5.3 Hormonal Coordination in Humans

These flashcards cover specification point 4.5.3 Hormonal Coordination in Humans. This includes 4.5.3.1 Human Endocrine System, 4.5.3.2 Control of Blood Glucose Concentration, 4.5.3.3 Maintaining Water & Nitrogen Balance in The Body (Biology Only), 4.5.3.4 Hormones in Human Reproduction, 4.5.3.5 Contraception, 4.5.3.6 The Use of Hormones to Treat Infertility, 4.5.3.7 Negative Feedback

• The endocrine system is composed of ________ which secrete chemicals called ___________ directly into the ____________.

• The blood carries the _________ to a _______ ________ where it produces an _______.

• Compared to the nervous system the effects are _________ but act for _______. 

• glands

• hormones

• bloodstream

• hormone

• target organ

• effect

• slower

• longer

• The pituitary gland in the brain is a ‘_____ _______’ which secretes several __________ into the blood in response to body conditions.

• These hormones in turn act on other _________ to _________ other hormones to be released to bring about ________.

• master gland

• hormones

• glands

• stimulate

• effects

What hormones does the pituitary gland secrete and what are these hormones’ functions?

• ADH — affects the amount of urine produced by the kidney.

• Growth Hormone — controls the rate of growth in children.

• TSH — stimulates the thyroid gland to make thyroxine

  • a hormone that helps control the rate of metabolism

• FSH — Follicle Stimulating Hormone:

  • Females — stimulates the ovaries to make oestrogen and to produce and release eggs.

  • Males — stimulates the testes to make sperm and the male sex hormone testosterone.

Label each part.

• A — pituitary gland

• B — thyroid gland

• C — adrenal gland

• D — pancreas

• E — ovary

• F — testes

What hormone does the pancreas secrete and what is that hormone’s function?

• Insulin

• Controls the levels of glucose in the blood

What hormone does the thyroid secrete and what is that hormone’s function?

• Thyroxine

• Controls the metabolic rate of the body

What hormone does the adrenal gland secrete and what is that hormone’s function?

• Adrenaline

• Prepares the body for stressful situations

What hormone does the ovary secrete and what is that hormone’s function?

• Oestrogen

• Controls the development of the female secondary sexual characteristics and is involved in the menstrual cycle.

What hormone does the testes secrete and what is that hormone’s function?

• Testosterone

• Controls the development of the male secondary sexual characteristics and is involved in the production of sperm.

What is blood glucose concentration monitored and controlled by?

Pancreas

Eating foods that contain ______________ increases the glucose levels in the blood.

carbohydrates

What happens if blood glucose concentration is too high?

• The pancreas produces insulin

• Insulin binds in target organs (muscles and liver) causing:

  • Glucose to move from the blood into muscle cells for respiration

  • Excess glucose to be converted into glycogen which is stored in the liver

• The blood glucose concentration is reduced

Rigorous activity, (e.g. _______), uses ________ for _________ and therefore there is less in the blood.

• exercise

• glucose

• respiration

What happens if blood glucose concentration is too low?

• The pancreas produces glucagon

• Glucagon binds to the liver cells cause glycogen to be broken down into glucose

• Glucose is released into the blood, increasing blood glucose concentration

What is insulin?

The hormone produced by the pancreas when blood glucose concentration is too high.

What is glycogen?

An insoluble carbohydrate made from glucose that is stored in the liver and muscles.

What is glucagon?

The hormone produced by the pancreas when blood glucose concentration is too low.

What causes type 1 diabetes?

The cells of the pancreas stop producing insulin.

What is the main risk factor for type 1 diabetes?

Some genetic tendency

What causes type 2 diabetes?

• The pancreas makes insulin (could be less than the body needs).

• The cells of the body stop responding to insulin.

What are the main risk factors for type 2 diabetes?

• Age

• Obesity

• Lack of exercise

• Some genetic tendency

What are the characteristics of type 1 and type 2 diabetes?

• Raised blood glucose levels

• Glucose in the urine

• Thirst

• Tiredness

• Lack of energy

How is type 1 diabetes treated? (2)

• Insulin injections/Insulin pumps

• Low carbohydrate diet and regular meals

How do insulin injections help treat type 1 diabetes?

• It allows glucose to be taken into the body cells and converted into glycogen in the liver.

  • This stops blood glucose concentration from getting too high.

• As blood glucose levels fall, the glycogen is converted back into glucose.

  • Blood glucose levels are kept as stable as possible.

How does a low carbohydrate diet help treat type 1 diabetes?

• It prevents large spikes in blood glucose levels

  • As carbohydrates are broken down into glucose

What are 3 ways to treat type 2 diabetes?

• Eating a balanced diet — controlled amount of carbohydrates

• Losing weight

• Regular exercise

What types of drugs are there to treat type 2 diabetes? (3)

There are drugs that:

• help insulin work better on the body cells

• help the pancreas make more insulin

• reduce the amount of glucose absorbed from the gut

Control of blood glucose concentration is an example of __________ _________.

negative feedback

• Water leaves the body via the ________ during _________.

• _______, ______, and ______ are lost from the skin in sweat.

• There is no control over ______, ____, or ______ loss by the _______ or skin.

• lungs

• exhalation

• Water

• ions

• urea

• water

• ion

• urea

• lungs

• Carbon dioxide __________ out of the cells into your blood down a ___________ ________.

• It then ________ from the ________ into the air in the ________ of your lungs.

• This air containing the excreted carbon dioxide is removed from your body when you ________.

• As a side effect of exhalation, you lose ________ when the moist air from inside your lungs is forced out of your body.

• diffuses

• concentration gradient

• diffuses

• blood

• aveoli

• exhale

• water

What is osmosis?

The movement of water molecules from an area of high water concentration to an area of low water concentration through a partially permeable membrane.

• Excess water, ions and urea are removed via the _________ in the _______.

• If body cells lose or gain too much water by _________ they do not function efficiently.

• kidneys

• urine

• osmosis

What does the digestion of proteins from the diet result in?

Excess amino acids that need to be excreted safely.

Where in the body are amino acids are deaminated to form ammonia?

Liver

Ammonia is ______ and so it is immediately converted to ______ for safe __________.

• toxic

• urea

• excretion

• The carbon dioxide made by the body cells during __________ must be removed, because dissolved carbon dioxide produces an ________ solution.

• This change in pH would affect the working of all the __________ in the cells.

• respiration

• acidic

• enzymes

How is urea produced?

The breakdown of excess amino acids in your liver.

How is urea removed from the body?

• Filtered out of the blood by the kidneys.

• Passed out of the body in the urine produced by the kidneys.

What do the kidneys do?

It makes urine by:

• filtering out waste products

• selectively reabsorbing useful substances (e.g. glucose, ions, and water)

How do the kidneys work?

• Glucose, mineral ions, urea, and water all move out of the blood into the kidney.

• The blood cells and large proteins are too big to leave the blood in the filtering process — they do not go into the kidney tissues.

• All of the glucose is reabsorbed back into the blood by diffusion and active transport.

• The amount of water and dissolved mineral ions that are reabsorbed back into the blood varies based on what is needed by your body.

  • This is selective reabsorption.

Which gland is ADH (anti-diuretic hormone) secreted by?

Pituitary gland

_________ cells in the brain detect the concentration of ________ in the blood plasma.

• Receptor

• solutes

What happens if the water concentration in the blood is too high (solute concentration is too low/dilute)?

• Pituitary gland releases less ADH into the blood

• Less water moves out of the tubules and back into the bloodstream

• Large volume of very dilute (solutes) urine

What happens if the water concentration in the blood is too low (solute concentration is too high/concentrated)?

• Pituitary gland releases lots of ADH into the blood

• ADH travels in the bloodstream to the kidney tubules

• ADH increases the kidney tubules’ permeability to water

  • More water moves out of the tubules and back into the bloodstream

• Smaller volume of very concentrated (solutes) urine

The control of water concentration in the blood is an example of ___________ __________.

negative feedback

What are 2 ways that kidneys can be damaged and/or destroyed?

• Infections

• Accidents

What are 2 ways of treating kidney failure?

• Dialysis

• Kidney transplants

What happens if kidney failure is left untreated?

• Toxins (e.g. urea) build up

• Mineral ion and water balance of body is not maintained

  • This affects all the cells

How does dialysis work?

• Blood moves between partially permeable membranes surrounded by dialysis fluid.

• Useful ions and glucose are not lost from the blood but urea, excess ions, and water diffuse across the membrane.

What is the concentration of glucose in dialysis fluid?

Same as healthy levels in blood plasma.

What is the concentration of mineral ions in dialysis fluid?

Same as healthy levels in blood plasma.

What is the concentration of urea in dialysis fluid?

None

Explain the movement of glucose during dialysis.

No net movement out of the blood.

Explain the movement of mineral ions during dialysis.

Excess mineral ions (e.g. sodium) diffuse from blood into dialysis fluid down their concentration gradient.

Explain the movement of urea during dialysis.

Diffuses from blood into dialysis fluid down the steep concentration gradient.

What is the final concentration of glucose in the blood after dialysis?

Healthy plasma levels

What is the final concentration of mineral ions in the blood after dialysis?

Healthy plasma levels

What is the final concentration of urea in the blood after dialysis?

Much reduced concentration of urea

Why must patients on dialysis control their protein intake?

To keep urea levels low.

Why must patients on dialysis control their salt intake?

Their kidneys cannot get rid of excess mineral ions.

What is the advantage of dialysis?

It acts as an artificial kidney and keeps people alive while they wait for a transplant.

What are the disadvantages of dialysis?

• Patient must have a very controlled diet (low protein and salt).

• Patient spends regular, long sessions connected to a dialysis machine.

• There is only a short amount of time where the balance of substances in the blood are at the right levels.

  • So the patient may be tired and unwell as the next dialysis session approaches.

• Expensive

• Eventually causes serious damage to the body.

How do kidney transplants overcome the problem of kidney failure?

It functions like a healthy kidney and it cleans and balances the blood.

What is the main problem with a kidney transplant?

Rejection

Why may the patient’s body reject the donor kidney?

• The antigens (proteins on the cell surface) of the donor organ will be different to those of the recipient.

• There is a risk that the antibodies of the immune system of the recipient will the attack the antigens on the donor organ.

What are the ways to reduce the chance of rejection? (2)

• Use a donor kidney with a tissue type very similar to the recipient.

• Use immunosuppressant drugs.

What is the advantage of using immunosuppressant drugs?

It prevents rejection of the donor kidney by the recipient’s immune system.

What are the disadvantages of using immunosuppressant drugs?

• They may prevent the patient from dealing effectively with infectious diseases.

• The patient has to take them for the rest of their lives.

What are the advantages of a kidney transplant?

• No restrictions that come with regular dialysis sessions.

• They can eat and drink whatever they want.

• Cheaper than dialysis

What are the disadvantages of kidney transplants?

• Risk of rejection

• Taking immunosuppressants every day for the rest of your life

• Transplanted kidneys don’t last forever

What are the primary sexual characteristics in males?

Testes

What are the primary sexual characteristics in females?

Ovaries

What is the main reproductive hormone in males?

Testosterone

Where is testosterone produced?

Testes

What does testosterone do?

Stimulates sperm production

What is the main reproductive hormone in females?

Oestrogen

Where is oestrogen produced?

Ovaries

How long is the menstrual cycle?

28 days

What day does ovulation occur?

Day 14

What hormones are involved in controlling the menstrual cycle? (4)

• Oestrogen

• Follicle stimulating hormone (FSH)

• Luteinising hormone (LH)

• Progesterone

What is ovulation?

The part of the menstrual cycle where a mature egg is released from the ovary.

Where is follicle stimulating hormone (FSH) produced?

Pituitary gland

Where is luteinising hormone (LH) produced?

Pituitary gland

Where is progesterone produced?

• Ovaries

  • Secreted from the empty egg follicle in the ovary after ovulation.

Menstrual Cycle:

Roles of Hormones:

• FSH:

  • Secreted by _________ ________

  • Makes eggs ________ in their follicles in the _______

  • Stimulates ________ to produce __________

• Oestrogen:

  • Made and secreted by _________

    • in response to ______

  • Stimulates the lining of the _______ to grow after menstruation

  • High levels of oestrogen:

    • inhibit the production of more _____

    • stimulate the release of ___

• LH:

  • Secreted by _________ _______

  • Stimulates the release of a _______ egg from the ______

  • After _________, LH levels fall

• Progesterone:

  • Secreted by ________ ____ _______ in the _____ after _________

  • Helps maintain pregnancy if the egg is __________

    • Maintains the lining of the _______ in the second half of the cycle

  • Inhibits _____ and ___

Cycle:

• If the egg is not fertilised:

  • Levels of all hormones drop

  • Lining of the uterus pulls away and is lost from the body (period)

  • New cycle begins — levels of ______ and ________ increase

FSH

• pituitary gland

• mature

• ovary

• ovaries

• oestrogen

Oestrogen

• ovaries

• FSH

• uterus

• FSH

• LH

LH

• pituitary gland

• mature

• ovary

• ovulation

Progesterone

• empty egg follicle

• ovary

• ovulation

• fertilised

• uterus

• FSH

• LH

Cycle

• FSH

• oestrogen

The interaction between FSH and oestrogen is an example of __________ __________.

negative feedback

What hormone does FSH stimulate the production of?

Oestrogen

What hormone does oestrogen stimulate the production of?

LH

What hormone does oestrogen inhibit the production of?

FSH

What hormones does progesterone inhibit the production of?

• FSH

• LH

What is contraception?

The use of artificial or natural methods to prevent pregnancy by stopping fertilisation or implantation.

Fertility can be controlled by a variety of ___________ and ____________ methods of contraception.

• hormonal

• non-hormonal

What are the hormonal methods of contraception? (3)

• Contraceptive pills

• Injections, implants, and patches

• Intrauterine devices (plastic)

What are the non-hormonal methods of contraception? (4)

• Barrier methods and spermicides

• Intrauterine devices (copper)

• Abstinence

• Sterilisation

Combined Pill:

• The combined pill is an ____ _____________.

• It contains low doses of ___________ along with some ______________.

• The hormones inhibit the production and release of ________ by the __________ _________.

  • As a result, no eggs _____ in the _________, preventing pregnancy.

• The pill hormones also stop the ______ _______ developing, preventing ___________, and make the _______ in the cervix ______ to prevent sperm getting through.

• oral contraceptive

• oestrogen

• progesterone

• FSH

• pituitary gland

• mature

• ovaries

• uterus lining

• implantation

• mucus

• thick

What are the advantages of the combined pill?

• Quite effective

• Easy to use

What are the disadvantages of the combined pill?

• Side effects

  • high blood pressure

  • blood clots

  • breast cancer

• Has to be taken regularly

• No protection against STIs

Progesterone-only Pill:

• It is an ____ ____________ that only contains progesterone

  • prevents the _______ from releasing the egg

  • thickens the _______ in _______ so sperm cannot swim

  • stops ________ eggs from ___________ in the uterus

• _______ side effects than the combined pill

• It is especially important to take the progesterone-only pill very regularly otherwise:

  • the artificial __________ levels drop

  • the body's own hormones take over very ________

  • may lead to the unexpected release of an ______ when a person thinks they are protected from ___________

• oral contraceptive

• ovaries

• mucus

• cervix

• fertilised

• implanting

• Fewer

• hormone

• quickly

• egg

• pregnancy

What are the advantages of the progesterone-only pill?

• Less side effects than combined pill

• Quite effective (if taken very regularly)

What are disadvantages of the progesterone-only pill?

• Must be taken very regularly

• No protection against STIs