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 Bilayer. The phospholipids organize themselves in a bilayer to hide their hydrophobic tail regions and expose the hydrophilic regions to water. This organization is spontaneous, meaning it is a natural process and does not require energy.This structure forms the layer that is the wall between the inside and outside of the cell.ipid Bilayer Structure. The lipid bilayer is a universal component of all cell membranes. Its role is critical because its structural components provide the barrier that marks the boundaries of a cell. The structure is called a lipid bilayer because it is composed of two layers of fat cells organized in two sheets.