1.5.6 neurons

Question 1

Neurones

Answer 1

Neurones are cells that transmit information from receptors to effectors

Question 2

sensory neurones

Answer 2

Sensory neurones carry nervous impulses from receptors (e.g. pressure receptors) into the Central Nervous Systems (CNS).

Question 3

motor neurones

Answer 3

Motor neurones carry impulses from the CNS to effector organs (e.g. muscles or glands).

Question 4

relay neurones

Answer 4

Relay neurones are intermediate neurones.

Relay neurones receive impulses from a sensory neurone and relay them to motor neurones.

Question 5

basic structure

Answer 5

Neurones can be myelinated or non-myelinated but all neurones have the following basic structures:
Dendrites - carries nervous impulses towards a cell body.
Axons - carries nervous impulses away from the cell body.
Cell body - where the nucleus is normally located.

Question 6

myelinated motor neurones

Answer 6

Motor neurones in vertebrates are usually myelinated.
Schwann cells are wrapped around the axon of the neurone. These cells form the myelin sheath.
Gaps between adjacent Schwann cells are called nodes of Ranvier.
Most neurones in the central and peripheral nervous system are myelinated. This is because fast transmission from the brain to muscles is often required.
Myelin sheaths insulate neurones, increasing the speed of impulse transmission.

Question 7

non-myelinated neurones

Answer 7

on-myelinated neurones do not contain a myelin sheath. They still contain dendrites, axons, and a cell body.
They conduct impulses slower than myelinated neurones.
Non-myelinated neurons tend to be found in the autonomic nervous system.
The autonomic nervous system is the part of the nervous system that supplies the internal organs, such as the stomach, intestine, and kidneys.
Nerve transmission to internal organs often does not need to be as fast as transmission to muscles.