4. Nervous System

Question 1

Neurons may be classified according to their ______ or ______

Answer 1

structure or function

Question 2

Name the three functional classifications of neurons

Answer 2

sensory (afferent)
motor (efferent)
interneurons (association)

Question 3

Define sensory neurons

Answer 3

cell body outside the CNS
unipolar in PNS
carry info from receptors to CNS

Question 4

Define motor neurons

Answer 4

cell body inside CNS
multipolar
carry info from CNS to viscera/muscles/glands

Question 5

The two characteristics of neurons are:

Answer 5

irritability & conductivity

Question 6

Irritability

Answer 6

ability to respond to stimuli

Question 7

Conductivity

Answer 7

ability to transmit electrical impulses

Question 8

Membrane potential

Answer 8

difference in electrical charge across membrane

Question 9

Action potential

Answer 9

nerve impulse, signal sent along axon of neuron

Question 10

The plasma membrane of a resting neuron is ______

Answer 10

polarised

Question 11

Polarised membrane:

Answer 11

more positive + on outside, more negative - on inside

Question 12

Main intracellular positive ions:

Answer 12

potassium

Question 13

Main extracellular positive ions:

Answer 13

sodium

Question 14

Stimulus changes the permeability of the membrane to create an _______

Answer 14

action potential

Question 15

Examples of stimuli able to excite neurons and generate action potential:

Answer 15

light, sound, heat, pressure, neurotransmitters

Question 16

Define depolarisation:

Answer 16

stimulus changes the permeability of membrane
sodium channels open, allowing Na+ ions to diffuse rapidly into cell
inside of membrane becomes more positive, outside more negative, at that site.

Question 17

Depolarisation causes:

Answer 17

membrane polarity to be completely reversed, action potential initiated.

Question 18

Define repolarisation:

Answer 18

potassium channels open, allowing K+ ions to diffuse out of the cell
restores negative charge on inside, positive charge on outside

Question 19

Sodium-potassium pump:

Answer 19

restores ionic conditions of the resting state
pumps excess sodium ions out & potassium in
fuelled by ATP

Question 20

Schwann cells produce _______

Answer 20

myelin sheaths the wrap around axon

Question 21

Myelination causes the nerve signal to _________

Answer 21

travel faster because it has to jump from node of Ranvier to node of Ranvier = saltatory conduction

Question 22

Central Nervous System:

Answer 22

brain & spinal cord

Question 23

Peripheral Nervous System:

Answer 23

cranial & spinal nerves

Question 24

Cranial nerves:

Answer 24

carry impulses to & from the brain

Question 25

Spinal nerves:

Answer 25

carry impulses to & from the spinal cord

Question 26

Two divisions of peripheral nervous system:

Answer 26

1. sensory/afferent

2. motor/efferent

Question 27

Two subdivisions of motor/efferent division:

Answer 27

1. somatic

2. autonomic

Question 28

The somatic nervous system:

Answer 28

controls skeletal muscles, under voluntary control

Question 29

The autonomic nervous system:

Answer 29

controls smooth & cardiac muscle, glands

Question 30

The two subdivisions of the autonomic nervous system:

Answer 30

1. sympathetic - ‘fight or flight’ - ‘s’ for ‘stress’

2. parasympathetic - ‘rest & digest’

Question 31

Somatic motor neurons control which type of muscle?

Answer 31

skeletal muscle

Question 32

Autonomic motor neurons control which type of muscle?

Answer 32

smooth and cardiac muscle