Neuro Anatomy and Physiology Flashcards
1
Q
What is the basal ganglia?
A
Collection of neuronal cell bodies buried in white matter.
2
Q
What is the function of the limbic system?
A
Stores and retrieves processed information.
3
Q
Which Brodmann’s area is the Primary motor cortex?
A
Area 4 frontal lobe.
4
Q
What is area 44/45?
A
Broca’s area of motor speech. It is the inferior frontal gyrus.
5
Q
What function occurs within the prefrontal cortex?
A
Cognitive functions of higher-order intellect, judgement, prediction and planning.
6
Q
Which Brodmann’s areas make up the Primary Sensory Area?
A
Areas 3,1,2.
Post central gyrus.
7
Q
What is the function of the Primary sensory area?
A
Receives general sensations from contralateral half of body.
8
Q
What is the function of the superior parietal lobule?
A
Association area.
Interprets general sensory information and conscious awareness of contralateral half of body.
9
Q
What is the function of the inferior parietal lobule?
A
Interface between somatosensory cortex and visual and auditory association areas.
In dominant hemisphere it also contributes to language functions.
10
Q
What does a parietal lobe lesion result in?
A
Hemisensory neglect - defect in attention and awareness of one side of field of vision due to damage to 1 hemisphere.
Acalculia - acquired impairment where individual struggles to perform simple mathematical tasks.
Agraphia - acquired impairment where individual loses ability to communicate via writing.
Right-left agnosia - inability to process sensory information.
11
Q
Which Brodmann’s areas make up the Primary auditory cortex?
A
Areas 41 & 42.
Superior temporal gyrus.
12
Q
What is the function of the auditory association areas?
A
Crucial for understanding spoken word and has connections with other language areas.
Wernicke’s area in dominant hemisphere.
13
Q
What is the function of the inferior surface of the temporal lobe?
A
Receives fibres from olfactory tract to provide the conscious appreciation of smell.
14
Q
Which Brodmann’s area is the Primary Visual Cortex?
A
Area 17
Either side of calcarine sulcus on medial surface.
15
Q
Which Brodmann’s areas make up the visual association cortex?
A
Areas 18 & 19
Rest of occipital lobe.
16
Q
What is the function of the visual association cortex?
A
Interpretation of visual images.
17
Q
What is the limbic lobe?
A
Functional area of the medial surface of cerebral hemispheres.
Involved in memory and emotional aspects of behaviour.
Includes the cingulate gyrus, hippocampus, parahippocampal gyrus and the amygdala.
18
Q
What is Aphasia?
A
Problem with speech due to damage to one or more speech areas within the brain.
19
Q
What are the characteristics of Broca’s aphasia?
A
Understands speech Misses out small words Aware of their difficulty to speak Damage to frontal lobe Weakness/ paralysis on 1 side of body.
20
Q
What are the characteristics of Wernicke’s aphasia?
A
Can't understand speech. Fluent speech with new made up words. Doesn't make sense. Unaware of mistakes in speech. Damage to temporal lobe No paralysis.
21
Q
What are commisural fibres?
A
Myelinated axon fibres that connect corresponding areas of the 2 hemispheres. = Corpus Callosum.
22
Q
What are association fibres?
A
Myelinated axon fibres that connect one area of cortex to the next. Can be short or long fibres.
23
Q
What are projection fibres?
A
Myelinated axon fibres that run between cerebral cortex and various subcortical centres. Pass through corona radiata and the internal capsule.
24
Q
What is the internal capsule?
A
White matter collection of projection fibres that pass to and from the cerebral cortex. Fibres form the corona radiata.
Lies between the thalamus and caudate nucleus medially and the lentiform nucleus laterally.
Supplied by the middle cerebral artery.
25
What is the basal ganglia?
Subcortical nuclei deep within each cerebral hemisphere.
26
What structures make up the Basal ganglia?
Caudate nucleus
Putamen
Globus Pallidus
27
What is the function of the basal ganglia?
Helps regulate initiation and termination of movements. Plays a role in controlling the motor system.
28
How is the substantia nigra related to the basal ganglia?
Both the substantia nigra and the basal ganglia have the same function, they are just anatomically separate as the substantia nigra is found in the midbrain.
29
What is a tract?
Fibre pathway passing through the CNS carrying a specific modality e.g pain sensation, motor fibres, touch sensation.
30
What are ventricles?
Spaces within the brain that contain cerebrospinal-spinal fluid.
31
What are the 2 major arteries that supply the brain?
Internal carotid arteries
| Vertebral arteries
32
What is the function of the circle of willis?
Protective mechanism against vaso-occlusion of large arteries.
33
What area of the brain does the Anterior cerebral artery supply?
Medial aspect of cerebral hemispheres, excluding the occipital lobe.
34
What area of the brain does the Middle cerebral artery supply?
Lateral aspect of cerebral hemispheres?
35
What area of the brain does the Posterior cerebral artery supply?
Inferior aspect of cerebral hemispheres and the occipital lobe.
36
What is the venous drainage of the brain?
Superficial and deep veins drain into venous sinuses located in between 2 layers of dura mater. These then drain into the internal jugular vein.
37
What are the 3 primary vesicles?
Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)
38
What are the 5 secondary vesicles?
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Telencephalon
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon
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39
Which structures make up the brainstem?
Midbrain
Pons
Medulla
40
Which cranial nerves arise from the brainstem?
Cranial nerves III - XII.
41
What other structures are present with the brainstem?
Spinal cord tracts and Vital centres e.g cardiorespiratory centres.
42
What is the function of brainstem centres?
Produce the rigidly programmed automatic behaviours essential for survival.
43
What are the surface features of the medulla?
Pyramids and their decussation (crossing over)
Olives that sit laterally.
Inferior cerebellar peduncle connects it to cerebellum.
Cranial nerves IX, X, XI and XII arise from its surface.
44
What are the surface features of the Pons?
Anterior to IV ventricle.
Middle cerebellar peduncle attaches it to cerebellum.
Cranial nerves V, VI, VII and VIII arise from its surface.
45
What are the surface markings of the Midbrain?
Cerebral peduncle.
Superior cerebellar peduncle connects it to cerebellum.
Corpora quadrigemina (Superior and inferior colliculus).
Cranial nerves III and IV arise from its surface.
46
What separates the right and left hemispheres of the cerebellum?
Vermis
47
How many lobes does each cerebellar hemisphere have?
3 - anterior, posterior and flocculonodular lobes.
48
What is the function of the cerebellum?
Posture maintenance
| Fine tuning motor activity.
49
Where is the diencephalon located?
Deep within the cerebral hemispheres, around the III ventricle.
50
What is the Thalamus?
Egg shaped body on either side of the III ventricle that makes up 80% of the diencephalon. Mainly contains groups of nuclei.
51
What is the function of the thalamus?
Sensory relay station.
52
Where is the hypothalamus located?
Inferior the thalamus, separated by the hypothalamic sulcus.
53
What is the function of the hypothalamus?
Main visceral control centre and is essential for maintaining overall homeostasis.
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Autonomic control centre
Body temp. regulation
Regulates food intake
Regulates water/thirst
Regulation of sleep/wake cycle.
Control of endocrine system functioning.
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54
What do somatic motor fibres supply?
Striated muscle (skeletal and cardiac)
55
What do visceral motor fibres supply?
Division of parasympathetic that supplies smooth muscle and glands.
56
What information do visceral sensory fibres carry?
Inputs from pharynx, larynx, heart, lung, gut etc. Not normally conscious.
57
What information do general sensory fibres carry?
Inputs from skin and mucous membranes e.g touch, temp and pain.
58
What information do special sensory fibres carry?
Taste, smell, vision, hearing and balance.
59
What is the pathway of the olfactory nerve (CNI)?
Receptors in olfactory epithelium of nasal cavity - pass through foraminifera in cribriform plate - olfactory bulb in anterior cranial fossa.
60
What fibres does CNI possess?
Special sensory (smell)
61
What is the pathway of the Optic nerve (CNII)?
Enters via optic canal and joins to form optic chiasm. Fibres from nasal half of each retina cross to from the optic tract.
62
What fibres does the CNII possess?
Special sensory (vision)
63
What is the pathway of the Oculomotor nerve (CNIII)?
Emerges from midbrain and exits via superior orbital fissure.
64
What fibres are present within CNIII?
Somatic motor - extra ocular muscles and eyelid.
| Visceral motor - parasympathetic to pupil causing constriction and to ciliary muscle causing accommodation of the lens.
65
What is the pathway of the Trochlear nerve (CNIV)?
Emerges from dorsal surface of midbrain and exits via the superior orbital fissure.
66
What fibres are present within CNIV?
Somatic motor - extra ocular muscle (superior oblique).
67
What is the pathway of then Abducent nerve (CNVI)?
Emerges between the pons and medulla and exits via the superior orbital fissure.
68
What fibres are present within CNVI?
Somatic motor - extra ocular muscle (lateral rectus that abducts the eye).
69
What is the pathway of the Ophthalmic division of the trigeminal nerve (CNV1)?
Emerges from the Pons, Travis through the trigeminal ganglion and exits via the superior orbital fissure.
70
What fibres are present within CNV1?
General sensory - from cornea, forehead, scalp, eyelids, nose and mucosa of nasal cavity and sinuses.
71
What is the pathway of the Maxillary division of the trigeminal nerve (CNV2)?
Emerges from the Pons, travels through the trigeminal ganglion and exits via the foramen rotundum.
72
What fibres are present within CNV2?
General sensory - from face over maxilla, maxillary tenth, temperomandibular joint, mucosa of nose, maxillary sinuses and palate.
73
What is the pathway of the Mandibular division of the trigeminal nerve (CNV3)?
Emerges from pons, travels through the trigeminal ganglion and exits via the foramen ovale.
74
What fibres are present within CNV3?
General sensory - from face over mandible, mandibular teeth, temperomandibular joint, mucosa of mouth and anterior 2/3rds of tongue.
Somatic motor - muscles of mastication, part of digastric , tensor veli palatine and tensor tympani.
75
What is the pathway of the facial nerve (CNVII)?
Emerges between pons and medulla and exits via internal acoustic meatus, facial canal and stylomastoid foramen.
76
What fibres are present within CNVII?
Somatic motor- muscles of facial expression and scalp. stapedius of middle ear, part of digastric muscle.
Visceral motor - parasympathetic innervation of submandibular and sublingual salivary glands, lacrimal glands, glands of nose and palate.
Special sensory - taste from anterior 2/3rds of tongue and soft palate.
General sensory - from external acoustic meatus.
77
What is the pathway of the Vestibulocochlear nerve (CNVIII)?
Emerges from between the Pons and medulla and exits via internal acoustic meatus, dividing into vestibular and cochlear nerves.
78
What fibres are present within CNVIII?
Special sensory - Vestibular sensation from semicircular ducts, utricle, saccule gives sense of position and movement.
Hearing from spiral origin.
79
What is the pathway of the Glossopharyngeal nerve (CNIX)?
Emerges from medulla and exits via jugular foramen.
80
What fibres are present within CNIX?
Special sensory - Taste from posterior 1/3rd of tongue.
General sensory - Cutaneous sensations from middle ear and posterior oral cavity.
Visceral sensory - sensation from carotid body and carotid sinus.
Visceral motor - parasympathetic innervation of parotid gland.
Somatic motor - To stylopharyngeus,, helps with swallowing.
81
What is the pathway of the Vagus nerve CNX?
Emerges from the medulla and exits via jugular foramen - then everywhere!
82
What fibres are present within CNX?
Special sensory - taste from epiglottis and palate.
General sensory - sensation from auricle, external acoustic meatus.
Visceral sensory - from pharynx, larynx, trachea, bronchi, heart, oesophagus, stomach and intestine.
Visceral motor - parasympathetic innervation of muscle in bronchi, gut, heart.
Somatic motor - to pharynx, larynx, palate and oesophagus.
83
What is the pathway of the Accessory nerve (CNXI)?
Small cranial roots from medulla and large spinal roots exit via jugular foramen.
84
What fibres are present within CNXI?
Somatic motor - striated muscle of soft palate, pharynx, larynx and sternocleidomastoid and trapezius.
85
What is the pathway of the Hypoglossal nerve (CNXII)?
Emerges from the medulla and exits through the hypoglossal canal.
86
What fibres are present within CNXII?
Somatic motor - muscles of the tongue.
87
What information do Ascending pathways carry?
Sensory
88
What information do Descending pathways carry?
Motor
89
What are some characteristics of the Corticospinal tract?
Carries motor impulses from motor cortex to skeletal muscles.
Control of voluntary skilled movements.
Starts in area 4, motor cortex of brain.
Blood supply by middle cerebral artery.
Fibres go to contralateral limb.
Decussation at pyramids within medulla.
Involves 2 neurons (Motor) - ventral horn is site of lower motor neurone.
Begin in anterior column but after decussation go into lateral column.
90
What are some characteristics of the Posterior (dorsal) column?
Carries sensation of fine touch, tactile localisation, vibration sense and proprioception.
Involves 3 neurons = Sensory.
1st order ends by synapsing with cell body of 2nd neurone in medulla.
2nd order decussates in medulla and travels up to thalamus.
3rd order passes through internal capsule and radiates to post-central gyrus (areas 3,1,2).
91
What are some characteristics of the Lateral Spinothalamic tract?
Carries sensation of pain and temperature.
Involves 3 neurons = Sensory.
1st order enters grey matter and ends at same level.
2nd order decussates at that same level and ascends to thalamus.
3rd order passes through internal capsule and radiates to post-central gyrus (areas 3,1,2).
92
What is the function of the stretch reflex?
Control of muscle tone and posture.
93
What is the function of the flexor reflex?
Protection from painful stimuli.
| Withdrawal from stimulus with extensor response in contralateral limb.
94
What happens to reflexes and muscle tone in an upper motor lesion?
Reflexes become exaggerated (hyper-reflexia)
| Tone is increased (spasticity).
95
What pathologies occur with an upper motor lesion at level of internal capsule in the corticospinal tract?
Contralateral paralysis
Hyper-reflexia
Spasticity
96
What pathologies occur with an upper motor lesion at level of upper cervical spinal cord in the corticospinal tract?
Ipsilateral paralysis
Hyper-reflexia
Spasticity
97
What pathologies occur with a lower motor lesion of the corticospinal tract?
Ipsilateral paralysis
Absent reflexes
Flaccidity
98
What pathologies occur in a lesion above the decussation of the posterior column?
Contralateral sensory loss
99
What pathologies occur in a lesion below the decussation of the posterior column?
Ipsilateral sensory loss
100
What pathologies occur in lesions of the lateral spinothalamic tract?
Contralateral loss of pain and temperature.
| Always contralateral because lesion is always above level of decussation.
101
What are the four systems that control voluntary movement/
Descending control pathways.
Basal ganglia.
Cerebellum.
Local spinal cord/brainstem circuits.
102
What is the spatial map of the body's musculature in the spinal cord?
Medio-laterally.
e.g More proximal muscles are mapped to more medial motoneurons.
103
What is the stretch reflex?
Monosynaptic reflex that provides automatic regulation of skeletal muscle length.
Sensory afferents divide and make 3 connections:
1 - activate alpha motoneurons in stretched muscle causing rapid contraction of agonist muscle.
2- activates inhibitory interneurons which cause antagonist muscle to relax.
3- ascends in dorsal columns and makes connections in somatosensory cortex to tell brain about length of muscles.
104
What is the Golgi tendon organ reflex?
Protective reflex that causes muscle relaxation when muscle tension is monitored to be very high. Polysynaptic.
Increase in GTO AP firing causes:
1- activation of inhibitory interneurons to the agonist muscle (decrease in contraction strength).
2- Activation of excitatory interneurons to antagonist muscles.
3- Afferents ascend in dorsal column to somatosensory cortex.
105
What is the withdrawal reflex
Polysynaptic and protective reflex that withdraws part of the body away from a painful stimulus. Flex the affected part drawing it towards body. Slowest reflex.
Increased sensory APs from pain receptors cause:
1- increase in activity of flexor muscles of affected part via excitatory neurons.
2- Antagonistic extensor muscles are inhibited.
3- excitatory interneurones cross spinal cord and excite the contralateral extensors.
4- Several interneurons also inhibit the contralateral flexors to maintain an upright posture.
5- sensory info ascends to brain in the contralateral spinothalamic tract.
106
How can reflexes be overridden?
Descending signals from higher centres can override certain reflexes. E.g holding a baby.
107
What is nociception?
Detection of tissue damage by specialised transducers connected to A-delta and C fibres. Responds to thermal, chemical, mechanical noxious stimuli.
108
What are the characteristics of A-delta fibres?
Carry fast/sharp pain
Lightly myelinated
Medium fibres
109
What are the characteristics of C fibres?
Unmyelinated
Slow conductors
Carry dull pain.
110
Where does pain perception occur?
Somatosensory cortex
111
What is Substance P?
Acts as a neurotransmitter and neuromodulator.
Transmits pain signals from sensory nerves to the CNS.
Also helps regulate stress and anxiety.
Binds to neurokinin 1 receptors.
112
What is nociceptive pain?
Sensory experience that occurs when specific peripheral sensory neurones (nociceptors) respond to noxious stimuli.
Localised at site of injury.
Usually resolves when damaged tissue heals.
Tends to respond to conventional analgesics.
113
What is neuropathic pain?
Pain initiated or caused by a primary lesion or dysfunction in the somatosensory nervous system.
Painful region may not be same as site of injury.
Almost always chronic.
Responds poorly to conventional analgesics.
114
What is the treatment for transduction pain?
Rest, ICE, NSAIDs, LA blocks.
115
What is the treatment for transmission pain?
Nerve blocks, opioids, anti-convulsants, surgery, DREZ, cordotomy.
116
What is the treatment for perception of pain?
Education, mirror box therapy, cognitive behavioural therapy, distractions, relaxation.
117
What is the treatment for descending modulation?
Placebos, opioids, anti-depressants, spinal cord stimulation.
