Module 5: Integumentary System Flashcards
Integumentary System includes:
skin, nails, hair, sudoriferous glands, sebaceous glands
Functions of Integumentary System
Protection Regulation of body temp Receptors of stimuli Metabolic activity Storing blood Excretion
Protection
Skin protects body from bacterial invasion, physical injury, fluid loss
Acidic oils stop growth of pathogenic invaders
Skin is waterproof due to protein, Keratin
Regulation of Body Temp
Dilation and constriction of blood vessels and activity of sweat glands
Too hot = vessels dilate, sweat glands excrete water
Too cold = vessels constrict and warm blood temporarily bypasses the skin
Receptors of Stimuli
Skin has receptors that indicate heat, cold, touch, pressure
Exteroceptors relay info about environment so brain can make changes to prevent or minimize injury
Metabolic Activity
UV rays assist skin cells in producing Vit D (needed for normal bone growth and development)
Blood Reservoir
5% of body’s blood is in the skin
When extra blood is needed, nervous system constricts vessels in skin and more blood is free to flow into other areas of the body
Excretion
Excess water and salts excreted by skin
Layers of the skin
Epidermis (outer layer) and dermis (inner layer)
Epidermis
Outer layer (stratified squamous epithelium)
Closely packed cells form barrier to protect body (with keratin)
Surface cells are dead
Deeper layers are alive and constantly dividing to replace surface cells
No blood supply
Deep layers contain melanin
Layers of Epidermis
Deep to superficial: Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum (found in palms and soles only) Stratum corneum "CORi's GRANny SPINs BASketballs"
Dermis
Called corium (True skin)
Found beneath epidermis
Strong, flexible loose and dense connective tissues
Contains blood and lymph vessels, nerves, hair follicles, sweat glands
Composed of 2 layers: Upper papillary layer and lower reticular layer
Upper Papillary Layer
Composed of papillae that extend into epidermis
Blood vessels, nerve endings, sensory receptors extend into these to bring them closer to the skin surface
Papillae form distinct patterns on hands and feet (fingerprints)
Lower Reticular Layer
Attached to underlying hypodermic
Reticular layer is strong
Skin Color Pigments (3)
Melanin, carotene, hemoglobin
Melanin
Brown-black pigment found in epidermis
Formed in cells called Melanocytes (Plentiful mucous membrane, penis, nipples, face, arms, legs)
All races have same # of melanocytes but amount of melanin produced is different
Carotene
Yellow-orange pigment found in vegetable build ups in the Stratum corneum and fatty parts of dermis
Hemoglobin
Reddish pigment (NOT found in skin cells; in RBCs)
Oxygenated blood flowing through dermis gives skin pinkish color
Significant decrease in O2, skin will have bluish color
Cyanosis
bluish color of the skin
Sudoriferous (sweat) glands
Secrete sweat 3 Million/person Found in dermal region of skin Lots in palms and soles 2 Types: Apocrine Glands and Eccrine Glands
Apocrine Glands
Associated with hair follicles found in armpits/genitals
Become active during puberty
Accumulation of sweat changed by bacteria into unpleasant smelling chemical (aka body odour)
Eccrine Glands
Not associated with hair follicles
Function throughout lifetime
Found all over body (esp. forehead, upper lips, palms, soles)
Sebaceous (oil) Glands
Secrete Sebum (oily substance)
Associated with hair follicles
Found in all areas with hair
Sebum helps to waterproof hair and skin, and inhibit growth of bacteria on the skins surface
Hair
Found on nearly all surfaces except palms and soles, ends of fingers/toes, lips, nipples
Hair grows 1mm/3 days, when it becomes long it stops growing
Functions of hair
Protections
Eyebrows, eyelashes, nostril hairs protect from particles in the air
Hair on scalp provides “cushion” for head injury
Structures of Hair
Shaft, roots, medulla
Nails
Epidermal cells that have been converted to hard Keratin
Free edge, nail body, nail root
Eponychium (cuticle) is a fold of stratum corneum
Lunula (whitish crescent-shaped part)
Protect underlying tissue from trauma
First-degree burn
eg. sunburn
Superficial cells of epidermis are destroyed
Skin is inflamed and tender
Second-degree burn
Superficial and deeper cells of epidermis are destroyed (dermis may be affected)
Blisters on skin, burn is painful
Third-degree burn
All epidermal and dermal cells are destroyed
Skin is charred, no sensation at all
Immediate threat to life is loss of body fluids (several litres/day)
