Homeostasis and Response 2

Question 1

What is the function of the pituitary gland?

Answer 1

The pituitary gland produces many hormones that regulate body conditions. It is sometimes called the ‘master gland’ because these hormones act on other glands, directing them to release hormones that bring about change.

Question 2

What is the function of the thyroid?

Answer 2

This produces thyroxine, which is involved in regulating things like the rate of metabolism, heart rate and temperature.

Question 3

What is the function of the adrenal gland?

Answer 3

This produces adrenaline, which is used to prepare the body for a ‘fight or flight’ response.

Question 4

What is the function of the pancreas?

Answer 4

This produces insulin and glucagon which is used to regulate the blood glucose level.

Question 5

What is the role of the ovaries?

Answer 5

Produce oestrogen, which is involved in the menstrual cycle.

Question 6

What is the role of the testes?

Answer 6

Produce testosterone, which controls puberty and sperm production in males.

Question 7

What is the difference between nerves and hormones?

Answer 7

Nerves are faster but act for a shorter time and act on a very precise area.

Question 8

Describe Type 1 Diabetes.

Answer 8

Where the pancreas produces little or no insulin. It is controlled using insulin injections, insulin therapy (limiting the intake of simple carbohydrates) and taking regular exercise.

Question 9

Describe Type 2 Diabetes.

Answer 9

Where a person becomes resistant to their own insulin. It can be controlled by eating a carbohydrate-controlled diet and getting regular exercise.

Question 10

What substances are removed from the body in urine?

Answer 10

Urea - Proteins can’t be stored by the body - so any excess amino acids are converted into fats and carbohydrates, which can be stored. This occurs in the liver and involves a process called deamination. Ammonia is produced as a waste product from this process and is also filtered out of the blood in the kidneys and excreted from the body in urine.
Excess ions and water are also removed from the body in urine.

Question 11

What is a anti-diuretic hormone (ADH)?

Answer 11

ADH is released by the pituitary gland to reabsorb water from the kidney tubules if the water content is too low. The release of ADH is lowered if the water content is too high.

Question 12

What is a dialysis used for?

Answer 12

It is used by individuals with kidney damage or failure. Dialysis has to be done regularly to keep the concentrations of dissolved substances in the blood at normal levels, and to remove waste substances.

Question 13

How does a dialysis machine work?

Answer 13

The person’s blood flows between partially permeable membranes, surrounded by dialysis fluid. It’s permeable to things like ions and waste substances, but not big molecules like proteins (just like membranes in the kidney).

Question 14

What are the disadvantages of dialysis?

Answer 14

Frequent sessions (3-4 hours 3 times per week), can cause blood clots or infections and is very expensive for the NHS.

Question 15

What is the 1st stage of the menstrual cycle?

Answer 15

Stage 1 - Menstruation starts. The uterus lining breaks down for about 4 days.

Question 16

What is the 2nd stage of the menstrual cycle?

Answer 16

Stage 2 - The uterus lining builds up again, from day 4 to day 14, into a thick spongy layer full of blood vessels, ready to receive a fertilised egg.

Question 17

What is the 3rd stage of the menstrual cycle?

Answer 17

Stage 3 - An egg develops and is released from the ovary at day 14 - this is called ovulation.

Question 18

What is the 4th stage of the menstrual cycle?

Answer 18

Stage 4 - The wall is then maintained for about 14 days until day 28. If no fertilised egg has landed on the uterus wall by day 28, the spongy lining starts to break down and the whole cycle starts again.

Question 19

What is the FSH (follicle-stimulating hormone) hormone?

Answer 19

A hormone produced in the pituitary gland. It causes an egg to mature in one of the ovaries in a structure called a follicle. It stimulates the ovaries to produce oestrogen.

Question 20

What is oestrogen?

Answer 20

A hormone produced in the ovaries. It causes the lining of the uterus to grow. It stimulates the release of LH (which causes the release of an egg) and inhibits release of FSH.

Question 21

What is LH (luteinising hormone)?

Answer 21

It is a hormone produced by the pituitary gland. It stimulates the release of an egg at day 14 (ovulation).

Question 22

What is progesterone?

Answer 22

A hormone produced in the ovaries by the remains of the follicle after ovulation. It maintains the lining of the uterus during the second half of the cycle. When the level of progesterone falls, the lining breaks down. It inhibits the release of LH and FSH.

Question 23

What is the combined oral contraceptive pill?

Answer 23

An oral contraceptive containing oestrogen and progesterone. Oestrogen inhibits the release of FSH, so keeping the level of oestrogen permanently high stops egg development and production. Progesterone also reduces fertility, e.g. by stimulating the production of thick mucus which prevents any sperm getting through and reaching an egg. It is very effective however it can cause side effects. The pill can also be in the form of a contraceptive patch.

Question 24

What are some ways of contraception?

Answer 24

Contraceptive pills, patches, implants, injections and a intrauterine device (IUD) (these either release progesterone or kill sperm).

Question 25

What are non-hormonal methods of contraception?

Answer 25

Condoms, diaphragm (a shallow plastic cup that fits over the cervix (the entrance to the uterus) to form a barrier) and spermicides.

Question 26

What is IVF?

Answer 26

IVF involves collecting eggs from the woman's ovaries and fertilising them in a lab using the man's sperm. Sperm can also be injected directly into the egg if the man has a very low sperm count. The fertilised eggs are then grown into embryos in a laboratory incubator. Once the embryos are small balls of cells, one or two of them are transferred to the woman's uterus to improve the chance of pregnancy. FSH and LH are given before egg collection to stimulate several eggs to mature.

Question 27

What are disadvantages of IVF?

Answer 27

Multiple births can occur, the success rate of IVF is low and IVF is emotionally stressful.

Question 28

What is the function of adrenaline?

Answer 28

It gets the body ready for 'fight or flight' by triggering mechanisms that increase the supply of oxygen and glucose to cells in the brain and muscles. For example, adrenaline increases the heart rate.

Question 29

What is the function of thyroxine?

Answer 29

It regulates the basal metabolic rate (at rest) and stimulates protein synthesis for growth and development.

Question 30

What is auxin?

Answer 30

Auxin is a plant hormone that controls growth near the tips of shoots and roots in response to light (phototropism) and gravity (gravitropism or geotropism).

Question 31

What are uses of auxin?

Answer 31

Killing weeds - They disrupt the growth patterns of certain plants which eventually kills them. Growing cuttings with rooting powder - Grows parts of a plant that has been cut off into new plants, enabling the production of clones. Growing cells in tissue culture - Tissue culture can be used to grow clones of a plant from a few of its cells by adding auxin to the growth medium to stimulate the cells to divide to from both roots and shoots.

Question 32

What is gibberelin?

Answer 32

Gibberelin is another type of plant growing hormone that stimulates seed germination, stem growth and flowering. It is used for controlling dormancy, inducing flowering and growing larger fruit.

Question 33

What is the function of ethene in fruit?

Answer 33

Ethene is a gas produced by aging parts of a plant. It influences the growth of the plant by controlling cell division. It also stimulates the enzymes that cause fruit to ripen.