Integumentary System

1. Integumentary System Ch 4

2. CLASSIFICATION OF BODY MEMBRANES • Epithelial memb- epi over conn • Serous memb- lines cavities • Serous fluid • pericardium, pleura, peritoneum • Connective memb- lubricating fluid at joints (bursae)

3. INTEGUMENTARY SYSTEM (SKIN) • Skin, hair, nails, sweat and oil glands

4. BASIC SKIN FUNCTIONS • Covering (stretchable) • keeps water and minerals in the body • keeps water and bacteria out (waterproof/washable) • protects (repairs small cuts, rips, and burns) • insulates and cushions

5. STRUCTURE OF THE SKIN • 2 connected layers: • outer EPIDERMIS- stratified squamous; keratinizing • underlying DERMIS • Can be separated by a burn or friction (blister) • Subcutaneous layer under dermis (shock absorber)

6. Epidermis • Avascular;Keratin- tough and protective (cornified) • 1 in2 of skin contains about 20 million skin cells

7. 5 strata (layers): • Stratum basale- deepest layer of the epidermis; millions of cells are made daily; pushed upwards and become the • Spinosum- and then the • Granulosum- flatter and keratin increases,die and become • Lucidum occurs only where the skin is thick and hairless (palms, soles of feet) • Corneum- outermost layer and is 20-30 cell layers thick; these are dead cells remnants and flake off making way for a “new” epidermis; we have a totally new epidermis every 25-45 days.

8. Melanin • Pigment (yellow to brown to black); produced by cells called melanocytes (found in the stratum basale layer) • When the skin is exposed to sunlight, the melanocytes are stimulated (tanning). • The melanin forms an umbrella over the pigments and protects the DNA from the UV radiation. • Freckles and moles are seen where melanin is concentrated in one spot.

9. BAD STUFF • Over exposure to the sun causes the elastic fibers in skin to clump, leading to leathery skin. • Immune system is also depressed after too much sun. Herpes simplex, or cold sores, is more likely to appear after sun exposure. • Overexposure can also alter DNA of skin cells, leading to skin cancer.

11. Dermis • Helps hold the body together; varies in thickness (very thick on palms and soles, thin on eyelids); Leather products • 2 regions: • Papillary- upper region; pain and touch receptors. Unique capillaries arrangement on the fingertips(fingerprints) • Reticular- contains blood vessels, sweat and oil glands, and deep pressure receptors (Pacinian corpuscles). The phagocytes found here prevent bacteria from getting deeper in the body.

12. Dermis, Cont. • Both collagen (toughness) and elastic fibers (elasticity) are found throughout the dermis. decrease as we age, and skin sags and wrinkle. • Very vascular; helps w/ body temperature. • Fever= swollen dermal capillaries= red and warm skin (giving off heat) • Any change in normal blood supply to skin will result in cell death or if prolonged Decubitus ulcers (bedsores). Pg 98 picture • Hospital patients; This can lead to permanent damage to blood vessels and tissue.

15. SKIN COLOR • 3 pigments: • The amount and kind of melanin in the epidermis (yellow, red-brown, or black) • The amount of carotene (orange-yellow pigment found in carrots) in the stratum corneum and subcutaneous tissue • The amount of oxygen bound to the hemoglobin (pigment in RBC) in the dermal blood cells.

16. BAD STUFF • When hemoglobin oxygen levels are low, both the blood and the skin of Caucasians appear blue (cyanosis). Cyanosis is common during heart failure and severe breathing disorders. Cyanosis also occurs in the mucous membranes and the nails.

17. Other reasons for Skin colorings: • Emotional stimuli and certain disease states • Redness (erythema)- embarrassment, fever, HBP, allergy, or inflammation • Pallor (blanching)- emotional stress, anemia, LBP, or impaired blood flow to an area • Jaundice (yellow)- liver disorder where wastes aren’t excreted properly • Bruises- blood clots in tissue spaces (hematomas), Vit. C deficiency, or hemophilia (easy bleeding

21. Oil Glands • Sebaceous glands (oil)- all over the skin, except palms and soles of feet; secretes sebum (keeps hair from being brittle and skin soft and moist and kills bacteria); • Are very active during puberty leading to oily skin during adolescence • If the sebaceous glands become blocked by sebum, whiteheads will appear. If that material oxidizes and dries, a blackhead is formed. Acne is an active infection of the sebaceous glands. Acne can be mild or it can be scarring.

22. Sweat Glands • Sudoriferous glands; about 2.5 million per person; 2 types of sweat glands • Eccrine glands- far more numerous and found all over the body; produce sweat, which is primarily water, salt, Vit. C, metabolic wastes (ammonia, urea, uric acid), and lactic acid (attracts mosquitoes); sweat is acidic (4-6) which inhibits growth of bacteria; helps w/ internal body temperature

23. Sweat Glands, cont. • Apocrine glands- axillary and genital areas; secretions contain those of eccrine plus fatty acids and proteins; may have a milky or yellowish color; functions are quite understood yet, but they are activated by nerve fibers during pain and stress and during sexual foreplay; secretions are odorless, but due to bacteria on skin and FA and proteins, has a musky, unpleasant odor

24. Hair and Hair follicles • Lost most of usefulness • Root- part of the hair enclosed in the hair follicle • Shaft- hair projecting from the scalp or skin (dead protein)  • Due to friction, the cuticle often wears away, leading to split ends. • Arrector pili- smooth muscle cells that connect the hair follicle to the dermal tissue. When contracted, they “dimple” the skin, causing goose bumps.

25. Hair Types • If follicle is straight and circular, the hair stand will be straight • If it is slightly curved and oval = the hair strand will be wavy to curly • If follicle is deeply curved and near flat= the hair strand will be curly or kinky • Melanocytes cause hair pigment (color) and different amounts combine for different shades of color.

26. Nails • Transparent and nearly colorless, but look pink because of the blood supply; made of primarily dead cells

27. Infections and Allergies • Athlete’s foot- itchy, red peeling; results from fungus infection; aka tinea pedis • Boils and carbuncles- inflammation of hair follicles and oil glands; carbuncles are boils caused by bacterial infections (Staphylococcus aureus)

30. Infections and Allergies • Cold sores (fever blisters)- blisters that itch and sting; caused by herpes simplex infection; virus lies dormant until emotional stress, fever, or UV radiation stimulates; usually occur around lips • Contact dermatitis- itching, redness, swelling of skin, blistering; Caused by exposure to chemicals that cause allergic reaction (poison ivy)

32. Infections and Allergies • Impetigo- pink, water filled lesions (mouth and nose) that develop a yellow crust and rupture; caused by highly contagious staph infection; common in children • Psoriasis- red lesions on skin covered w/ dry silvery scales; often hereditary

35. Burns • Tissue damage and cell death caused by intense heat, electricity, UV radiation (sunburn), or chemicals (acids) • Body loses fluids that contain proteins, nutrients. • Dehydration and electrolyte imbalance • Kidneys shut down and body goes into shock. • Later on, infection causes trouble (leading cause of death in burn victims) • Burned skin is sterile for 24 hours, after that, bacteria and fungi invade

36. Rule of Nines • page 104 • The body is divided into 11 areas, each accounting for 9% of the total surface area. The area surrounding the genitals (perineum) accounts for 1%. • Determines how much/extent of the body is burned • Facial burns are dangerous due to the possibility of burned respiratory passageways, which could lead to suffocation.

37. Burns Classification • First degree- epidermis. The area is red and swollen. Generally heal in 2 or 3 days. Most sunburns. • Second degree- epidermis and upper dermis. red and painful; blisters form. Scars will not show up w/ proper medical care. • Third degree- entire thickness of the skin. Nerve endings are destroyed;gray-white or black. Not painful. Regeneration is not possible and skin grafts are performed.

38. 2nd Degree burn

39. Skin cancer • Basal cell carcinoma- least malignant and most common; face or sun-exposed areas of the body; relatively slow growing; 99% full cure after removal; about 75% of all skin cancers • Squamous cell carcinoma- found on scalp, ears, hands, lips; shallow ulcer w/ firm, raised border; complete cure good if detected early and removed; 20% of all skin cancers • Malignant melanoma- Cancer of the melanocytes; 5% of all skin cancers; often deadly; often develops from pigmented moles; spreads quickly; 50% survival rate

41. Basal Cell

42. Malignant Melanoma

44. ABCD of Skin Cancer • ACS suggests the ABCD rule for early detection: • A- Asymmetry: the 2 sides of the pigmented spot or mole do not match • B- Border irregularity: the borders are not smooth, but have indentions • C- Color: pigmented spot contains different colors in areas • D- Diameter: the spot is larger than 6 mm in diameter 

45. Developmental Aspects of Skin and Body Membranes • At birth, skin is covered by vernix caseosa, • Adolescence- acne • 20s and 30s- best skin appearance • Old age- skin wrinkles and sags; subcutaneous tissue decreases; injury. • We lose 1/3 of our hair follicles by age 50 • A closer look: page 106