trigger pain and discriminate from touch
allows a response only to noxious stimuli
When do nociceptors become more sensitive ?
threshold is lowered - previous damage means non-noxious stimuli cause pain
responsiveness increased - nociceptor damage leads to increased sensitivity
What is the role of peripheral sensitisation ?
protective role - reduces the likelihood of damage
How does peripheral sensitisation occur ?
when chemicals from damage and inflammation act on nociceptors reducing the threshold for the firing of Action potentials
Examples of chemicals that can reduce the threshold of nociceptors ?
ATP
histamine
serotonin
What is the role of neutrophils in peripheral sensitisation ?
release cytokines which act on nociceptors making them more sensitised
What does central sensitisation mean ?
a sensitised CNS means that pain pathways are more sensitive
How does central sensitisation occur ?
alter the synaptic strength between neurones
stronger synapses mean more sensitivity
Where does central sensitisation occur ?
spinal chord - lamina I and V
thalamus
amydala
anterior cingualte cortex
How does central sensitisation alter synaptic strength ?
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
What is the gated theory of pain ?
non painful input can close the nerve gates to painful input preventing sensation travelling to the CNS
What is the role of collateral branches in the gated theory of pain ?
act on interneurones to feedback on pain pathways to inhibit ascending pain pathways
What do different sensory modalities do ?
interact to modify pain input to the CNS
in which areas are pain perceived ?
thalmaus - ventral posterior medial/lateral nucleus
primary somatosensory cortex - has a discriminative component
hypothalamus
lymbic system
What is referred pain and how does it happen ?
feeling pain away from the area of damage
due to convergence of sensory input of 2nd order neurones
What does the periaqueductal grey matter do ?
receives signals from hypothalamus , amygdala and cortex
What does the locus coereleus do ?
secrete noradrenaline
What does the raphe nucleus do ?
release serotonin
What is the centrifugal pathway ?
the descending system which acts to reduce the response to pain
Describe the centrifugal pathway ?
sensory cortex , frontal and limbic cortex receives sensory info
periventricular nucleus of hypothalamus - OPIOIDS
periaqueductal grey - SEROTONIN
raphe nucleus/locus coerelus
spinal chord - ENDORPHINS
What does the raphe nucleus do ?
inhibits ascending pathways by interneurons in the centrifugal pathway
What is usually released at the synapse between the interneurones and the centrifugal pathway ?
GABA
an inhibitory neurotransmitter which controls the centrifugal pathway
What do opioids do ?
inhibit the internerones and stop the inhibition of the descending pathway
What is a motor unit ?
made up of the motor neuron and the skeletal muscle fibres innervated by the motor axon terminals
Why do motor units differ in size ?
depending on the grading of movement
What do alpha motoneurones do ?
activate skeletal muscle fibres
they are under descneding control
What do gamma motoneurones do ?
activate intrafusal fibres within the muscle spindle
What does the muscle spindle do ?
brings back information via 1a afferents about the degree of muscle stretch
Damage to a lower motoneurone causes what ?
flaccid paralysis
Damage to a upper motoneurone causes what ?
spastic paralysis
What is the myotatic stretch reflex ?
muscle contraction in response to stretching within the muscle
What does excitatory input come through in the myotatic reflex ?
1a afferents
Information from the 1a afferents causes what ?
excitation of the flexor
A stretch in the muscle spindle has what effect on the extensor ?
a stretch in the muscle spindle is fed forward to the alpha motoneurone which inhibits the extensor via inhibitory interneurones
Describe the myotatic reflex ?
change in muscle length muscle spindle stretched 1a afferents activated alpha motoneurones activated muscle contracts - flexor is excited whilst the extensor is inhibited
What is the muscle spindle ?
length controlled by gamma-motoneurone
1a afferents signal change in muscle length
stimulates muscle contraction
What is the golgi tendon organ ?
found in tendons
sends signals to the spinal chord via 1b afferents to signal change in tension
inhibit muscle contraction
What is the inverse stretch or inverse myotatic reflex ?
stretch of a tendon leads to inhibition of the muscle nut activation of the antgonistic muscle
In the myotatic reflex stretch of a tendon leads to ?
activation of 1b afferents via the golgi tendon organ
Is the inverse reflex faster or slower than the normal reflex ?
slower as it involves another synapse bteween the 1b afferents and the motoneurone - normally the 1a afferents go straight to the motoneurone
How do 1b afferents work ?
through inhibitory interneurones
An increase in muscle length leads to what ?
both the stretch and tendon reflexes being activated- they have opposite effects
What is the purpose of the tendon relfex ?
to dampen dwn the stretch reflex and prevent excessivve muscle contraction
What is the purpose of the stretch reflex ?
to increase muscle contraction
What is the cross extensor reflex ?
a withdrawal reflex
What happens in the cross extensor reflex ?
flexors in the withdrawing limb contract
extensors relax
in the stationary limb flexors relax and extensors contract
How is the cross extensor reflex coordinated ?
reciprocal inhibition of flexors and extensors via interneurones act to coordinate both sides in routine movements
What is the stimulus in the cross extensor reflex and how is it detected ?
temeprature or pain from group III afferents
What is the central pattern generator ?
neuronal circuits that produce rhythmic motor patterns
they generate alternate activities for routine movements
Where are central pattern generators located ?
brainstem or spinal chord
What is an example of an activity regulated by the central pattern generator ?
breathing and swallowing
What are the types of sensory receptors in the skin ?
merkel cells
meisners corpuscles
pacinian corpuscles
ruffini corpuscles
What are merkel cells ?
slow adapting receptors near border of the epidermis respond to touch and pressure large myelinated axons uncapsulated A-beta fibres are parent fibres
What are meissners corpuscles ?
in the dermal papillae of skin
rapidly adapting
touch
A-beta fibres are parent fibres
What are pacinian corpuscles ?
occur in the skin and deep tissues
rapidly adapting
respond to vibration mainly and pressure
A-beta fibres
What are ruffini corpuscles ?
slow adapting mechanoreceptors
dermis of the skin
respond to touch and stretch
A-beta parent fibres
What are hair follicle receptors ?
sensation- motion and direction
Fibre type - II
What are mesissners corpuscles ? (C)
Sensation- Tap and futter (5-40 Hz)
Fibre type - II
RF- small
What are pacinian corpuscles ? (C)
Sensation- Vibration
FIbre type - II
Receptive field- large
What are merkel cells ? (C)
Sensation- pressure
Fibre type- II
RF- small
What are ruffini corpuscles ? (C)
Sensation - skin and stretch
Fibre type - II
RF- large
What are free nerve endings ?
Sensation- nociception
Fibre type- III and C
Skin receptors generally have which type of threshold ?
low
except for nociceptors which have a high threshold
What is sensory transduction ?
conversion of sensory stimuli from one form to another
Describe the process of signal transduction in the pacinian corpuscle ?
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
Sensory receptors generate what type of action potentials ?
tonic - steady and constant firing
Coding of sensory information occurs due to ?
changes in the firing rates (increase/decrease)
Duration of time action potentials last for
Activation of different parts of receptive fields
What are rapidly adapting receptors ?
they respond to the application and removal of a stimulus
fail to respond to a maintained stimulus
What are examples of rapidly adapting receptors ?
meissners corpuscles
hair follicle recpetors
pacinian corpuscles
What are slow adapting receptors ?
Encode stimulus intensity
Active for the duration of the maintained stimulus
increase their tonic firing rate if the stimulus intensity increases
What are examples of slow adapting receptors ?
merkel cells
hair follicle receptors
ruffini corpuscles
What are receptive fields ?
space occupied by a sensory receptor that can elicit the response to a stimulus
The size of the receptive field determines what ?
the discriminatory nature of the stimulus
The finger tips have what type of receptive fields ?
small and numerous - highly discriminatory response
The back has what type of receptive fields ?
large and sparse receptive fields - low discrimination
What is convergence ?
one postsynaptic neurone receives a convergent input from a number of postsynaptic neurones
What is divergence ?
An individual neurone can make many divergent connections to a number of postsynpatic neurones
Where are divergence and convergence seen?
sensory pathways
What is the purpose of convergence and divergence ?
can lead to one sensory modality altering the other like in the Gated theory of pain
multisensory processing
In sensitive areas what do receptive fields do ?
they overlap
What happens upon stimulation of the centre of the field ?
the lateral aspects can also be stimulated
Which neurone will have the strongest and weakest response ?
strongest - middle neurone
weakest - middle neurone
What happens to the lateral neurones ?
they are inhibited by interneurones from the middle neurone
What does the brain receive in lateral inhibition ?
info from the middle neurone to provide a more accurate and discriminative input
The primary somatosensory cortex is the site of termination of what ?
thalamocortical pathway
The primary somatosensory cortex contains what ?
a topographical map of senses that is proportional to the amount of sensory information
What are Brodmans areas 1,2 and 3 ?
in the post ccentral gyrus - compartmentalisation based on different functions
What is area 3b ?
primary somatosensory corte
What is area 3a ?
proprioception
What is area 1 and 3b ?
cutaneous stimuli
What is area 2 ?
tactile proprioception - size and shape
How is the post central gyrus organised ?
columnar organisation
What does columnar organisation of the post central gyrus allow for ?
allows for exact info from body areas to be extracted
as well as the processing of information from nearby modalities
Where is the secondary somatosensory cortex located ?
towards the end of the post ccentral gyrus
superior aspect is the lateral sulcus
What are the higher order functions of the secondary somatosensory cortex ?
sensorimotor integration
integration from 2 bodily halves - bilateral
attention , learning and memory
Where is the association cortex for the primary somatosensory cortex located ?
posterior parietal cortex
What is the role of the posterior parietal cortex ?
integrates sensory information and allows recognition of objects by touch
What does the lateral corticospinal tract control ?
voluntary control of distal musculature
What does the anterior corticospinal tract control ?
voluntary control of proximal musculature
Where do the reticulospinal tracts originate and terminate ?
from the pontine and medullary reticular formation to the spinal chord
What is the role of the reticulospinal tract ?
regulates flexor reflexes and initiates patterned activity
eg. locomotion and swallowing
Where do the tectospinal tracts run from ?
the tectum in the midbrain to mainly the cervical region of the spinal chord
What is the role of the tectospinal tracts ?
orientation to auditory and visual stimuli
controle head movements in response to visual stimuli
Where do the vestibulospinal tracts run from ?
from the vestibular nucleus to the spinal chord
What does the lateral vestibulosponal tract do ?
antigravity muscles for balance
What do the medial vestibulospinal tracts do ?
regulate head movements
What are upper motor neurones ?
found in the cerebral cortex and brainstem
carry information to lower motor neurones directly or indirectly
How can UMN project directly onto LMN ?
corticospinal or corticobulbar tracts
Damage to the direct pathways causes what ?
babinskis sign
paralysis
paresis of fine skilled movements
segmental (local) relfexes are unaffected
What are the indirect pathways that UMN can project onto LMN ?
from brainstem nuclei to LMN (rest of the pathways)
What is the role of the indirect pathways of projection ?
they integrate supporting musculature during voluntary movements
facilitate spinal reflexes to do with balance , posture and equilibrium
Where does the lateral corticospinal tract decussate ?
at the medulla-spinal chord junction - innervates the LMN on the opposite side
Where does the anterior corticospinal tract decussate ?
at the segmental level in the spinal chord
Where is the internal capsule located ?
between the basal ganglia and the thalamus
What passes through the internal capsule ?
corticospinal and corticobulbar fibres
How is the internal capsule organised ?
it is segmented to receive fibres for different limbs and parts of the face
What type of stroke affects the internal capsule ?
lacunar stroke - this can take out the corticobulbar and corticopinal fibres
What does the tectum consist of ?
superior and inferior calliculus - located in the midbrain
What is the role of rubrospinal tracts ?
excite flexor activity and inhibit extensor activity
What is the reticular formation ?
collection of neurones and nuclei not in a specific nucleus or pathway
What does the reticular formation contain ?
many nuclei and fibres that travel to the cortex and release neuromodulators such as serotonin , acetylcholine and noradrenaline
What does the reticular formation do ?
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
Where does the reticular formation spread from ?
from the pons to the spinal chord
What is the vestibular nucleus ilnked to and what does this mean ?
to the cerebellum - controls same side
What does the lateral vestibulospinal tract do ?
assist postural adjustments
What does the medial vestibulospinal tract do ?
assist in head position
What is babinskis sign ?
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.
What is the early neural tube surrounded by ?
alar and basal laminae
What does the alar lamina develop into ?
dorsal horn - sensory - lateral
What does the basal lamina develop into ?
ventral horn - alpha motoneurones - medial
What are the afferent components of CN fibres ?
general somatic afferent
special visceral afferent
special somatic afferent
general visceral afferent
What are the efferent components of CN fibres ?
special visceral efferent
general somatic efferent
general visceral efferent (autonomic)
What are the function of general somatic afferents ?
general sensation from skin joints and bone
What are the function of special visceral afferents ?
taste and visceral sense
What is the function of special somatic afferents ?
vision hearing and balance
What is the function of special visceral efferents ?
skeletal muscle from the pharyngeal arches - muscles of facial expression and mastication
What is the role of general somatic efferent ?
skeleta muscle from the somites
What is the role of general visceral efferent ?
smooth muscle and glands - parasympathetic
Which cranial nerves join to the brainstem ?
oculomotor - hypoglossal
Which cranial nerves join to the diencephalon ?
olfactory and optic
Where do motor cranial nerves attach ?
more medially
What are the sensory only cranial nerves ?
olfactory
optic
vestibulocochlear
What are the motor only cranial nerves ?
oculomotor trochlear abducens accessory hypoglossal
What are the sensory and motor neurones ?
vagus
glossopharyngeal
facial
trigeminal
Which cranial nerves contain parasympathetic preganglionic fibres ?
vagus , facial , oculomotor and glossopharyngeal
What are the general somatic motor nuclei ?
nucleus of the oculomotor
nucleus of the trochlear
nucleus of the abuducens
nucleus of the hypoglossal
Where is the nucleus of the oculomotor ?
midbrain
Where is the nucleus of the trochlear ?
midbrain
Where is the nucleus of the abducens ?
pons
Where is the nucleus of the hypoglossal ?
medulla
What is the function of the nucleus of the oculomotor ?
superior , inferior and medial rectus
inferior oblique
levator palpebrae superioris
What is the function of the nucleus of the trochlear ?
superior oblique
What is the function of the nucleus of the abducens ?
lateral rectus
What is the function of the nucleus of the hypoglossal ?
muscles of the tongue
What type of fibres emerge from general somatic motor nuclei ?
general sensory efferents
What type of fibres emerge from special visceral motor nuclei ?
special visceral efferents
What are the special visceral motor nuclei ?
motor nucleus of V
nucleus of the facial nerve
nucleus ambiguus
Where is the motor nucleus of V ?
pons
Where is the nucleus of the facial nerve ?
pons
Where is the nucleus of ambiguus ?
medulla
IX X XI
What is the function of the motor nucleus of V ?
muscles of mastication
tensor tympani / tensor veli palatini
mylohyoid
anterior belly of digastric
What is the function of the nucleus of the facial nerve ?
muscles of facial expression
posterior belly of digastric
stylohyoid
stapedius
What is the role of the nucleus ambiguus ?
skeletal muscles of the pharynx , larynx and soft palate
What fibres emerge from the general visceral motor nuclei ?
general visceral efferents - parasympathetic
What are the general visceral motor nuclei ?
edinger- westphal nucleus
superior salivatory nucleus
inferior salivatory nucleus
dorsal nucleus of X
Where can you find the edinger-westphal nucleus ?
midbrain
Where can you find the superior salivatory nucleus ?
pons
Where can you find the inferior salivatory nucleus ?
medulla
Where can you find the dorsal nucleus of X ?
medulla
What is the function of the edinger-westphal nucleus ?
sphincter pupillae
ciliary muscle
What is the function of the superior salivatory nucleus ?
submandibular , sublingual and lacrimal glands
What is the function of the inferior salivatory nucleus ?
parotid gland
What is the function of the dorsal nucleus of X ?
cervical , thoracic and abdominal viscera
What are the fibres from the visceral sensory nuclei ?
general visceral afferent
somatic visceral afferent
What are the visceral sensory nuclei ?
nucleus of the solitary tract - facial , glossopharyngeal and Vagus
Where can you find the nucleus of the solitary tract ?
medulla
What is the function of the nucleus of the solitary tract ?
taste and visceral sensation
Where does the vagus provide taste ?
from the epiglottis
What are the fibres from general somatic sensory nuclei ?
general sensory afferent
What are the general somatic sensory nuclei ?
mesencephalic nucleus of V
chief sensory nucleus of V
Spinal nucleus of V
Where can you find the mesencephalic nucleus of V ?
pons-midbrain
Where can you find the chief sensory nucleus of V ?
pons
Where can you find the spinal nucleus of V ?
pons to C3
What is the function of the mesencephalic nucleus of V ?
proprioception
What is the function of the chief sensory nucleus of V ?
fine touch on the face
What is the role of the spinal nucleus of V ?
pain and temperature from the face
Where do corticobulbar fibres run from ?
cortex to the cranial nerve nuclei
What is the innervation of lower motor neurones ?
cranial nerve nuclei
What is the innervation of V and VII ?
bilateral projections from the primary motor cortex - upper face
What is the innervation of VII - lower face ?
contralateral
What is the innervation of XI ?
ipsilateral from PMC
What is the innervation of II , IVand VI ?
contralateral innervation from frontal and parietal eye fields
What is the innervation of XII ?
bilateral from PMC except for genioglossus - contralteral
Where does the trigeminal carry pain afferent run from ?
face, nose , orbit , meninges and muscles of mastication
Where does the facial nerve carry pain afferents from ?
ear and the canal
Where does the vagus nerve carry pain afferents from ?
meninges , ear canal and the larynx
Where does the glossopharyngeal carry pain afferents from ?
posterior tongue and pharynx
Where do the cervical spinal nerves carry pain afferents from ?
neck , meninges in the psoterior cranial fossa
Where are the sensory neurone cell bodies of the trigeminal found ?
in the trigeminal ganglion
Where are the proprioception cell bodies of the trigeminal found ?
mesencephalic nucleus of V
What does the spinal nucleus of V receive information about ?
firm touch , pain and temperature from skin of the face , oral and nasal cavities and palate
What does the main nucleus of V receive information from ?
fine touch from skin of face , oral cavity and palate
What information does the mesencephalic nucleus of V receive ?
proprioception from muscles of head
Where are the sensory neurone cell bodies ?
geniculate ganglion
Where do the general somatic afferents in the facial nerve come from ?
skin of the ear , ext.auditory meatus to spinal nucleus of V in medulla
Where are the sensory neurone cell bodies of the vestibulocochlear nerve ?
vestibular and spiral ganglia
Where are the somatic sensory neurone cell bodies of the glossopharyngeal nerve ?
superior ganglion
Where are the visceral sensory neurone cell bodies ?
petrosal ganglion
Where does the glossopharyngeal bring general somatic afferents from ?
firm touch , pain and temperature from posterior third of the tongue , oropharynx , nasal cavity and paranasal sinuses to the spinal nucleus of V
Where are the somatic sensory neurone cell bodies of the vagus ?
jugualr ganglion
Where are the visceral sensory neurone cell bodies of the Vagus ?
nodose ganglion
Where does the vagus carry general somatic afferentss from ?
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
What is the plexus of Raschkow ?
a central plexus in the pulp of the tooth - pain from teeth is mediated through this
What type of pain do A-fibres transmit ?
rapid and sharp pain
belong to the myelinated group
What can A-fibres end branches to ?
odontoblastic processes located on the periphery of the pulp and dnetinal tubules
Where are A-fibres located ?
on the periphery of the pulp
What may trigger pain sensation in the teeth ?
fluid movement in the dentinal tubules
What type of pain is conducted by C-fibres ?
dull aching pain
Are C-fibres myelinated or unmyelinated ?
unmyelinated
Where do C-fibres terminate ?
in the pulp proper as free nerve endings or branches around blood vessels
What is the route of A and C fibres ?
run in the branches of V2 and V3 and then terminate in the spinal nucleus of V - passing to the thalamus and cortex
Where is pain associated with emotional distress processed ?
anterior cingulate cortex
Where is the periaqueductal grey matter located ?
around the cerebral aqueduct in the tegmentum of the midbrain
What does the periaqueductal grey matter do ?
plays a role in the descending modulation of pain
What neurones are found in the periaqueductal grey ?
enkephalin releasing neurones
What do enkephalin releasing neurones do ?
suppress pain
What is released from the raphe nuclei ?
serotonin
What does serotonin do ?
descends to the dorsal horn of the spinal chord where it forms excitatory connections with inhibitory interneurones in laminae II
When activated what do the interneurones do ?
release enkephalin
binds to opioid receptros - descending pain modualtion
What is the corneal reflex ?
touch cornea with a cotton wisp which elicits the bilateral blink reflex
What is the pathway of the corneal reflex ?
sensory input from V1 - spinal nucleus of V - facial motor nucleus - orbicualris oculi
What is the gag reflex ?
touching the back of the oropharynx elicits brief elevation of the paate and brief constriction of the pharyngeal constrictors
What is the pathway of the gag reflex ?
sensory input from the glossopharyngeal - nucleus of solitary tract - nucleus ambiguus - vagus to the pharyngeal constrictors
What is the jaw jerk reflex ?
tapping on the chin leads to contraction of masseter and jaw closing
What type of reflex is the jaw-jerk reflex ?
monosynaptic
What is the pathway of the jaw-jerk reflex ?
afferent fibres from muscle spindle - mesencephalic nucleus of V - motor nucleus of V as efferents to masseter
What is the jaw unloading reflex ?
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
Which 3 cortices can pain pathways synapse in ?
insular cortex
somatosensory cortex
anterior cingulate cortex
What is the spinal nucleus of V continuous with ?
dorsal horn of the spinal chord
Where is the primary visual cortex ?
occipital lobe - either side of the calcarine sulcus
Where does light first hit ?
retinal ganglion cells
How do impulses tavel from the retina to the bvrain ?
sensory neurones
What does the retina consist of ?
pigmented epithelium
rods and cones
Where are the cones situated ?
fovea
Where are the rods sitted ?
peripheries
How do the rods synapse ?
many rods synapse on one bipolar sensory neurone - more sensitive to lower light
How do cones synapse ?
cones synapse on one bipolar neurone providing higher resolution
What are the membraneous discs ?
thye contain proteins that respond to light - rods contain rhodopsin and cones contain photopsin
What is the disinhibition of bipolar neuroness ?
light hits photoreceptors leading to hyperpolarisation which stops the release of neurotransmitter
Where does the optic nerve travel ?
through the optic canal
What is the pathway of the optic nerve ?
passes through the optic tract and the optic chiasm to the thalamus
Where in the thalamus does the optic nerve pass to ?
lateral geniculate nucleus
Alternatively where does the optic nerve pass to ?
superior calliculus
What are the 4 cranial nerve nuclei that control the movements of the eye ?
edinger- westphal nucleus
oculomotor nucleus
abducens nucleus
trochlear nucleus
What does the edinger westphal nucleus supply ?
ciliary muscle and the iris muscle
What is the papillary light reflex ?
light shone in one eye - contraction of both pupils - direct light reflex
contraction if the pupil oppsote leads to consensual light reflex
What is the accomodation relfex ?
focus on the incoming object leads to pupillary constriction- convergence of eyes as eyes focus on the near object
What is the pathway of the pupillary light reflex ?
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
What is the pathway of the accomodation relfex ?
information travels tothe primary visual cortex
bilateral innervation of the oculomtor (eye muscles) and edinger westphal nucleus (eye focus)
Where is the primary auditory cortex located ?
in the superior tempora; gyrus
How are action potentials triggered in the ear ?
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
What does the cochlear consist of ?
semi circular canals utricle sacculae ampullae cochlea nerve
What is the organ odf corti ?
between the scala vestibuli and the scala tympani
has a tectoriul and basilar membrane
What does the sensory ganglion contain ?
sensory cell bodies of the cochlea nerve
What does the sound on the tympanic membrane cause ?
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.
What is the action of stapees ?
vibrates on the oval window
What is the helicotrema ?
a gap at the end of the unravelled cochlea allows fluid to move constantly
High frequency sounds are picked up by what ?
proximal end of the cochlea
Low frequency sounds are picked up by what ?
distal end of the cochlea
Which hair cells are sensory ?
95% of inner hair cells
What is the role of the outer hair cells ?
receive efferents from the superior olive
modulate basilar membrane motions
What are sterocilia ?
organ of corti hair cells
What are present on hair cells ?
potassium ion channels - linked mechanically
Moving hair cells side to side causes what ?
physically opens the potassium channels and triggetrs voltage sensitive calcium channels - calcium cascade - vesicle movement and fusion with the presynaptic membrane
Desribe the auditory pathway ?
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
Describe the auditory stream ?
primary auditory cortex association auditory cortex wernickes area arcuate fasciculus brocas area motor cortices
Where is brocas speech area located ?
in the frontal lobe
What are the roles of the auditory cortrex ?
processing of sound
receives information from the medial geniculate nucleus
tonotopic representation of frequencies- different parts of the cortex pick up different f requencies
What is the vestibular system concerned with ?
balance
What is the vestibular system ?
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
What are otolith organs ?
ear stones
What are the ear stones ?
utricle and the saccule
What is the sensory epithelium of the ear stones called ?
macula
What do the ear stones do ?
sense tilt and linear head motions
respond to gravity and linear acceleration
Where are the otolith organs ?
in a gelatinous mucous on top of hair cells
What are the otolith organs made of ?
CaCo3 deposits
What is the effect on the otolith organs of moving backwards ?
gravity pulls stones backwards and this pulls on the hair cells triggering a response
Describe the vestibuLar pathway ?
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
performance of voluntary movements requires ?
job/task identification
planning for the activity
execution of the task and job
What are the 3 levels of motor control ?
motor areas of thee cerebral cortex
brainsntem
spinal chord
What are the roles of the motor areas of the cerebral cortex ?
issue sequential and parallel commands
change intensities of different patterns
modify timing
What are the roles of the brainstem ?
maintain axial tone for standing
What are the roles of the spinal chord ?
programmed , local pattern of muscle movement
location of complex pattern of rhythmical and reciprocal motion
What are the cortices of the brain related to motor control ?
posterior parietal cortex
primary motor cortex
What is the role of the posterior parietal cortex /
association and representation
initiation , planning and thought of activities
What is the role of the primary motor cortex ?
corticospinal and corticobulbar fibres arise from here
What are the 2 loops from the posterior parietal cortrex ?
1 to basal ganglia
1 to pontine nuclei and the cerebellum
Describe the basal ganglia loop for planning , carrying out and modulating activities ?
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
What do the basal ganglia store ?
patterned movements are stored , responsible for initiation and planning of movement
Describe the pontine nuclei loop for planning , carrying out and modulating movement ?
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
What does the cerebellum do in modifying movements ?
it looks at intended movement and the current position of the muscles and decides which muscles to move
What does the cerebellum receive input from ?
the inferior olive- proprioception information from muscles
What arises from the primary motor cortex ?
corticospinal and corticobulbar fibres that travel in the internal capsule
What does the paramedian midbrain reticular formation do ?
regulates walking
What do the pontine reticulospinal pathways do ?
control extensor lower motoneurones
What do medullary reticulospinal pathways do ?
control flexor lower motoneurones
What does the posterior parietal cortex produce ?
produces internal models of movement prior to the involvement of the premotor and motor cortices
What do the prefrontal areas do ?
decisions here are made about what action to take
integrates info
concerned with personality , reasoning and conscience
`What does the premotor area do ?
controls axial and proximal limb muscles in the initial phases of orientating the body and arm to a target
What does the supplemnetary motro area do ?
execute stages of complex movements based on past experiences
What side of the body does the cerebellum control ?
ipsilateral side
What does the cerebellum consist of ?
vermis - central
folia - folds
flocularnodular lobe
deep cerebellar nuclie
What are the 4 deep cerebellar nuc,ei from lateral to medial ?
dentate nucleus emboliform nucleus globose nucleus fastigial nucleus interposed nucleus - some individuals have this - emboliform and globose
What are the 3 functional parts of the cerebellum ?
vestibulocerebellum
spinocerebellum
neocerebellum
What is the vestibulocerebellum ?
flocculo-nodular lobe and part of the vermis
What is the function of the vestibulocerebellum ?
posture and balance
input from the vestibular nucleus and the dorsal spinocerebellar tract
output to the vestibular nucleus
What is the spinocerebellum ?
vermis and the fastigial nucleus and the intermidiate part or cerebellar hemisphere , globose and emoboliform nuclei
What is the function of the spinocerebellum ?
updating ongoing movements
input from the primary motor cortex via pontine nuclei, DSCT, ASCT and olivary nucleus
output to red nucleus
What is the neocerebellum ?
lateral part of the hemisphere and the dnetate nucleus
What is the role of the neocerebellum ?
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
What is the route for planning and prediction in the cerebellum ?
from the cerebral cortex to the dentate nucleus via corticopontine fibres back to the thalamus to the cerebral cortex
What is the route for modification of ongoing movement ?
from the inferior olivary nucleus to the interposed nucleus to the red nucleus and the rubrospinal tract
What is the input and output of the olivary nucleus ?
output as climbing fibres to opposite cerebellum
input from cortex and spinal chord
What is the role of the olivary nucleus ?
plays a role in movement inititation and motor learning
How is a lesion in the vestibulocerebellum presented ?
staggering gat
How is a lesion in the spinocerebellum presented ?
ataxia
How is a lesion in the corticocerebellum presented ?
slow movement onset
What are the basal ganglia ?
caudate nucleus putamen globus pallidus subthalamic nucleus substantia nigra
What is the circuit of the basal ganglia ?
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)
How do the basal ganglia act ?
act ispilaterally
What do basal ganglia tend to do ?
inhibit movements therefore lesions produce unwanted movements
What are the 2 circuits through the basal ganaglia ?
putamen ciruit- putamen - globus pallidus to the thalamus and the cortex
What is the role of the putamen circuit ?
subconscious execution of learned patterns of movement
What is the caudate circuit ?
cognitive planning of movement - feedback to cortex
What does the substamtia nigra do ?
releases dopamine into the putamen circuit which acts on D1 and D2 receptors
Describe the direct pathway ?
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
Which pathway is normally inhibited ?
indirect pathway
Describe the indirect pathway ?
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
What are hypokinetic disorders ?
insufficient direct pathway output
excess indirect pathway output
What are hyperkinetic disorders ?
excess directy pathway ouput
insuufficient indirect pathway output
How is chewing iniitated ?
by voluntary movement
followed by a period of reflex activity
What do CPGS do in mastication ?
generate masticatory rhythms - alternative action of jaw openers and closers
Where are the CPGs for mastication ?
in the pontine reticular nucleus
How is chewing modulated ?
feedback from peripheral receptors
Describe the process of mastication ?
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
Describe the control of mastication ?
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
Which receptors control masticatory force ?
periodontal ligament receptors
What do periodontal ligament receptors do ?
inhibit neurones in the trigmeinal motro nucleus via inihbitory interneurones
What is the limbic system ?
neuronal cicitry that controls emotional behabviour and motivational drivees
What does the anteiror conguakte gyrus do ?
emotional aspect of pain
Where is the hippocampus and what does it do ?
medial aspect of the temporal lobe and is involved in memory formation
What is the hypothalamus and what does it do ?
major part of the limbic system and controls internal body conditions - vegetative behavior and endocrine fucntions
What are the outputs of the thalamus ?
to the braisntem RF
anterior thalamus and the limbic portion of teh cerebral cortex
hypothalamic infindibulum - pituitary glands
What are the functions of the thalamus ?
sexual behaviour
endocrine function
homeostasis
What does the hypothalamus do in terms of endocrine function ?
neuroendocrine cells reelase hormones that act in the pituitary gland and this releases more hormones
Which part of teh hypothalamus is to do with sexdual behaviour in fmelaes ?
ventromedial hypothalamus
Which part of the hypothalamus is to do with sexual behaviour in males ?
preoptic region
How does the hypothtlmaus carry out temperature reguaktion ?
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
Which area of the hypothalmaus creates a thirst sensation ?
laterla hypothalamic area
Which nucleus of the hypothalamus controsl the excretion fo water into urine ?
supraoptic nucleus
Which ara regualtes hunger in the hypothalamus ?
lateral hypothalamic area
Which area of the hypothalamus creates a desire for food ?
satiety centre in the ventromedial nucleus
What area of the hypothalamus carries out GI activity ?
mammillary bodies
What is the orexigenic response ?
response to low glucose and the need to eat more food
What is the anorexigenic response ?
high nutrients - stop eating food like GI stretch , circadian rhythms
What does GI stretch do ?
inihibits te orexigenic response and excites the anorexigenic response
What are circadain rhythms ?
endodogenous entrainsble 24 hour rhythmicity
What nucleus are circadian rhythms controlled by ?
suprachiasmatic nuclei
Where is the amygdala located ?
below the hypothakmaus and i the inferior portion of the laterla ventricvle
What ae the fucntions of teh amygdala ?
emotional letrning and memeorty
fear and fear cinditioning
reward
What does activation of the amygdala lead to ?
indices fea anxiety and violence
What does deactivation of the amygdala lead to ?
incapable pof fear
How is the amygdala involved in emotional learning and memory ?
amygdala assesses the emotional significance of inputs
much more likely to remember something with emotional significance
How is thye amygdala involved in fear and fear conditioning ?
amygdala and the medial temporal lobe are invollved in the mediating , acquisition and storage of fear and memory
What is the reward system for ?
liking and positive reinforcement
What are the important structures in the reward system ?
ventral tegmental area - origin amygdala nucleus accumbens hippocampus prefrontal cortex
What is the reticular formation ?
a complex group of neurones and nuclei in the brainstem
What are the afferent inouts to the RF ?
spinal chord
cranial nerves
cerebellum
forebrain
What are the efferent ouputs of the RF ?
spinal chord and cortex
What are the fucntiomns of the RF ?
sleep and consciousness somatic motor cintrol - CPGs cardiovascular control pain modulation habituation
What are the 4 nuclei of the reticualr acting syste, ?
locus coereleus
raphe nucleus
ventral tegmental area
basal forebrain - nucleus of meynert
Where are the dopaminergic pathways of the RF ?
VTA - mesocorticolimbic pathway
and substantia nigra - dopamine to basal ganglia
Where are the serotonergic pathways ?
raphe nuclei and the nucleus raphe magnus
ascending pathways to the cortex
descending pathways to the spinal chiord - pain modulation
Where are the noradrenergic pathways ?
locus coereleus
Where are the cholinergic pathways ?
basal forebrain and nucleus of meynert
to the hippocampus
When does rapid eye movement sleep occur ?
JUST BEFORE WE WAKE UP
Wehre is rapid eye movement sleep regulated ?
pontine RF
What is needed to prevent the acting out of ndreams ?
connections between the pontine RF and the spinal chord
What nuclei are involved in sleep ?
Arpahe nuclei
dorsolaterla pontine RF
What are the motor effects if the reticular formation ?
meduallry reticulospinal tract - laterla
pontine reticulospinal tract- medial
What is the function of the pontine RT ?
enhances antigravity muscles and reflexes of the soinal chord
helps maintain a standing posture by resisting the effects of gravity
What is the function of the medullary RT ?
liberates the antigravity muscles from reflex control
What is the collective fucntion of the reticulospinal fibres ?
modualte muscle tone
regualte psoture
participate in automatic reflexes involving extensor musculature
What are CPG s?
trigger the correct enets at the right time
2 processes occur and they interact sequentially
What are the repsiratory CPGs ?.
pontine respiratory group
medullary respiratory group - DRG and VRG and the pre botzinger complex
What is the paccemaker theory of CPGs ?
self activating fibres that trigger events
What is the network theory of CPGs ?
VRG made of inspiratory and expiratory neurones
reciprocal imnhibition
What is the embonuic serivation of the CNS ?
ectoderm
What is the name of the process which i the formation of the central nervous system ?
neuralation
What happens to the ectoderm ?
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
What ar ethe neural crest deruvatives ?
odontoblasts adrenal medulla aprafollicular cells of the thmus gland autonomic ganglia melanoytes
What is spina bifida ?
failure of fusion of caudal neurpores
What in anencephaly ?
failure of fusion of cephalic neuropores
What is teh development of CNS cells ?
embryonic CNS stem cell
neural progenitor
glial progenitor
glial progemitor ito astrocyte and oligodendrocyte progenitor
Where is teh pre motor cortex ?
anteiror to the primary motor cortex in the postewrior parts of the frontal gytur
Where is the prefrontal cortex ?
most extensive regions of the frontal lobe
Where is the somatosensory association cortex ?
superiuor and inferior parital lobules
Where is the primary visual cortex ?
medial aspects of the occipital lobes
Where is brocass area ?
inferior frontal gyrus
motor speech area
Whrer is wernickes ares ?
Superior temporal gyrus
speech comprehension area
Where do the vertebral arteires fuse to fomr the basillar arteyr ?
ponto medullary junction
What are the branches of the veretbelra arteires ?
anterior and posterior spina arteries
posterior inferior cerebellar artery
Where does the basillar artery run from ?
from the ponto-medulalry junction to the ponto-midbrain junction
What are the branche sof the basillar arteyr ?
superior cerebellar
anterior inferior cerebellatr
posteriuor cerebral
What are the branches of the interbal carotid arteyr >/
opthalmic artery posterior communicating artery anterior choridal arery anterior and middle crebral arteires anterior commumicati g rteyr
What are the 3 primary brain vesicles that from after 5 weeks ?
prosencephalon
mesencephalon
rhomoencephalon
What does the prosencephalon divide into ?
telencephalon
diencephalon
What does the mesencephalon divide into ?
no dividsion - jut the midbrain
What does the rhomencephalon ddivide into ?
metencephalon
myelencephaoon
What does the telencephalon form ?
cerebral hemipsheres
What does the diecneohalon form ?
thalamus
What does the metencephalon form
pons and the cerebellum
What does the myelencephalon fomr ?
meduall oblangata
Where doe sthe CSF gfo from the 4th ventricle ?
to the subarachnoid apce via the median and laterla apertures
How is CSF absorbed into the blood stream ?
by the superior agittal swinus through th eubarachnoid villi
Which artery supplies blood to the retina and the cranial dura ?
opthalmic arteyr
How does a bipolar sensory neurone work ?
one axon attaches to the sensory organ the opther to the CNS
What are the examp[les of the rapidly adpting receptros ?
meissners corpuscles
pacinian corpsusles
hair follice recptors
What are examples of the slow adapting receptors ?
merkel cells
ruffini corpuscles
some hair follice receptors
Are reticulospinal tracts bilateral or unilateral ?
bilaterla
What is the nucleus of the thalamus in the DCML ?
ventral posterior lateral nucleus
Main output from the basal ganglia is from where ?
globus pallidus
What are the nuclei of the thalamus related to motor relay and basal ganglia ?
Ventral anterior
Ventral lateral
What are the receptor organs responsdibl;e for detecting vibrations in the basialr membrane ?
organ of corti and the ampullae
What are sensory projections on the hair cells known as ?
sterocilia
What are the receptor organs responsible ofr snesing baalnnce ?
ampullae
Where are the ampullae located ?
in the semi circular canals of the cochlea
Which nuclei in the brainstem does the ouput from the vestibular nucleus go to ?
nucleus of oculomotr , trochlear and abducens
What are the outputs of the supplementary motor cortex ?
primary motor cortex
reticular formation
cortocspinal and corticobulbar
Which area of the brain is responsible for making an internal model of move,ent when assessing movements ?
posterior parietal cortex
Which nuclei are responsible for adaptation of movement in response to external stimuli ?
red nucleus
olivary nucleus
In huntingtons disease which of the basal ganglia are effected /
globus pallidus
Which of the hypothalamic nuclei are responsible for thirst ?
laterla hypothalamic nucleus
Which of the nuceli are responsible for conbtrol of water excretion ?
supra optic nuclei
Where is the satiety centre which controls hunger ?
ventromedial nuclei
What are the 5 structures responsible for the reward system ?
ventral tegmental area nucleus accumbens hippocampus amygdala pre frontal cortex
What are thee nuclei of the reticular formation and what do thy release ?
nucleus of meynert- acetylcholine
nucleus raphe magnus/raphe nuckeus- serotonin
ventral tegmental area- dopmaine
locus coerleus- noradrenaline
What are the fucntion sof teh reticular formation ?
CVS control pain modulation habituation cpg- skeletal muscle control Sleep
What happens during rapid eye movement sleep ?
paralysis of voluntary mucle and active brain
What happens during non rapid eye movemnt sleppe ?
lowering of body temeratir
movement of muscles
lowering of heartr rate
How can you identify a ruffini corpuscle ?
highly branched
How can you identify a pacinian corpuscle ?
round
How can you identify merkel cells ?
individual cells
How can you identify a meissner corpuscle ?
bunch of cells
How can you identify hair follicle receptors ?
around the hair
What are the structural components of the cerebellum ?
vermis
intermdiate zone
cerebellar hemispheres
floculonodular lobe
What are the functional components of cerebellum ?
spinocerebellum
vestibulocerebellum
neocerebellum
What is the vestibulocerebellum ?
floculonodular lobe
posture and balance
What is the neocerebellum ?
posterior lobe
planning of movement
What is the spinocerebellum ?
anterior lobe
monitoring of ongoing movements
