Nervous System

Question 1

Identify the labelled phases and periods

Answer 1

A - stimulus

B - depolarising phase

C - repolarising phase

D - relative refractory period

E - absolute refactory period

F - after-hyperpolarising phase

Question 2

Explain what happens in the stimulus phase.

Answer 2

stimulus causes depolarisation to threshold

Question 3

Explain what happens in the depolarisation phase.

Answer 3

voltage-gated Na+ channel activation gates are open

Question 4

Explain what happens in the repolarising phase.

Answer 4

Voltage-gated K+ channels are open; Na+ channels are inactivating

Question 5

Explain what happens in the after-hyperpolarising phase.

Answer 5

voltage-gated K+ channels are still open; Na+ channels are in resting state.

Question 6

Explain what happens during the absolute refractory period.

Answer 6

a second stimulus cannot initiate a second action potential

Question 7

Explain what happens during a relative refractory period.

Answer 7

A second stimulus can now initiate a second action potential.

Question 8

Name five neurotransmitters.

Answer 8

epinepherine, norepinephrine, dopamine, seratonin, acetylcholine

Question 9

What is a function of dopamine?

Answer 9

regulates muscle tone; pleasure

Question 10

What is a function of norepinepherine?

Answer 10

regulates mood

Question 11

What is a function of epinephrine?

Answer 11

increase blood flow and heart rate (fight or flight)

Question 12

What is a function of serotonin?

Answer 12

mood regulation

Question 13

What is a function of acetylcholine?

Answer 13

learning and memory

(aceing the test, acetylcholine)

Question 14

Is acetylcholine excitatory or inhibitory, or both?

Answer 14

both

Question 15

Is dopamine excitatory or inhibitory, or both?

Answer 15

inhibitory

Question 16

Is serotonin excitatory or inhibitory, or both?

Answer 16

inhibitory

Question 17

Is epinephrine excitatory or inhibitory, or both?

Answer 17

both

Question 18

Is norepinephrine excitatory or inhibitory, or both?

Answer 18

both

Question 19

Define graded potential.

Answer 19

small deviations from resting membrane potential

Question 20

Describe hyperpolarising and depolarising graded potential in terms of polarity and change in charge of the membrane.

Answer 20

hyperpolarising: more polarised, inside has become more negative
depolarising: less polarised, inside has become less negative

Question 21

Name the two types of receptors that neurotransmitters attach to which either produce an EPSP or IPSP.

Answer 21

ionotropic or metabotropic receptors

Question 22

Describe the criteria which ionotropic receptors are classified.

Answer 22

binding site and ion channel on the same protein

Question 23

Describe the criteria which metabotropic receptors are classified.

Answer 23

binding site and ion channel on different proteins

Question 24

List the two classes of sensory modalities.

Answer 24

general senses and special senses

Question 25

Name the four events that typically occur for a sensation to arise.

Answer 25

stimulation of the sensory receptors, transduction of the stimulus, generation of nerve impulse and integration of sensory input

Question 26

Describe stimulation of the sensory receptor.

Answer 26

appropriate stimulus occurs within receptor’s receptive field; selectivity of receptor

Question 27

Describe the transduction of the stimulus

Answer 27

converts energy in stimulus into a graded potential

Question 28

Describe generation of nerve impulse

Answer 28

when graded potential reaches threshold, triggers nerve impulse/s, propagates towards CNS

Question 29

Describe integration of sensory input

Answer 29

particular region of CNS (cerebral cortex) receives and integrates sensory nerve impulse

Question 30

Name the five components of the autonomic reflex arc.

Answer 30

sensory receptor, sensory neuron, integrating centre, pre and postganglionic motor neuron and visceral effectors

Question 31

Describe the event/s that occur at the sensory receptor.

Answer 31

dendrites act as sensory recpetors, responding to a specific stimulus; graded potential is produced, threshold level of depolarisation is reached and nerve impulse is triggered

Question 32

Describe the event/s that occur at the sensory neuron.

Answer 32

nerve impulse from sensory receptor moves along the axon of the neuron to the axon terminals in the CNS

Question 33

Describe the event/s that occur at the integrating centre.

Answer 33

region within the central nervous system that relay impulses from sensory neurons to motor neurons

Question 34

Describe the event/s that occur at the motor neuron.

Answer 34

axon conducts impulses from the integrating centre to the effector

Question 35

Describe the event/s that occur at the effector.

Answer 35

muscle or gland responds to the motor neuron impulse

Question 36

Name the two neurotransmitters that are released by andrenergic and cholinergic neuronal types.

Answer 36

acetylcholine and norepinephrine

Question 37

List the two types of cholinergic recpetors.

Answer 37

nicotinic and muscarinic

Question 38

Describe the structure of nicotinic receptors.

Answer 38

inotropic receptor

Question 39

Describe the structure of muscarinic receptors.

Answer 39

metabotropic receptors

Question 40

Where are nicotinic receptors located?

Answer 40

plasma membrane of postganglionic sympathetic and parasympathetic neurons

Question 41

Where are muscarinic receptors located?

Answer 41

effectors innervated by parasympathetic postganglionic neurons

Question 42

Do nicotinic recptors result in excitation and/or inhibition?

Answer 42

excitation only

Question 43

Do muscarinic receptors result in excitation and/or inhibition?

Answer 43

both excitation and inhibition