A heart attack happens when blood flow to the heart suddenly. becomes blocked and the heart canât get oxygen. quickly, the heart muscle fails to pump and begins to die. disease (CHD), also called coronary artery disease.
The B-cell receptor is composed of two parts: i) A membrane-bound immunoglobulin molecule of one isotype (IgD, IgM, IgA or IgE).he B-cell receptor is composed of two parts: i) A membrane-bound immunoglobulin molecule of one isotype (IgD, IgM, IgA or IgE).
The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes. To be more specific, photoreceptor proteins in the cell absorb photons, triggering a change in the cell's membrane potential.The two classic photoreceptor cells are rods and cones, each contributing information used by the visual system to form a representation of the visual world, sight.o be more specific, photoreceptor proteins in the cell absorb photons, triggering a change in the cell's membrane potential. The two classic photoreceptor cells are rods and cones, each contributing information used by the visual system to form a representation of the visual world, sight.