heat definition In physics, a form of energy associated with the movement of atoms and molecules in any material. The higher the temperature of a material, the faster the atoms are moving, and hence the greater the amount of energy present as heat.
Cilia (singular: cilium) are microscopic, hair-like structures that extend outwardfrom the surface of manyanimal cells. These structures are important in the cell cycle and replication, and cilia play a vital part in human and animal development and in everyday life. A typical cilium is between one and ten micrometers long, and usually less than one micrometer wide.
There are two types of cilia, motile cilia (moving cilia) and non-motile cilia. Motile cilia constantly beat in a single direction, whilst non-motile cilia typically sense the cellsâ environment. Non-motile cilia are often referred to as âprimaryâ cilia.ormally a cell only has one non-motile cilium. There are some cells in the body that have a specialized primary cilium which have a very important job to do. For example in the human eye, there is a primary cilium that connects the outer segment of the rod photoreceptor cell to its cell body.