Organs of the Endocrine System
The endocrine system is made up of many glands that are located in different areas of the body. Hormones are made and secreted by cells in endocrine glands. Endocrine glands are ductless organs that secrete hormones directly into the blood or the fluid surrounding a cell rather than through a duct. The major glands of the endocrine system are shown in Figure. Many other organs, such as the stomach, heart, and kidneys secrete hormones and are considered to be part of the endocrine system.
- Pituitary gland
- Adrenal glands
- Ovary (female)
- Testicles (male)
You can take a look to a video about endocrine system to learm the vocabulary.
The body produces many different hormones, but each hormone is very specific for its target cells. A target cell is the cell on which a hormone has an effect. Target cells are affected by hormones because they have receptor proteins that are specific to the hormone. Hormones will travel through the bloodstream until they find a target cell with the specific receptors to which they can bind. When a hormone binds to a receptor, it causes a change within the cell.
The effects of hormones vary widely, and certain hormones, called tropic hormones (or tropins), regulate the production and release of other hormones. Many of the responses to hormones regulate the metabolic activity of an organ or tissue.