topic 7: animal coordination and homeostasis

Question 1

what is a hormone

Answer 1

a chemical messenger secreted by a gland, they travel through the bloodstream to targeted organs, though they are slower acting that electrical impulses they are longer lasting.

Question 2

what are the two hormones responsible for controlling blood glucose

Answer 2

insulin-decreases blood glucose by encouraging the liver to turn glucose into glycogen stores

glucagon- signals the liver to break down glycogen back into glucose for respiration

Question 3

how do contraceptive pills stop women getting pregnant

Answer 3

contains progesterone that inhibits the production of LH and FSH making an egg unable to grow in the uterus

Question 4

what hormone causes the lining of the uterus to thicken

Answer 4

oestrogen

Question 5

what is a disadvantage of treating infertility with hormone treatment

Answer 5

increase’s complications and there is a likelihood of more that one birth

Question 6

what is metabolic rate

Answer 6

the rate at which energy stored in your food is transferred by all the reactions that take place in your body to keep you alive

Question 7

what is adrenalin do and what are its effects (target organs include heart, muscles and liver)

Answer 7

.binds to receptors in the heart, making it contract more frequently and increase overall heart rate

.increases blood flow to muscles allowing cells to receive more oxygen and glucose for respiration

.adrenaline binds to liver and causes it to break glycogen stores into glucose for respiration

Question 8

how does thyroxine control metabolic rate (when levels are low)

Answer 8

.low levels of thyroxine stimulate the hypothalamus to release TRH

.TRH stimulates the pituitary gland to release TSH

.TSH stimulates the thyroid gland to release thyroxine, causing thyroxine levels to rise again

Question 9

how does thyroxine control metabolic rate (when levels are too high)

Answer 9

.higher than normal levels of thyroxine inhibit the production of TRH

.low levels of TRH inhibit production of TSH which cause thyroxine levels to drop

.thyroxine levels get lower as a result of negative feedback

Question 10

what are the 4 physical stages of the menstrual cycle

Answer 10

stage 1: menstruation starts the lining of the uterus breaks down and is released

stage 2: the uterus lining is repaired from day 4-14 and thickens in preparation for a fertilised egg

stage 3: egg develops and is released by ovaries

stage 4: if no egg is fertilised the spongy lining begins to breakdown by day 28 and the cycle repeats.

Question 11

what are the hormonal stages of the menstrual cycle

Answer 11

FSH: released by the pituitary causes a follicle to mature in the ovaries and stimulates oestrogen

Oestrogen: released by the ovaries, thickens the uterus lining and stimulates LH surge at high levels

LH: released by the pituitary gland LH stimulates ovulation where the follicle ruptures and an egg is released

the remains turns into a corpus luteum which secrets progesterone

Progesterone: released by corpus luteum after ovulation, maintains the lining and inhibits FSH and LH.
When progesterone levels drop oestrogen gets low and so the uterus lining of the uterus falls.

low progesterone stimulates FSH and the cycle repeats

Question 12

what are the 5 types of hormonal contraceptives

Answer 12

IUD
combined pill
progesterone only pill
contraception patch
contraceptive implant

Question 13

how does the combined pill work

Answer 13

oestrogen: stimulates thick mucus preventing sperm from reaching the egg

progesterone: inhibits the production of FSH meaning no egg is released

Question 14

how does the contraceptive implant work

Answer 14

slowly releases progesterone for up to 3 years

Question 15

how does the IUD work

Answer 15

implanted into the uterus
releases progesterone

Question 16

describe the process of IVF

Answer 16

.women are given FSH and LH to stimulate egg maturation

.eggs are collected and fertilised outside the body

.eggs are placed in a incubator to grow into embryo

.some are reinserted back into the mother uterus to grow

Question 17

pros and cons of IVF

Answer 17

pros: allows for infertile couples

cons: doesn’t always work
stressful and upsetting
often leads to multiple births which could lead to still births

Question 18

why is thermoregulation so important

Answer 18

to maintain an optimum temperature for enzyme activity, with an optimum of (37), if temp drops the enzyme activity will slow down, if they get too high they might denature

Question 19

what does the body do when temperature is too hot

Answer 19

.erector muscles relax so hairs lie flat

.sweat forms on the top of the skin, when it evaporates thermal energy is removed from the body

.blood vessels close to the surface of skin dilate to allow more blood to flow near the surface to transfer energy out into the surroundings

Question 21

what does the body do when temperatures are too low

Answer 21

.erector muscles stand up to trap an insulating layer of air

.little sweat is produced to reduce heat energy transfer

.blood vessels near the skin surface restrict to reduce energy transferred to the surroundings

.shivering allow muscle to contract increasing rate of respiration and more energy

Question 22

what role does the hypothalamus have in thermoregulation

Answer 22

contains receptors that are sensitive to the blood temperature in the brain
receives impulses from receptors in the skin that give information on external temperatures, located in the epidermis and the dermis

Question 23

what is the epidermis

Answer 23

outer layer of the skin

Question 24

what is the dermis

Answer 24

deeper layer of the skin below the epidermis

Question 25

what causes type 1 diabetes

Answer 25

when pancreatic cells do not produce insulin because cells have been destroyed by the body’s immune system

Question 26

how is type 1 diabetes controlled

Answer 26

insulin injections

Question 27

how does type 2 diabetes occur

Answer 27

when insulin producing cells do not produce enough insulin or organs do not respond properly to the insulin produced

Question 28

how to treat type 2 diabetes

Answer 28

.eating healthier or reducing amount of sugar in diet
.increasing physical activity
.