Cell Membrane Receptors

Cell Membrane Receptors
Many cell membranes have receptor molecules on their surface.   These receptor sites play an important role in allowing cells and organs to communicate with one another.

Hormonal Regulation
Hormones provide a primary way for cells to communicate with each other.   A hormone is a chemical messenger with a specific shape that travels through the bloodstream influencing another target cell or target organ.    Upon reaching the cell the hormone is targeted for, the hormone often activates a gene within a cell to make another necessary compound.   One example of this is provided by the pituitary gland.   This gland at the base of the brain makes a hormone called LH (luteinizing hormone).  This hormone travels through the bloodstream and stimulates the ovary to produce yellow tissue that produces the hormone progesterone, which maintains the thickness of the uterus lining.   The graphic below illustrates how this kind of hormonal regulation can work in a plant cell.    Animal cell hormonal regulation involves a similar mechanism.

A Hormonal Feedback Mechanism
The animation at the right illustrates how a hormone can bind to receptors on a cell membrane and trigger that cell to produce a needed compound.

Nervous Regulation
Nerve cells or neurons also allow cells to communicate with each other.   Neuron communications are one way organism can detect and respond to stimuli at both the cellular and organism level.   This detection and response to stimuli helps to maintain homeostasis in the cell or organism.   Neurons may stimulate other nerve cells or muscle cells, thus causing the later to contract and produce movement.

Any change in nerve or hormone signals will change the communication between cells and organs in an organism and thus may cause problems for organism’s stability and ability to maintain homeostasis.