Chapter 12: Human endocrine system

Question 1

What is the difference between hormonal communication and communication using nerve impulses?

Answer 1

Hormonal communication is based on proteins (hormones) which are released into the blood and detected by target tissues, making it slower but more longer-lasting than communication using nerves

Question 2

What is the pituitary gland?

Answer 2

The gland in the brain that produces growth hormones, ADH, TSH, FSH and LH, and links the nervous system to the endocrine system

Question 3

What is glycogen?

Answer 3

An insoluble store of glucose found in the liver and muscles

Question 4

What is insulin?

Answer 4

A hormone produced in your pancreas that lowers blood glucose by converting it to glycogen and storing it in the liver

Question 5

What is glucagon?

Answer 5

A hormone produced in your pancreas that raises blood glucose by breaking down glycogen stored in the liver

Question 6

What is Type 1 diabetes?

Answer 6

A type of diabetes with an unknown cause in which the pancreas loses the ability to produce insulin (its insulin-producing cells are destroyed by the immune system), causing their blood glucose levels to rise to harmful levels. It usually appears early in life

Question 7

How is Type 1 diabetes treated?

Answer 7

Insulin injections after meals

Question 8

What is Type 2 diabetes?

Answer 8

A type of diabetes (different to Type 1 diabetes) where either the pancreas is unable to produce enough insulin or muscle and liver cells are unable to respond to it. Symptoms include tiredness, thirst and frequent urination.

Question 9

What are the causes of Type 2 diabetes?

Answer 9

Unhealthy diet, obesity, lack of exercise

Question 10

What is the treatment for Type 2 diabetes?

Answer 10

Eating a balanced diet and exercising regularly. Injecting insulin does not work

Question 11

How was insulin discovered?

Answer 11

Banting and Best closed the tube that excreted insulin from the pancreas of a dog. After monitoring the dog’s blood glucose levels over the next 8 weeks they realised that the pancreas had something to do with controlling blood glucose concentration. They removed organs from two dogs, injected them into the first dog, and found that the dog’s blood glucose concentration decreased. They then went on to purify insulin

Question 12

Why are bacteria used to produce insulin as opposed to animals?

Answer 12

Some people are allergic to animal insulin

Question 13

What is ADH (anti-diuretic hormone)?

Answer 13

A hormone produced in the pituitary gland that regulates the volume of urine you excrete

Question 14

How do your kidneys control the amount of urea and water released in your urine?

Answer 14

Filtering your blood for these substances and re-absorbing a certain amount of each based on ADH concentration in the blood

Question 15

Summarise the control of water content in the blood

Answer 15

Increase in water in blood => Less in ADH => More water in urine (and vice versa)

Question 16

How does kidney dialysis work?

Answer 16

Blood is temporarily removed from the body and pumped through a machine, where it passes alongside a liquid called dialysis liquid. The two liquids are separated by a selectively permeable membrane and have the same concentrations of glucose and salts. The dialysis fluid has no urea, meaning urea diffuses out of the patient’s blood, which is then returned to them

Question 17

What happens during a kidney transplant?

Answer 17

A donor is chosen, whose kidney will not be attacked by the patient’s immune system (rejection). After the surgery, drugs are given to the patient to reduce the chances of rejection. To reduce the chances of rejection, many donations are made by the patient’s family members. Tissue typing is used to find a close match.

Question 18

What is testosterone?

Answer 18

A male sex hormone produced in the testes that controls puberty and stimulates the production of sperm

Question 19

What is oestrogen?

Answer 19

A female sex hormone produced in the ovaries that controls puberty and prepares the uterus for pregnancy

Question 20

What is progesterone?

Answer 20

A female sex hormone produced in the ovaries that prepares the uterus for pregnancy

Question 21

List female secondary sex characteristics

Answer 21

Growth of breasts, wide hips, growth of underarm hair, growth of pubic hair, growth spurt

Question 22

List male secondary sex characteristics

Answer 22

Growth of penis, increased muscle mass, broadening of shoulders, deepening of voice, growth of underarm and facial hair, growth of pubic hair, growth spurt

Question 23

What is FSH (follicle-stimulating hormone)?

Answer 23

A hormone released by the pituitary gland that causes an ovum to mature in the ovary and stimulates the ovaries to produce estrogen

Question 24

What is LH (lutenising hormone)?

Answer 24

A hormone released by the pituitary gland that stimulates ovulation (release of the ovum from the ovary)

Question 25

What is the role of oestrogen in the menstrual cycle?

Answer 25

It causes the uterine lining to thicken in the first half of the cycle, and can also switch off release of FSH and turn on release of LH

Question 26

What is the role of progesterone in the menstrual cycle?

Answer 26

If the fertilised ovum implants in the uterus, progesterone is released by the ovaries. It maintains the thick uterine lining and can stop the cycle if concentrations are too high

Question 27

What is a vasectomy?

Answer 27

A contraceptive medical procedure in which a man’s sperm ducts are blocked

Question 28

What is tubal ligation?

Answer 28

A contraceptive medical procedure in which a woman’s Fallopian tubes are blocked

Question 29

What is thyroid-stimulating hormone (TSH)?

Answer 29

A hormone produced by the pituitary gland that regulates the thyroid gland

Question 30

What is the thyroid gland?

Answer 30

A gland in the neck that produces thyroxine to regulate how quickly your body uses energy and synthesises proteins, and how sensitive it is to other hormones

Question 31

What is goitre?

Answer 31

A medical condition that occurs when you don’t have enough iodine in your diet, making you less able to produce thyroxine. This causes the pituitary gland to produce more TSH to try to stimulate the thyroid, inflaming it in the process

Question 32

What is adrenaline?

Answer 32

A hormone produced by the adrenal glands that causes an increase in heart rate, increased blood glucose, increased blood pressure and suppression of the immune system

Question 33

How can infertility be treated chemically?

Answer 33

Injecting women with FSH and LH can treat infertility caused by a lack of these hormones

Question 34

How does in vitro fertilisation work?

Answer 34

1. Several injections of FSH and LH are given
2. Several ova mature
3. These ova are removed from the ovaries and mixed with a man’s sperm
4. One or more of the fertilised embryos is then placed back inside the uterus and allowed to gestate for 9 months

Question 35

What is a follicle?

Answer 35

A structure in an ovary in which an ovum matures

Question 36

What is the corpus luteum?

Answer 36

What an empty follicle turns into after ovulation. The corpus luteum releases progesterone

Question 37

How does the oral contraceptive pill work?

Answer 37

The oral contraceptive pill contains estrogen and progesterone. The woman takes one pill per day, at the same time. Only 21 of the 28 pills in a 1-month packet contain hormones; the other 7 are placebo (the woman is likely to be menstruating during this time). The prevents ovulation by inhibiting the production of FSH. It also thickens the mucus in the uterus, making it harder for sperm to navigate. It can also thin the lining of the uterus so that there is a reduced chance of the fertilised ovum settling to develop into a fetus.

Question 38

What are the side effects of the pill?

Answer 38

Advantages: Lighter periods, reduced risk of cancer in the ovaries
Disadvantages: Nausea, headaches, mood swings, breast tenderness