B5 homeostasis and response Flashcards
what does the retina do
contains receptor cells that are sensitive to the brightness of colour of light
what does the optic nerve do
carries impulse to rest of brain
what does the sclera do
forms a tough outer layer with a transparent region at the front called the cornea
what does the iris do
controls the size of the pupil and the amount of light entering the retina
what does the ciliary muscle and suspensory ligament do
can change shape of lens to focus light onto the retina
what are the scientific terms for short sightedness and long sightedness and explain them
myopia= lens is too curved so distant things are blurry
hyperopia= lens is too flat so close things are blurry
what is it called when blood vessels constrict
vasoconstriction
what is it called when blood vessels dilate
vasodilation
what is the pituitary gland
secretes hormones into the blood to activate other hormones or have effect on the body
what does the pancreas do
-secretes insulin which reduces blood glucose levels by storing glucose as glycogen
-it can also secrete glucagon which gets the liver to break down glycogen into glucose to go back into the blood
what does the thyroid do
secretes thyroxine which controls metabolic rate, heart rate and temperature
what does the adrenal gland do
secretes adrenaline which activates flight or fight
what does the ovaries do
secretes oestrogen which is involved in menstrual cycle and female pubity
what does the testes do
involved in the making of sperm
explain type 1 diabetes and how it can be stopped
-type 1 diabetes is when the pancreas cannot produce insulin
-can be treated with insulin injections and reducing amount of simple carbs consumed
-doctors are trying to stop it by using pancreatic cell transplants
what is type 2 diabetes and how can it be stopped
-body cells don’t respond to insulin
-can be stopped by exercising more, reducing fat and reducing amount of simple carbs eaten
-there are drugs that can increase effectiveness as well
how does the kidney create urine
-filtering out waste products
-selectively reabsorbing important substances like glucose, ions and water
what is ADH
a hormone involved in the control of loss of water
how does ADH work
-released by the pituitary gland
-travels through the blood stream to the liver tubules
-this increases the tubules’ permeability so more water gets into the blood stream
-this means less urine is lost through urination
what is kidney failure and name the ways you can fix it
when the kidney cannot filter waste products which then slowly build up and cause death it can be cured through dialysis and kidney transplants
how does dialysis cure kidney failure and what are the adv and dis adv
-the function of the kidney is carried out with artificial membranes surrounded by dialysis fluid which has the same concentration of ions and glucose as blood
-must be done three times a week
-has a possibility of blood clots and you must follow a strict diet
describe the menstrual cycle with reference to hormones released
-FSH creates maturation of an egg in the ovaries within the follicle and then stimulates ovaries to produce oestrogen
-oestrogen then causes the line of the uterus to grow again and causes the secretion of LH
-LH releases an egg from one of the ovaries
-progesterone supports a pregnancy
