B7 Animal Control, Coordination and Homeostasis

Question 1

What does the pituitary gland secrete?

Answer 1

TSH, FSH, LH

Question 2

What does the thyroid gland secrete?

Answer 2

Thyroxine

Question 3

What does the adrenal glands secrete?

Answer 3

Adrenaline

Question 4

What does the testes secrete?

Answer 4

Testosterone

Question 5

What does the ovaries secrete?

Answer 5

Oestrogen

Question 6

What effects does adrenaline have on the body?

Answer 6

1. More frequent muscle contractions with more force so increased heart rate and blood pressure
2. Increased blood flow to the muscles, so the cells receive more oxygen and glucose for respiration
3. Liver breaks down glycogen stores to release glucose to be transported to the cells

Question 7

What does thyroxine regulate?

Answer 7

Metabolic rate

Question 8

What happens when the blood thyroxine levels are too low?

Answer 8

1. The hypothalamus releases TRH
2. TRH stimulates the pituitary gland to release TSH
3. TSH stimulate the thyroid gland to release thyroxine, so the blood thyroxine levels rise back to normal
4. When the blood thyroxine levels become higher than normal, the release of TRH from the hypothalamus is inhibited, which reduces the production of TSH so the blood thyroxine levels fall

Question 9

What are the stages of the menstrual cycle?

Answer 9

Stage 1: The lining of the uterus breaks down and is released
Stage 2: Day 4-14, the uterus lining builds up and becomes thick and spongy
Stage 3: Day 14 - the egg develops and is released from the ovary
Stage 4: The lining is maintained until day 28. If no fertilised egg landed on the uterus wall by day 28, the lining breaks down and the cycle repeats

Question 9

What is the role of FSH in the menstrual cycle?

Answer 9

It is released by the pituitary gland and causes a follicle to mature in the ovaries. It stimulates the production of oestrogen

Question 9

What is the role of LH in the menstrual cycle?

Answer 9

It is released by the pituitary gland which stimulates ovulation. It also stimulates the corpus luteum to secrete progesterone

Question 9

What is the role of oestrogen in the menstrual cycle?

Answer 9

It is released by the ovaries and causes the lining of the uterus to thicken and grow. A high level stimulates LH

Question 10

What is clomifene therapy?

Answer 10

FSH and LH is released into the body, stimulating egg maturation and ovulation. The couple can have intercourse during this time period to improve the chance of becoming pregnant

Question 10

What is the role of progesterone in the menstrual cycle?

Answer 10

It is released by the corpus luteum after ovulation to maintain the lining of the uterus. It inhibits the release of FSH and LH and when it falls, the uterus lining breaks down

Question 10

What is IVF?

Answer 10

FSH and LH are given and then eggs are collected from the woman’s ovaries and fertilised in the lab using the man’s sperm. These are then grown into embryos and transferred into the woman’s uterus to improve the chance of pregnancy

Question 10

What is the mini-pill?

Answer 10

A pill that only contains progesterone

Question 10

What is the combined pill?

Answer 10

A pill that contains both oestrogen and progesterone

Question 11

What happens if the blood glucose concentration is too high?

Answer 11

1. Pancreas secretes insulin
2. The insulin makes the liver turn glucose into glycogen or the uptake of glucose in the body cells
3. Blood glucose concentration is decreased

Question 12

What happens if the blood glucose concentration is too low?

Answer 12

1. Glucagon is secreted by the pancreas
2. Glycogen is then turned into glucose
3. Glucose is released into the blood by the liver
4. Blood glucose concentration is increased

Question 13

What is type 1 diabetes?

Answer 13

When the body’s immune system destroys the insulin-producing cells in the pancreas

Question 14

How can type 1 diabetes be treated?

Answer 14

An insulin injection in fat under the skin

Question 15

What is type 2 diabetes?

Answer 15

When the pancreas doesn’t produce enough insulin or the person becomes resistant to insulin

Question 16

How can type 2 diabetes be treated?

Answer 16

Exercising regularly

Question 17

What happens when you’re too hot?

Answer 17

1. Erector muscles lie flat
2. Lots of sweat is produced in sweat glands in the dermis. The sweat is released onto the surface of the skin through pores in the epidermis which evaporates and transfers energy from your skin to the environment
3. Blood vessels close to the surface of the skin widen causing vasodilation. It allows more blood to flow near the surface so it can transfer more energy into the surroundings

Question 18

What happens when you're too cold?

Answer 18

1. Erector muscles contract. Hairs stand on end to trap an insulating layer of air 2. Very little sweat is produced 3. Blood vessels near the surface of the skin constrict (vasoconstriction). This means less blood flows near the surface, so less energy is transferred to the surroundings 4. You shiver, increasing your rate of respiration which transfers more energy to warm the body

Question 19

How is blood filtered in nephrons?

Answer 19

1. The glomerulus is capillaries wound into a tight ball, creating high pressure. The small parts of blood such as glucose, ions, and urea are filtered into the Bowman's capsule with larger molecules such as red blood cells and proteins staying in the blood. 2. As the liquid flows along the nephron, all the glucose, some ions and water are selectively reabsorbed against the concentration gradient using active transport in the first convoluted tubule. 3. Whatever isn't reabsorbed continues out of the nephron via the collecting duct into the ureter then the bladder as urine. Urine is released through the urethra

Question 20

How is water content controlled?

Answer 20

In the loop of Henle, if the water concentration is low, the pituitary gland releases ADH which makes the collecting duct more permeable so water is able to be absorbed by the blood. If water concentration is too high, ADH is inhibited which makes the loop of Henle less permeable so water isn't absorbed by the blood