SKIN

Layers of Skin Epidermis Dermis Hypodermis

Facts about the skin  Different thickness -.5mm (eyelid) to 5mm (middle of your back  21.5 square feet surface of your body.  Skin is the largest organ of the body.

Epidermis  Greek = epi, over & derma, skin.  Top layer of epidermis is called Stratum corneum - soft keratin which keeps the skin elastic.  Stratum lucidum -has translucent layers of dead cell that contain protein called eleidin which is only in the palms of the hands and soles of the feet.

More Layers of epidermis  Stratum granulosum - layer of dying cells  Stratum spinosum - interlocking spine- like projections help support this binding layer.  Stratum basale -basement next to the dermis. Continuous cell division - new cells are made. Where melanocytes are found.

Dermis Means True Skin  Papillary layer  Reticular layer  Hypodermis layer

Papillary layer  Loose connective tissue  Papillae helps to join to epidermis  Double layers in hands and soles  Causes finger prints  Aids in gripping surfaces

Reticular layer  Dense connective tissue  Coarse caliginous fibers and bundles  Fibers crisscross forming a strong, elastic layer

Reticular layer  Where most of the gland and things are located. Hair Hair Oil gland Oil gland Corpuscles of touch Corpuscles of touch

Hypodermis  Also known as Subcutaneous layer  Lies beneath the dermis  Composed of loose, fibrous connective tissue  Thicker than the dermis  Large supply of lymphatic and blood vessels

Hypodermis  Sweat glands (sudoriferous)  Base of hair follicles  Can be tight or loose  More hypodermis give us padding Heels Heels Breast Breast

Function of Skin  Temperature Sweat Sweat Constriction & dilation of blood vessels Constriction & dilation of blood vessels Goose bumps Goose bumps  Excretion Sweat Sweat 1g nitrogen every hour 1g nitrogen every hour

More Functions  Synthesis Vitamin D - makes strong bones and teeth Vitamin D - makes strong bones and teeth Helps to prevent Rickets Helps to prevent Rickets  Sensory reception Heat & cold Heat & cold Touch & pressure Touch & pressure Pain Pain

Color of Skin  Presence of Melanin Dark skinned people produce more Dark skinned people produce more Asian people have very little Asian people have very little  Accumulation of carotene  Blood reflected through epidermis

PPPPlatelets (thrombocytes) and fibrinogen form a net LLLLess than 24 hrs. becomes dehydrated and a scab forms. TTTTwo or three days after the wounding, monocytes enter the wound. AAAAbout 10 days after, epidermis is restored & the scab is gone. Tough scar tissue continues to form.

Sudoriferous (Sweat) Gland EEEEccrine gland Over entire body None in nail beds, lips, eardrum Secrete perspiration Emotions cause the palms, fingers and soles to respond more. Keeps the body from over heating

 Apocrine or odiferous gland In armpits, dark region around nipples, others In armpits, dark region around nipples, others Female breast contain these glands that adapted to secrete and release milk. Female breast contain these glands that adapted to secrete and release milk. Become active at puberty Become active at puberty Respond to stress and has an odor. Respond to stress and has an odor. Contains a specific human pheromone Contains a specific human pheromone Glands in the ear canals that produce wax. Glands in the ear canals that produce wax.

Sebaceous (Oil) Glands LLLLubrication PPPProtection against bacteria & fungi PPPPermeability barrier SSSSkin softening agent

 Protection  Scalp hair protects & insulations  Eyelashes & eyebrows  Arrector pili muscle  Parts are Shaft, Shaft, Root Root Bulb Bulb

Parts of the Skin

When things go Wrong

Blackheads & Pimples

Warts

Ring Worm

Staphylococci

Staphylococci