Skin - "The jack of all trades" (bio chem ch 13)

Functions of the skin

Protection, sensation, temperature regulation, storage of food, grip.

Epidermis

The outer thinner part of the skin, formed of stratified epithelium piled in layers.

Stratum corneum

The outermost layer of the epidermis, consisting of several layers of flattened dead cells made of keratin.

Keratin

A fibrous structural protein found in the cornified layer, nails, hair, horns, hooves, and silk.

Granular layer

A thin middle layer of the epidermis consisting of two or three sub-layers of flattened cells.

Stratum malpighi

The innermost region of the epidermis, also known as the germinative layer.

Melanin

A pigment contained in the cells of the malpighian layer that determines skin coloration.

Leukoderma

Also called vitiligo, it is a condition where skin pigmentation (melanin) is lost from patches on the body.

Albinism

Complete loss of skin pigmentation, hair, eyebrows, eyelashes, and iris, appears pinkish due to underlying blood capillaries.

Dermis

The inner thick layer of connective tissue consisting of elastic fibers, rough and flexible.

Papillae

Small raised processes in the outer region of the dermis containing blood capillaries and nerve endings.

Hair shaft

The part of the hair that projects from the skin and may extend slightly below the epidermis surface.

Hair follicle

A structure enclosing the hair root composed of epithelial and connective tissue sheaths.

Meibomian glands

Modified sebaceous glands that open on the margins of the eyelids to lubricate them.

Ceruminous glands

Modified sebaceous glands found in the auditory canal that secrete cerumen (earwax) to protect the eardrum.