How do protein hormones act on target cells?
How do protein hormones act on target cells?
Hormones activate target cells by diffusing through the plasma membrane of the target cells (lipid-soluble hormones) to bind a receptor protein within the cytoplasm of the cell, or by binding a specific receptor protein in the cell membrane of the target cell (water-soluble proteins).
What hormones affect target cells?
For instance, steroid hormones, like the sex hormone groups estrogens and androgens, seek out specific target cells and bind to receptor proteins located inside the nucleus of the cell, as shown below.
Where are the target cells for each hormone located?
| Endocrine gland/ source of hormone | Hormone | Target organ or tissue |
|---|---|---|
| Anterior pituitary (adenohypophysis) | ACTH (adrenocorticotrophic hormone) | Adrenal cortex |
| FSH (follicle stimulating hormone) | Ovaries / testes (tubules) | |
| LH (luteinizing hormone) | Ovaries / testes (Leydig cells) | |
| GH (growth hormone) | All tissues |
What are examples of protein hormones?
Some examples of protein hormones include growth hormone, which is produced by the pituitary gland, and follicle-stimulating hormone (FSH), which has an attached carbohydrate group and is thus classified as a glycoprotein. FSH helps stimulate the maturation of eggs in the ovaries and sperm in the testes.
How does a target cell respond to a hormone?
A target cell responds to a hormone because it bears receptors for the hormone. In other words, a particular cell is a target cell for a hormone if it contains functional receptors for that hormone, and cells which do not have such a receptor cannot be influenced directly by that hormone.
How are hormones secreted into the blood stream?
A traditional part of the definition of hormones described them as being secreted into blood and affecting cells at distant sites. However, many of the hormones known to act in that manner have been shown to also affect neighboring cells or even have effects on the same cells that secreted the hormone.
How are antibodies produced in white blood cells?
Antibodies are proteins produced by a type of white blood cell (B cells or B lymphocytes). Antibodies are able to stick very tightly to specific targets. Antibodies are currently being used as anti-cancer drugs (i.e. Herceptin). . Natural Killer Cells ( 50-400 cells/µL; 5-10% of total lymphocytes ).
What causes crescent shaped red blood cells ( RBC )?
These crescent or sickle-shaped red blood cells (RBCs) are present with Sickle cell anemia, and stand out clearly against the normal round RBCs. These abnormally shaped cells may become entangled and block blood flow in the small blood vessels (capillaries).