Transcript Skin and body membranes - Doral Academy Preparatory

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