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.
A co-receptor is a cell surface receptor that binds a signalling molecule in addition to a primary receptor in order to facilitate ligand recognition and initiate biological processes, such as entry of a pathogen into a host cell.n immunology in particular, the term co-receptor often describes a secondary receptor used by a pathogen to gain access to the cell, or a receptor that works alongside T cell receptors such as CD4, CD8, or CD28 to bind antigens or regulate T cell activity in some way.
A photoreceptor cell is a specialized type of neuron found in the retina that is capable of phototransduction. 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.