NEURO WK 2

Question 1

structures of the neurone (5)

Answer 1

axon
dendrite
soma (cell body)
axon hillock and initial segment
synapse

Question 2

4 functional regions of neurones

Answer 2

input
integrative
conductile
output

Question 3

What does a ‘leaky’ nerve cell membrane mean? What law can represent this?

Answer 3

not a perfect insulator
ohm’s law V = IR
smaller diameter, greater resistance, narrower axon

Question 4

methods of increasing passive currents spread ?? and therefore increase action potential velocity

Answer 4

increase axon diameter
more myelin

Question 5

demyelinating disorders - what are they and give examples (2)

Answer 5

MS
GBS

damage to the myelin sheath -> nerve conduction impaired -> neurological symptoms

Question 6

chemical neurotransmission - overview and its 9 steps

Answer 6

uptake of precursor

synthesis and storage of transmitter

calcium is needed for fusion

neurotransmitter will bind to a specific receptor and cause receptor to activate

Question 7

3 types of synapse - what is the most common one?

Answer 7

axodendrite - very common
axosomatic
axoaxonic

Question 8

2 types of neurotransmitters

Answer 8

inotropic - direct effect, nicotinic ACh receptor channel activation, usually excitatory

metabotropic - indirect effect through g-protein complex, muscarinic ACh receptor activation, inhibitory

Question 9

Fast vs. slow EPSP

Answer 9

Excitatory postsynaptic potential

FAST = ligand gated, activation of nicotinic or ionotropic receptors. conduct sodium and potassium. eg ACh acting on inotropic receptor = fast EPSP

SLOW = muscarinic or G protein-coupled ACh receptors. closes potassium channel

Question 10

main excitatory / inhibitory neurotransmitter of the brain ??

Answer 10

glutamate
GABA

Question 11

2 TYPES OF GABA receptors

Answer 11

GABA A - ligand gated channels,
allows chloride ions to flow into the neuron
eg. benzodiazepines (e.g., diazepam), barbiturates, and alcohol.

GABA B - G coupled protein receptors
allows opening of potassium channels
eg. baclofen for muscle spasticity

Question 12

different types of sensory modalities (5)

Answer 12

vision
auditory
gustatory
olfactory
touch - somatosensory

Question 13

3 types of adaption. Adaptation determines the firing rate of sensory neurones in response to changing stimuli.

Answer 13

phasic or transient - rapid decrease, CNS

tonic or sustained - gradual decrease, CNS

peripheral or short term, sensory receptor level

Question 14

low threshold unit / mechanoreceptors * - what fibre class and where does it terminate??

Answer 14

mechanoreceptors - light touch and pressure

alpha beta - large and fast

Meissner’s corpuscles - light touch, superifical

Pacinian corpuscles - pressure and vibration, deep

Merkel cells - sustained pressure and detecting objects
ruffini endings - sustained pressure and skin stretch

Question 15

conduction velocity types (4), what is fastest conduction v / thickest myelination?? what type of sensory receptor do they conduct??

Answer 15

type A - FASTEST, big, myelinated, has motor and sensory functions

B - medium sized and time, lightly myelinated, motor fibers responsible for involuntary functions such as digestion, sweating, and cardiovascular regulation.

Adelta - small, myelinated, sharp pain

C - SLOWEST and small, unmyelinated, primarily sensory fibers responsible for transmitting sensations of pain, temperature

Question 16

Brodmann areas (4)

Answer 16

Primary Motor cortex
Primary visual cortex
Primary somatosensory cortex
Broca/Wernicke’s area

Question 17

Cutaneous receptors (5)

Answer 17

mechanoreceptors
thermoregulators
free nerve endings
nociceptors
hair follicle receptors/specialised

Question 18

stretch reflex

Answer 18

aka myotatic or deep tendon reflex

Question 19

extrapyramidal pathways - 4 tracts

Question 20

neuronal coding in the primary motor cortex (4). What does the primary motor cortex control??

Answer 20

Brodmann area 4, pre-central gyrus
contralateral control

Question 21

what are the 3 FORMS OF PAIN

Answer 21

nociceptive
neuropathic
mixed

Question 22

What type of fibres mediate pain??

Answer 22

a delta and c fibres

Question 23

allodynia

Answer 23

heightened sensitivity to touch, so that sensations that are typically not painful become painful

Question 24

brown sequard syndrome

Answer 24

pain and temp on opposite side
ipsilateral

Question 25

THE WHO ANALGESIC LADDER, what are the 3 steps ??

Answer 25

analgesics weak opiods strong opioids

Question 26

NSAIDs mechanism

Answer 26

reversibly inhibit the COX1/2

Question 27

What mediates opioid action?? what do opioid receptors produce??

Answer 27

opiod receptors, binding

Question 28

what are the 3 classes of opioids receptors

Answer 28

GPCRs Mu delta kappa

Question 29

rods see in _____ light. rod system has more __________ than cones. Differences between rods and cones

Answer 29

rods - dim, low light cones - day light more rods than cones

Question 30

what is the function of the dark current??

Answer 30

steady influx of sodium ions (Na⁺) into photoreceptor cells (rods and cones) in the absence of light. this is essential for maintaining photoreceptor cells in a state of partial depolarization, and maintaining resting potential.

Question 31

centre surround organisation / lateral inhibition

Question 32

the OFF / ON pathway

Question 33

6 LAYERS OF LATERAL GENICULATE NUCLEUS *

Question 34

structures of the labyrinth

Answer 34

within the inner ear that consists of the bony labyrinth and membranous labyrinth. It houses the sensory organs responsible for hearing (cochlea) and balance (semicircular canals and otolithic organs),

Question 35

High vs. low frequency - Which end of the basilar membrane is wider and how does this relate to pitch?

Answer 35

basilar membrane is narrower and stiffer at the base (near the oval window) and wider and more flexible at the apex (farther along the cochlear spiral). base = high frequency

Question 36

inner vs outer hair cells - the 2 types of hair cells

Answer 36

within the organ of Corti

Question 37

function of otolith organs

Answer 37

utricle and saccule responsible for detecting linear acceleration, changes in head position relative to gravity, and contributing to balance and postural control

Question 38

INPUT AND OUTPUT TO / OF THE BASAL GANGLIA

Question 39

What releases dopamine?? - What are the 2 methods??

Answer 39

substantia nigra and the ventral tegmental area (VTA) phasic (burst) release in response to rewarding stimuli and tonic (steady-state) release to maintain baseline dopamine levels.

Question 40

disorders of the Basal Ganglia - Parkinson’s, Huntington's. What happens to the pathway?

Answer 40

PD - substantia nigra is affected striatum (specifically the caudate nucleus and putamen