eye and reflexes Flashcards
conjunctiva role
lubricates and protects surface of eye
scelera role
tough outer layer that protects eye
cornea role
bends light into eye
lens role
focuses light into retina
optic nerve role
carries impulses from receptors to brain
distant object
-ciciliary muscles relax
-suspensory ligaments pull tight
-lens goes thin
-refracrts light by a smaller amount
near object
-ciciliary muscles contract
suspensory ligaments slacken
-lens goes fat
-increased amount it refracts light
what is reflex for near and distance object called
accommodation reflex
bright light
-circular muscles contract
-pupil becomes smaller
-letting less light in
dim light
-radial muscles contract
-pupil dilates
-lets more light in
fovea role
focus point for light for clear eyesight
short sighted
cornea bends light too much (light focuses in front of retina)
long sighted
cornea or lens doesn’t bend light enough (light focuses behind the retina)
cells in retina
cone and rod
cone cells
colour of light
(don’t work well in low light)
light
rod cells
more sensitive
black and white
dim light
fovea cells
only cone
mps for nerves
-stimuli
-sensory neurone
(via synapse)
-relay neurone
(via synapse)
-motor neurone
-effector muscle
which neurone is in cns
relay
effects of adrenaline
increases:
-heart rate
-blood flow to muscles
-blood sugar level
reflex
automatic response to certain stimuli to protect organism form danger
adrenaline reflex
goes from receptor to effector through reflex arc
order of neurones
sensory
relay
motor
synapses mps
-chemicals called neurotransmitters
-diffuse
-these chemicals set of new signal in next neurone
