Question

What are the different types of cell communication? Is there any significant similarities/differences between them all?

Answer 1

• Cells in multicellular organisms have to assume specialized roles and must know when to carry out specific activities.Cells communicate to change in behavior in one cell and coordinate activities. The language of cells consists of small molecules Receptors in cells detect small molecules and connections between receptors and cellular machinery interpret the signals.Cells respond to small molecules by activating certain biochemical pathways.
• The different types of cellular communication all follow the same steps but distinguish themselves by the speed of the signaling process and the distance at which it acts like Nerve cells signals rapidly but it works locally while glands which releases hormones work slowly but it has a network of full organism.
• Cells use different types of signaling depending on which other cells they want to reach. cell communication or cell signalling are of four types.

1. Paracrine: It diffuse signal which target local cells.The originating cell produces the chemical signal that diffuses throughout the tissue nearby. The chemical is not stable and deteriorates if it has to travel long distances.Hence used as a local cell communication. The chemical that has been released is targeted by receptors present on targeted cells while it doesnot affect any non target cells due to lack of receptors.Example; Paracrine signaling is also used to communicate inside muscle tissue. A paracrine chemical signal from the nerve cells in the muscle causes the muscle cells to contract, allowing for muscle movement in the larger organism.

2. Autocrine: It promotes growth and it is similar to paracrine signalling  but acts on the cell that initially secretes the signal.The original cell produces a chemical signal, but the receptors for the signal are on the same cell. As a result, the cell stimulates itself to change its behavior.Example, a cell could secrete a chemical that promotes cell growth. The signal diffuses throughout the local tissue but is captured by receptors on the originating cell.

3. Endocrine: the originating cell secretes a hormone that is stable over long distances. The hormone diffuses through the cell tissue into capillaries and travels through the circulatory system of the organism.Endocrine hormones spread throughout the body and target cells in locations that are remote from the signaling cell. The targeted cells have receptors for the hormone and change their behavior when the receptors are activated. Example, Adrenaline is secreted by adrenal glands and is released during  "fight or flight" mode. the hormone spreads through out of the body via blood vessels and reaches the target cells. Reaction of the body is that Blood vessels constrict to increase blood pressure for the muscles, the heart pumps more quickly and some sweat glands are activated.

4. Synaptic: It links the two cells.When two cells continuously have to exchange extensive signaling, it make sense to build special communication structures to facilitate the exchange of chemical signals. Cells develops synapse which is a cell extension that brings the outer cell membranes of two cells into close proximity.Chemical signals released into the synaptic gap are immediately taken up by the partner cell receptors.Example, Typical synaptic communication takes place between neurons in the brain. The brain cells construct synapses to establish preferred communication channels with some neighboring cells.

• In summary,all the types of cell communications have similar mode of action. Sending a cellular communication signal is relatively straight forward as the cell secretes the chemical and the signal is distributed according to its type.the target cell must have receptors corresponding to the chemical signal. The receptors are chemicals on the surface of the cell that can bind to certain chemical signals. When a receptor binds to a chemical signal, it releases a trigger on the inside of the cell membrane which then engages a process of signal transduction process.Type of cell communication varies on the distance at which target receptor is present and act accordingly.