section 6 - coordination and response Flashcards
what do receptors do
detect stimuli from changes in environment
what do effectors do
response to stimuli - include muscle cells and cells found in glands
what are neurones
nerve cells
what are 3 main types of neurone
sensory, relay, motor
what does the CNS consist of
brain and spinal chord
how do neutrons transmit information
high speed impiulses and rapid responses
what is the connection between 2 neurone called
synapse
what are the chemicals called that transfer nerve signals
neurotransmitters which diffuse across the gap
what to the chemicals set off
a new electrical signal in the next neurone
what is an example of a reflex
bright light causing ur pupils to get smaller. blinking
describe the reflex arc
stimulus detected by receptors causes and electrical impulse to be sent along a sensory neurone to CNS. in the CNS the sensory neurone passes to relay neurone to the motor neurone to the effector. it is quicker than a normal resp[onse
what is the conjunctive for
protects the eye
what is the function of the cornea
refracts light into the eye
what is the iris for
controls diameter of the pupil and how much light enters the eye
what is the lens for
focuses the light onto the retina
fovea
blind spot
what is the retina for
captures the light
what does the optic nerve do
carries impulses from the receptors to the brain
at happens in bright lite
circular muscles contract, radial muscles relax and the pupils constrict
what happens in dim light
circular muscles relax, radial muscles contract causing the pupil to dialate
what is changing the shape of the lense called
acommodation
what happens at distant objects
cililary muscles relax, suspensory muscles pull tight, lens goes thin and less curved so refracts light by smaller amount
what happens with near objects
ciliary muscles contract, suspensory ligaments slacken. lens becomes fat and more curved which increases the amount of light it refracts
what happens to eyes as you get older
lens loses flexibility so cant easily spring back to round shape which means light can’t be focused well for near viewing.