Ch. 12 Coordination and response Flashcards
What are stimuli?
Changes in the organism’s environment
What are stimuli sensed by?
Receptors
What are effectors?
Part of body which responds to stimulus
What is necessary between receptors and effectors?
Communication
What’s coordination?
The way in which receptors detect stimuli and pass information to effectors
What are nerves?
A group of neurone axons lying together
What are ways into which informations are transmissed?
- Nerves
- Chemicals (hormones)
What are neurones?
Cells used to conduct electrical impulses rapidly
What do neutrons contain?
Nucleus, cytoplasm, cell membrane
What is an axon?
A fibre of cytoplasm that extends from body cell of a neurone, allows it to pass information quickly
What are dendrites?
Shorter fibres of cytoplasm extending from cell body
What are nerve impulses?
Electrical signals that pass rapidly along an axon
What are nerve impulses picked up by? What are they passed to?
Picked up by dendrites, passed to cell body, then to axon, then to next neurone
What are the two nervous system?
- CNS
- PNS
What’s CNS? What is it made up by?
- Central nervous system
- Made up by brain and spinal chord
What’s PNS? What is it made up by?
- Peripheral nervous system
- Made up by nerves extending from brain and spinal chord
How does neurone transmission work?
Sensory receptor detects something
Receptor starts off electrical impulse
Sensory neurone carries impulse from sensory receptor
Relay neurone passes impulse to brain and to motor neurone
Motor neurone passes impulse to effector
What is a reflex arc?
The pathway the nerve impulse (sensory neurone, relay neurone, motor neurone) passes
What’s a reflex action?
A means of automatically and rapidly integrating and coordinating stimuli with the response of effectors
What are synaptic gaps?
Gaps between a pair of neurones
What are synapses?
End of two neurones + small gap between them
How do synapses work?
Ends of neurone contain vesicles
vesicles contain neurotransmitter
electrical impulse causes vesicles to move
vesicles attach to end of neurone
vesicles empty content (neurotransmitter)
neurotransmitter attach to receptor proteins
this binding causes an electrical impulse
Why are synapses important?
They are a one way valve which ensures travel in only one direction
What are sense organs?
A group of cells that respond to a specific stimulus
What is the retina?
A tissue at the back of the eye that contains receptor cells that respond to light
Why are eyes always humid?
Because a fluid containing lysozyme (bacteria killer enzyme) is washed across eye by eyelids
Where does retina send electrical impulse?
Through optic nerve
What is the blind spot?
The part where optic nerves leaves ad where there are no receptor cells
What is the fovea?
The part where the receptor cells are packed most closely together
What are rods?
A kind of receptor which is sensitive to dim light but not colour