(4.5.3)(Hormonal Coordination in humans)

What is the Endocrine system composed of and what does it do?

Glands which secrete chemicals called hormones directly into the bloodstream. The blood carries the hormone to a target organ where it produces an effect.

In comparison to the nervous system is the endocrine system faster or slower and are the effects longer or shorter?

The effects of the endocrine system are slower but act for longer.

What is the Pituitary gland and what does it do?

The pituitary gland in the brain is a 'master gland' which secretes several hormones into the blood in response to body conditions. These hormones in turn act on other glands to stimulate other hormones to be released to bring about effects.

Name all the parts of the body.

Where is blood glucose concentration is monitored and controlled?

In the pancreas.

What happens if the blood glucose concentration is too high?

The pancreas produces the hormone insulin that causes glucose to move from the blood into the cells. In liver and muscle cells excess glucose is converted to glycogen for storage.

What is Type 1 diabetes?

Type 1 diabetes is a disorder in which the pancreas fails to produce sufficient insulin.

What are symptoms of Type 1 diabetes?

It is characterised by uncontrolled high blood glucose levels and is normally treated with insulin injections

What is Type 2 diabetes?

Type 2 diabetes the body cells no longer respond to insulin produced by the pancreas.

What is a treatment for Type 2 diabetes?

A carbohydrate controlled diet and an exercise regime are common treatments.

What is a risk factor of Type 2 diabetes?

Obesity.

What happens if the blood glucose concentration is too low?

If the blood glucose concentration is too low, the pancreas produces the hormone glucagon that causes glycogen to be converted into glucose and released into the blood.

Explain how glucagon interacts with insulin in a negative feedback cycle to control blood glucose (sugar) levels in the body.

Glucagon raises blood sugar by releasing stored glucose, while insulin lowers blood sugar by storing excess glucose. They work in a negative feedback loop to maintain blood glucose levels within a normal range.

What happens to the body cells during exhalation?

Water leaves the body via the lungs.

What happens to the body cells when you sweat?

Water, ions and urea are lost from the skin

What happens to the body cells when you urinate?

Excess water, ions and urea are removed via the kidneys.

What happens if body cells lose or gain too much water by osmosis?

Does not function properly.

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

Results in excess amino acids which need to be excreted safely.

What happens to these amino acids in the liver?

In the liver these amino acids are deaminated to form ammonia.

What is ammonia converted to for safe excretion and why?

Ammonia is toxic and so it is immediately converted to urea for safe excretion.

How do the kidneys produce urine?

The kidneys produce urine by filtration of the blood and selective reabsorption of useful substances such as glucose, some ions and water.

How is the water level in the body controlled by ADH?

The water level in the body is controlled by the hormone ADH which acts on the kidney tubules. ADH is released by the pituitary gland when the blood is too concentrated and it causes more water to be reabsorbed back into the blood from the kidney tubules. This is controlled by negative feedback

What are the two ways to treat kidney failure?

People who suffer from kidney failure may be treated by organ transplant or by using kidney dialysis.

How does dialysis work?

Dialysis filters blood to remove waste products. Blood flows through a machine with a partially permeable membrane. Waste substances diffuse from blood into a dialysis fluid. Because the fluid has the same concentration of glucose and ions as healthy blood therefore no useful substances diffuse only the waste substances such as urea diffuse.

What are the advantages and disadvantages of treating kidney failure with mechanical devices?

Advantages of treating organ failure with mechanical devices include immediate availability and reduced risk of rejection. Disadvantages include potential complications and limited lifespan.

What are the advantages and disadvantages of treating kidney failure with transplants?

An advantage is no more dialysis for the patient.

Disadvantage is chance of rejection and life long medication.

What is the main female reproductive hormone and where is it produced?

Oestrogen is the main female reproductive hormone produced in the ovary.

What is ovulation?

When puberty eggs begin to mature and one is released approximately every 28 days.

What is the main male reproductive hormone and where is it produced?

Testosterone is the main male reproductive hormone produced by the testes and it stimulates sperm production.

What are the 4 hormones involved in the women’s menstrual cycle?

Follicle stimulating hormone (FSH).

Luteinising hormone (LH).

Oestrogen and progesterone.

What does Follicle stimulating hormone (FSH) do?

Follicle stimulating hormone (FSH) causes maturation of an egg in the ovary.

What does Luteinising hormone (LH) do?

Luteinising hormone (LH) stimulates the release of the egg.

What do Oestrogen and Progesterone do?

Oestrogen and progesterone are involved in maintaining the uterus lining.

What are the different ways fertility can be controlled?

oral contraceptives that contain hormones to inhibit FSH production so that no eggs mature

injection, implant or skin patch of slow release progesterone to inhibit the maturation and release of eggs for a number of months or years

barrier methods such as condoms and diaphragms which prevent the sperm reaching an egg

intrauterine devices which prevent the implantation of an embryo or release a hormone

spermicidal agents which kill or disable sperm

abstaining from intercourse when an egg may be in the oviduct

surgical methods of male and female sterilisation.

What is Vitro Fertilisation?

In Vitro Fertilisation (IVF) treatment.

• IVF involves giving a mother FSH and LH to stimulate the maturation of several eggs.

• The eggs are collected from the mother and fertilised by sperm from the father in the laboratory.

• The fertilised eggs develop into embryos.

• At the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus (womb).

What are the disadvantages of fertility treatment?

it is very emotionally and physically stressful.

the success rates are not high.

it can lead to multiple births which are a risk to both the babies and the mother.

What is adrenaline, where is it produced and when is it produced?

Adrenaline is produced by the adrenal glands in times of fear or stress. It increases the heart rate and boosts the delivery of oxygen and glucose to the brain and muscles, preparing the body for ‘fight or flight’.

What is thyroxine and where is it produced?

Thyroxine from the thyroid gland stimulates the basal metabolic rate. It plays an important role in growth and development.