The Integumentary system

The integumentary system : (From Latin integumentum, from integere 'to cover'; from in- + tegere 'to cover') Is the organ system that protects the body from damage, comprising the skin and its appendages(including hair, scales, feathers, and nails).organ system skinhairscalesfeathersnails

General Facts  Covering the entire outside of the body, For example a 68 kg person, For example a 68 kg person, Skin measures about- Skin measures about- Diameter-1.7 m² Diameter-1.7 m² weighs - 4 kg. weighs - 4 kg.  Grows faster than any other organs in the body. People continuously renew their skin throughout their lifetime.  Renewal time-45 to75 days approximately.  average thickness is 0.3 cm. The Thick skin on upper back, palms and soles, Thin on eyelids and inner folds of elbows.

Skin Skin is the largest organ in the body. Consists of three layers – Epidermis, Dermis Subcutaneous tissue. Hair and Nails are both modified forms of skin.

Epidermis  Epidermis is divided into the following 5 sub layers or strata:  Stratum corneum  Stratum lucidum  Stratum granulosum  Stratum spinosum  Stratum germinativum (also called "stratum basale")

Dermis  The dermis is the bottom-most, thick inner layer of skin  comprises blood vessels, connective tissue, nerves, lymph vessels, sweat glands and hair shafts.  Two main layers: a) Upper Papillary: Contains touch receptors which communicate with the central nervous system and is responsible for the folds of the fingerprints. a) Upper Papillary: Contains touch receptors which communicate with the central nervous system and is responsible for the folds of the fingerprints. b) Lower Reticular: Made of dense elastic fibers that house the hair follicles, nerves, and gland b) Lower Reticular: Made of dense elastic fibers that house the hair follicles, nerves, and gland

SKIN ADNEXA  Hair and Nails are modified versions of skin. Hair maintains warmth in the body by preserving heat. Hair located around the eyes and in the nose and ears protects these areas from small particles such as dust. It also cushions the body against injury.  Muco-cutaneous junctions i.e. oral, conjuntival and anal or mucosa of external orifices works in close relation with skin or act anatomically & functionally as modified skin structure.

SKIN ADNEXA Cutaneous glands :  Sweat gland (also known as sudoriferous glands) - excrete sweat to regulate temperature.  Sebaceous glands- oil-producing glands that keep skin and hair moist and soft.  Ceruminous glands - glands of the ear canal that produce earwax.  Mammary glands - milk-producing glands located in the breasts.

Functions of the skin  Protection. prevents infectious and other harmful substances entering the body. shields internal organs, muscles, nerves, blood vessels and other structures from UV rays and from injury.  Prevent the loss of essential fluids and substances.  Prevent the loss of essential fluids and substances.  Regulation of body temperature.  Sensation. The skin senses painful and pleasant stimuli.

 Waste disposal.  Serves as an organ for the metabolism of many important molecules such as synthesis of vitamin D.  Indication of health problems. The skin’s characteristics (e.g., texture, temperature, color, clarity) provide information about a person’s general health and disease.