Skin and Body Membranes - Integumentary System PDF

**Skin and Body Membranes** - Function of body membranes - Line or cover body surfaces - Protect body surfaces - Lubricate body surfaces **Classification of Body Membranes** - Epithelial membranes - Cutaneous membrane - Mucous membrane - Serous membra...

**Skin and Body Membranes** - Function of body membranes - Line or cover body surfaces - Protect body surfaces - Lubricate body surfaces **Classification of Body Membranes** - Epithelial membranes - Cutaneous membrane - Mucous membrane - Serous membrane - Connective tissue membranes **Cutaneous Membrane** - Cutaneous membrane = skin - A dry membrane - Outermost protective boundary - Superficial epidermis - Keratinized stratified squamous epithelium - Underlying dermis - Mostly dense connective tissue Mucous Membranes - Surface epithelium - Type depends on site - Underlying loose connective tissue (lamina propria) - Lines all body cavities that open to the exterior body surface - Often adapted for absorption or secretion **Serous Membranes** - Surface simple squamous epithelium - Underlying areolar connective tissue - Lines open body cavities that are closed to the exterior of the body - Serous layers separated by serous fluid - Specific serous membranes - Peritoneum - Abdominal\ cavity - Pleura - Around the\ lungs - Pericardium - Around the\ heart Connective Tissue Membrane - Synovial membrane - Connective tissue only - Lines fibrous capsules surrounding joints **Integumentary System** - Skin (cutaneous membrane) - Skin derivatives - Sweat glands - Oil glands - Hairs - Nails **Skin Functions** - Protects deeper tissues from: - Mechanical damage - Chemical damage - Bacterial damage - Thermal damage - Ultraviolet radiation - Desiccation - Aids in heat regulation - Aids in excretion of urea and uric acid - Synthesizes vitamin D **Skin Structure** - Epidermis -- outer layer - Stratified squamous epithelium - Often keratinized (hardened by keratin) - Dermis - Dense connective tissue - Deep to dermis is the hypodermis - Not part of the skin - Anchors skin to underlying organs - Composed mostly of adipose tissue **Layer of Epidermis** - Stratum basale - Cells undergoing mitosis - Lies next to dermis - Stratum spinosum - Stratum granulosum - Stratum lucidum - Occurs only in thick skin - Stratum corneum - Shingle-like dead cells Melanin - Pigment (melanin) produced by melanocytes - Color is yellow to brown to black - Melanocytes are mostly in the stratum basale - Amount of melanin produced depends upon genetic and exposure to sunlight Dermis - Two layers - Papillary layer - Projections called dermal papillae - Pain receptors - Capillary loops - Reticular layer - Blood vessels - Glands - Nerve receptors **Skin Structure**  **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 **Appendages of the Skin** - Sebaceous glands - Produce oil - Lubricant for skin - Kills bacteria - Most with ducts that empty into hair follicles - Glands are activated at puberty - Sweat glands - Widely distributed in skin - Two types - Eccrine - Open via duct to pore on skin surface - Apocrine - Ducts empty into hair follicles **Sweat and Its Function** - Composition - Mostly water - Some metabolic waste - Fatty acids and proteins (apocrine only) - Function - Helps dissipate excess heat - Excretes waste products - Acidic nature inhibits bacteria growth - Odor is from associated bacteria **Appendages of the Skin** - Hair - Produced by hair bulb - Consists of hard keratinized epithelial cells - Melanocytes provide pigment for hair color 0407c.jpg 0000A97EKARL\'s Pocketrans B81D7FDE: **Hair Anatomy** - Central medulla - Cortex surrounds medulla - Cuticle on outside of cortex - Most heavily keratinized **Associated Hair Structures** - Hair follicle - Dermal and epidermal sheath surround hair root - Arrector pilli - Smooth muscle - Sebaceous gland - Sweat gland **Appendages of the Skin** - Nails - Scale-like modifications of the epidermis - Heavily keratinized - Stratum basale extends beneath the nail bed - Responsible for growth - Lack of pigment makes them colorless **Nail Structures** - Free edge - Body - Root of nail - Eponychium -- proximal nail fold that projects onto the nail body  **Skin Homeostatic Imbalances** - Infections - Athletes foot - Caused by fungal infection *(Tinea pedis)* - Boils and carbuncles - Caused by bacterial infection (Staphylococcus) - Cold sores - Caused by virus - Infections and allergies - Contact dermatitis - - Impetigo - - Psoriasis - - - - - - - - **Rules of Nines** - Way to determine the extent of burns - Body is divided into 11 areas for quick estimation - Each area represents about 9% **Severity of Burns** - First-degree burns - Only epidermis is damaged - Skin is red and swollen - Second degree burns - Epidermis and upper dermis are damaged - Skin is red with blisters - Third-degree burns - Destroys entire skin layer - Burn is gray-white or black **Critical Burns** - Burns are considered critical if: - Over 25% of body has second degree burns - Over 10% of the body has third degree burns - There are third degree burns of the face, hands, or feet **Skin Cancer** - Cancer -- abnormal cell mass - Two types - Benign - Does not spread (encapsulated) - Malignant - Metastasized (moves) to other parts of the body - Skin cancer is the most common type of cancer **Skin Cancer Types** - Basal cell carcinoma - Least malignant - Most common type - Arises from statum basale - Squamous cell carcinoma - Arises from stratum spinosum - Metastasizes to lymph nodes - Early removal allows a good chance of cure - Malignant melanoma - Most deadly of skin cancers - Cancer of melanocytes - Metastasizes rapidly to lymph and blood vessels - Detection uses ABCD rule **ABCD Rule** - A = Asymmetry - Two sides of pigmented mole do not match - B = Border irregularity - Borders of mole are not smooth - C = Color - Different colors in pigmented area - D = Diameter - Spot is larger then 6 mm in diameter