1. The Integumentary System and Body Membranes
Human Anatomy and Physiology
November 2015

2. Classification of Body Membranes
Classification of Body Membranes (Figure 5-1)
Epithelial membranes
Composed of epithelial tissue and an underlying layer of connective tissue
Connective tissue membranes
Composed exclusively of various types of connective tissue

3. Classification of Body Membranes
Epithelial Membranes
Cutaneous membrane
The skin
Serous membranes
Simple squamous epithelium on a connective tissue basement membrane
Types:
Parietal – line walls of body cavities
Visceral – cover organs found in body cavities

4. Classification of Body Membranes
Serous membranes (continued)
Examples
Pleura – line walls of thoracic cavity and cover lungs
Peritoneum – cover organs found in body cavities

5. Classification of Body Membranes
Serous membranes (continued)
Diseases
Pleurisy – inflammation of the serous membranes that line the chest and cover the lungs
Peritonitis – inflammation of the serous membranes in the abdominal cavity

6. Classification of Body Membranes
Mucous membranes
Line body surfaces that open directly to the exterior
Produce mucus
Thick secretion that keeps the membranes soft and moist

7. Classification of Body Membranes
Connective tissue membranes
Do not contain epithelial components
Produce lubricant called synovial fluid
Examples:
Synovial membranes that line spaces between joints and lining of bursal sacs.

8. The Skin
The Skin
Structure (figure 5-2) -- two primary layers called epidermis and dermis
Epidermis
Outermost and thinnest layer of skin
Composed of several layers of stratified squamous epithelium
Stratum basale (germinativum)
innermost layer of cells
Continually reproduces
New cells move toward surface
As cells approach surface they are filled with a tough, waterproof protein called keratin and eventually flake off

9. The Skin Stratum corneum outermost layer of keratin-filled cells
Stratum granulosum - Pigment-containing layer
Melanocytes - produce pigment
Pigment is called melanin
Blisters
Caused by breakdown of union between cells or primary layers of skin
Dermal-epidermal junction - specialized area between two primary skin layers

10. The Skin Dermis Deeper and thicker layer composed of connective tissue
Upper area of dermis characterized by parallel rows of peglike dermal papillae
Ridges and grooves in dermis form pattern unique to each individual (fingerprints)

11. The Skin
Deeper areas of dermis filled with network of tough collagenous and stretchable elastic fibers
Number of elastic fibers decreases with age and contributes to wrinkle formation
Dermis also contains nerve endings, muscle fibers, hair follicles, sweat and sebaceous glands, and many blood vessels

12. The Skin Appendages of the skin Hair (figures 5-5 and 5-6)
Lanugo - soft hair of fetus and newborn
hair follicle - epidermal tubelike structure required for hair growth
Hair growth begins from hair papilla
Hair root lies hidden in follicle and visible part of hair is called the shaft
Alopecia - hair loss
Arrector pili - specialized muscle fiber that produces “goose pimples” and causes hair to stand up straight

13. The Skin Receptors (figure 5-8)
Specialized nerve endings make it possible for skin to act as a sense organ
Meissner’s corpuscle - detects light touch
Pacinian corpuscle - detects pressure

14. The Skin Nails (figure 5-9)
Produced by epidermal cells over terminal ends of fingers and toes
Visible part called nail body
Root lies in a groove and is hidden by cuticle
Crescent-shaped area nearest root called lunula
Nail bed may change color with change in blood flow

15. The Skin
Skin glands
Types
Sweat or sudoriferous
Sebaceous

16. The Skin Sweat or sudoriferous glands Types Eccrine sweat glands
Most numerous, important, and widespread
Produce perspiration or sweat which flows out through pores on skin surface
Function throughout life and assist in body heat regulation

17. The Skin Apocrine sweat glands
Found primarily in axilla and around genitalia
Secrete a thick milky secretion different from eccrine perspiration
Breakdown of secretion by bacteria produces odor

18. Sebaceous glands
Secrete oil or sebum for hair and skin
Level of secretion increases during adolescence
Amount of secretion regulated by sex hormones
Sebum in sebaceous gland ducts may darken to form a blackhead
Acne vulgaris - inflammation of sebaceous gland ducts

19. Functions of the Skin Protection - first line of defense
Against infection by microbes
Against ultraviolet rays from sun
Against harmful chemicals
Against cuts and tears

20. Functions of the Skin Temperature Regulation
Skin can release almost 3000 calories of body heat per day
Mechanisms of temperature regulation
Regulation of sweat secretion
Regulation of flow of blood close to the body surface

21. Functions of the Skin Sense organ activity
Skin functions as an enormous sense organ
Receptors serve as  receivers for the body, keeping it informed of changes in its environment

22. Functions of the Skin Disorders of the skin skin lesions
Elevated lesions - cast a shadow outside their edges
Papule - small, firm raised lesion
Plaques - large raised lesions
Vesicle - blister
Pustule - pus-filled lesion
Crust - scab
Wheal (hive) - raised, firm lesion with a light center

23. Functions of the Skin Disorders of the Skin (continued) Lesions
Flat lesions - do not cast a shadow
Macule - flat discolored region
Depressed lesions - cast a shadow within their edges
Excoriation - missing epidermis (such as in a scratch wound)
Ulcer - crater like lesion
Fissure - deep crack or break

24. Burns
Treatment and recovery or survival depends on total area involved and severity or depth of the burn
Estimating body surface area using the “rule of nines” (figure 5-11) in adults
Body divided into 11 areas of 9% each
Additional 1% of body surface area around genitals

25. Burns Classification of burns (figure 5-12)
First-degree (partial-thickness) burns
Only surface layers of epidermis involved
Second-degree (partial thickness) burns
Involved the deep epidermal layers
Almost always cause injury to the upper level of the dermis
Third-degree (full-thickness) burns
Complete destruction of epidermis and dermis
May involve underlying muscle and bone
Lesion is insensitive to pain because of destruction of nerve endings immediately after injury - intense pain is soon experienced

26. Skin Infections Impetigo - highly contagious staphylococcal infection
Tinea - fungal infection (mycosis) of the skin; several forms occur
Warts - benign neoplasms caused by papilloma virus
Boils - furuncles; staphylococci infection in hair follicles

27. Vascular and Inflammatory Skin Disorders
Decubitus ulcers (bedsores) - develop when pressure slows down blood flow to local areas of the skin
Urticaria or hives - red lesions caused by fluid loss from blood vessels
Scleroderma - disorders of vessels and connective tissue characterized by hardening of the skin;
two types: localized and systemic
Psoriasis - chronic inflammatory condition accompanied by scaly plaques
Eczema - common inflammatory condition characterized by papules, vesicles, and crusts; not a disease itself but a symptom of an underlying condition

28. Skin Cancer Three common types
Squamous cell carcinoma - most common type, characterized by hard raised tumors
Basal cell carcinoma - characterized by papules with a central crater; rarely spreads
Melanoma - malignancy in a nevus (mole); the most serious type

29. Skin Cancer
The most important causative factor in common skin cancers is exposure to sunlight
Kaposi’s sarcoma, characterized by purple lesions, is associated with AIDS and other immune deficiencies.