The Integumentary systemThe 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).

General FactsGeneral Facts

Covering the entire outside of the body, 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 Grows faster than any other organs in the body. People continuously renew their skin throughout their lifetime.continuously renew their skin throughout their lifetime.

Renewal time-45 to75 days approximately.Renewal time-45 to75 days approximately.

average thickness is 0.3 cm. The Thick skin on upper back, average thickness is 0.3 cm. The Thick skin on upper back, palms and soles, Thin on eyelids and inner folds of elbows.palms and soles, Thin on eyelids and inner folds of elbows.

SkinSkin

• 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.

EpidermisEpidermis

Epidermis is divided into the following 5 sub layers or Epidermis is divided into the following 5 sub layers or strata:strata:

Stratum corneumStratum corneum Stratum lucidumStratum lucidum Stratum granulosumStratum granulosum Stratum spinosumStratum spinosum Stratum germinativum (also called "stratum basale") Stratum germinativum (also called "stratum basale")

DermisDermis

The dermis is the bottom-most, thick inner layer of skinThe dermis is the bottom-most, thick inner layer of skin

comprises blood vessels, connective tissue, nerves, lymph comprises blood vessels, connective tissue, nerves, lymph vessels, sweat glands and hair shafts.vessels, sweat glands and hair shafts.

Two main layers:Two main layers: a) Upper Papillary: Contains touch receptors which a) Upper Papillary: Contains touch receptors which

communicate with the central nervous system and is responsible communicate with the central nervous system and is responsible for the folds of the fingerprints.for the folds of the fingerprints.

b) Lower Reticular: Made of dense elastic fibers that house the b) Lower Reticular: Made of dense elastic fibers that house the hair follicles, nerves, and glandhair follicles, nerves, and gland

SKIN ADNEXASKIN ADNEXA

Hair Hair and and NailsNails are modified versions of skin. Hair maintains are modified versions of skin. Hair maintains warmth in the body by preserving heat. Hair located around the warmth in the body by preserving heat. Hair located around the eyes and in the nose and ears protects these areas from small eyes and in the nose and ears protects these areas from small particles such as dust. It also cushions the body against injury.particles such as dust. It also cushions the body against injury.

MMuco-cutaneous junctions i.e. oral, conjuntival and anal or uco-cutaneous junctions i.e. oral, conjuntival and anal or mucosa of external orifices works in close relation with skin or mucosa of external orifices works in close relation with skin or act anatomically & functionally as modified skin structure.act anatomically & functionally as modified skin structure.

SKIN ADNEXASKIN ADNEXA

Cutaneous glands :Cutaneous glands :

Sweat gland (also known as sudoriferous glands) - Sweat gland (also known as sudoriferous glands) - excrete sweat to regulate temperature .excrete sweat to regulate temperature .

Sebaceous glands- oil-producing glands that keep skin Sebaceous glands- oil-producing glands that keep skin and hair moist and soft .and hair moist and soft .

Ceruminous glands - glands of the ear canal that Ceruminous glands - glands of the ear canal that produce earwax.produce earwax.

Mammary glands - milk-producing glands located in the Mammary glands - milk-producing glands located in the breasts. breasts.

Functions of the skinFunctions of the skin

ProtectionProtection. prevents infectious and other harmful . prevents infectious and other harmful substances entering the body. shields internal organs, substances entering the body. shields internal organs, muscles, nerves, blood vessels and other structures muscles, nerves, blood vessels and other structures from UV rays and from injury.from UV rays and from injury.

PreventPrevent the loss of essential fluids and substances.  the loss of essential fluids and substances. 

RegulationRegulation of body temperature. of body temperature.

Sensation.Sensation. The skin senses painful and pleasant The skin senses painful and pleasant stimuli.stimuli.

Waste disposalWaste disposal..

Serves as an organ for the metabolism of many Serves as an organ for the metabolism of many important molecules such as important molecules such as synthesis of vitamin Dsynthesis of vitamin D. .

Indication of health problemsIndication of health problems. The skin’s . The skin’s characteristics (e.g., texture, temperature, color, clarity) characteristics (e.g., texture, temperature, color, clarity) provide information about a person’s general health and provide information about a person’s general health and diseasedisease..