Neuronal communication

Question 1

what is a stimulus?

Answer 1

change in environment

Question 2

what is a transducer?

Answer 2

device that converts energy from one store to another

Question 3

what receptor is an example of a transducer?

Answer 3

sensory receptors
because convert energy from one form into energy in an electrical impulse in a sensory neurone.

Question 4

name some examples of transducers?

Answer 4

photoreceptors in eyes - detect light intensity
light energy -> electrical energy

receptors in the skin detect pressure
kinetic energy -> electrical energy

Question 5

what energy does a transducer always convert the previous energy into?

Answer 5

electrical energy

Question 6

what do baroreceptors detect?

Answer 6

detect changes in blood pressure as in walls of blood vessels

Question 7

what receptor is the pacinian corpuscle an example of?

Answer 7

A mechanoreceptor found deep in the skin.

found in fingers, soles of feet deep in the skin

Question 8

what is a mechanoreceptor?

Answer 8

in the muscles detect how much muscles are stretched

Question 9

role of pacinian corpuscle?

Answer 9

respond to changes in pressure

Question 10

a pacinian corpuscle detects changes in pressure and results in a generator potential (electrical impulse)
why does this happen?
*not long short simple answer

Answer 10

receptors stimulated by pressure on the skin which leads to the establishment of a generator potential

Question 11

what neurone are pacnian corpuscles found?

Answer 11

sensory neurone

Question 12

what part of the sensory neurone is a pacinian corpuscle found?

Answer 12

at the end of the sensory neurones axon

Question 13

describe the structure of a pacinian corpuscle?

Answer 13

made of many layers of membrane surrounding a neurone

separated by gel that contains positively charged sodium ions

Question 14

a pacinian corpuscle is separate from the neurone by a gel, what ions does this gel contain?

Answer 14

positively charged sodium ions

Question 15

in a sensory neurone where is the cell body?

Answer 15

in the middle

Question 16

name all the parts of a neurone

Answer 16

1. dendrites
2. dendron
3. nucleus
4. cell body
5. axon
6. axon terminals
7. Schwann cell
8. myelin sheath

Question 17

role of myelin sheath?

Answer 17

insulates an axon

Question 18

on a neurone there are small uninsulated sections, what are these called?

Answer 18

nodes of ranvier

Question 19

what is the myelin sheath made up of?

Answer 19

Schwann cells

Question 20

name the similarities between motor and sensory neurones?

Answer 20

both have dendrites
axon
cell body with nucleus
myelin sheath voltage gated channels

Question 21

state the differences between a motor and sensory neurone?

Answer 21

motor neurone has cell body in CNS whereas sensory not in CNS

in a sensory neurone cell body in the middle , in motor at the end

motor has a longer axon , sensory has a shorter axon

sensory has a dendron , motor doesn’t

Question 22

Which type of neurone is short and highly branched?
A) Sensory
B) Relay
C) Motor

Answer 22

B

Question 23

Which neurones are sensory receptors connected to?

Answer 23

sensory neurones

Question 24

Why are sensory receptors described as transducers?

Answer 24

They transfer energy from one store to another

Question 25

What is the correct method of energy transfer by a Pacinian corpuscle?

Answer 25

Kinetic energy -> electrical energy

Question 26

Which kind of ions establish a generator potential when they enter a neurone?

Answer 26

Sodium (Na+)

Question 27

during resting potential, what has more negative electrical potential, inside or outside the neurone?

Answer 27

inside

Question 28

in the sodium-potassium ion pump, how many sodium ions in/out and how many potassium ions in/out

Answer 28

3 sodium ions out 2 potassium ions in

Question 29

does the sodium-potassium ion channel require energy?

Answer 29

yes ATP required

Question 30

protein channels are less permeable to what ion?

Answer 30

less permeable to sodium ions

Question 31

define action potential?

Answer 31

change in distribution of electrical charge across cell surface membrane of a neurone

Question 32

what should the potential difference be for depolarisation to be triggered?

Answer 32

-55mV

Question 33

at the end of depolarisation what is the potential difference?

Answer 33

+30mV

Question 34

at the end of repolarisation what is the potential difference?

Answer 34

-70mV

Question 35

when will a impulse be transmitted ?

Answer 35

initial stimulus is sufficient to increase the membrane potential above a threshold potential (usually -55 mV).

Question 36

what is the strength of the stimulus determined by?

Answer 36

frequency of the action potential

Question 37

EQ The generation of an action potential follows the all or nothing principle. Explain what this means?

Answer 37

if a stimulus is not strong enough the threshold value is not reached so depolarisation of membrane is insufficient and an action potential is not generated

Question 38

Synapses that use acetylcholine as a neurotransmitter are described as??

Answer 38

Cholinergic synapse

Question 39

EQ: name one chemical that transfers a nerve impulse from one neurone to another?

Answer 39

acetylcholine

Question 40

Name the process by which acetylcholine travels across synaptic cleft?

Answer 40

diffusion

Question 41

EQ: explain what causes transmission at the synapse to occur only in one direction?

Answer 41

neurotransmitters only in presynaptic neurone and receptors only on post synaptic neurone

Question 42

what triggers the release of neurotransmitters in the presynaptic neurone?

Answer 42

influx of calcium ions

Question 43

EQ: 2 marks Describe how calcium ions are involved in synaptic transmission.

Answer 43

calcium ions enter presynaptic neurone and cause fusion of vesicles with presynaptic membrane

Question 44

name the two types of summation?

Answer 44

temporal spatial

Question 45

what is temporal summation?

Answer 45

when multiple impulses arrive with quick succession

Question 46

describe what happens in temporal summation which causes a sufficient number of sodium ions pass through the membrane?

Answer 46

A large amount of acetylcholine is released into the synaptic cleft. Therefore a large number of the gated ion channels open.

Question 47

what is spatial summation?

Answer 47

when multiple impulses arrive simultaneously at different synaptic knobs whilst simulating the same body cell which generates an action potential

Question 48

how does spatial summation cause an action potential?

Answer 48

multiple impulses result in large amount of acetylcholine being released into synaptic cleft , resulting in action potential

Question 49

during synaptic transmission, acetylcholine diffuses across the synaptic cleft into the post synaptic neurone. Acetylcholine is then hydrolysed. what causes the hydrolysation of acetylcholine and what is it broken down into?

Answer 49

caused by the enzyme acetylcholinesterase catalysing the hydrolysis broken down into choline and acetate

Question 50

acetylcholine can be hydrolysed into choline and acetate by the enzyme acetylcholinesterase. Which molecule produced is then absorbed back into the presynaptic membrane?

Answer 50

choline

Question 51

choline can be reabsorbed back into the presynaptic membrane to be converted back into acetylcholine for synaptic transmission. what does it need to react with to convert back?

Answer 51

reacts with acetyl Coenzyme A to form acetylcholine

Question 52

during synaptic transmission, what ion channels are present on the post synaptic membrane that triggers depolarisation?

Answer 52

sodium ion channels

Question 53

on the presynaptic membrane during synaptic transmission there are ion channels, which ion channels are these?

Answer 53

calcium ion channels