B9.1 - Nervous control in humans Flashcards
What is a nerve impulse?
An electrical signal that passes along nerve cells called neurones.
What is the Central Nervous System made up of?
The brain and the spinal cord.
What are neurones?
- nerve cells
- carry info as electrical impulses
- up to 100 m/s
What nerves are in the peripheral nevous system?
Sensory neurones and motor neurones.
What nerves are in the CNS?
Relay neurones.
What is the placement of the cell body on a sensory neurone?
Off to one side.
What is the placement of the cell body on a motor neurone?
At the end.
What is the axon?
A long fibre which carries info away from the cell body.
What is the placement of the cell body on a relay neurone?
In the middle.
What is the fatty sheath made of?
Myelin.
What are the 7 parts of a reflex arc?
- Stimulus
- Receptor
- Sensory neurone
- Relay neurone
- Motor neurone
- Effector
- Response
What is a reflex action?
A rapid, automatic, involuntary response to certain stimuli that don’t involve the conscious part of the brain.
What is a voluntary action?
An action involving a conscious decision so they take longer. The responses can be different.
What is an involuntary action?
An action that does not involve a conscious decision. They are faster than voluntary actions and produce the same responses to certain stimuli.
Name two reflexes.
Pupil reflex.
Knee jerk.
Move body part away from hot surface.
(any two)
