B1: The Nervous System Flashcards
What is a stimulus?
Something that detects change in the environment
What are the five different sense organs?
- Eyes
- Ears
- Nose
- Tongue
- Skin
What is a receptor?
A group of specialised cells, which are sensitive to a stimulus and change the stimulus energy into electrical impulses.
What receptor does the eye contain?
- Light receptors that are sensitive to light.
- They have a nucleus, cytoplasm and a cell membrane.
What receptor does the ear contain?
- Sound receptors that are sensitive to sound.
- Balance receptors which are sensitive to changes in position.
What receptor does the nose contain?
- Smell receptors that are sensitive to chemical stimuli.
What receptor does the mouth contain?
- Taste receptors that are sensitive to bitter, salt, sweet, sour and the taste of savoury things. This is also chemical stimuli.
What receptor does the skin contain?
- It is sensitive to touch, pressure, pain and temperature change.
What are the sensory neurones?
The nerve cells that carry signals as electrical impulses from the receptors in the sense organs to the central nervous system.
What are the 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 central nervous system to the effector muscles or glands.
What are the effectors?
- The muscles and glands
- Muscles contract in response to a nervous impulse
- Glands secrete hormones in response to a nervous impulse.
What does CNS stand for?
The Central Nervous System.
What is the CNS?
Where all the information from the sense organs is sent and where reflexes and actions are coordinated.
What do the neurones do all together?
They transmit information very quickly to and from the CNS.
