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 body’s normal physiology. 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 between cells having physical contact with each other. This happens at the cell membrane level.
One cell has a signal molecule, and the other has a receptor moiety on its cell surfaces.
But both the cells are physically connected where the signaling occurs.
In animal cells, gap junctions facilitate this, while in plant cells, there are plasmodesmata.
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 prostaglandins show this type of signaling. Spinal cord development.
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 given by one cell to another 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 in the nervous tissue.
The signal is passed from one nerve cell to another through the neurotransmitter.
The nerve cell secretes acetylcholine, dopamine, and other neurotransmitters at its nerve ending in the synapse. Here, the released neurotransmitters act on the receptors of other nerve cell membranes.
How can plants and animals affect neighboring cells directly
Plant and animal cells can affect the neighboring cells through contact-dependent and paracrine signaling mechanisms.
