cells + control // nervous system

Question 1

List the parts of the nervous system

Answer 1

The brain and the spinal cord.

Question 2

Describe how the nervous system detects stimuli

Answer 2

Receptors are groups of specialised cells. They detect a change in the environment stimulus. In the nervous system this leads to an electrical impulse being made in response to the stimulus. Sense organs contain groups of receptors that respond to specific stimuli

Question 3

Describe the structure of sensory neurones

Answer 3

Most sensory neurones have an axon that branches into two extensions — one connected to dendrites that receive sensory information and another that transmits this information to the spinal cord

Question 4

Describe the routes that impulses take to and from the brain

Answer 4

Receptor in the skin detects a stimulus (the change in temperature). Sensory neurones send electrical impulses to relay neurones, which are located in the spinal cord. They connect sensory neurones to motor neurones. Motor neurone sends electrical impulses to an effector. Effector produces a response (muscle contracts to move hand away).

Question 5

Explain how sensory neurones are adapted to their functions

Answer 5

They are adapted to carry electrical impulses from one place to another. A bundle of neurones is called a nerve. In a stimulated neurone, an electrical nerve impulse passes along the axon. the axon is insulated by a fatty (myelin) sheath - the fatty sheath increases the speed of the nerve impulses along the neurone.