eye Flashcards
What is the conjunctiva and its role?
Layer covering eye. Helps to lubricate it.
What is the lens and its role?
Transparent structure behind pupil. Helps to refract and focus light
What is the pupil and iris and their role?
Pupil- hole in centre of iris
Iris- lightened tissue.
Controls amount of light entering the eye
what is the job of the CNS
to coordinate a response
what does the CNS consist of
brain and spinal cord
order of the message
Recepotors detect stimulus
Send electrical impulses along sensory neutrons to the CNS
CNS send effector along a motor neurone
The effector then responds accordingly
what is a synapse
the connection between two neutrons
what are reflexes
responses that you don’t have to think about so they are quicker
what is the sclera
is the tough outer layer that protects the eye
what is the optic nerve
carries impulses form the receptors to the brain
what happens to the eye in bright light
triggers a reflex that makes the pupil smaller allowing less light in
what happens to the eye in dim light
in dim light the radial muscles contract which makes the pupil bigger
what happens when looking at distance muscles
the Hillary muscles relax which allows the suspensory ligaments to pull tight
this makes the lens go thin
so it refracts light by a smaller amount
to look at near objects
the ciliary muscles contract which slackens the suspensory ligaments
the lens becomes fat
this increases the amount by which it refracts light
what happens with short sighted people
cornea ir lens bends to much light so the imagine of distant objects are brought into focus in front of the retina
what happens with long sighted people
when the corn or lens doesnt bend the light enough. the objects are brought into focus behind the retina
what is the role of adrenaline
readies the body for a fight or flight response
what is the source adrenaline
adrenal glands
what are the effects of adrenaline
increases heart rate, blood flow to muscles and blood sugar level
where is source of insulins
pancreas
what is the role of insulin
helps control the blood sugar level
what are the effects of insulin
stimulates the liver to turn glucose into glycogen for storage
what is the source of testosterone
testes
what is the role of testosterone
main male sex hormone
what is the role of testorstorone
main male sex hormone
what are the differences between hormones and nerves list 4
hormones slower messages act for a longer time act in a more general way use chemical signals
what is the source of progesterone
ovaries
what is the source of oestrogen
ovaries
what is the role of progesterone
supports pregnancy
what is the role of oestrogen
main female sex hormone
what is the effect of progesterone
maintains the lining of the uterus
what is the effects of oestrogen
controls the menstral cycles and promotes female secondary sexual characterises
what is the role of ADH
controls the water content
what is the source of ADH
pituitary gland
what is the role of FSH
female sec hormone
what is the role of LH
female sex hormone
what is the source of FSH
pituitary gland
what is the source of LH
puitairay gland
what is the effects of ADH
increases the permeability of the kidney tubules to water
what is the effects of FSH
causes an egg to mature in an ovary stimulates the ovaries to produce oestrogen
what is the effects of LH
stimulates the realise of an egg from an ovary
