Nerve Impulses

Question 1

Nerve impulse

Answer 1

A self propagating wave of electrical disturbance which travels along the surface of a neurone membrane

Question 2

Motor neurone

Answer 2

Connects CNS with effectors

Question 3

Sensory neurone

Answer 3

Connects sensory receptors to the CNS

Question 4

Myelin

Answer 4

-secreted by Schwann cells which completely surround axon
-electrical insulator which prevents ions leaking out of axon and insulates an axon from electrical activity in adjoining cells
-axons may be myelinated
-myelinated neurones are surrounded by a layer of fatty myelin

Question 5

Neurone membranes

Answer 5

-have various types of carrier molecule embedded within them: essential for transmission of nerve impulses
-sodium potassium pumps
-voltage gates na+ k+ channels
-carriers which allow facilitated diffusion of ions

Question 6

Resting potential

Answer 6

-the state of membrane when no impulse is passing along it
-inside of the axon is negatively charged with respect to the outside : there is a potential difference of -70mV
-membrane is said to be polarised

Question 7

Action potential

Answer 7

-the charge is reversed and the membrane becomes depolarised