The Nervous System Flashcards
(26 cards)
What is the function of the nervous system?
It allows you to react to what goes on around you
What is a stimulus?
A change in your environment which you may need to react to
What are the 5 sense organs?
- Eyes
- Ears
- Nose
- Tongue
- Skin
What are receptors?
A group of cells which are sensitive to stimulus. They change stimulus energy into electrical impulses
Name examples of a stimulus
Light, sound, touch, pressure, chemical, change in position or temperature
Name the receptors for each sense organ
Eye- light receptors
Ears- sound receptors, sensitive to change in position
Nose- smell receptors , sensitive to chemical stimuli
Skin- touch, pressure and temperature change
Tongue - taste receptors, chemical stimuli
What are the job of sensory neurones?
These are the nerve cells that carry signals as electrical impulses from the receptions in the sense organs to the central nervous system
What are relay neurones?
The nerve cells that carry signals from sensory neurones to motor neurones
What are motor neurones?
The nerve cells that carry signals from the CNS to the effector muscles or glands
What are effectors?
Muscles and glands that respond in different ways. Muscles contract in response to a nerve impulse and glands secrete hormones
What does the CNS consist of?
The brain and spinal chord
What is the job of neurones?
To send information very quickly to and from the CNS
What is the connection between two neurones?
A synapse
How is a nerve single transferred across a synapse ?
By chemicals which diffuse across the gap
What do the chemicals in a synapse do?
The chemicals set off a new electrical signal in the next neurone
What is a reflex ?
An automatic response to a stimuli - they reduce the chances of being injured
What is a reflex arc?
The passage of information in a reflex from receptor to effector
Where do the neurones in a reflex arc travel?
Through the spinal chord or an unconscious part of the brain
Explain the process of the reflex arc, referring to synapses
After the stimulus has been detected, the impulses reach the synapse between the sensory neurones and a relay neurone and they trigger chemicals to be relatedness these chemicals cause impulses to be sent along the relay neurone. The impulses reach a synapse between the relay and motor neurone and the same thing happens. Impulses are sent along the motor neurone
State the block diagram of a reflex arc
Stimulus - receptor - sensory neurone - relay neurone - motor neurone - effector - response
What are hormones?
Hormones are chemical messengers which travel in the blood to activate target cells
How are hormones carried?
They are carried in the blood plasma to other parts of the body
What do hormones control?
Things in organs and cells that need constant adjustment
What does the pituitary gland produce?
FSH and LH
