Cell signaling is a method of communication of one cell with other cells. This is done by following methods like
- Contact dependent cell signaling
- Paracrine signaling
- Autocrine signaling
- Endocrine signaling
- Synaptic signaling.
Cells need to communicate with other cells for the normal physiology of the body. Sometimes they signal the nearby cells, and other times they signal to distant cells.
Types of cell signaling
Contact dependent cell signaling
Here the cell signal occurs in between cells having physical contact with each other. This occurs at the cell membrane level.
One cell has a signal molecule, and the other has a receptor moiety on their cell surfaces.
But both the cells are physically connected where the signaling occurs.
Paracrine signaling
This is a signal where one cell signals nearby neighboring cells. This is somewhat similar to the above type. But, the cells need not be directly connected.
The signal molecules are released by one cell. These molecules reach nearby cells around and transmit the signal.
Examples: Cytokines like the prostaglandins show this type of signaling
Autocrine signaling
This is a type of cell signal where a cell gives a signal to itself.
A signal molecule is released out of the cell.
This molecule, in return, acts and gives a signal to the same cell through surface receptors.
Examples: The monocytes produce cytokines that affect themselves.
Endocrine signaling:
This is a signal which is given by one cell to another cell located in a distant region. The signal molecule is released into the bloodstream.
This is then carried away and distributed by the blood to other cells. These distant cells receive the signal.
Example: Endocrine gland cells secrete hormones to affect the distant cell.
Synaptic signaling
This is a signal which occurs between two nerve cells. It is specific and occurs only at the nervous tissue.
Here the signal is passed from one nerve cells to another through the neurotransmitter.
The nerve cell secretes acetylcholine, dopamine, and other neurotransmitters at its nerve ending into the synapse. Here, the released neurotransmitters act on the receptors of other nerve cell membranes.
