Hormonal coordination in humans Flashcards
Describe the human endocrine system.
It is a group of glands which secrete hormones directly into the blood.
Explain the role of hormones in the human body.
Hormones are proteins which act as chemical messengers.
They are secreted into the blood by glands.
They travel in the blood until they reach their target organ.
They effect a change in the target organ.
Identify common examples of hormones and the gland which produces them.
- TSH- thyroid stimulating hormone produced by the pituitary gland.
- Adrenaline - produced by the adrenal gland
- Insulin and glucagon- produced by the pancreas
- Thyroxine - produced by the thyroid
- Oestrogen - produced by the ovaries
- Testosterone - produced by the testes.
Describe the function of TSH and it’s target organ.
TSH targets the thyroid gland and controls the release of hormones from that gland.
Describe the function adrenaline and it’s target organ.
Adrenaline prepares the body for the flight or fight mechanism. It targets the heart and other vital organs to prepare for increased demand for oxygen to the muscles.
Describe the function of insulin and glucagon and their target organ.
Insulin increases the conversion of blood glucose to glycogen in the liver.
Glucogon decreases it.
Describe the function of thyroxine and it’s target organ.
Thyroxine targets a number of organs, it controls your metabolism and how quickly you use energy.
Describe the function of oestrogen and it’s target organ.
Targets the reproductive organs and controls puberty and the menstrual cycle.
Describe the function of testosterone and it’s target organ.
Targets the reproductive organs and controls puberty
Explain the role of the pituitary gland in hormonal coordination
The pituitary gland is pea sized and is situated in the brain, it is often described as the master gland. It releases hormones which have other glands as their target organs. In this way it controls growth and blood pressure as well as partly controlling functions of the ovaries and testes and kidneys.
Hormones it produces include TSH, FSH (in women) LH (in women)
Explain how hormones control blood glucose concentration.
- Carbohydrase enzymes break down carbohydrates into glucose which can be absorbed through the villi into the bloodstream.
- The pancreas monitors and controls the amount of glucose (blood sugar) in the blood , too little and the cells cannot respire, too much can put you in a coma.
- The pancreas releases insulin and glucagon to increase and decrease the amount of glucose in the blood, the liver is the target organ which does this.
- Excess glucose is converted to glycogen and stored in the liver.
- Control of blood glucose is an example of homeostasis because it involves the body automatically return to a normal state.
Explain the role of insulin in controlling blood glucose levels
Insulin is produced in the pancreas and lowers blood sugar by converting glucose into gycogen which is stored in the liver.
The pancreas detects increased blood sugar levels and releases insulin. The insulin targets the liver cells which absorb the glucose and convert it to insoluble glycogen. This lowers the glucose levels in the blood. Glycogen can also be formed in the muscles to help reduce blood sugar levels.
Explain the role of glycogon in controlling blood glucose levels
Glycogon is produced in the pancreas and raises blood sugar by converting insoluble glycogen which is stored in the liver and muscles back into soluble glucose.
This is an example of negative feedback control, all examples of homeostasis involve negative feedback.
Explain the causes and effects of type 1 diabetes.
Diabetes is a non communicable disease which reduces a persons ability to control blood glucose levels.
The causes of type 1 diabetes are unknown and usually starts in children and young adults.
The Immune system attacks the insulin producing cells in the pancreas destroying them, without these cells blood glucose levels can rise to fatal levels.
People with type 1 diabetes inject insulin to control blood glucose levels.
They also need to be careful with their diet, controlling sugar intake and take exercise to help keep blood glucose levels low.
There is no cure for type 1 diabetes.
Uncontrolled diabetes has many long term health risks.
Explain the causes and effects of type 2 diabetes.
Diabetes is a non communicable disease which reduces a persons ability to control blood glucose levels.
People with type 2 diabetes either cannot produce enough insulin or their liver and muscle cells do not respond to it.
Glucose therefore does not get converted into glycogen and blood glucose levels remain high.
Obesity is an important risk factor in type 2 diabetes, it usually develops in older people however the amount of it is increasing and the age of people with it is lowering.
Type 2 is usually controlled with drugs as well as diet and exercise as the cells in the liver and muscles do not respond to insulin.
Uncontrolled diabetes has many long term health risks.
