What are the types of hormone signalling?
Signalling mechanisms that occur in multicellular organisms are:
- Autocrine signalling –¬†In autocrine signalling, hormones do not travel to other cells but cause changes in the same cell that release them.
- Paracrine signalling –¬†Hormones have the capability to impact isolated cells alongside that of¬†neighbouring cells. Hormones act on local cells through secretion¬†into the interstitial fluid that surrounds the cells. These hormones will then diffuse to nearby target cells. This type of signalling is described as “paracrine signalling”.
- Endocrine signalling –¬†When a hormone binds to a target cell receptor, it creates¬†changes within the cell. This, in turn, influences the function within the cell. ¬†Hormone signalling that occurs in this manner is called “endocrine signalling”. The reason for this is that¬†the hormones affect target cells over an area or distance.
- Direct signalling –¬†Direct signalling occurs¬†by transferring signalling molecules across gap junctions between neighbouring cells.