Integumentary System

The skin has many functions such as: thermoregulation pathogen protection protection against UV rays energy storage vitamin D production mechanical damage protection

The top layer of the skin which includes the: stratum cornneum and acidic mantle

Made up of 25-30 sub layers of flattened cells that provide protection to the skin and body. These cells are constantly exfoliated by friction and replaced by new cells.

The stratum corneum are cells are rich in the structural protein keratin to provide protective properties

Cells found in the deepest epidermis layer that become rounder, flatter and harder before moving to the surface (stratum corneum) to replace the stratum corneum layer

Also found on the surface of the skin, and is slightly acidic as it’s the body’s first line of defence against pathogens

The tough, elastic middle layer of the skin, made up of interlaced (white) fibrous tissue and (yellow) elastic fibres

blood vessels lymphatic vessels sweat glands and ducts sebaceous glands Hair follicle and strands hair erector muscles

A tube like structure (pore) which surrounds the root and strand of hair to provide a pathway for the hair shaft (strand) to grow through. The white bulb at the base of hair strands is a protein called keratin

The muscle contracts (under the influence of the connected nerve) to cause hairs to erect (stand on end)

A gland which connects to the hair follicle to release sebum to the surface of the skin

An oily substance produced by the sebaceous gland that: protects the skin from drying out lubricates to reduce friction makes the skin more impervious to moisture

A natural dark skin pigment that caused the hair, eyes & skin to become pigmented (appear darker). The amount of you have depends on: genetics previous ancestral exposure to UV

Absorbs harmful UV rays to protect the skin against cellular damage from UV light exposure. It makes skin appeared ‘tanned’ during the summer a the sun causes melanin to move to the surface of the skin. Eventually fades away as sun is less prevalent during winter.

The process of sweating, involving: sweat glands duct of sweat glands sweat pore

A gland in the dermis which produces sweat (a mixture of water and salts) which is carried through the sweat gland duct to the epidermis where it’s released onto the skin through the sweat pore. To reduce body temperature

The deepest layer of the skin (8% thicker in female then male). It connects to underlying organs and is made of: loose fibrous connective tissue (collagen) interlaced with blood vessels fat (adipose tissue)

The subcutaneous layer (mainly adipose) provides insulation for the body, energy release, stores lipids, cushions the body, used for communication & is important for tissue repair

The skin absorbs UV rays from the sun to help with the production of UV rays from the sun, which is needed for strong bones and good eyesight

Vasodilation: blood vessels (arterioles) open up and move closer to the skin to increase volume of blood so more heat can be loss by evaporation. Vasoconstriction: blood vessels (arterioles) constrict and move further from the skin to reduce blood volume flow so less heat escapes

Pilorelaxation: hair erector muscle relax so hairs on the surface of the skin flatten Piloerection: hair erector muscles contract so hairs stand up (goosebumps) to trap a layer of insulating air around the skin

High temperatures Hypothalamus detects high temperatures so sends impulses to the skin to reduce temperature: Produce sweat (evaporates quickly to reduce temp) Pilorelaxation Vasodilation NO shivering

Hypothalamus detects low temperatures so sends impulses to the skin to increase temperature: Shivering (rapid contraction to produce heat energy from ATP) Piloerection Vasoconstriction NO sweating