1. Skin and Body Membranes Anatomy and Physiology Chapter 4

2. Function of Skin and Membranes
Line or cover body surfaces
Protect body surfaces
Lubricate body surfaces

3. Classification of Body Membranes
Epithelial
Cutaneous Membranes
Mucous Membranes
Serous Membranes
Connective Tissue
Synovial Membranes

4. Cutaneous Membrane = SKIN
What is it’s job?
Outermost protective boundary
Where is it found?
Superficial epidermis
A dry membrane (exposed to air)
What is it made of?
Keratinized stratified squamous epithelium
Underlying dermis is mostly dense connective tissue

5. Mucous Membranes What is it’s job?
Lines all body cavities that open to the exterior body surface
Often adapted for absorption or secretion
Where is it found?
Surface epithelium
What is it made of?
Type depends on site
Underlying loose connective tissue (lamina propria)

6. Specific serous membranes
What is it’s job?
Lines open body cavities that are closed to the exterior of the body
Where is it found?&What is it made of?
Surface simple squamous epithelium
Underlying areolar connective tissue
Serous layers separated by serous fluid
Specific serous membranes
Peritoneum: abdominal cavity
Pleura: around the lungs
Pericardium: around the heart

7. Connective Tissue Membrane
What is it’s job?
Provide a smooth surface and secrete a lubricating fluid
Where is it found?
Lines fibrous capsules surrounding joints
Line bursae and tendon sheaths
What is it made of?
Synovial membranes
Soft areolar CT
No epithelial cells

8. Integumentary System Skin (cutaneous membrane) Skin derivatives
Sweat glands
Oil glands
Hairs
Nails

9. Protects deeper tissues from:
Skin
Functions to:
Aid in heat regulation
Aid in excretion of urea and uric acid
Synthesize vitamin D
Protects deeper tissues from:
Mechanical damage
Chemical damage
Bacterial damage
Thermal damage
Ultraviolet radiation
Desiccation

10. Skin Structure Epidermis Dermis Hypodermis
Stratified squamous epithelium
Often keratinized (hardened by keratin)
Dermis
Dense connective tissue
Hypodermis
Not part of the skin
Anchors skin to underlying organs
Composed mostly of adipose tissue

11. Layers of Epidermis Stratum Corneum Stratum Lucidum Stratum Granulosum
Stratum Basale (Stratum Germinativum)
Cells undergoing mitosis
Lies next to dermis
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum
Occurs only in thick skin (like the palm)
Flatter, full of keratin
Stratum Corneum
Shingle-like dead cells
¾ epidermal thickness
20-30 cell layers thick

12. Melanin Pigment produced by melanocytes
Color is yellow to brown to black
Melanocytes are mostly in the stratum basale
Amount of melanin produced depends upon genetics and exposure to sunlight
NPR Story:

13. Dermis: 2 Layers… Animal “hide”
Projections called dermal papillae
Pain receptors
Capillary loops
Papillary layer
Blood vessels
Glands
Nerve receptors
Deepest skin layer
Reticular layer

14. Skin Structure

15. Normal Skin Color Determinants
Melanin
Yellow, brown or black pigments
Carotene
Orange-yellow pigment from some vegetables
Hemoglobin
Red coloring from blood cells in dermis capillaries
Oxygen content determines the extent of red coloring

16. Appendages of the Skin Sebaceous Glands Sweat Produce oil
Lubricant for skin
Kills bacteria
Most with ducts that empty into hair follicles
Glands are activated at puberty
Sweat
Widely distributed in skin
Two types
Eccrine - Open via duct to pore on skin surface
Apocrine - Ducts empty into hair follicles