Hormones in the Human Body is open for . The scholarship allows level programm(s) in the field of taught at . The deadline of the scholarship is .Different Types of Hormones in the Human Body
In your body, there are things called endocrine glands which produce hormones. Hormones regulate functions such as growth and development, water balance, sexual reproduction and the rate of chemical reaction in cells.
The hormones in the body are as follows:
Hormones travel around the body (through blood and nerves) but only act on particular target cells. This means a hormone can't affect a different cell. Hormones are secreted in very small quantities, their concentration in blood is very low. They are excreted as urine when it passes the liver.
The nervous and endocrine systems work together and are both involved in response and control. Hormones have an advantage in which responses are long lasting and only small amounts are needed to carry out a response. Hormones can have long-term responses lasting up to weeks, months or years.
Adrenalin also known as the 'fight or flight' hormone is released from the adrenal glands and is triggered when you suddenly get scared. It causes our heart to beat faster, breathing rate increase, blood going to the muscles, making us more alert, dilating our pupils and making our skin stand on the end.
The pituitary gland can be considered the master gland as it itself releases hormones and also instruct other glands to do so, so like it's the boss or some shit. The pituitary gland gets messages from the hypothalamus (hippopotamus) in the brain and is the link between the nervous system and endocrine glands.
The hypothalamus, pituitary and thyroid glands work together to control growth. The hypothalamus sends a message to the pituitary, telling it to release thyroid-stimulating hormone (TSH). TSH causes the thyroid gland to release thyroxin. Thyroxin controls the speed of cell reactions and therefore influences growth. A deficiency of thyroxin causes cretinism (stunted physical and mental growth). This can be cured in its early stages by administering thyroxin.
Another hormone produced by the pituitary, human-growth hormone (HGH), influences total body growth. Lack of HGH in childhood can lead to dwarfism. If diagnosed early, injections of HGH can be given to children suffering from lack of HGH. Too much HGH in childhood leads to gigantism, producing an abnormally tall person.
Controlling glucose levels
- Many substances must be kept constant at the correct level within the body. For example, cells need a continuous supply of glucose to produce energy and will die if glucose levels fall.
- Your pancreas produces two hormones, insulin and glucagon, that maintain your blood glucose levels within a narrow, acceptable range.
If you eat a piece of chocolate, the sugar it contains will quickly increase the glucose levels in your blood.
Insulin is released to counteract this increase. It does this by getting the cells to use more glucose and by stimulating your liver to store any excess. Blood glucose levels then drop, inhibiting further release of insulin.
Low glucose levels trigger the release of glucagon, which then directs the liver and cells to release glucose back into the blood.
Type I Diabetes
- Approximately one million people in Australia suffer from diabetes mellitus.
Diabetes mellitus is a disease in which blood glucose levels are not maintained within the required range. There are two basic types.
Type II Diabetes
- Around 15% of cases have Type I (insulin-dependent diabetes), which is caused by a defective pancreas.
High blood glucose levels result because the pancreas does not produce enough insulin.
This may result in glucose in the urine as the body tries to rid itself of its excess.
Long term effects of excess glucose include damage to vital organs such as the kidneys. Treatment involves the use of daily insulin injections.
- Type II, or non-insulin-dependent diabetics, do not produce enough insulin, or have cells that do not respond correctly to insulin. Treatment involves a special diet, an exercise program, use of drugs and possibly insulin injections.
- Hormones are not the only chemicals that influence the behaviour of animals. Other chemicals called pheromones can also dramatically affect behaviour, particularly sexual behaviour.
Many insects use pheromones to attract mates, and the opposite sex can often detect a tiny whiff of pheromones in the air from several kilometres away. These sex-attractant pheromones act directly on the CNS, producing immediate behavioural changes.
Other types of pheromones act more slowly, and affect growth and development. Termite queens use pheromones to stop larvae developing into new queens. Ants use pheromones to mark food trails.
Larger animals also use the scent of pheromones to communicate. Dogs and possums, for example, mark out their territories by spraying urine. Their particular scent tells others to keep out.
Plant growth hormones
- Plants also produce hormones which regulate their growth, flowering, fruit production and ripening, and seed germination. A response where a plant grows towards or away from a stimulus is called tropism.
Phototropism is when a plant grows towards light. It is a process controlled by a hormone belonging to a group called auxins. This particular hormone stimulates plant cells to elongate or grow longer. It is produced by the tips of growing shoots but is destroyed when exposed to light.
This means that the hormone in a shoot will live and elongate cells if it is in the shade, but will be destroyed in sunlight. Cells on the shady side, but will be destroyed in sunlight. Cells on the shady side will elongate more rapidly than on the sunny side, causing the shoot to bend towards the light.
A group of plant hormones called the gibberellins control plant growth and have a role in fruit development and seed germination.