5.1.3b sensory, relay and motor neurones

Question 1

what is the function of a neurone

Answer 1

transmit electrical impulses rapidly around the body

Question 2

structure of a neurone - features

Answer 2

cell body
dendrons
axons

Question 3

neurone - cell body

Answer 3

contains nucleus surrounded by cytoplasm
in cytoplasm large amounts of endoplasmic reticulum and mitochondria which are involved in production of neurotransmitters

Question 4

neurone - dendrons

Answer 4

short extensions that come from cell body
dendrons divide into dendrites
responsible for transmitting electrical impulses towards cell body.

Question 5

neurone - axons

Answer 5

singular elongated nerve fibres that transmit impulses away from the cell body.
fibre is cylindrical in shape and has very narrow region of cytoplasm surrounded by a plasma membrane

Question 6

what are the three types of neurones?

Answer 6

sensory
relay
motor

Question 7

sensory neurone

Answer 7

transmit impulses from receptor to CNS.
one dendron that carries impulses to the cell body
one axon that carries impulses away from cell body

Question 8

relay neurone

Answer 8

transmit impulses between neurones
have many short axons and dendrons

Question 9

motor neurone

Answer 9

transmit impulses from a relay or sensory neurone to an effector.
have one long axon and many short dendrites.

Question 10

electrical impulse pathway

Answer 10

Receptor –> sensory neurone –> relay neurone –> motor neurone –> effector cell

Question 11

what is myelin

Answer 11

an electrical insulator

Question 12

what is the myelin sheath formed by

Answer 12

Schwann cells growing around the axon several times

Question 13

what are nodes of Ranvier

Answer 13

gaps in the myelin sheath

Question 14

saltatory conduction

Answer 14

mechanism by which speed of an impulse is increased
action potential jumps from one node to the next
in myelinated neurones allows electrical impulse to travel much faster