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Physiology > Nervous System > Flashcards

Nervous System Flashcards

1
Q

two components of peripheral nervous system

A
  • autonomic nervous system
  • somatic nervous system
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2
Q

two comonents of central nervous system

A
  • spinal cord
  • brain
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3
Q

three divisions of the brain

A
  • forebrain
  • midbrain
  • hindbrain
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4
Q

two subdivisions of hindbrain

A

myelencephalon and metencephalon

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5
Q

what does mylencephalon contain

A

medulla oblongata

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6
Q

where is medulla oblongata found

A

most posterior part of brain, bordering spinal cord

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7
Q

medulla oblongata purpose

A

contains nuclei that control vital functions such as breathing and skeleton muscle tone

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8
Q

two brain parts contained in metencephalon

A

cerebellum and pons

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9
Q

cerebellum purpose

A
  • recieves information from sensory systems, muscles and vestibular system
  • co-ordinates this information to produce smooth movements
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10
Q

example of damage to cerebellum

A

cerebral palsy

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11
Q

what does damage to cerebellum do

A

impairs walking, balance, posture and skilled-motor activity

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12
Q

where is pons found

A

bulge on brainstem

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13
Q

pons function

A

involved in sleep and arousal

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14
Q

main subdivision of midbrain

A

mesencephalon

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15
Q

mesencephalon purpose

A
  • Controls basic physiological functions (breathing, swallowing, heartbeat)
  • Gates sensory and motor information
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16
Q

red nucleus function

midbrain

A

co-ordinates sensorimotor information

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17
Q

substantia nigra function

midbrain

A

cells make dopamine and project to basal ganglia

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18
Q

Periaqueductal Grey Matter function

midbrain

A

involved in pain supression due to high concentration of endorphins

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19
Q

two subdivisions of forebrain

A

diencephalon and telencephalon

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20
Q

two main components of diencephalon

A

thalamus and hypothalamus

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21
Q

how does thalamus work

A
  • Separate but interconnected nuclei recieve information from sensory systems and relay it to sensory processing areas in the cortex
  • Relay system and can thus influence almost all of brain
  • May also play role in learning and memory
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22
Q

what is hypothalamus made up of

A

22 nuclei and pituitary gland

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23
Q

hypothalamus function

A
  • controls autonomic and endocrine systems
  • controls key aspects of behaviour including feeding, sex, sleep, temperature regulation and emotional behaviour
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24
Q

what are the hemispheres of the telencephalon separated by

A

longitudinal fissure

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25
Q

what are the hemispheres of the telencephalon connected by

A

corpus collosum

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26
Q

what is the corpus collosum

A

a bundle of nerve fibres

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27
Q

what is a fissure

A

deep cleft in surface of brain

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28
Q

what is a sulcus

A

shallow cleft in surface of brain

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29
Q

what is a gyrus

A

ridge in surface of brain

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30
Q

why is cortex referred to as grey matter

A

because there is predominately cells and they give it a grey appearance

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31
Q

where is white matter in the telencephalon

A

runs beneath cortex

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32
Q

what is white matter

A

axons covered by the myelin sheath

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33
Q

two functions of spinal cord

A
  • neuronal link between brain and PNS
  • integrating centre for spinal reflexes
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34
Q

how many spinal nerves are there

A

31 pairs emerging from spinal cord through spaces formed between vertebrae

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35
Q

dorsal root of spinal cord

A

afferent sensory

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36
Q

ventral root of spinal cord

A

efferent motor

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37
Q

what is spinal cord made up of

A

internal grey matter (neurons) surrounded by white matter (fibres) in periphery

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38
Q

what is phrenology

A

the idea that each part of the brain is specialized in a certain faculty, and the greater in size these areas are, the greater the tendencies towards those faculties are

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39
Q

is phrenology a valid scientific theory

A

nope

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40
Q

value of phrenology

A
  • first time a specific function was associated with a specific brain region
  • hints to the idea of brain plasticity
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41
Q

brocca’s aphasia

A

problems producing language

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42
Q

receptive aphasia (wernicke)

A

problems comprehending language

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43
Q

how else can aphasia occur

A

damage to the bundle of axons connecting Brocca’s and Wernicke’s areas

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44
Q

what is a neuron

A

most basic unit of nervous system
generates electrical signals and communicates them to other neurons

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45
Q

cell body

A
  • contains nucleus and organelles
  • sends projections
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46
Q

dendrite

A
  • receives signals from environment or other neurons
  • some contain spines where synapses occur
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47
Q

axons

A
  • begin at axon hillock (axonal cone)
  • can travel up to 1 meter
  • relays information in the form of chemicals
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48
Q

presynaptic neuron

A

neuron which sends information

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49
Q

postsynaptic neuron

A

neuron which recieves information

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50
Q

what are action potentials

A

a nerve impulse (electrical signal) which is generated and acted upon

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51
Q

what is a plasma membrane

A

lipid bilayer used as a barrier

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52
Q

what are plasma membranes made up of

A
  • phospholipids
  • glycolipids
  • cholesterol
  • membrane proteins
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53
Q

phospholipids

membrane composition

A
  • hydrophilic phosphate head
  • hydrophobic fatty acid tail
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54
Q

glycolipids

plasma membrane composition

A

lipids modified by sugars in the extracellular side

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55
Q

cholesterol purpose

membrane composition

A

essential for maintenance of membrane fluidity

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56
Q

simple diffusion

A
  • does not apply to ions: only small, uncharged molecules such as gases
  • passive transport
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57
Q

electrochemical gradient

A
  • determining force for ion transport
  • neural membrane is negatively charged in the cytoplasmic side and positively charged on the extracellular side
  • the electrochemical gradient is the combination of concentration and charge differences across the membrane
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58
Q

facilitated diffusion

A
  • moves down a gradient
  • main driving force for ions
  • passive transport
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59
Q

carrier proteins

A

bind solutes tightly and undergo conformational changes

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60
Q

ion channels

A

selective pores which let specific ions in

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61
Q

active transport

A

energy is required to move a substance across a membrane against its concentration gradient

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62
Q

why must the electrochemical gradient be restored

A

because the neuron will lost its ability to get electrically excited

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63
Q

how is the electrochemical gradient restored

A
  • exchangers: transport two different ions, one with the concentration gradient, one against. the energy generated by the first is used to carry the second
  • ATPase pumps: break down ATP to obtain necessary energy to transport ion against gradient
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64
Q

charge (Q)

A

arises from a net imbalance in the number of positively and negatively charged particles in a given place

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65
Q

Current (I)

A

a flow of electrically charged particles, in the fluids of the body these charged particles include Na+, K+ and Cl-

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66
Q

Voltage (V)

A

a measure of the potential difference between two points, one of which is at a positive potential relative to the other. An electrical voltage represents an electrical potential energy gradient, down which charged particles would like to move, if permitted.

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67
Q

what happens when a cell is not stimulated

A

its under resting conditions and the net charge of its interior is maintained

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68
Q

electrical gradient

A
  • influenced by overall electrical charge
  • positive ions would flow towards areas of negative charge
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69
Q

chemical gradient

A
  • influenced by individual concentration of a particular ion
  • all ions move from areas of high to low concentrations
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70
Q

what does the direction an ion moves in depend on?

A
  • overall net effect of electrical and chemical gradients
  • permeability of membrane to ion
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71
Q

what maintains the electrochemical gradient and why

A
  • Na+K+ pump
  • because there is more sodium inside cell and potassium outside cell, meaning when channels are open sodium leaves and potassium comes in
  • they must make it back to original side at some point
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72
Q

why is ionic imbalance important

A
  • intracellular pH control
  • osmotic control
  • transport
  • excitability
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73
Q

steps of Na+K+ pump

A
  1. binding cytoplamsic Na+ stimulates autophosphorylation (ATP)
  2. phosphorlyation causes conformational changes
  3. Na+ is liberated outside and K+ binding sites are exposed inside
  4. Binding K+ triggers release of phosphate
  5. Release of phosphate restores original conformation
  6. K+ is released and Na+ binding sites are exposed again in the cytoplasm
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74
Q

equilibrium potential

A

the electrical potential difference that exatly counterbalances diffusion due to concentration difference

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75
Q

equilibrium potential for K+

A

-90mV

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76
Q

equilibrium potential for Na+

A

+60mV

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77
Q

equlibrium potential for Cl-

A

-70mV

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78
Q

what are ion channels

A
  • involve integral proteins that span membrane repetitively
  • central pore so ions can diffuse with polar amino acids forming a selective filter
  • composition of the pore differs in each channel
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79
Q

three types of ion channels

A
  • voltage-gated
  • ligand-gated
  • mechanically-gated
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80
Q

what are ligand gated ion channels

A

opening relies on binding of a ligand which is normally extracellular fluid

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81
Q

voltage-gated Na+ channel steps

A
  1. Voltage-gated Na+ and K+ channels are closed in resting state
  2. A stimulus opens the activation gate of some Na+ channels depolarizing membrane potential. If threshold is reached, more Na+ channels open, triggering an action potential.
  3. Above this threshold, potential activation gates of all Na+ channels are open. K+ channels are mostly closed but slowly begin to open.
  4. The Na+ channel inactivation gates close and K+ channels are fully open. Efflux of K+ from the cell drops membrane potential back to and below resting potential.
  5. Both gates of Na+ channel are closed but K+ channels are still open. Continued efflux of K+ keeps potential below resting level.
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82
Q

absolute refractory period

A
  • a period of complete resistance to stimulation
  • inactivation of Na+ channels means that after an action potential there is a brief period where no other action potential can be generated
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83
Q

relative refractory period

A
  • a period of partial resistance to stimulation
  • lasts as long as K+ channels are open
  • strong stimulus can trigger a new action potential
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84
Q

contiguous conduction

A

conduction of action potentials in unmyelinated fibres

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85
Q

conduction speed of contiguous conduction

A

rate of 10m/s so relatively slow

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86
Q

c-fibres

A
  • afferent fibres that carry sensory information from skin and muscles to brain
  • unmyelinated
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87
Q

what does damage to c-fibres cause

A

neuropathic pain

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88
Q

what does axon potential speed depend on

A
  • internal resistance of axon
  • resistance of axonal membrane
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89
Q

ow to have fast axon potential propagation

A
  • wide axon
  • insulated axon (increases membrane resistance)
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90
Q

salatory conduction

A

when myelin surrounds and insulates consecutive segments of axons in the PNS (schwann cells) and CNS (oligodendrocytes)

91
Q

myelin

A

membrane component of glial cells

92
Q

what is multiple sclerosis

A
  • autoimmune disease
  • myelin sheathe degenerates and forms hardened scars (sclerosis)
  • affected axons also slowly degenerate
  • results in slowing and eventual block of AP conduction
93
Q

perception

A

conscious interpretation of the external world derived from sensory input

94
Q

stimulus

A

a change detectable by the body

95
Q

stimulus to action potential pathway

A

Stimulus → Receptor → Receptor potential → Action potential (in afferent fibre)

96
Q

sensory transduction

A

srimulus to receptor potential - changing the energy of the stimulus to electrical energy which takes place at the cellular receptor

97
Q

sensory system composition

A

sensory receptors, their axonal pathways and targer areas in the brain involved in perception

98
Q

extroceptors

A

receptors outside of the body

99
Q

introceptors

A

receptors inside the body

100
Q

name five sensory receptors

A
  • photoreceptors
  • mechanoreceptors
  • thermoreceptors
  • chemoreceptors
  • nociceptors
101
Q

sense associated with photoreceptors

A

vision

102
Q

example of a stimulus that triggers photoreceptors

A

light

103
Q

senses associated with mechanoreceptors

A
  • touch
  • balance
  • hearing
  • proprioceptors
104
Q

example of a stimulus that triggers mechanoreceptors

A

mechanical energy (stretching muscle, hair cell movement)

105
Q

sense associated with thermoreceptors

A

temperature

106
Q

examples of aa stimulus that triggers thermoreceptors

A

heat and cold

107
Q

senses associated with chemoreceptors

A
  • taste
  • smell
108
Q

stimulus that triggers chemoreceptors

A

specific chemicals

109
Q

sense associated with nociceptors

A

pain

110
Q

examples of a stimulus that triggers nociceptors

A
  • excessive pressure
  • excessive temperature
  • certain chemicals
111
Q

two factors that impact nerve fibre velocity

A
  • axon diameter
  • myelin sheath
112
Q

how does axon diameter impact nerve fibre velocity

A

larger diameter has lower resistance for the current to flow down the length of the axon

113
Q

graded potential

A

what a stimulus induces in a receptor cell or a free nerve ending

114
Q

how are graded potentials different to action potentials

A

GP: proportional to stimulus strength
AP: all or nothing

115
Q

what shows stimulus intensity

A
  • the action potential frequency
  • the number of receptors activated
116
Q

where do receptor potentials occur

A

in seperate receptor cells

117
Q

how do receptor potentials work

A
  • stimulus opens ion channels in receptor causing graded membrane potential
  • receptor cell releases chemical messenger
  • chemical messenger opens ion channels in afferent neuron action potential generating region
  • if the threshold is reached, an action potential is generated
118
Q

where do generated potentials occur

A

in specialised nerve endings

119
Q

how do generated potentials work

A
  • stimulus opens ion channel in receptor causing local current flow
  • local current flow opne ion channels in afferent neuron action potential generating region
  • if the threshold is reached, an action potential is generated
120
Q

receptive field

A

Somewhere in the body where the presence of a stimulus will alter the firing of a sensory neuron

121
Q

examples of receptive fields

A
  • cochlea hair
  • a piece of skin
  • retina
122
Q

four things necessary for receptors to work

A
  • receptor must have specificity for the stimulus energy
  • the receptors receptive field must be stimulated
  • stimulated energy mist be converted into a graded potential
  • a generated potenial in the associated sensory neuron must reach the threshold
123
Q

transducation

A

the process of converting energy forms into electrical signals via a receptor/generator potential which triggers an action potential if it i s large enough to reach the threshold

124
Q

adaptation

A

When a long-lasting stimulus changes the receptors sensitivity to it

125
Q

how does adaptation mostly occur

A

by rapidly-adapting receptors

126
Q

how do rapidly adapting receptors work

A
  • pressure, touch, hearing smell
  • adapt very quickyl - repsond less if stimulus remains constant (frequently exhibits an off response when stimulus is removed)
  • allows us to shut out background noise
127
Q

how does adaptation occasionally occur

A

by slowly adapting receptors

128
Q

how do slowly-adapting receptors work

A
  • pain, proprioception, chemicals in blood or CSF
  • adapt slowly, continue to respond even when stimulus remains constant
  • continuous input is useful for some modalities because the body needs to make continuous responses to that kind of information, or because the stimulus needs to be constantly evaluated
129
Q

proportional receptors

A

provide continous information about the stimulus

130
Q

differential receptors

A

signals change in stimulus insensity

131
Q

two types of adaption mechanisms

A

mechancal and chemical

132
Q

how does mechanical adaption work

A
  • physical mechanical mechanism that induces the decrease in the response of a receptor neuron
  • specialised receptor endings in Pacinian cells of skin
133
Q

how does mechanical adaption work

A
  • physical mechanical mechanism that induces the decrease in the response of a receptor neuron
  • specialised receptor endings in Pacinian cells of skin
134
Q

how does chemical adapation work

A
  • membrane enzymes or intracellular signaling mechanisms induce response termination
  • common in olfactory responses
135
Q

three divisions of somatosensory system

A
  • cutaneous sensations (skin)
  • visceeral (internal organs and deep tissues)
  • proprioception (awareness of position of limbs and body in space
136
Q

name five sensory receptors present in skin

A
  • meissner’s corpuscle
  • merkel receptors
  • ruffini ending
  • pacianian corpuscle
  • bare/free nerve endings
137
Q

what does meissner’s corpuscle respond to

A

flutter and stroking movements

138
Q

what do merkel receptors sense

A

steady pressure and texture

139
Q

what does ruffini ending respond to

A

responds to skin stretch

140
Q

what does pacinian corpuscle sense

A

vibration

141
Q

what do free nerve endings respond to

A

pain and heat

142
Q

receptive field

A

region of space in which the presence of a stimulus will alter the firing of a neuron

143
Q

what haopens when many primary sensory neurons converge on a single secondary neuron

A
  • poor touch discrimination
  • creates a large receptive field
  • two stimuli are perceived as a single point because both fall within the same receptive field
144
Q

what happens when few primary sensory neurons converge on a single secondary neuron

A
  • good touch discrimination
  • receptive fields are much smaller
  • two stimuli activate seperate pathways and are thus perceived as distinct
145
Q

why do fingers have a better sense of touch

A
  • higher density of mechnoreceptors
  • enriched in receptors with snall receptive fields
  • more brain tissue dedicated to integrate info coming from fingertips
146
Q

where are 3rd order afferent neurons present

A

thalamus

147
Q

where do 3rd order afferent neurons project to

A

somatosensory cortex

148
Q

where are 2nd order afferent neurons

A

spinal cord

149
Q

what do 2nd order afferent neurons synapse with

A

3rd order afferents in the thalamus

150
Q

what are 1st order neurons also known as

A

primary sensory neurons

151
Q

where are 1st order afferent neuron cell bodies

A

peripheral sensory ganglion

152
Q

what do 1st order afferent neuron peripheral axons do

A

form or innervates receptors

153
Q

1st order afferent neuron central axon purpose

A

they synapse with 2nd order afferent neurons

154
Q

what do lesions in the somatosensory cortex cause

A

impairment of somatic sensations

155
Q

somototopic representation

A

representation of the body mapped on cortical surface

156
Q

how does phantom limb syndrome work

A

ascending pathways stimulate the somatosensory cortex from adjacent representations but descendent pathways interpret this incorrectly

157
Q

agnosia

A

inability to recognise an object even though simple sensory skills are normal

158
Q

what does posterior parietal lesions cause

A

spatial neglect

159
Q

spatial neglect symptoms

A
  • ignore contralateral extrapersonal space
  • deny body parts
  • incompete copy of drawing
160
Q

how do nociceptors work

A
  • free nerve endings found in every tissue execpt the brain
  • activated by intesne thermal, mechanical or chemical stimuli
  • tissue irritation or injury releases chemicals suach as prostaglandins, bradykinin, H+, K+ etc. that stimulate nociceptors
  • connected to C fibres
161
Q

Wavelength (λ)

A

distance between two peaks of an electromagnetic wave

162
Q

reflection

A

bouncing of light off a surface

163
Q

refraction

A

bending of light rays when they from one media to the other

164
Q

aborption

A

transfer of light energy to a particle

165
Q

pathway from retina to brain

A

Photoreceptors → horizontal cells → bipolar cells → amacrine cells → ganglion cells

166
Q

what are horizontal and amacrine cells

A

local interneurons which modulate transmission onto bipolar and ganglion cells

167
Q

name the seven layers of the retina

A
  • pigmented epithelium
  • photoreceptor outer segment
  • outer nuclear layer
  • outer plexiform
  • inner nuclear layer
  • inner plexiform
  • ganglion cell layer
168
Q

what are photoreceptors

A

receptors (rods and cones) tha transform electromagnetic radiation into electrical signals

169
Q

how many photopigments do rods have

A

one

170
Q

do rods see in black & white or colour

A

black and white

171
Q

what is the photopigment contained by rods called

A

rhodopsin

172
Q

what is rhodopsin composed of

A

retinal and opsin

173
Q

rod sensitivity to light

A

highly sensitive

174
Q

what kind of vision do rods provide

A

night vision

175
Q

where are rods located

A

all over retina except for fovea

176
Q

how mny rods in total

A

100 million

177
Q

do cones pick up on black & white or colour

A

colour

178
Q

how do cones see colour

A
  • each cone is sensitive to one type of light
  • brain assigns colours based on readout of 3 cone types
  • if all types of cones are equally active, they see white light
179
Q

how many photopigments do cones contain

A

3 different opsins (diff. absorption for green, red, or blue light)

180
Q

cone sensitivity to light

A

low sensitivity

181
Q

type of vision provided by cones

A

daylight sight

182
Q

where are cones located

A

mainly in macula (especially the centre which is called the fovea)

183
Q

how many cones are there

A

6 million

184
Q

phototransduction

A

conversion of light energy into membrane potentials

185
Q

what happens to photoreceptors in the dark

A

theyare depolarised

186
Q

how are photoreceptors depolarised

A
  • guanylyl cyclase produces cGMP in the dark
  • cGMP binds and activates Na+ channels
  • Na+ influx depolarises the membrane
  • membrane depolarisation induces liberation of glutamate
187
Q

what happens to photoreceptors in the light

A

they are hyperpolarised

188
Q

how are photoreceptors hyperpolarised

A
  • light activates rhodopsin and a G protein called transducin
  • transducin binding GTP activates PDE (phosphodiesterase)
  • active PDE breaks down cGMP
  • low levels of cGMP promote channel closing
  • Na+ influx decreases and the membrane hyperpolarises
  • membrane hyperpolarization reduces glutamate release
189
Q

what does glutamate do to bipolar cells

A

either depolarises or hyperpolarises them

190
Q

what is the bipolar cell receptive field

A

area of retina where a stimulus will evoke a response in that bipolar cell

191
Q

receptive field centre

A

direct connection from photoreceptors

192
Q

receotive field surround

A

connection from photoreceptors through horizontal cells

193
Q

receptive field centre and surround relationship

A

whatever response is triggered in the centre, the opposite will be triggered in the surround

194
Q

ganglion cells receptive field

A

area of the retina where a stimulus will evoke a response in that ganglion cell

195
Q

what do ganglion cells do

A

generate action potentials and are the only output of information to the rest of the brain

196
Q

what happens when light is shone on centre of the receptive field of a ganglion cell

A

ganglion produces action potentials

197
Q

what happens when light is shone on the surround of a ganglion cell receptive field

A

ganglion decreases action potential

198
Q

how is action potential firing rate affected in a ganglion cell

A
  • no change if centre and surround are in same level of illumination
  • greatest difference when there is large contrast between centre and surround
199
Q

two systems contained within the ear

A
  • vestibular
  • auditory
200
Q

vestibular system

A
  • inform brain of the position of the head and body and how they are moving
  • balance
201
Q

auditory system

A
  • detect sounds
  • locate them in space
  • identify sound nuances
  • hearing
202
Q

pitch

A

depends on frequency

203
Q

intensity

A

depends on amplitude

204
Q

timbre (quality)

A

depends on overtones

205
Q

auditory system steps

A
  1. sound waves move tympanic membrane
  2. tympanic membrane moves ossicles
  3. ossicles move oval window membrane
  4. movement in oval window moves fluid in cochlea
  5. fluid in cochlea induces response in sensory neurons
206
Q

how do sound waves reach the brain

A

Auditory receptors (cochlea) → brainstem → thalamus (medial geniculate nucleus) → primary auditory cortex

207
Q

explan attenuation reflex

A
  • malleus and stapes linked to skull by muscles
  • after a loud sound the brain will diminish hearing sensitivity by tensing the muscles
  • this leads to impairment of the amplification sysetem
208
Q

attenuation reflex functions

A
  • delayed protection
  • adatation to loud sounds
  • not hearing our own speech
209
Q

what happens at the apex of the cochlea

A

scala vestibuli and scala tympani communicate

210
Q

where does perilymph flow

A

from vestibuli to tympani when the stapes taps the oval window

211
Q

where does endolymph flow

A

inside the scala media

212
Q

concentration of endolymph inside the scala media

A

high in K+ and low in Na+

213
Q

how are waves generated in the basilar membrane

A

perilymph is displaced, which then displaces endolymph which in turn generates the waves

214
Q

where are high frequencies detected by the cochlea

A

near the narrow and stiff oval window

215
Q

where are low frequencies detected in the cochlea

A

near the wide and flexible apex

216
Q

what happens when the sterocilia are bent in direction A

A
  • ion channel opens
  • K+ influx occurs
  • cell is depolarised
217
Q

what happens when the steriocilia are straight

A
  • ion channel is semiclosed
  • K+ influx is at resting potential
218
Q

what happens when cilia are bent in direction B (opposite to A)

A
  • ion channel is closed
  • cell is hyperpolarised
219
Q

what does sound do outer hair cell

A

depolarises them

220
Q

what does the depolarisation of outer hair cells cause

A
  • induces cell to shorten or lengthen (electromotility)
  • the change of length amplifies teh movemnt of the basilar membrane
221
Q

mechanism of hearing

A
  1. sound waves induce oscillation in the tympanic membrane
  2. pressure waves are transmitted through the ossicles to the oval window
  3. pressure on the oval window induces movement of the basilar membrane
  4. displacement of basilar membrane depolarises hair cells
  5. depolarisation of outer hair cells change their morphology, amplifying the signal
  6. depolarisation of inner hair cells induce neurotransmtter release
  7. neurotransmitter evokes action potential in the cochlear nerve
222
Q

mechanism of hearing

A
  1. sound waves induce oscillation in the tympanic membrane
  2. pressure waves are transmitted through the ossicles to the oval window
  3. pressure on the oval window induces movement of the basilar membrane
  4. displacement of basilar membrane depolarises hair cells
  5. depolarisation of outer hair cells change their morphology, amplifying the signal
  6. depolarisation of inner hair cells induce neurotransmtter release
  7. neurotransmitter evokes action potential in the cochlear nerve
223
Q

when is a cochlear implant useful

A

when the cause of deafness is sensorineural ie. damage or death of hair cells but a mostly functioning auditory nerve

224
Q

how does a cochlear imlpant differetitate frequencies

A

uses natural tonotopy

Physiology (6 decks)

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