Nervous System

Question 1

What is the CNS made up of

Answer 1

Spinal chord and brain

Question 2

What is the peripheral system made up of

Answer 2

All the other neurones

Question 3

What does the peripheral system split into

Answer 3

Systematic nervous system and the autonomic nervous system

Question 4

Systematic nervous system

Answer 4

Conscious control

Question 5

Autonomic nervous system

Answer 5

Unconscious body activating

Question 6

What is the autonomic nervous system made up of

Answer 6

Parasympathetic- slows things down - acytlcholine ….

Sympathetic-speeds things up- noradrenaline

Question 7

Receptor

Answer 7

Specific, will only detect one type of stimulus. Can be cell or protein, transforms stimuli into electrical impulse ( chemical change)

Question 8

Sensory neurone

Answer 8

Single long dendron, single short axon

Question 9

Relay neurone

Answer 9

Within the CNS, many short dendrites, many short axons

Question 10

Motor neurone

Answer 10

Many short dendrites, single long axon, ends with a neuromuscular junction

Question 11

Effector

Answer 11

Muscle or gland, brings about a response

Question 12

Potential difference

Answer 12

More positive ions on outside than on the inside so we say this is the resting potential

Question 13

Resting potential

Answer 13

When,

(1) SODUIM POTASSIUM PUMP: active transport 3Na+ out, 2K+ in
(2) VOLTAGE GATED SODIUM ION CHANNEL: closed, membrane is not permeable to Na+
(3) POTASSIUM ION CHANNEL: open, some k+ diffuses out down electrochemical gradient, doesn’t reach equilibrium due to positive charge on outside

Question 14

What makes up an action potential ( in order)

Answer 14

1. Resting potential
2. Generator potential
3. Threshold
4. Depolarisation
5. Depolarisation
6. Re polarisation
7. Hyper polarisation

Question 15

What is the refractory period

Answer 15

Another action potential cannot be started, makes action potentials- discrete ( don’t overlap)- unidirectional (one way)

Question 16

AP:resting potential

Answer 16

Sodium potassium pump
Active transport
Na out
k in

Question 17

AP Generator potential

Answer 17

Weak stimulus 
Some Na channels open
Some Na diffuses in
Does in reach threshold
Nak pump stores resting potential

Question 18

AP Threshold

Answer 18

Greater potential reaches threshold
Many voltage gated Na channels open
Na diffuses into axon
Positive feedback

Question 19

AP depolarisation

Answer 19

Na channels are open

Na diffuses in

Question 20

AP Repolarisation

Answer 20

K channels open ( voltage gated)
K diffuses out
Voltage gated Na close

Question 21

AP Hyperpolarosation

Answer 21

When membrane potential is more negative than resting potential , k channels close

Question 22

The all or nothing law

Answer 22

If a generator potential reaches threshold it will trigger an action potential

Question 23

What’s the myelin sheath

Answer 23

Schwann cells make the myelin, it’s an electrical insulator - prevents depolarisation, prevents movement of ions in/out of the neurone

Question 24

Saltatory conduction

Answer 24

When an action potential jumps between the nodes of ranvier

Question 25

Points to remember about saltatory conduction

Answer 25

Speeds up transmission of nerve impulse, cytoplasm conducts enough charge to depolarise the next node

Question 26

Nodes of ranvier

Answer 26

The gaps in the myelin sheath, lots of Na and K channels

Question 27

What can only happen at the nodes of ranvier

Answer 27

Depolarisation

Question 28

Diameter of the axon

Answer 28

Less resistance, more surface area for ion movement, greater diameter the faster the speed of action potential

Question 29

Synapse

Answer 29

A junction between two neurones

Question 30

Describe the steps of a cholinergic synapse

Answer 30

1. AP arrives at presynaptic knob 2. Ca channels open and diffuse in 3. Causes vesicles to fuse with membrane 4. Ach diffuses across cleft 5. Ach binds to receptors on postsy 6. Some Na channels open and diffuses in 7. Voltage gated Na channels open 8. AP triggered at postsy 9. Acetylcholinerase breaks down Ach 10. Products reabsorbed into presy

Question 31

Evidence that synapse are unidirectional

Answer 31

Only receptors on the post synaptic membrane, neurotransmitters released from presy, diffuse from high to low concen across synaptic cleft

Question 32

Synaptic divergence

Answer 32

When one neurone joins many neurones, spreads the AP to other parts of the body

Question 33

Synaptic convergence

Answer 33

When many neurones join a single neurone, amplifies signal

Question 34

Spatial summation

Answer 34

When neurotransmitters from multiple neurones combine to trigger an action potential in a post synaptic neurone

Question 35

Temporal summation

Answer 35

A strong stimulus will cause more frequent AP's, release more neurotransmitters which add up to trigger an AP in the postsy

Question 36

Neuromuscular junction

Answer 36

A synapse between a motor neurone and a muscle fibre

Question 37

Differ eat compared to a cholinergic synapse

Answer 37

More receptors on postsy, so an AP is always generated in postsy, acetlycholinerase found in pits in postsy, receptors called nichotinic chollinergic receptor

Question 38

Exteroceptors

Answer 38

Respond to a stimuli from the external environment

Question 39

Enteroceptors

Answer 39

Respond to stimuli from the internal environment

Question 40

Proprioceptors

Answer 40

Respond to tension with tendons and muscles

Question 41

Why is there lots of mitochondria in the synaptic bulb

Answer 41

ATP for active transport, making neurotransmitters, synaptic vesicles-Golgi, removal of calcium after AP

Question 42

Cholinergic synapse

Answer 42

Neurones that release acytlcholine

Question 43

Adrenergic synapse

Answer 43

Neurones that relates noradrenaline