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”
 Living
layer
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”
 Dead
layer
cells
5 LAYERS OF THE EPIDERMIS (CLGSB)

Stratum corneum
 Outermost
 Shingle
layer
like – rough
 Dead
cells filled with
keratin
 Repels
 Can
water
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