discuss some theories of the purposes served by variouskinds of hair; and
discuss some theories of the purposes served by various
kinds of hair; and
Hair is a flexible strand of dead keratinized epithelial cells and is made up of two distinct parts : The hair shaft and the hair follicle. Hairs are produced by hair follicles and extend outside the body which is called the hair shaft.
The Hair itself consists of three layers of cells, the innermost is the medulla containing large cells and soft keratin. Next layer is the cortex made up of several layers of flattened cells. The last layer is the cuticle, which is a single layer of most keratinized overlapping cells in the hair.
Hair follicle is a pocket that folds down a few millimeters below from the surface of the epidermis. The deep end is slightly expanded to form a structure called a hair bulb attached to many nerve bundles that act as receptors. Hair papilla made up of the dermal tissue protrudes into the bulb to supply signals and nutrients for hair growth. In addition each follicle has an arrector pili, a small bundle of muscle cells that can contract and pull the follicle to produce what we refer to as goose bumps when cold.
Step by step
Solved in 2 steps
