stimulus + response

Question 1

stimulus

Answer 1

change in internal or external environment

Question 2

receptor

Answer 2

a specific cell which detects change

Question 3

coordinator

Answer 3

normally CNS - can also be a gland/organ - processes information from receptors

Question 4

effector

Answer 4

usually muscle or gland - br

Question 5

taxis

Answer 5

move towards or away from a stimulus (directional stimuli, directional movement)

Question 6

kinesis

Answer 6

keeping moving in unfavourable conditions to remove itself from such conditions - non directional stimuli

Question 7

myogenic

Answer 7

contracts without stimulation from brain

Question 8

autonomic nervous system

Answer 8

controls involuntary responses

Question 9

somatic nervous system

Answer 9

controls voluntary movements

Question 10

peripheral nervous system made of

Answer 10

motor neurone

sensory neurone

Question 11

2 divisions of autonomic nervous system

Answer 11

sympathetic

parasympathetic

Question 12

how is heart rate controlled whilst exercising

Answer 12

• increase CO2 decreases pH of blood as it forms carbonic acid
• chemoreceptors in aorta detect drop in pH
• send impulse to medulla oblongata via sensory neurone
• frequency of impulses sent to SAN via sympathetic nervous system increase
• heart rate increases

Question 13

dendron

Answer 13

part of nerve cell leading towards cell body

Question 14

axon

Answer 14

part of nerve cell leading away from cell body

Question 15

Schwann cells - function

- how does it carry out function

Answer 15

insulation, making impulses faster

as contains lots of lipid myelin, as it grows its wraps cell membrane around nerve cell

Question 16

gap between Schwann cells

Answer 16

node of ranvier

Question 17

how is a resting potential in a neurone established?

Answer 17

• sodium potassium ion pump pumps 3 sodium ions out of the cell for every 2 potassium ions it pumps in
• using energy from hydrolysis of ATP to ADP + Pi
• as sodium ion channels are closed, a resting potential is created

Question 18

resting potential value

Answer 18

-70mv

Question 19

refractory period

Answer 19

period after an action potential where no other action potentials can occur

Question 20

How is action potential established/reached

Answer 20

• Na+ ions diffuse rapidly into cell through open voltage gates sodium channels
• if value is above threshold value, rapid depolarisation of the axon will occur as all the voltage gated sodium ion channels open

Question 21

How Is resting potential established after an action potential?

Answer 21

• Na+ voltage gated channels close, reducing membrane permeability to Na+
• K+ channels open, allowing H+ ions to renter cell
• depolarising the membrane
• allowing repolarisation of the axon
• leading to hyper polarisation until Na+K+ pump resets resting potential

Question 22

period where membrane potential is lower then resting potential

Answer 22

hyperpolarisation

Question 23

d. resting membrane potential

Answer 23

difference in charge between interior and exterior of cell

Question 24

action potential

Answer 24

moving depolarisation along the cell

Question 25

reason action potential occurs (2)

Answer 25

- all Na+ channels closed | - resting potential not yet established

Question 26

function of refractory period (2)

Answer 26

- ensures impulses travel in ONE direction along the axon | - produces discrete and separate action potentials - allows frequency to be detected

Question 27

difference between myelinated cells and non-myelinated cells

Answer 27

- myelinated cells: action potentials jump from node of to node - meaning depolarisation only occurs at nodes of ranvier - via SALTATORY CONDUCTION - and not all the way along the cell = faster impulse - sodium ion channels concentrated at nodes

Question 28

pressure sensory =

Answer 28

Pacinian corpuscle

Question 29

how are action potentials in Pacinian corpuscle initiated

Answer 29

- same but membrane of neurone is stretched, causing Na+ channels to open

Question 30

3 factors affecting speed of conduction of action potentials

Answer 30

- myelination - - axon diameter - less resistance to ion flow = depolarisation reaches other parts of the cell faster - temp - as ions diffuse faster - past 40 degrees proteins denature

Question 31

pressure sensing receptors

Answer 31

baroreceptors

Question 32

where are.... - baroreceptors - chemoreceptors found?

Answer 32

- artery walls - carotid artery wall | - wall of aorta, wall of carotid artery

Question 33

describe the process of a action potential being transmitted across a synapse

Answer 33

- AP arrives at pre-synaptic terminal - causing voltage gated calcium ion channels to open - diffusion of Ca2+ into neurone - Ca2+ causes vesicles containing neurotransmitter (acetylcholine) to fuse with pre-synaptic membrane - acetylcholine released into synaptic cleft - diffuses across synaptic cleft - binds to complimentary neuroreceptor - if threshold value reached = rapid depolarisation of post synaptic neurone - acetylcholine-esterase released into synaptic cleft - hydrolysis of Ash into acetyl and choline (preventing continual depolarisation of axon) - products diffuse back across the cleft and into knob - hydrolysis of ATP provides energy for recombination of acetyl and choline -> acetylcholine - back into vesicles ready for another AP

Question 34

2 ways of reaching an AP

Answer 34

- spatial summation | - temporal summation

Question 35

spacial summation

Answer 35

multiple synapses stimulated - combined effect of both APs

Question 36

temporal summation

Answer 36

high frequency AP = high amounts of neurotransmitter - frequency of APs is determining factors

Question 37

inhibitory synapses

Answer 37

ones which make it less likely for an AP to occur in the post synaptic neurone

Question 38

how does an inhibitory synapse work

Answer 38

- presynaptic neurone released neurotransmitter that binds to chloride ion protein channels on post synaptic membrane - causing them to open - Cl- move into post synaptic membrane by facilitated diffusion - binding of transmitter caused opening of nearby K+ protein channels - K+ out of post synaptic neurone into synapse ∴ potential difference is more negative ∴ hyperpolarisation - less likely a new AP produced as more Na+ needed to meet threshold value

Question 39

function of choroid layer of eye

Answer 39

stops light bouncing around - absorbs

Question 40

resting potential value

Answer 40

70mv

Question 41

features of RODS (3)

Answer 41

- cant distinguish between wavelengths of light - vision in low light intensities in B&W - more numerous then cones - multiple joined to a single bipolar neurone - - therefore achieve generator potential by RETINAL CONVERGENCE - SUMMATION increases change of threshold value being reached

Question 42

how is a generator potential reached?

Answer 42

pigment is broken down by certain wavelengths of light

Question 43

why is there low visual acuity with rods

Answer 43

- multiple joined to one bipolar cell (one sensory neurone) brain received one message for many rods stimulated - cut distinguish between 2 discrete items due to retinal convergence

Question 44

features of CONES (2)

Answer 44

- each cone joined to its own bipolar neurone - high visual acuity as each cone is connected to a single bipolar neurone therefore brain received separate impulses as no summation and can distinguish between 2 discrete items

Question 45

greater conc of cones at...

Answer 45

fovea