Nervous Coordination (not finished)

Question 1

What does the central nervous system consist of?

Answer 1

• Brain.

- Spinal cord.

Question 2

What does the peripheral nervous system consist of?

Answer 2

All neurones other than the brain and spinal cord.

Question 3

What is the somatic nervous system?

Answer 3

Conscious control.

Question 4

What is the autonomic nervous system?

Answer 4

Unconscious control.

Question 5

What does the parasympathetic nervous system do?

Answer 5

Slows things down.

Question 6

What does the sympathetic nervous system do?

Answer 6

Speeds things up.

Question 7

What do receptors do?

Answer 7

• They are specific so will only detect one type of stimulus.
• They transform stimulus into an electrical impulse.

Question 8

What is the sensory neurone consist of?

Answer 8

• Single long dendron.

- Single short axon.

Question 9

What does the relay neurone consist of?

Answer 9

• Many short dendrites..

- Many short axons.

Question 10

What does the motor neurone consist of?

Answer 10

• Many short dendrites.
• Single long axon.
• Ends with neuromuscular junction.

Question 11

What can the effector be?

Answer 11

• Muscle.

- Gland.

Question 12

What are the sodium potassium pumps doing during resting potential?

Answer 12

• Active transport (using ATP).
• 3 Sodium out.
• 2 potassium in.

Question 13

What are voltage gated sodium ion channels doing during resting potential?

Answer 13

• Closed.

- Membrane is not permeable to Na+.

Question 14

What are the potassium ion channels doing during resting potential?

Answer 14

• Open.
• Some K+ diffuses out down the electrochemical gradient.
• Doesn’t reach equilibrium because of the positive charge outside.

Question 15

What are the stages of an action potential?

Answer 15

1 - resting potential.
2 - generator potential.
3 - threshold.
4 - depolarisation.
5 - repolarisation.
6 - hyperpolarisation.

Question 16

What happens is a generator potential does not reach threshold?

Answer 16

• Weak stimulus.
• Some Na+ channels open.
• Some Na+ diffuses in.
• Does not reach threshold.
• Sodium-potassium pump restores resting potential.

Question 17

What happens if the generator potential reaches threshold?

Answer 17

• Many voltage gated Na+ channels open.

- Na+ diffuses into axon.

Question 18

What happens during depolarisation?

Answer 18

• Na+ channels open.

- Na+ diffuses in.

Question 19

What happens during repolaristiaon?

Answer 19

• K+ channels open (voltage gated).
• K+ diffuses in.
• Voltage gated Na+ close.

Question 20

What happens during hyperpolarisation?

Answer 20

• When membrane potential is more negative than resting potential.
• K+ channels are slow to close.

Question 21

Why is a refractory period essential?

Answer 21

• Another action potential cannot be started.

- Makes action potentials discrete (don’t overlap) and unidirectional (one-way).