Topic 7

Question 1

State the endocrine gland that releases oestrogen

Answer 1

Ovaries

Question 2

During clomifene therapy, the woman has a blood test on day 20 of the menstrual cycle.

The blood test shows a high level of progesterone.

Explain the cause of this high level of progesterone on day 20 of the menstrual cycle

Answer 2

Day 20 is after ovulation
this means progesterone is produced by the corpus luteum
to maintain the lining of the uterus

Question 3

Which hormone causes ovulation

Answer 3

LH

Question 4

State why a barrier method of contraception may be used in addition to a hormonal method

Answer 4

To prevent transmission of STIs

Question 5

Explain why taking high levels of oestrogen and progesterone in the combined contraceptive pill reduces the chance of pregnancy

Answer 5

Inhibit the release of FSH so the eggs do not develop in the follicle / eggs mature

inhibits the release of LH so ovulation is prevented

Question 6

Where is progesterone produced

Answer 6

corpus luteum

Question 7

Explain how clomifene therapy may increase the chance of a woman over the age of 50 becoming pregnant

Answer 7

It causes the release of FSH

which stimulates eggs to develop in the follicles

Question 8

How does IVF help improve female fertility

Answer 8

Involves fertilisation outside of the body

the fertilised egg cell can be implanted directly into the uterus

Question 9

How does Clomifene therapy improve female fertility

Answer 9

It introduces hormones to the body

it can stimulate hormones such as LH and FSH

Which allows eggs to be released

Question 10

Explain how the release of adrenalin can result in the improved performance of an athlete

Answer 10

Adrenaline causes an increased heart rate

so there is an increased blood flow

so there is increased oxygen

to increase the rate of respiration

to release energy for the muscles

Question 11

What are the target organs for the pancreas

Answer 11

Liver and muscles

Question 12

How is adrenaline transported around the body

Answer 12

Dissolved in blood plasma

Question 13

Explain how negative feedback, involving the thyroid gland controls metabolic rate

Answer 13

Low levels of thyroxine cause TRH to be produced

TRH is produced in the hypothalamus

this causes TSH to be released from the pituitary

TSH causes the thyroid gland to produce thyroxine

as thyroxine levels increase it inhibits the release of TRH

Question 14

Explain the effects of adrenaline on liver cells during exercise

Answer 14

Adrenaline binds to liver cells

it triggers liver cells to convert glycogen into glucose

this increases the glucose blood concentration

Question 15

How is a sweat gland involved in thermoregulation

Answer 15

It releases water onto the surface of the skin, this is where heat is removed by evaporation of the water

Question 16

Explain the role of vasodilation in thermoregulation

Answer 16

Vasodilation cools down the body

it causes more blood to flow near the surface

and less blood to flow in the shunt valves, this causes an increase in thermal energy loss

Question 17

What controls the body temperature

Answer 17

The hypothalamus

Question 18

The kangaroo rat has a longer loop of Henle than most mammals.

Explain why this adaptation is beneficial to the kangaroo rat

Answer 18

The Kangaroo rat lives in the desert, this means it needs to retain as much water as possible

as most water is reabsorbed in the loop of Henle, a longer loop gives more surface area for the water to be reabsorbed

Question 19

Explain how the blood entering the nephron of the kangaroo rat is filtered to remove excess sodium ions and water.

Answer 19

Ultrafiltration occurs in the glomerulus where the liquid part of the blood passes into the Bowmans capsule

Reabsorption takes place as it travels through the proximal convoluted tube into the loop of Henle

Finally urine production occurs in the collecting duct and excess fluid and sodium ions are removed

Question 20

Explain how sweating helps to cool the body

Answer 20

Water is released onto the skin and is evaporated

Question 21

Explain how shivering helps to regulate body temperature

Answer 21

Causes increased muscle contractions, this generates energy by friction, shivering stops the body temperature from falling when the external temperatures drop

Question 22

Explain how controlling the diet can be used to treat type 2 diabetes

Answer 22

Reducing the levels of glucose in the diet ensures that the glucose levels do not rise too quickly, so the insulin can cope

Question 23

What does type 2 diabetes mean

Answer 23

That the cells have stopped responding to insulin

Question 24

What does type 1 diabetes mean

Answer 24

That the patient does not produce insulin

Question 25

Describe what happens to urea as the blood passes through the dialysis machine

Answer 25

Blood is filtered in a dialysis machine

urea moves out the blood into the dialysis solution

by diffusion

Question 26

What is urea made from

Answer 26

Excess amino acids

Question 27

How does shivering increase body temperature

Answer 27

Shivering causes increased muscle contractions, this generates energy by friction so causes body temperatures to increase

Question 28

How do muscles and hairs help regulate your body temperature when it is too cold

Answer 28

The muscle contracts, causing the hair to stand up

this traps an insulating layer of air close to the skin

so less heat is lost

Question 29

Explain how high levels of amino acids in the blood causes a high concentration of urea in urine

Answer 29

Excess amino acids are broken down into urea

amino acids are broken down in the liver

then transported in the blood to the kidney

it enters the nephron during ultrafiltration, but not reabsorbed back into the blood

urine with a high concentration forms in the collecting duct

Question 30

Explain the effects of type 2 diabetes on the body

Answer 30

Blood glucose levels are high

as cells are resistant to insulin

so the liver does not convert glucose to glycogen