the nervous system Flashcards
What does a co-ordinated response require?
- a stimulus
- a receptor
- an effector
How are organisms able to respond to changes in their environment?
The nervous system allows organisms to respond to changes in their environment.
How does the nervous system work?
Changes in our environment are detected by receptors.
A neurone carries nerve impulses from the receptor to the coordinator.
The coordinator determine whether to respond to the change or not.
A neurone will carry information from the coordinator to an effector.
What are the coordinators?
The brain or the spinal cord.
What is an effector?
An effector is a muscle or gland which can carry out a response.
what is a receptor?
A receptor is a group of specialised cells which detect a change in the environment.
For example, skin receptors detect temperature and pressure but eye receptors detect light.
How does hormonal communication control responses?
First hormones produced by the endocrine glands are released by the pituitary gland into the bloodstream.
These hormones travel in the bloodstream to target tissue where they bind to special receptors to produce a response.
What are the differences between hormonal and nervous systems?
The nervous system is fast while the hormonal system is slow.
The nervous system uses electrical impulses to trigger a response and the hormonal system uses hormones.
What does the central nervous system consist of?
The brain and the spinal chord.
What links the central nervous system and the sense organs?
Nerves
What happens when receptors in the sense organs are stimulated?
Electrical impulses are sent along nerves into and out of the central nervous system to trigger fast responses.
What is the role of neurotransmitters at synapses?
What do motor neurones do?
They carry nerve impulses away from the central nervous system.
What do relay neurones do?
They carry nerve impulses from the sensory neurones to the motor neurones.
What do sensory neurones do?
They carry nerve impulses towards the central nervous system.
