The Nervous System

Question 1

A change in a membrane potential from +30mV to -70mV is an example of:

Answer 1

Repolarisation

Question 2

A threshold potential is:

Answer 2

The point at which there is an explosive increase in Na+ permeability

Question 3

Graded Potentials:

Two Answers

Answer 3

• Are local changes in membrane potential that occur in varying degrees of magnitude
• Serve as short distance signals

Question 4

Myelinated axons conduct impulses much faster because:

Four reasons

Answer 4

• The myelin insulates the axon
• Channels only have to open at the nodes
• Voltage is not lost through along myelinated areas
• Saltatory conduction

Question 5

Permeability of which ion is affected by a positive feedback mechanism once threshold is reached?

Answer 5

Sodium

Question 6

The relative refractory period occurs after the action potential is complete because of the:
(Two Reasons)

Answer 6

• Lingering inactivation of the voltage gated Na+ channels

- Slowness of the voltage gated channels

Question 7

The trigger zone of a neuron:

Three Answers

Answer 7

• Precedes the axon
• Is located in the Hillock
• Contains voltage gated channels

Question 8

Sequence the following events correctly:

1. Neurotransmitter diffuses across cleft
2. Calcium induces exocytosis of neurotransmitter
3. Permeability of postsynaptic membrane altered
4. Ion channels open
5. Neurotransmitter binds to receptor on chemically gated channel

Answer 8

2, 1, 5, 4, 3

Question 9

What is the normal direction of movement of an action potential along part of a neuron?

Answer 9

Dendrites to cell body

Question 10

The nodes of Ranvier are:

Answer 10

Breaks in the Myelin covering

Question 11

What characteristic is relevant to the endocrine system, rather than the nervous system?

Answer 11

Signalling may target many diverse cells

Question 12

Which of the following is not part of the Peripheral Nervous System?
A) Motor neurons
B) Sympathetic Nervous System
C) Spinal cord
D) Afferent division
E) Autonomic Nervous System

Answer 12

C) Spinal cord

Question 13

Afferent Neurons:

Answer 13

Transmit messages to the spinal cord

Question 14

Which of the following is not accomplished by the cerebral cortex?

A) Voluntary initiation of movement
B) Control of breathing, circulation and digestion
C) Final sensory perception
D) Language ability
E)	 Personality traits

Answer 14

B) Control of breathing, circulation and digestion

Question 15

Which of the following does not participate in control of skeletal muscle activity?

A) Limbic system
B) Cerebellum
C) Supplementary motor area
D) Premotor cortex
E) Posterior parietal cortex

Answer 15

A) Limbic System

Question 16

Which of the following functions is not associated with the hypothalamus?

A) Control of respiration and circulatory function
B) Control of thirst and urine output
C) Control of body temperature
D) Control of food intake
E) Extensive involvement with behavioural patterns

Answer 16

A) Control of respiration and circulatory function

Question 17

Which of the following statements concerning the brain stem is incorrect?
A) The medulla is part of the brain stem
B) The brain stem is a critical connecting link through which all fibres traversing between the periphery and higher brain centres must pass
C) The brain stem controls sociosexual behaviours conducive to mating
D) The brain stem contains centres that control respiration, blood vessel and heart function, and digestive activities

Answer 17

C) The brain stem controls sociosexual behaviours conducive to mating

Question 18

Information travels up the spinal cord to the brain via:

Answer 18

Ascending tracts

Question 19

Receptors:

Four answers

Answer 19

• Respond to various physical or chemical changes in their environment
• Change other forms of energy into electrical energy
• Respond more readily to their adequate stimulus
• Are found at the peripheral endings of afferent neurons

Question 20

Select the incorrect association:
A) Chemoreceptor/oxygen concentration
B) Mechanoreceptor/skeletal muscle stretch
C) Nociceptor/solute concentration
D) Photoreceptor/light
E) Thermoreceptor/heat and cold

Answer 20

C) Nociceptor/solute concentration