A close up of an eye showing the capillaries. The definition of a capillary is a small blood vessel that is part of the network of the small arteries and small veins, or an extremely thin tube through which nothing thicker than a human hair can pass.
Phospholipid bilayer. Definition. noun. The two layers of phospholipids arranged in such a way that their hydrophobic tails are projecting inwards while their polar head groups are projecting on the outside surfaces. Supplement. This arrangement of phospholipids in bilayer is used to describe the cell membranes of many animal and plant cells. The two layers of phospholipids are arranged in a way that their hydrophobic tails are projecting to the interior whereas their hydrophilic heads are projecting the exterior.
The cell membrane is called the phospholipid bilayer because the phospholipids form two distinct lay â¦ ers. In each layer, the phospholipid molecules lie with the hydrophilic heads at the membrane surface and the hydrophobic tails on the inside, in association with cholesterol and small quantities of other lipids.he phospholipid bilayer is fluid due to the unsaturated hydrocarbon tails of phospholipids found in the hydrophobic region. These unsaturated hydrocarbon tails do not have al â¦ l the hydrogen it can possibly have, so carbon forms a double bond.