physiology

Question 1

what is the role of oligodendrocytes

Answer 1

produce myelin to insulate axons in the CNS

Question 2

what is the consequence of demyelination

Answer 2

slower conduction and reduced consistency of neuronal conduction

Question 3

name an autoimmune cause of demyelination

Answer 3

MS

Question 4

name a virus that causes demyelination and the disease it can cause

Answer 4

JC virus - progressive multifocal leukoencephalopathy

Question 5

who usually presents with progressive multifocal leukoencephalopathy

Answer 5

immunocompromised patients

Question 6

what causes central pontine myelinosis and what is the clinical consequence

Answer 6

rapid correction of hyponatraemia
SEVERE neurological deficit

Question 7

where in the circle of willis is the most common area for a stroke to occur and why

Answer 7

middle cerebral artery
has direct pathway from the heart via the internal carotid artery

Question 8

what lobe does the middle cerebral artery supply

Answer 8

temporal

Question 9

what lobe does the posterior cerebral artery supply

Answer 9

occipital lobe

Question 10

what is common presentation of carotid artery disease

Answer 10

contralateral weakness or sensory loss

Question 11

in which vascular lesion would you expect weakness predominantly in the contralateral face and arm

Answer 11

middle cerebral artery stroke

Question 12

What symptoms are characteristic of an anterior cerebral artery (ACA) stroke

Answer 12

Contralateral leg weakness and sensory loss

Question 13

Which artery disease is associated with vertigo, ataxia, dysarthria, and dysphagia

Answer 13

vertibro-basilar artery disease

Question 14

Why does an MCA stroke often cause more pronounced weakness in the face and arm than in the leg

Answer 14

MCA supplies the lateral aspect of the cerebral cortex, including the primary motor and sensory cortices responsible for the face and upper limbs

Question 15

How can vertebro-basilar artery disease lead to visual disturbances?

Answer 15

supplies the occipital lobes, where the visual cortex is located

Question 16

what do glial cells arise from

Answer 16

neuroectoderm

Question 17

whar do microglia arise from

Answer 17

mesoderm

Question 18

role of M1 microglia and M2

Answer 18

1 are proinflammatory
2 phagocytose

Question 19

what does dysfunction of astrocytes cause

Answer 19

leaky blood brain barrier

Question 20

what type of cells produce CSF

Answer 20

ependymal cells

Question 21

what does the presence of red neurons on histology indicate

Answer 21

irreversible neuronal injury within the last 12-24 hours

Question 22

what does neuronal atrophy on histology suggest

Answer 22

chronic injury e.g. neurodegenerative disease

Question 23

name 3 conditions which cause reactive gliosis

Answer 23

alzheimers, MS, stroke

Question 24

what is cytotoxic oedema and how does it occur

Answer 24

oedema due to cell death
dying cells take up water as ions move into cells

Question 25

what causes ionic oedema

Answer 25

changes in blood e.g. excess water

Question 26

what causes vasogenic oedema

Answer 26

partial breakdown in the blood brain barrier

Question 27

what causes haemorrhagic conversion oedema

Answer 27

complete breakdown of the blood brain barrier

Question 28

name some features of non-REM sleep

Answer 28

synchronised, rhythmic EEG partial relaxation of muscles and reduced cerebral blood flow reduced HR, blood pressure and tidal volumes

Question 29

name some features of REM sleep

Answer 29

fast activity on EEG - similar to wakefulness atonic muscles increased cerebral blood flow, impaired thermal regulation

Question 30

what are the 3 main types of pain

Answer 30

nociceptive, inflammatory and pathological

Question 31

what causes nociceptive pain

Answer 31

immediate protective response to intense stimuli

Question 32

what causes inflammatory pain

Answer 32

activation of the immune system in injury or infection

Question 33

what are the 2 main types of pathological pain

Answer 33

neuropathic and dysfunctional

Question 34

what 2 types of fibres are nociceptors made of

Answer 34

Aδ-fibres and C-fibres

Question 35

what receptors mediate fast pain and how is this described

Answer 35

Aδ-fibres - stabbing, pricking sensation

Question 36

what receptors mediate slow (secondary pain) and how is this described

Answer 36

C-fibres - burning, throbbing, cramping, aching

Question 37

where do nociceptors synapse with the CNS

Answer 37

dorsal horn of the spinal cord

Question 38

what kind of pain fibres are transmitted by the spinoreticular tract

Answer 38

C-fibre pain

Question 38

what is the role of dendrites

Answer 38

receive inputs from other neurones and convey electrical signals to the soma

Question 39

what is the role of axons

Answer 39

conducts output signals as action potentials to the presynaptic terminal

Question 40

what causes depolarisation

Answer 40

increase in sodium into the cell causes a reduction in negative charge (increase in charge)

Question 41

what causes repolarisation

Answer 41

increase in potassium out of the cells reduces the membrane potential

Question 42

what are the 3 main types of neurotransmitters based on their function

Answer 42

excitatory, inhibitory, neuromodulators

Question 43

what is the most abundant neurotransmitter in the brain

Answer 43

glutamate

Question 44

what are the 2 main types of ACh receptors

Answer 44

nicotinic and muscarinic

Question 45

what is transduction

Answer 45

conversion of a physical stimulus into a change in membrane potential

Question 46

what is the role of first order neurones

Answer 46

transduction of a stimulus into electrical activity

Question 47

name 2 factors that affect the speed of axon conduction

Answer 47

diameter of the axon and myelination

Question 48

what causes shingles

Answer 48

infection of the dorsal root ganglion neurones by varicella zoster

Question 49

where is the somatosensory cortex found

Answer 49

post central gyrus of the parietal cortex immediately posterior to the central sulcus

Question 50

what innervates skeletal muscles

Answer 50

alpha motor neurons

Question 51

what is a motor unit

Answer 51

a motor neuron and all the fibres it innervates

Question 52

what spinal level is being assessed with supinator (wrist) reflex

Answer 52

C5-6

Question 53

what spinal level is being assessed with biceps reflex

Answer 53

C5-6

Question 54

what spinal level is being assessed with triceps reflex

Answer 54

C7

Question 55

what spinal level is being assessed with quadriceps reflex

Answer 55

L3-4

Question 56

what spinal level is being assessed with the gastrocnemius (ankle) reflex

Answer 56

S1

Question 57

what reflex protects a muscle from excessive contraction

Answer 57

the golgi tendon reflex

Question 58

where does the rubrospinal tract originate

Answer 58

red nucleus of the midbrain

Question 59

where does the vestibulospinal tract originate

Answer 59

vestibular nuclei

Question 60

what is the role of the vestibulospinal tract

Answer 60

posture and supporting against the force of gravity

Question 61

where do the tectospinal tracts originate

Answer 61

superior colliculi

Question 62

what is the role of the tectospinal tracts

Answer 62

mediate orienting towards visual targets

Question 63

where does the reticulospinal tract originate

Answer 63

reticular formation - collection of neurons in the pons and medulla

Question 64

what is the role of the reticulospinal tract

Answer 64

involved in balance

Question 65

what is the direct pathway for visual signal transmission

Answer 65

photoreceptors - bipolar cells - ganglion cells - merge to form the optic nerve

Question 66

what are the 2 types of photoreceptors

Answer 66

rods and cones

Question 67

what is the visual pigment molecule called

Answer 67

rhodopsin

Question 68

what is visual aciuty

Answer 68

the ability to distinguish between 2 nearby points

Question 69

where does transduction occur in the auditory pathway

Answer 69

organ of corti hair cells

Question 70

what are the 2 main components of the vestibular system

Answer 70

semicircular canals saccule and utricle

Question 71

what is the role of the semicircular canals

Answer 71

sense head angular acceleration (head rotation)

Question 72

what is the role of the saccule and utricle

Answer 72

sense linear head acceleration

Question 73

what are the semicircular canals filled with

Answer 73

endolymph

Question 74

what is the role of the vestibulo-ocular reflex and what does it cause

Answer 74

allows objects to remain in focus during head movements causes eyes to move in the opposite direction to head movement

Question 75

what is the role of the vestibulo-colic reflex

Answer 75

keeps the head still in space, or on a level plane when walking

Question 76

what is the role of the vestibulo-spinal reflex

Answer 76

adjusts posture for rapid changes in position

Question 77

how do the cerebellum and basal ganglia work in association with the motor cortex

Answer 77

cerebellum sends excitatory output basal ganglia sends inhibitory output

Question 78

what is the role of the cerebellum

Answer 78

important in coordination, precision and timing of movements as well as in motor learning

Question 79

what are the 3 functional areas of the cerebellum

Answer 79

cerebrocerebellum spinocerebellum vestibulocerebellum

Question 80

what is the role of the cerebrocerebellum

Answer 80

planning movements and motor learning regulates the coordination of muscle activation

Question 81

what is the role of the spinocerebellum

Answer 81

regulates body movements by allowing for error correction

Question 82

what is the role of the vestibulocerebellum

Answer 82

involved in controlling balance and ocular reflexes - mainly fixation on a target

Question 83

what is dysdiadochokinesia

Answer 83

difficulty in carrying out rapid, alternating movement

Question 84

what is ataxia

Answer 84

impaired coordination, balance and speech

Question 85

what is an intention tremor

Answer 85

involuntary tremor that increases as they approach the target, often resulting in past pointing