Nervous System- Reflex

Question 1

What are the 2 divisions of the nervous system?

Answer 1

1) Central (brain and spinal) Nervous system

2) Peripheral (pairs of nerves which originate from the CNS) Nervous system

Question 2

What is the peripheral nervous system divided into?

Answer 2

Sensory and motor neurones

Question 3

What are the 3 neurones in the reflex arc?

Answer 3

1) Sensory neurone
2) Intermediate neurone
3) Motor neurone

Question 4

What are the 9 stages of the reflex arc?

Answer 4

1) Stimuli
2) Receptor
3) Sensory neurone
4) Synapse
5) Intermediate neurone
6) Synapse
7) Motor neurone
8) Effector ( eg muscle)
9) Response

Question 5

What are the benefits of the reflex arc?

Answer 5

1) Protection from harmful stimuli
2) Effect from birth
3) Involuntary
4) Short pathway (fewer synapses so faster)

Question 6

What are the feature of a Pacinian corpuscle?

Answer 6

1) Responds to mechanical pressure
2) Found in ligaments and joints
3) Contains stretch mediated Na+ channels in the membrane
4) The neurone is found in the centre of the corpuscle

Question 7

What happens when a pressure is applied to a pacinian corpuscle?

Answer 7

1) When pressure is applied the membrane of the neurone is stretched, Na+ channels widen allowing Na+ to diffuse into the neurone
2) Causes a change in polarity of the neurone creating a generated potential
3) Generated potential causes an action potential

Question 8

How do drugs affect the synapses?

Answer 8

1) They can mimic neurotransmitters
2) They can break receptor proteins on the post synaptic membrane
3) They can inhibit acetylcholinesterase
4) They can block proteins on the presynaptic membrane so neurotransmitters are not reabsorbed.