Skin and Body Membranes 11/7/2018 2:54 AM Skin and Body Membranes © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

I. Function of Body Membranes A. Cover surfaces B. Line body cavities C. Form protective sheets around organs

II. Classification of Body Membranes A. Epithelial Membranes (coverings and linings) 1. Cutaneous Membrane – Skin a. Composed of keratinized stratified squamous epithelium b. Exposed to air, dry c. Underlying dermis of dense connective tissue

2. Mucous Membranes (Wet membranes) a. Rest on loose connective tissue b. Lines body cavities that are open to outside c. Usually composed of stratified squamous epithelium or simple columnar epithelium d. Adapted for absorption and secretion

3. Serous Membranes a. Composed of a layer of simple squamous epithelium b. Rests on areolar connective tissue c. Lines body cavities that are not exposed to the exterior d. Secrete serous fluid to reduce friction

B. Connective Tissue Membranes 1. Synovial Membranes a. Composed of areolar connective tissue b. Surround joints

III. The Integumentary System (Skin) A. Functions

B. Structure 1. Epidermis – outermost layer, stratified squamous epithelium 2. Dermis – dense connective tissue 3. Hypodermis – aka subcutaneous layer, composed of adipose tissue

1. Composed of 5 layers called strata C. Epidermis 1. Composed of 5 layers called strata 1. Stratum basale – deepest, constantly undergoing mitosis 2.Stratum spinosum 3. Stratum granulosum 4. Stratum lucidum – dead cells, not always present 5. Stratum corneum – dead cells, 20 – 30 layers thick Inner Most Keratin increases each level Outer most

2. Mostly composed of keratinocytes – cells that produce keratin (a protein) 3. Melanocytes – mostly found in stratum basale, produce melanin (pigment that darkens skin and ranges in color)

D. Dermis – contains collagen and elastic fibers 1. Papillary layer – upper layer of dermis, forms fingerprints, contains pain receptors 2. Reticular layer – lower layer, contains blood vessels, sweat and oil glands, pressure receptors

E. Skin Color 1. 3 pigments – melanin (tan/brown), carotene (orange), hemoglobin (red/pink)

2. Cyanosis – bluish tint due to lack of oxygen or abnormal hemoglobin

3. Erythema – redness, due to embarrassment, allergy, or inflammation

4. Pallor/Blanching – white, can be caused by fear, low blood pressure

5. Jaundice – yellowing, usually due to liver disorder and build up of bilirubin (excess bile pigments)

6. Hemotomas – bruises, clotted blood under skin from injury 7. Carotenosis – orange – too much carotene in diet

F. Skin appendages 1. Cutaneous glands – exocrine glands – release secretions through ducts a. Sebaceous glands – secrete oil (called sebum), empty it into hair follicles

Sweat Glands – aka sudoriferous glands, over 2.5 million on the body a. 2 kinds – eccrine (most everywhere) and apocrine (arm pits, groin area, become active at puberty)

3. Hair and Hair follicles – follicle produces hair which is non-living a. Arrector pili attached – goose bumps b. Hair shaft – above skin c. Hair root – below skin

IV. Common skin disorders A. Athletes foot – fungal infection, itchy, red

B. Boils and carbuncles – inflammation of the hair follicles and sebaceous glands

C. Cold Sores – “fever blisters”, herpes viral infection

D. Dermatitis – redness, often from exposure to chemicals, poison ivy, allergens

E. Impetigo – staph infection, common in children, very contagious

F. Psoriasis – chronic, autoimmune disease, overproduction of skin cells

V. Burns A. Caused by heat, electricity, uv radiation, chemicals B. Degrees of damage 1. 1st degree – only damages epidermis

2nd degree – burns upper regions of dermis, blisters form 3. 3rd degree – through all of dermis, often gray, white, black, destroys nerve endings

C. Rule of Nines 1. Used to determine severity of burns 2. Body is divided into 11 sections, each comprising 9% of the surface area of the body

Burns considered critical if -Over 25% of body has 2nd degree burns -Over 10% of body has 3rd degree burns -There are 3rd degree burns on face, hands, or feet

VI. Skin Cancer A. Basal Cell Carcinoma – most common, least often malignant, cancer of the stratum basale, the cells don’t form keratin, can invade dermis

B. Squamous cell carcinoma – starts in the stratum spinosum, usually sun-induced, tends to spread to lymph nodes

C. Malignant melanoma – most deadly, most likely to spread, begins in the melanocytes

D. ABCD Rules

https://www.youtube.com/watch?v=Orumw-PyNjw https://www.youtube.com/watch?v=EN-x-zXXVwQ