Intercellular Signalling | Cell to Cell Communication

Cell signaling can be classified as either mechanical or biochemical based on the type of the signal. Mechanical signals are the forces exerted on the cell and the forces produced by the cell. These forces can both be sensed and responded to by the cells.[15] Biochemical signals are biochemical molecules such as proteins, lipids, ions, and gases. These signals can be categorized based on the distance between signaling and responder cells. Signaling within, between, and amongst cells is subdivided into the following classifications : Intracrine signals are produced by the target cell that stay within the target cell. Autocrine signals are produced by the target cell, are secreted, and affect the target cell itself via receptors. Sometimes autocrine cells can target cells close by if they are the same type of cell as the emitting cell. An example of this are immune cells. Juxtacrine signals target adjacent (touching) cells. These signals are transmitted along cell membranes via protein or lipid components integral to the membrane and are capable of affecting either the emitting cell or cells immediately adjacent. Paracrine signals target cells in the vicinity of the emitting cell. Neurotransmitters represent an example. Endocrine signals target distant cells. Endocrine cells produce hormones that travel through the blood to reach all parts of the body. Cells communicate with each other via direct contact (juxtacrine signaling), over short distances (paracrine signaling), or over large distances and/or scales (endocrine signaling).