Coordination And Control - Mammals

Question 1

The mammalian nervous system can be divided into 2 systems. What are they?

Answer 1

Central Nervous System (CNS) = brain and spinal cord
Peripheral Nervous System (PNS) = cranial nerves, spinal nerves.

Question 2

What’s the difference between receptors and effectors?

Answer 2

Receptors receive the stimulus
Effectors bring about response.

Question 3

What is the functional unit of the nervous system?
What is a nerve?

Answer 3

The neurone.
A nerve is a bundle of neurones.

Question 4

Where would the cell body of a motor neurone be located?
What do motor neurones transmit?

Answer 4

The CNS
Motor neurones transmit impulses from the CNS to effectors.

Question 5

What do sensory neurones transmit?

Answer 5

Sensory neurones conduct an impulse form a receptor to the CNS.

Question 6

What is the name of the supporting cell that produces the myelin sheath?

Answer 6

Schwann cell

Question 7

What is the main factor determining the resting potential of a neurone?
What is the approximate magnitude of resting potential?

Answer 7

The resting potential is determined by an unequal distribution of charged ions inside and outside a neurone, making the inside negative to the outside. This is mainly due to an excess of sodium ions outside.

-70mV

Question 8

Suggest why a refractory period is important for neurone function.

Answer 8

During the refractory period the membrane, immediately behind that exhibiting an action potential, is unexcitable and so the impulse can only be propagated forward.
The refractory period is largely responsible for the unidirectional propagation of action potentials along neurones.

Question 9

Suggest a disadvantage of the nodes of ranvier being
a) closer together
b) further apart

Answer 9

a) The impulse would be slower as it would have to make more jumps.
b) No impulse because the nodes are too far apart to form a circuit; too far for the action potential to jump.

Question 10

Which mineral ion causes synaptic vesicles to fuse with pre-synaptic membrane?

Answer 10

Calcium

Question 11

Explain the role of mitochondria in the synaptic bulb.

Answer 11

They produce ATP for the synthesis of neurotransmitter substance (e.g. acetylcholine from choline and ethanoic aciddiffusing back into the bulb).