Transcript The Integumentary system

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).
General Facts
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Covering the entire outside of the body,
For example a 68 kg person,
Skin measures aboutDiameter-1.7 m²
weighs - 4 kg.
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Grows faster than any other organs in the body. People
continuously renew their skin throughout their lifetime.
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Renewal time-45 to75 days approximately.
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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 –
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Epidermis,
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Dermis
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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
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The dermis is the bottom-most, thick inner layer of skin
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comprises blood vessels, connective tissue, nerves, lymph
vessels, sweat glands and hair shafts.
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Two main layers:
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a) Upper Papillary: Contains touch receptors which
communicate with the central nervous system and is responsible
for the folds of the fingerprints.
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b) Lower Reticular: Made of dense elastic fibers that house
the hair follicles, nerves, and gland
SKIN ADNEXA
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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.
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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 :
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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.
 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.