A2 Nervous system

Question 1

what is the central nervous system made up of

Answer 1

brain and spinal cord

Question 2

what is the peripheral nervous system made up of

Answer 2

All other nerves outside the brain and spinal cord

Question 3

what is an axon

Answer 3

a long neuron that action potential ( electrical impulses) travel along

Question 4

what is a myelin sheath

Answer 4

layer of fat around the axon

Question 5

what is the node of ranvier

Answer 5

the gap where impulses can jump from node to node

Question 6

what is depolarised

Answer 6

there is a influx of sodium ions into the axon making the inside more positive

Question 7

What is repolarised

Answer 7

Potassium ions move rapidly out the axon restoring the negative charge

Question 8

What is polarised

Answer 8

A neurone is at resting potential and the inside of the membrane is negatively charged

Question 9

What is the name for a nerve travelling down an axon

Answer 9

Action potential

Question 10

What is the role of a sodium potassium pump

Answer 10

Move 3 sodium ion out the neurone for every 2 potassium ions that move in

Question 11

What is hyper polarised

Answer 11

When too many potassium ions diffuse out of the neurone

Question 12

What restores hyper polarised

Answer 12

Sodium potassium pump return the rate back to resting potential

Question 13

What is the effect of mylenation of transmittion speed

Answer 13

faster because only need to depolarise the node of Ranvier

Question 14

What does the sensory neurone do

Answer 14

Connect receptors to the coordinator

Question 15

What does the relay neurone do

Answer 15

These coordinate the correct response to the stimulus

Question 16

What does the motor neurone do

Answer 16

These send the signal from the coordinator to the effector

Question 17

What is a stimulus

Answer 17

A change to the body’s internal or external environment

Question 18

What is are the coordinators

Answer 18

Brain and spinal cord

Question 19

What are the effectors

Answer 19

Muscle or glands

Question 20

What are the reasons for reflexes

Answer 20

To protect you tissues from harm
Keep you safe and alive

Question 21

Where does the ‘thinking’ take place

Answer 21

Central nervous system

Question 22

What is a reflex

Answer 22

An automatic response to a stimulus

Question 23

What is a synapse

Answer 23

A gap between neurones

Question 24

What is the term for the process where the action potential leaps from Node of Ranvier to Node of Ranvier?

Answer 24

Saltatory Conduction

Question 25

What is the gap from one neurone to the next called?

Answer 25

Synapse

Question 26

Name the components of the synapse.

Answer 26

* Presynaptic neurone * Synaptic cleft * Post synaptic neurone

Question 27

What is found in the presynaptic neurone?

Answer 27

* Neurotransmitters

Question 28

What happens when an action potential arrives at the presynaptic neurone

Answer 28

Synaptic vesicles move towards and fuse with the cell membrane in the synaptic cleft

Question 29

What process releases neurotransmitters from synaptic vesicles?

Answer 29

Exocytosis

Question 30

What occurs to neurotransmitters after they are released into the synaptic cleft?

Answer 30

They diffuse across the synaptic cleft

Question 31

What must happen for an action potential to be generated in the post synaptic neurone?

Answer 31

Enough neurotransmitters must bind to receptors

Question 32

What is the correct term for a nerve impulse travelling down an axon?

Answer 32

Action potential

Question 33

What controls the sodium and potassium ion levels in a neurone?

Answer 33

Sodium potassium pump

Question 34

What state is a neurone in when it has a higher concentration of sodium ions outside than potassium ions inside?

Answer 34

Polarised

Question 35

What must occur before an action potential can be generated?

Answer 35

Neurone must be at resting potential

Question 36

What happens during depolarisation?

Answer 36

Rapid influx of sodium ions into the axon

Question 37

What effect does depolarisation in one area of the neurone's axon have?

Answer 37

Causes depolarisation in the next region

Question 38

What occurs during repolarisation?

Answer 38

Potassium ions move rapidly out of the axon

Question 39

What is the refractory period?

Answer 39

Time during which no new action potentials can be transmitted

Question 40

What restores the resting potential after an action potential?

Answer 40

Sodium potassium pump

Question 41

How does myelination affect the transmission speed of action potentials?

Answer 41

Increases speed by allowing depolarisation only at the Nodes of Ranvier

Question 42

Fill in the blank: The _______ creates a myelin sheath around axons.

Answer 42

Schwann cells

Question 43

What is the result of a neurone being depolarised?

Answer 43

Inside of the membrane becomes more positive

Question 44

Explain why the speed of transmission of impulses is faster along a myelinated axon than a non myelinated axon

Answer 44

Myelinated means myelin sheath this allows impulses to jump from node of ranvier to node of ranvier this is called saltatory conduction, only need to depolarise the node of ranvier Non myelinated depolarise the whole length of the membrane