Integumentary System

Vitamin D is synthesised by the skin on exposure to sunlight.

Keratocytes produce keratin which gives strength and flexibility to the skin.

Hypodermis stores fat cells in the form of adipose tissues.

The stratum basale cells divide continuously. As new cells form, older ones are pushed toward the skin surface. Thus, it helps in formation of new skin.

In skin infections, the local Langerhans cells take up and process microbial antigens to become fully functional antigen-presenting cells; thus it plays a major role in immunity.

The stratum granulosum, the thin middle layer, initiates keratinisation (production of keratin). This process starts the death of epithelial cells.

Pheomelanin is responsible for light coloured skin.

Excessive Sun exposure affects the genetic material which invariably causes cancer.

Skin of eyelids is very thin and it does not have stratum lucidum.

Papillary layer produces the ridged fingerprints on fingertips.

Sudoriferous glands are the sweat producing glands.

Both glands secrete sweat.

These sweat glands secrete pheromones.

People often use a deodorant to control the odour from sweat released by the apocrine glands in the armpit.

Arrector pili muscles are smooth muscle cells attached to hair follicles. When they contract, they pull the hair into an upright position, causing skin dimples (goose bumps).

Dermis is called true skin. It is below epidermis.

Apocrine glands become active during puberty.