s kin and body membranes. b ody m embranes what is the function of the plasma membrane of a cell?
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SKIN AND BODY MEMBRANES
BODY MEMBRANES
What is the function of the plasma membrane of a cell?
BODY MEMBRANES
Function of body membranes
Cover body surfaces Line body cavities Form protective sheets around organs
CUTANEOUS MEMBRANE
Cutaneous membrane = skin Dry membrane Outermost protective boundary
CUTANEOUS MEMBRANE
MUCOUS MEMBRANE
Surface epithelium varies
Lines all body cavities that open to the exterior
body surface
Often adapted for absorption or secretion
Mouth, esophagus
MUCOUS MEMBRANE
SEROUS MEMBRANES
Lines open body cavities that are closed to the exterior of the body
Occur in pairs separated by serous fluid
Visceral layer: outside of the organ Parietal layer: portion of the wall of ventral body
cavity
SEROUS MEMBRANES
SEROUS MEMBRANES
Specific serous membranes
Pleura Around the lungs
Pericardium Around the heart
CONNECTIVE TISSUE MEMBRANE
Synovial membrane
Connective tissue only Lines capsules surrounding joints Secretes a lubricating fluid
CONNECTIVE TISSUE MEMBRANE
THE INTEGUMENTARY SYSTEM
The skin and the associated organs of sweat and oil glands, hairs, and nails make up the Integumentary system
THE SKIN
Fun Facts:
Avg. makes up about 9-11 lbs. or 7% of your weight Regenerates every 25-45 days
FUNCTIONS OF THE SKIN Take a rubber glove, cup of water (add some
pepper), and a toothpick
SKIN STRUCTURE (EDH)
epidermis (epithelial) dermis (fibrous) hypodermis (subcutaneous – fat)
SKIN STRUCTURE (EDH)
SKIN STRUCTURE
Epidermis—outer layer Stratified squamous epithelium Often keratinized (hardened by keratin)
Dermis Dense connective tissue
SKIN STRUCTURE
Hypodermis is deep to dermis
Not part of the skin Anchors skin to underlying organs Composed mostly of adipose tissue
(subcutaneous tissue)
5 LAYERS OF THE EPIDERMIS (CLGSB)
Stratum corneum
Statum lucidum
Stratum granulosum
Stratum spinosum
Statum basale
5 LAYERS OF THE EPIDERMIS (CLGSB)
Stratum basale
“Base”
Next to dermis
Cells undergoing mitosis
New cells are pushed upward
Melanin protects new cells from UV light
5 LAYERS OF THE EPIDERMIS (CLGSB)
Stratum spinosum
“Spiny” layer
Living cells
Protein synthesis-keretin
5 LAYERS OF THE EPIDERMIS (CLGSB)
Stratum granulosum
“Granular” layer
Thin
Cells dying and begin moving up
5 LAYERS OF THE EPIDERMIS (CLGSB)
Stratum lucidum
Occurs only in thick, hairless skin of the palms of hands and soles of feet
“Clear” layer
Dead cells
5 LAYERS OF THE EPIDERMIS (CLGSB)
Stratum corneum
Outermost layer
Shingle like – rough
Dead cells filled with keratin
Repels water
Can become thick from irritation (callus)
NOTE: Thick skin- covers palms, fingertips, soles of
feet Thin skin – covers rest of body
missing stratum lucidum and sometimes stratum granulosum
MELANIN
Pigment produced by melanocytes
Amount of melanin produced depends upon genetics and exposure to sunlight
MELANIN – SKIN COLOR
GENETICS is the key factor Quantity of melanin
(yellow to reddish- brown to black)protects skin from UV radiation
Melanocytes use enzyme tyrosinase to convert tyrosine into dark brown melanin pigment, albinos lack DNA code to make tyrosinase
ALBINISM IN HUMANS
MELANIN – SKIN COLOR Sunlight increases
melanin production by the release of hormones
freckles or moles are accumulations of melanin
other pigments such as carotene or hemoglobin contribute to skin color
MELANIN – SKIN COLOR
Prolonged exposure causes substantial melanin buildup which helps protect the DNA of viable skin cells from UV radiation by absorbing the light and dissipating the energy as heat