4. Structure of the human skin

4.1 Description and Functions of parts of the human skin

Transverse section of the skin classified based on the skin layers.

The human skin consists of the two main layers , namely the (i) epidermis and (ii) dermis.

Detailed structure of the skin.

EPIDERMIS

Epidermis consists of 3 layers –

1. Cornified layer

2. Granular layer

3. Malpighian layer

DERMIS

The dermis contains a wide range of structures

1. Blood vessels

2. Hair

3. Sweat glands

4. Sensory receptors

Blood vessels

• Blood vessels can dilate in diameter (vasodilation) or constrict in diameter (vasoconstriction).

• When the weather is hot, the blood vessels dilate and more blood flows to the skin surface resulting in "flushing".

• When the weather is cool, the blood vessels constrict and less blood flows to the skin surface resulting in the skin to turn pale.

Hair

• Hair erector muscles attached to hair follicles.

• Contraction of hair erector muscles cause the hairs to stand on their ends.

Sweat gland, sweat duct and sweat pore

• The sweat gland is involved in the formation of the sweat.

• Sweat flows through a sweat duct and sweat pore to the skin surface.

Sensory receptors

• Sensory receptors found in epidermis and the dermis enable one to sense pain, pressure or temperature changes in the external environment.