Topic 6A - Stimuli and Respnses Flashcards
What is a stimulus?
A stimulus is a change in the internal or external environment.
What detects a stimulus?
A receptor.
What carries out a response to a stimulus?
An effector.
Why do organisms respond to their environment?
To increase their chance of survival.
What is a tactic response?
A directional movement is response to a stimulus.
What is a kinetic response?
A non-directional movement in response to a stimulus.
What are receptors? (2)
They can be cells or proteins on cell surface membranes.
What are effectors? (2)
They can be muscles or glands.
What do sensory neurones do?
Transmit electrical impulses from receptors to the CNS.
What do relay neurones do?
Transmits electrical impulses between sensory neurones and motor neurones.
What do motor neurones do?
Transmit electrical impulses from the CNS to the effector.
What is the CNS?
The central nervous system, which consists of the brain and spinal cord.
What is the pathway of nervous communication?
A stimulus is detected by receptor cells and and electrical impulse is sent along a sensory neurone. The CNS processes the information and sends impulses along a motor neurone to an effector, which carries out a response.
What is a reflex?
A rapid, involuntary response to a stimulus.
What is the reflex arc?
Stimulus –> Receptors –> Sensory neurone –> Relay neurone –> Motor neurone –> Effectors –> Response
