Neurones

Question 1

All neurones have a ___ with a nucleus and other usual organelles of an animal cell. This has extensions connecting to other neurones - ___ and ___ carry impulses towards this, and ___ away.

Answer 1

cell body, dendrons, dendrites, axons

Question 2

Some ___ are surrounded with ___, a fatty layer that acts as an ___ insulator, speeding up the electrical impulse.

Answer 2

axons, myelin sheaths, electrical

Question 3

Describe the structure of a sensory neurone.

Answer 3

Sensory neurones have one long dendron that carries nerve impulses from receptor cells to the cell body, which is located in the middle of the neurone. One short axon carries nerve impulses from the cell body to the CNS.

Question 4

Describe the structure of a motor neurone.

Answer 4

Motor neurones have many short dendrites, which carry nerve impulses from the CNS to the cell body. One long axon carries nerve impulses from the cell body to effector cells.

Question 5

Describe the structure of a relay neurone.

Answer 5

Relay neurones have many short dendrites. These carry nerve impulses from sensory neurones to the cell body. An axon carries nerve impulses from the cell body to motor neurones.