Neurobiology - part 1

Question 1

grey matter

Answer 1

neuronal cell bodies, dendrites, glial cells, synapses

Question 2

white matter

Answer 2

axons and oligodendrocytes

Question 3

types of glial cells

Answer 3

atrocytes - homeostatic regulators of neurons
oligodendrocyte - make myelin
microglia - macrophages of brain

Question 4

peripheral sensitisation

Answer 4

nociceptors are sensitised A-delta and C fibres

Question 5

central sensitisation

Answer 5

sensitisation within spinal cord/ brain (thalamus, amygdala)

Question 6

allodynia

Answer 6

threshold of non-noxious stimuli is lowered

Question 7

hyperalgesia

Answer 7

responsiveness to noxious stimuli increases

primary hyperalgesia - hyperalgesia at site of injury (C fibre sensitisation - peripheral mechanism implicated)
secondary hyperalgesia - hyperalgesia at uninjured areas (central mechanism implicated)

Question 8

neuralgia

Answer 8

pain from nerves themselves

Question 9

palsy

Answer 9

facial weakness due to tumours, stroke, trauma

Question 10

brain is folded

Answer 10

gyrus - top of fold

sulcus - bottom of fold

Question 11

two causes of stroke

Answer 11

ischaemia (blockage)

haemorrhage (bleed)

Question 12

axon transport

Answer 12

using cytoskeleton filaments
fast anterograde - kinesin transports neurotransmitters and vesicles from cell body to axon terminal
slow anterograde - actin, myosin, microtubules carry soluble substances
fast retrograde - dynein transports lysosomes (containing surplus membrane, metabolites) from axon terminal to cell body

Question 13

nernst potential

Answer 13

calculate voltage generated by specific ion at known concentration gradient across a membrane

Question 14

types of Na+ channels

Answer 14

h gate - internal, inactivation (open in resting potential)

m gate - external, activation (open for depolarisation)

Question 15

types of K+ channels

Answer 15

n gate - activation (open for repolarisation)

Question 16

types of neurotransmitter receptors

Answer 16

ionotropic (ligand-gated ion channels) - directly linked to ion channel
metabotropic (G-protein coupled receptors) - uses secondary messenger

Question 17

autonomic nervous system parasympathetic
fibres
neurotransmitters

Answer 17

preganglionic B fibres acetylcholine

postganglionic C fibres acetylcholine

Question 18

autonomic nervous system sympathetic fibres
fibres
neurotransmitters

Answer 18

preganglionic B fibres acetylcholine

postganglionic C fibres noradrenaline

Question 19

somatic nervous system

fibres to where

Answer 19

A-α fibres/ motoneuron to skeletal muscle

A-γ fibres/ motoneuron to muscle spindle

Question 20

nociceptors fibres

Answer 20

A-δ fibres sharp pain, faster, myelinated

C fibres dull pain, slower, unmyelinated

Question 21

dorsal column-medial lemniscus pathway

Answer 21

fine touch (discriminative)
1st neuron
- ipsilateral
- synapses at medulla at cuneate fasciculus nuclei (upper body), gracile fasciculus nuclei (lower body)
2nd neuron
- contralateral at medulla
- synpase at ventral posteriolateral nucleus at thalamus
3rd neuron
- to primary somatosensory cortex at post central gyrus

Question 22

anterolateral system/ spinothalamic tract

Answer 22

crude touch (non-discriminative), pain
1st neuron
- ipsilateral
- synapse at dorsal column in spinal cord
2nd neuron
- contralateral at spinal cord
- synapse at ventral posteriolateral nucleus at thalamus
3rd neuron
- to primary somatosensory cortex at post central gyrus

Question 23

trigeminothalamic system

Answer 23

fine touch (discriminative)
1st neuron
- ipsilateral enter pons via trigeminal ganglion
- synapse at chief/ principal sensory nucleus of TNC at medulla
2nd neuron
- contralateral at pons
- synapse at ventral posteriomedial nucleus at thalamus
3rd neuron
- sensory cortex at the post central gyrus

Question 24

pain and temperature system/ spinotrigeminal tract

Answer 24

crude touch (non-discriminative)
1st neuron
- ipsilateral enter pons via trigeminal ganglion
- synpase caudalis nuclei of spinal trigeminal nuclei of TNC at medulla
2nd neuron
- contralateral at medulla
- synapse at ventral posteriomedial nucleus at thalamus
3rd neuron
- sensory cortex at the post central gyrus

Question 25

somatogenic pain

Answer 25

with known cause localised in body tissue e. g. nociceptive pain - activation of nociceptors e. g. neuropatic pain - injury to nervous system

Question 26

psychogenic pain

Answer 26

no known physical cause but processing of sensitive information in CNS is disturbed

Question 27

nuclei for fine touch of the face

Answer 27

2nd and 3rd neuron synapse at chief/ principal sensory nucleus of TNC (CN V) at medulla

Question 28

nuclei for nociception of the face

Answer 28

2nd and 3rd neuron synpase caudalis nuclei of spinal trigeminal nuclei of TNC (CN V) at medulla

Question 29

plexus of Raschkow

Answer 29

A-δ and C fibres in core of pulp and cell rich zone of tooth for pulpal innervation and nociception

Question 30

sensory receptors of skin which are A-β fibres

Answer 30

``` hair follicle (touch) Meissner corpuscle (light touch) Merkel cell (light touch) Pacinian corpuscle (vibration, pressure) Ruffini endings (stretch, temperature) ```

Question 31

sensory receptors of skin which are A-δ and C fibres

Answer 31

free nerve ending (pain, heat, cold)

Question 32

tonic activity

Answer 32

sensory receptors continuously fire action potential

Question 33

rapid adapting mechanoreceptors (RA)

Answer 33

respond to application/ removal of stimulus (not maintained stimulus to prevent overstimulation) e.g. hair follicle, Meissner corpuscle and Pacinian corpuscle

Question 34

slow adapting mechanoreceptors (SA)

Answer 34

slow increase and decrease in response to application and removal of stimulus and maintain firing e.g. hair follicle, Merkel cell, Ruffini ending

Question 35

high discriminatory

Answer 35

small, numerous receptive field

Question 36

low discriminatory

Answer 36

large, sparse receptive field

Question 37

lateral inhibition

Answer 37

ability of activated neurons to inhibit activity of neighbouring neurons

Question 38

convergence

Answer 38

many bipolar neurons converge into one neuron to synapse with second order neuron increases efficiency of response (spatial summation?? many EPSPs from multiple neuron -> neuron)

Question 39

divergence

Answer 39

one neuron diverges into many neurons increase response of brain to stimulation (temporal summation?? many EPSPs from one neuron -> neuron)