B5 homeostasis and response

Question 1

what does the retina do

Answer 1

contains receptor cells that are sensitive to the brightness of colour of light

Question 2

what does the optic nerve do

Answer 2

carries impulse to rest of brain

Question 3

what does the sclera do

Answer 3

forms a tough outer layer with a transparent region at the front called the cornea

Question 4

what does the iris do

Answer 4

controls the size of the pupil and the amount of light entering the retina

Question 5

what does the ciliary muscle and suspensory ligament do

Answer 5

can change shape of lens to focus light onto the retina

Question 6

what are the scientific terms for short sightedness and long sightedness and explain them

Answer 6

myopia= lens is too curved so distant things are blurry
hyperopia= lens is too flat so close things are blurry

Question 7

what is it called when blood vessels constrict

Answer 7

vasoconstriction

Question 8

what is it called when blood vessels dilate

Answer 8

vasodilation

Question 9

what is the pituitary gland

Answer 9

secretes hormones into the blood to activate other hormones or have effect on the body

Question 10

what does the pancreas do

Answer 10

-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

Question 11

what does the thyroid do

Answer 11

secretes thyroxine which controls metabolic rate, heart rate and temperature

Question 12

what does the adrenal gland do

Answer 12

secretes adrenaline which activates flight or fight

Question 13

what does the ovaries do

Answer 13

secretes oestrogen which is involved in menstrual cycle and female pubity

Question 14

what does the testes do

Answer 14

involved in the making of sperm

Question 15

explain type 1 diabetes and how it can be stopped

Answer 15

-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

Question 16

what is type 2 diabetes and how can it be stopped

Answer 16

-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

Question 17

how does the kidney create urine

Answer 17

-filtering out waste products
-selectively reabsorbing important substances like glucose, ions and water

Question 18

what is ADH

Answer 18

a hormone involved in the control of loss of water

Question 19

how does ADH work

Answer 19

-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

Question 20

what is kidney failure and name the ways you can fix it

Answer 20

when the kidney cannot filter waste products which then slowly build up and cause death it can be cured through dialysis and kidney transplants

Question 21

how does dialysis cure kidney failure and what are the adv and dis adv

Answer 21

-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

Question 22

describe the menstrual cycle with reference to hormones released

Answer 22

-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