Inferior vena cava. The inferior vena cava (or IVC) (Latin: vena, vein, cavus, hollow) is a large vein that carries deoxygenated blood from the lower and middle body into the right atrium of the heart. Its walls are rigid and has valves so the blood does not flow down via gravity.
Tight Junctions The tight junction (also referred to as a zonula occludens) is a site where the membranes of two cells come very close together. In fact, the outer leaflets of the membranes of the contacting cells appear to be fused. Tight junctions, as their name implies, act as a barrier so that materials cannot pass between two interacting cells.
Cell Junctions. There are three major types of cell junctions: anchoring junctions, tight junctions, and gap junctions. They consist of protein complexes and are found in various tissues of vertebrates, especially muscles and epithelial tissues. Cell junctions are made from proteins called cell adhesion molecules, which are signal receptors in the cell membrane.