5.1.3

Question 1

What does the pacinian corpuscle do?

Answer 1

when pressure is applied
membrane surrounding neurone stretches
causes gaps/spaces to appear between phosopholipids
opens Na+ channels
Na+ rushes in a long electrochemical gradient generating an action potential

Question 2

How is resting potential maintained and established?

Answer 2

3Na+ out and 2k+ actively transported
using the Na+ k+ pump some K+ leaks back out
membrane is more permeable to K+
sodium voltage gated channels are closed

Question 3

What happens when pressure is applied to the pacinian corpuscle?

Answer 3

membrane surrounding neurone stretches

Question 4

What does the membrane surrounding the neurone stretching cause?

Answer 4

gaps/spaces to appear between phospholipids

Question 5

What happens when gaps / spaces appear between phospholipids?

Answer 5

Na+ channels open

Question 6

What happens when Na+ channels open?

Answer 6

Na+ rush in along electrochemical gradient

Question 7

What happens when Na+ rush in along the electrochemical gradient?

Answer 7

generates an action potential

Question 8

How many volts is resting potential?

Answer 8

-70mV

Question 9

What is the ratio for Na:K in the resting potential?

Answer 9

3Na out and 2K in

Question 10

How are 3Na+ transported out and 2 K+ transported in?

Answer 10

active transport
using Na+/K+ pump

Question 11

What happens to some K+ in the Na/K+ pump?

Answer 11

Some K+ leak out

Question 12

Why do some K+ leak out of the Na+/K+ pump?

Answer 12

the membrane is more permeable to K+

Question 13

What happens to the sodium voltage gated channels in resting potential?

Answer 13

CLOSED

Question 14

What happens in depolarisation?

Answer 14

Na+ voltage gated channels open
Na+ rush into membrane along the electrochemical gradient
inc membrane potential
positive feedback

Question 15

What channels open in depolarisation?

Answer 15

Na+ voltage gates channels

Question 16

What ion rushes into the membrane along the electrochemical gradient in depolarisation?

Answer 16

Na+

Question 17

What happens when Na+ voltage gated channels close?

Answer 17

repolarisation

Question 18

What happens in repolarisation?

Answer 18

Na+ voltage gated channels closed
K+ voltage gated channels open
K+ rush out of membrane along electrochemical gradient
dec membrane potential

Question 19

What channels open and close in repolarisation?

Answer 19

Na+ close
K+ open

Question 20

What happens to K+ in repolarisation?

Answer 20

rush out of membrne along electrochemical gradient

Question 21

What happens to membrane potential in depolarisation?

Answer 21

inc

Question 22

What happens to membrane potential in repolarisation?

Answer 22

dec

Question 23

What happens in the refractory period?

Answer 23

K+ voltage gated channels close but there is an overshoot of K+ ions
hyperpolarisation

Question 24

What channels close in the refractory period?

Answer 24

K+ voltage gated channels close

Question 25

What is beneficial about the refractory period?

Answer 25

allows action potential to move in 1 direction along the neurone

Question 26

How does myelination help action potentials?

Answer 26

membrane is only depolarised at nodes of ranvier creates a longer localised circut inc rate of impulse transmission

Question 27

Outline synaptic transmission?

Answer 27

Action potential trqavels down presynaptic membrane Ca2+ channels open Ca2+ rushes into presynaptic membrane along electrochemical gradient rush of Ca2+ causes vesicles containing neurotransmitter to fuse with PSM release neurotransmitter into the synaptic cleft by exocytosis acetyl cholien diffuse across synaptic cleft acetyl choline binds to receptors on Post synpatic membrane receptors found on Na+ voltage gated channels causing them to open Na+ rush in and depolarise membrane trigger action potential enzyme breaks acetyl choline Na+ channels close Acetyl choline diffuse back into the presynaptic membrane

Question 29

What is temporal summation?

Answer 29

filters out background of low level stimuli

Question 30

What is spatial stimuli?

Answer 30

allows convergence impulses from more than 1 neurone to be passed to a single eurone filters out background of low level stimuli

Question 31

What is the role of the synapse?

Answer 31

allows neurones to COMM ensures transmission in 1 direction allows convergece allows divergence filters out backgroud of low level stimuli

Question 32

Why does the synpase allow transmission in 1 direction?

Answer 32

Vesicles containing neurotransmitter ony fround in presynaptic knob receptors on Na+ voltage gated channels can onl be found on post synaptic membrane Calcium chanel only found on presynaptic membrane

Question 33

What isa sensory neurone

Answer 33

dendron present and links to cell body cell body centre of neurone dendrites dont connect to cell body axon shorter than motor neurone connects t sensory receptor

Question 34

What does a relay neurone look like?

Answer 34

short axon dendrites present found in CNS

Question 35

What does a motor neurone look like?

Answer 35

no dendrons cell body on end dendrites connected to cell body axon longer than sensory neurone neurone endsat motor end plate

Question 36

What travels down the presynaptic membrane?

Answer 36

action potential

Question 37

What opens when the action potential travels down the presynaptic membrane?

Answer 37

Ca2+ channels open

Question 38

What rushes in along the electrochemical gradient when Ca2+ channels open?

Answer 38

Ca2+

Question 39

What does the rushing in of Ca2+ cause?

Answer 39

causes vesicles containing neurotransmitter to fuse with the presynaptic membrane

Question 40

How is neurotransmitter released into the synpatic cleft?

Answer 40

exocytosis

Question 41

What diffuse across synaptic cleft?

Answer 41

acetyl choline

Question 42

What does acetyl choline do after diffusing across the synaptic cleft?

Answer 42

binds to receptors on post synaptic membrane

Question 43

Where are the receptors on the post synaptic membrane found?

Answer 43

on Na+ voltage gated channels

Question 44

What happens when acetyl choline binds to receptors on post synaptic membrane?

Answer 44

Na+ voltage gated channels open

Question 45

What happens when Na+ voltage gated channels open?

Answer 45

Na+ rush in and depolarise the membrane triggering action potential

Question 46

What breaks acetyl choline down?

Answer 46

enzymes

Question 47

What channels close when acetyl choline is broken down by enzymres?

Answer 47

Na+ voltage gated channels

Question 48

What happens to acetyl choline when Na+ voltage gated channels c.lose?

Answer 48

diffuse back into presynaptic membrane