coordination and response Flashcards
(56 cards)
what do receptors detect
stimuli and effectors produce a response
receptors in the sense organs are groups of cells that detect external stimuli
what are effectors
are cells that bring about response to stimuli. They include muscle cells and cells found in glands e.g the pancreas. Effectors respond in different ways
what do receptors do
communicate with effectors via the nervous system the hormonal system or sometimes both
what is the cns
central nervous system (cns) coordinates information
consist of the brain and spinal cord
what are the 3 main types of neuron
sensory neuron
relay neuron
motor nueron
what is the job of the CNS
coordinate the respond accordingly
coordinated responses always need a stimulus a receptor and an effector
what do reflexes help
prevent injury
what are reflexes
automatic response to certain stimulia - they can reduce the chance of being injured
name the 6 steps a reflex arc goes through
- cupcake candle burns finger
- stimulation of the pain receptor
- impulses travel along the sensory neurone
- impulses are passed along a relay neurone, via a synapse.
- impulses travel along a motor neurone, via a synapse
- when impulses reach muscle, it contracts
what is the block diagram to reflect a reflex arch
stimulus|Receptor|sensory|Relay|Motor|Effector|respons
Neurone
Learn the eye with all its labels
p45
what is the conjunctiva
lubricates and protects the surface of the eye
what is the cornea
refracts (bends) light into the eye. The cornea is tansparent and has no blood vessels to supply it with oxygen so diffuses it from outer layers
what is the iris
controls the diameter of the pupil (the hole in the middle of the eye) and therefore how much light enters
what is the lense
focuses the light onto the retina (the light sensitive part - its covered in light receptors called rods and cones)
what is the optic nerve
carries impulses from the receptors to the brain
what happens to the pupil in bright light
it shrinks (circular muscles contract)
what happens to the pupil in low light
it expands (circular muscles relax)
what is the process on focusing on near by objects
ciliary muscles contract, which slackens the suspensory ligment
lens becomes fat
what is the process on focusing on objects at a distance
ciliary muscles relax which allows the suspensory ligaments to pull tight
this makes the lens go thin
what happens to long sighted people
unable to focus on near objects
occurs when or lens doesn’t bend the light enough or the eye ball is too short. the image of near objects are bought to focus behind the retina
what happens to short sighted people
people are unable to focus on distant objects
this occurs when the cornea or lens bends the light too much or the eye ball is too long. The images of distant objects are bought into focus in front of the retina
what are hormones
chemical messengers sent in the blood
where are hormones released
released directly into the blood. They are carried in the blood plasma to other parts of the body but only affect particular cells (called target cells)
