Lesson 2: The Nervous system Flashcards
What are the 2 main parts of the nervous system?
- CNS (central nervous system)
- Neurones running to and from the CNS.
What is the CNS?
- The brain
- The spinal chord
What does the CNS do?
- The CNS coordinates the response of effectors which may be muscles contracting or glands secreting hormones.
How is information passed through the nervous system?
- Receptors detect stimulus
- Information passes from receptors to central nervous system as an electrical impulse via neurones.
What 2 things does the nervous system enable humans to do?
-React to their surroundings.
- Co- ordinate their behaviour.
What is the function of the motor neurone?
- Motor neurone sends impulse from CNS to muscle/ gland.
What is the function of the sensory neurone?
- Sensory neurone transmitts impulses from receptor cells to CNS.
Describe what happens when you touch a hot object…
( Reflex Arc.)
UP TO MOTOR NEURONE.
1.) Stimulus is detected by receptors.
2.) Electrical impulse passes through sensory neurone.
3.) At sensory synapse, chemical is released - diffuses across to relay neurone.
4.) Chemical triggers an electrical impulse. Electrical impulse passes through relay neurone.
5.) Chemical is released at synapse of relay neurone.
6.) Chemical triggers electrical impulse in motor neurone.
What are the junctions at the end of sensory neurones known as?
- Junctions at end of sensory neurones known as synapses.
Describe what happens when you touch a hot object.
After motor neurone
- Electrical impulse passes down motor neurone to an effector.
- The muscle contracts and pulls the hand away from the heat.
Reflexes don’t involve the conscious part (decision- making) of the brain. This means reflexes are…..
- Automatic and rapid
- And protect us from danger.
