SB7

Question 1

What are hormones?

Answer 1

Chemical messengers sent in the blood.

Question 2

What are target organs?

Answer 2

A specific organ on which a hormone, drug, or other substance acts.

The hormones affect particular cells in particular organs.

Question 3

Where are hormones produced?

Answer 3

In endocrine glands. These glands make up your endocrine system.

Question 4

Name the types or endocrine glands

Answer 4

1. Pituitary gland
2. Thyroid gland
3. Ovaries
4. Adrenal glands
5. Testes
6. The pancreas

Question 5

What does the pituitary gland produce?

Answer 5

It produces many hormones that regulate body conditions. For example ACTH, FSH, LH and growth hormones.

It’s sometimes called the master gland because these hormones act on other glands, directing them to release hormones that bring about change.

Head/brain

Question 6

What does the thyroid gland produce?

Answer 6

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

Low, from neck

Question 7

What do the ovaries produce?

Answer 7

Produce oestrogen, which is involved in the menstrual cycle.

Question 8

What do the adrenals glands produce?

Answer 8

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

Top of each kidney

Question 9

What do the testes produce?

Answer 9

They produce testosterone which controls puberty and sperm production.

Question 10

What does the pancreas produce?

Answer 10

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

Across the back of the abdomen

Question 11

What’s the difference between hormones and neurones?

Answer 11

Neutrons -
Very fast action.
Act for a very short time.
Act on a very precise area.

Hormones -
Slower action.
Act for a long time.
Act in a more general way.

Question 12

What does adrenaline do?

Answer 12

Prepares you for ‘fight or flight’. Standing you ground or running.

It does this by activating processes that increase the supply of oxygen and glucose to cells.
When you brain detects a stressful situation, it sends nervous impulses to the adrenal glands, which respond by secreting adrenaline. This gets the body ready for action.

Question 13

Give an example of how adrenaline works

Answer 13

1. Adrenaline binds to specific receptors in the heart. This causes the heart muscle to contact more frequently and with more force,so heart rate and blood pressure increase.
2. This increases blood flow to the muscles, so the cells receive more oxygen and glucose for increased respiration.
3. Adrenaline also binds to receptors in the liver. This causes the liver to break down its glycogen stores to release glucose.
4. This increases the blood glucose level, so there’s more glucose in the blood to be transported to the cells.

Question 14

How is hormone release affected by negative feedback?

Answer 14

Your body can control the levels of hormones (and other substances) in the blood using negative feedback systems. When the body detects that the level of a substance has gone above or below the normal level, it triggers a response to bring the level back to normal again.

Question 15

What does thyroxine regulate?

Answer 15

Metabolism

Question 16

What happens when a negative feedback system keeps the amount of thyroxine in the blood at the right level

Answer 16

1. When the blood thyroxine level is lower then normal the hypothalamus (structure in the brain) is stimulated to release thyrotropin releasing hormone (TRH).
2. TRH stimulates the pituitary gland to release thyroid stimulating hormone (TSH).
3. TSH stimulates the thyroid gland to release thyroxine so the blood thyroxine level rises back towards normal.
4. When the blood thyroxine level becomes higher than normal, the release of TRH from the hypothalamus is inhibited, which reduces the production of TSH, so the blood thyroxine level falls.

Question 17

Name and explain the 4 stages of the menstrual cycle.

Answer 17

Stage 1: Day 1 is when the menstruation starts. The lining of the uterus breaks down and is released.

Stage 2: the uterus lining is repaired, form day 4 to day 14 until it becomes a thick spongy layer full of blood vessels ready fro a fertilised egg to implant there.

Stage 3: an egg develops and is released from the ovary (ovulation) at about day 14.

Stage 4: the lining 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 again and the whole cycle starts over.

Question 18

Name the 4 hormones that the menstrual cycle is controlled by

Answer 18

1. FSH (follicle-stimulating hormone)
2. Oestrogen
3. LH (luteinising hormone)
4. Progesterone

Question 19

What does FSH (follicle-stimulating hormone) do in the menstrual cycle?

Answer 19

1. Released by the pituitary gland.
2. Causes a follicle (an egg and its surrounding cells) to mature in one of the ovaries.
3. Stimulates oestrogen production.

Question 20

What does oestrogen do in the menstrual cycle?

Answer 20

1. Released be the ovaries.
2. Causes the lining of the uterus to thicken and grow.
3. A high level stimulates an LH surge (a rapid increase).

Question 21

What does LH (luteinising hormone) do in the menstrual cycle?

Answer 21

1. Released by the pituitary gland.
2. The LH surge stimulates ovulation at day 14 - the follicle ruptures and the egg is released.
3. Stimulates the remains of the follicle to develop into a structure called a corpus luteinising - which secretes progesterone.

Question 22

What does progesterone do in the menstrual cycle?

Answer 22

1. Released by the corpus luteum after ovulation.
2. Maintains the lining of the uterus.
3. Inhibits the release of FSH and LH.
4. When the level of progesterone falls, and there’s a low oestrogen level, the uterus lining breaks down.
5. A low progesterone level allows FSH to increase and then the whole cycle starts again.

Question 23

What does infertile mean?

Answer 23

Means you cant reproduce naturally.

There are methods an infertile couple can use to become pregnant, many of which involve hormones. For example:

1. Clomifene therapy
2. IVF (in vitro fertilisation)

Question 24

What does clomifene therapy involve?

Answer 24

Some women are infertile because they don’t ovulate or they don’t ovulate regularly. These women can take a drug called clomifene.

This works by causing more FSH and LH to be released by the body, which stimulate egg maturation and ovulation. By knowing when the woman will be ovulating, the couple can have intercourses during this period to improve the chance of becoming pregnant.

Question 25

What does IVF involve?

Answer 25

IVF involves collecting eggs from the women’s ovaries and fertilising them in a lab using the mans sperm. These are then grown into embryos. Once the embryos are tiny balls of cells, one or two of them are transferred to the women’s uterus to improve the chance of pregnancy. FSH and LH re given before egg collection to stimulate egg production (so more than one egg can be collected). IVF is an example of Assisted Reproductive Technology (ART) - a fertility treatment that involves eggs being handled (and usually fertilised) outside of the body.

Question 26

How is oestrogen used as a contraceptive?

Answer 26

1. It can prevent the release of an egg. 2. Naturally it helps stimulate the release of eggs, but if its taken every day to keep the level of it permanently high, it inhibits the production of FSH. 3. After a while egg development and production stop and stay the stopped.

Question 27

How is progesterone used as a contraceptive?

Answer 27

1. It reduces fertility. It works in several different ways: 2. One of which is by stimulating the production of thick cervical mucus, which prevents any sperm getting through the entrance to the uterus (the cervix) and reaching an egg.

Question 28

Name some of contraceptives?

Answer 28

1. The combined pill (both oestrogen and progesterone). 2. The mini pill (progesterone only). 3. Barrier methods (put a barrier between the sperm and egg so they don’t meet) - e.g - condom.

Question 29

What are the pros and cons of hormonal and barrier contraceptives?

Answer 29

1. Generally, hormonal methods are more effective at preventing pregnancy than barrier methods. Also, hormonal methods mean the couple don’t have to think about contraceptives each time. 2. However, hormonal methods can have unpleasant side-effects, such as headaches, acne and mood changes. Also hormonal methods don’t protect against STI’s - (only condoms can do this)

Question 30

What is homeostasis?

Answer 30

It’s maintaining a constant internal environment.

Question 31

Name examples of homeostasis

Answer 31

1. Osmoregulation - regulating water content. 2. Thermoregulation - regulating body temperature. 3. Blood glucose regulation.

Question 32

What controls blood glucose concentration?

Answer 32

Insulin and glucagon

Question 33

What happens when blood glucose concentration is too high or low?

Answer 33

High - insulin added Low - glucagon added

Question 34

What is type 1 diabetes?

Answer 34

It’s a condition where the pancreas produces little or no insulin. The result is that a persons blood glucose can rise to a level that can kill them.

Question 35

How can you treat type 1 diabetes?

Answer 35

With insulin therapy. This involves injecting insulin into the blood. This is often done at mealtimes to make sure that the glucose is removed from the blood quickly once the food has been digested. This stops the level of glucose in the blood from getting to high and is a very effective treatment. The amount needed depends on the persons diet and how active they’re.

Question 36

As well as insulin therapy, what do people with type 1 diabetes need to think about?

Answer 36

1. Limiting the intake of foods rich in simple carbohydrates (sugars - which cause the blood glucose level to rise rapidly). 2. Taking regular exercise - this helps to remove excess glucose from the blood.

Question 37

What is type 2 diabetes?

Answer 37

It’s a condition where the pancreas doesn’t produce enough insulin or when a person becomes resistant to insulin. (Their bodies cells don’t respond properly to the hormone). In both of these cases, the blood glucose level rises.

Question 38

Explain the correlation between obesity and type 2 diabetes

Answer 38

This means tat obese people have an increase risk of developing type 2 diabetes. People are classified as obese when their BMI is over 30. ``` BMI = weight (kg) ————— Height 2 (m) ```

Question 39

Explain another risk of developing type 2 diabetes

Answer 39

Storing lots of fa around the abdomen. Calculating a persons waist-to-hip ratio gives an indication of how fat is stored. Waist-to-hip ratio = waist circumference (cm) ——————————— Hip circumference (cm) A ratio above 1.0 for men and 0.85 fro women is associated with an increased risk of type 2 diabetes because it indicates that a lot of fat is being stored around the abdomen.

Question 40

How can type 2 diabetes be controlled?

Answer 40

1. Eating healthy. 2. Regular exercise. 3. Loosing weight if needed. Some people have medication or insulin injections.

Question 41

What is thermoregulation and what controls is?

Answer 41

1. It’s the process your body uses to keep its internal temperature steady. 2. It’s controlled by the hypothalamus.

Question 42

What happens when you’re too hot?

Answer 42

1. Erector muscles relax, so hairs lie flat. 2. Lots of sweat (containing water and salts) is produced in sweat glands in the dermis. The sweat is released onto the surface of the skin through pores in the epidermis. When sweat evaporates it transfers energy from your skin to the environment, cooing you down. 3. Blood vessels close to the surface of the skin dilate (widen). This is called vasodilation. It allows more blood to flow near the surface so it can transfer more energy into the surroundings, which cools you down.

Question 43

What happens when you’re too cold?

Answer 43

1. Erector muscles contract. Hairs stand on end to trap an insulating layer of air near the surface of the skin, which helps keep you warm. 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. When you’re cold you also shiver (your muscles contract automatically). This increases your rate of respiration, which transfers more energy to warm the body.

Question 44

What’s osmoregulation?

Answer 44

It’s regulating water content of the blood - keeps cells functioning.

Question 45

What happens if the concentration of water in the blood is to high and low?

Answer 45

1. If to high then water will move into the body cells by osmosis If too much water moves into the cells the the cells may burst. 2. If to low then water will move out of the cells into the blood by osmosis. This causes the cells to shrink.

Question 46

What do kidneys do?

Answer 46

They help regulate water content by controlling how much water is reabsorbed and how much is lost in urine. They’re part of the urinary system.

Question 47

Name the 3 main roles of kidneys

Answer 47

1. Removal of urea from the blood (Urea is produced in the liver from the breakdown of excess amino acids). 2. Adjustment of ion levels in the blood. 3. Adjustment of water content of the blood. They do this by filtering stuff out of the blood under high pressure and then reabsorbing the useful things. The end product is urine.

Question 48

What do nephrons do?

Answer 48

They’re the filtration units in the kidneys.

Question 49

Explain what happens in each nephron?

Answer 49

1. The liquid part of the blood (containing water, urea, ions and glucose) is forced out of the glomerulus and into the Bowman’s capsule at high pressure (ultrafiltration). Bigger molecules (e.g - proteins) and blood cells can’t pass through the membranes and are not forced out. 2. A’s the liquid flows along the nephron, useful substances are reabsorbed: - All the glucose is selectively reabsorbed - its moved back into the blood against the concentration gradient. - sufficient ions are reabsorbed. - sufficient water is reabsorbed according to the level of the hormone ADH. 3. Whatever isn’t reabsorbed (e.g - urea, excess water and excess ions) continues out of the nephron via the collecting duct. It then passes into the ureter and down to the bladder as urine. Urine is released through the urethra.

Question 50

What controls water content?

Answer 50

A negative feedback system.

Question 51

What is ADH and what does it control?

Answer 51

1. Anti-diuretic hormone. | 2. The amount of water reabsorbed in the kidney nephrons.

Question 52

Explain how water content is controlled by a negative feedback system?

Answer 52

1. The brain monitors the water content of the blood and instructs the pituitary gland to release ADH into the blood according to how much is needed. ADH makes the collecting ducts of the nephrons more permeable so more water is reabsorbed back into the blood. This stops the body from becoming dehydrated. 2. Water loss = more ADH released = kidney reabsorbs more water. Water gain = less ADH released = kidney reabsorbs less water.

Question 53

What does a dialysis filter do?

Answer 53

Patients ho have kidney failure cant filter their blood properly. A dialysis machine can be used to filter their blood for them.

Question 54

Explain dialysis

Answer 54

1. It has to be done regularly to keep dissolved substances at the right concentrations, to remove waste. 2. Dialysis fluid has the same concentration of salts and glucose as blood plasma (which means those aren’t removed form the blood). 3. The barrier is permeable to things like ions and waste substances, but not big molecules like proteins (just like the membranes in the kidneys). So the waste substances (e.g - urea), plus excess ions and water from the blood, move across the membrane into the dialysis fluid. Cells and proteins stay in the blood.

Question 55

Explain the only cure for kidney disease and the cons

Answer 55

1. At the moment the only cure is a kidney transplant. Healthy kidneys are usually transplanted from people who have died suddenly, say in a car accident, and who are on the organ donor register or carry a donor card. 2. The donor kidney can be rejected by the patient’s immune system - treated like a foreign body and attacked by antibodies. To help prevent this happening, precautions are taken: - a donor with a tissue type that closely matches the patient is chosen. - the patient is treated with drugs that suppress the immune system, so that their immune system won’t attack the transplanted kidney.