How do Hormones work?
What is a Hormone?
They belong to the class member of molecules which act as signals in organisms which are multicellular and they are transported to all the organs which is used to regulate the behaviour and physiology.
They are required and are important for the correct functioning of any individual, either be animal or plant or even fungi. The correct definition for hormones is actually molecules which act as signals to organs of the body far distant from the site of production. We have many different types of hormones. We have one typical group of hormones known as eicosanoids, the common one called Steroids, amino acid derivative , peptides and other gases like ethylene etc.
Hormones are used for:
- Regulation and communication between the organs and tissues. They used to regulate the physiological processes and behaviours such as digestion, metabolism, respiration, sleep, growth and development, movement and reproduction. These are main signals for mood receptors. In plants hormones are mainly used for regulation to germination.
- As a result of hormones there are changes in cell function and this happens by cells binding to protein cells which act as receptors. There is signal activation and thus activates several mechanisms like gene transcription and also it results in expression of proteins. They act rapidly and have genomic effects. Some hormones like peptides and amines act on the target surface. Steroids pass through the plasma membranes of the cell it wants to target and they act with their nuclei.
How it happens in Plants:
They lack anything that can secrete hormones however there is hormonal production. For example the hormone AUXIN is produced in the tips of the young leaves and apical meristem shoot. However this is not always true, the secretion of hormones in plants can change over time and other factors and also may be produced, it all depends on the age and environment of the plant.
Some glands endocrine in nature are very special and they secrete hormones. These are secreted in response to some biochemical reactions or signals. For example high blood sugar like glucose will influence the production of insulin synthesis.
How regulation happens for Hormones:
These are stimulated and inhibited by other hormones, which can be releasing or stimulating and also other plasma concentrations of other ions. This is also stimulated by globulins and neutrons and their activities. This is also factored by some environmental factors, for example-light and temperature. WE have one special type of hormones that stimulate the hormonal production of other endocrine glands. Example- The TSH which is the Thyroid stimulating Hormone will cause growth and activity of the THYROID which in return will make the thyroid hormones.
In times of need the active hormones might secrete and store some cells and biologically inactive hormones in the form of pre-hormones. These can be quickly converted to active hormones when given some stimuli.
EICOSANOIDS are local hormones and they are termed and considered so because they have effect on the local cells very near to the site of production to these hormones. They have some cycle also in terms of degradation and this prohibits the reaching of distant sites in the body.
Hormones are necessarily LIGANDS which means they will bind to proteins when produced by a signal. These are inhibited and regulated. In some cases the hormones are unable to bind to the site and give a response to the target cell – this happens because there is another competing cell which had bound itself to thereceptor site and these are called Antagonists of the hormones.
STEROID or THYROID HORMONE:
TheHormone receptors are put inside the cell membrane of the cytoplasm of the cell which is the target. These particular receptors are actually from the nuclear receptors and this is ligand activated. These hormones first cross the cell membrane and then they try to move to the nuclear membrane into the cell nucleus and this they increase the protein levels in the genes. Steroid are not always located inside the cell. Some are also found to be in the plasma membrane.
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INSULIN: what they do is they reduce the glucose level and maintain the insulin level in the body. They are secreted and since they are water soluble these are moved across the circulatory system. These are lipid soluble also and they attach to the plasma glycoproteins and such these hormones are very active. Examples are Insulin and Growth Hormones. The endocrine system also directly secrete hormones and to the blood. This is done by some capillaries and thus they are different from exocrine system which secrete the hormones via ducts.