hormonal coordination Flashcards
What is the retina?
The area at the back of the eye with light receptor cells. Here, light is focused on by the lens
What is the sclera?
the tough white outer layer of the eye
What is the cornea?
the transparent cover to the sclera that lets light in
What does the Iris do?
It controls the size of the pupil in response to light, bright light contracts to reduce the amount of light entering through the pupil.
What do the suspensory ligaments and the ciliary muscles do?
They hold the lens in place and helps it to focus.
What does the lens of the eye do?
It focuses light onto the retina.
What is the blind spot?
The area of the retina by the optic nerve where there are no light receptor cells.
What does the lens do to project light on to the retina?
Light refracts through the focused lens and the cornea and jelly of the eyeball. The shape of the lens is altered by ciliary muscles to alter the amount of refraction. The image we generate is upside down and turned upside again by the brain.
What happens when the light receptor cells detect light on the retina?
impulses are sent through the optic nerve to the brain which flips the image the right way around.
How does the lens refract to look at a distant object?
The ciliary muscles relax, suspensory ligaments pulled tightly, lens flattens, refracts slightly onto retina.
How does the lens refract to see a nearby object?
The ciliary muscles contract, suspensory ligaments relax, lens thickens and curves, refracts strongly onto retina.
What is myopia?
Short sightedness
What is hyperopia?
Long sightedness
Name 3 ways to correct poor vision
- Contact lenses
- Laser eye surgery
- Replacement lens
What is it called when the lens changes shape?
Accommodation
What is the endocrine system?
A system of glands that secrete chemical hormones into the blood stream to target organs to control how they work.
How does the endocrine system compare to the nervous system?
The endocrine system is slower but has more long lasting effects.
What does the pituitary gland do?
It controls all other glands via secretion of many hormones in response to body conditions. The hormones stimulate other glands to produce hormones in a chain effect for specific outcomes in the body.
Which other glands are in the endocrine system?
The thyroid gland, pancreas, adrenal glands, ovaries, testes
What are the main hormones of the endocrine system?
Pituitary gland produces growth hormone, ADH, oxytocin. Thyroid produces Thyroid hormone. Pancreas produces insulin, glucagon. Adrenal gland produces adrenaline, noradrenaline, Ovary produces oestrogen and progesterone.
