Integumentary System and Body Membranes

Transcription

1 Integumentary System and Body Membranes The Skin and its appendages hair, nails, and skin glands Anatomy/Physiology NHS

2 I. System Functions A. Protection of underlying tissue (microbe-proof, waterproof) B. Excretion of salts, water, and organic wastes (urea) C. Synthesis of vitamin D 3 (steroid-used in hormones for balancing calcium) D. Storage of nutrients E. Detection of pain, pressure, touch, and temperature F. Regulate body heat

3 II. Integument Membranes A. Membranes sheets of tissues working together, lining the body 1. Serous membrane lines the interior of body cavities (parietal) and exterior of organs (visceral), secretes serous fluid (reduce friction) 2. Mucous membrane- lines cavities open to the outside world secretes mucous for invaders to stick to 3. Synovial membrane form the lining of free moving joints secretes synovial fluid (no epithelial components) 4. Cutaneous - skin

4 III. SKIN A. Largest organ, 16% of body weight B. Layers 1. Epidermis nonvascular, stratified squamous, layered, cells contain keratin and melanin 2. Dermis vascular, connective tissue, has accessory cells for hair, nerves, oil, sweat, collagen, elastin 3. Hypodermis (subcutaneous) below the dermis (mostly adipose

5 IV. Epidermis A. In some places skin is thick (hands, feet, face) most places skin is thin.

6 B. Layers of epidermis 1. Most cells of the epidermis produce keratin considered keratinocytes 2. Stratum basale basal layer is nourished from dermis. Basal cells (stem cells) mitosis replenishes upward layers (3-4 weeks epidermis is replenished) 3. stratum spinosum - the cells become irregularly polygonal 4. Stratum granulosum -the cells begin to release the contents of the lamellar granules (keratohyalin) 5. Stratum lucidum dead cells flatten, nuclei degenerate 6. Stratum corneum cells are completely filamentous (keratin) and lipids fill in the spaces (cement-waterproof)

7 C. Color of the epidermis 1. Melanin - skin pigment is produced in melanocytes that lie between the stratum basale cells. a. Melanin is kept in organelles called melanosomes within these cells b. Melanocytes extend cellular extensions throughout cells of the epidermis c. Melanocytes can transfer melanin to keratinocytes (basal cells usually) d. Skin pigment is under the exposure to light, hormones, and genetics

8 V. Dermis (corium) A. Composition 1. Made of dense connective tissue 2. Divided into two layers a. The papillary layer consists of loose, comparatively cell-rich connective tissue, which fills the hollows at the deep surface (dermal papillae) of the epidermis. Capillaries are frequent. Collagen fibres appear finer than in the reticular layer. b. The reticular layer appears denser and contains fewer cells.

9 B. Dermal Appendages 1. Hair a. Hair follicle tubelike depression b. Epidermis cells at base of follicle (bulb) produce (mitosis) shaft of hair (where cells keratinize)

10 2. Muscle (Arrector pili) a. Attaches each hair follicle to epidermis region b. Causes hair to stand and goose bumps

11 3. Oil glands Sebaceous Gland a. Groups of specialized epithelial tissue associated with hair (dumps contents into hair follicle) b. Secretion (sebum) helps waterproof and keep skin healthy

12 4. Sweat Glands Sudoriferous a. Sweat has ph of (99% H 2 O) b. Exocrine glands (has a duct/ tube) i. Eccrine most numerous, respond to high body ii. temperature Apocrine active when person is emotional found in armpit, nipples, and groin region. Begin secretion at puberty and are responsible for bacterial growth (smell) in these regions

13 5. Nails a. Protective coverings b. Keratinized stratified squamous c. Nail root nail cell mitosis (not visible from surface) d. Cuticle portion of epidermal stratum corneum that folds over nail root e. Lunula little moon most active growing region f. Nail bed epithelial the nail covers

14 6. Nerve receptors a. Myelinated Nerve Fibers - Free nerve endings pain b. Merkels Corpuscle immediately below epidermis very light touch c. Meissner s Corpuscle located toward the skin surface light touch d. Ruffini s corpuscle in dermis strecthing and vibrations + Heat e. Pacinian Corpuscle deep in dermis detects pressure f. Krause s end bulbs detect low frequency vibrations + cold

15 VI. Hypodermis (Subcutaneous) A. Loose CT (Areolar) and adipose B. Insulates and helps conserve body heat

16 SURPRISE QUIZ! Please take out a piece of paper and number Which membrane of the integument would you find lining the abdominal cavity? 2. Which membrane of the integument has no epithelial parts? 3. Which vitamin is produced in the skin? 4. What percentage of body weight does the skin make up? 5. What two proteins make up the epidermis of the skin? 6. Name one location of thick skin 7. What layer of the epidermis is the white box in? 8. What layer of the epidermis is the black box in? 9. What is the hypodermis made up of? 10. What layer of the dermis is the red box in?

17 VII. Physiology A. PROTECTION:Melanin protects from U.V. rays, Keratin is waterproof and microproof B. Temp. Regulation: Removes up to 3,000 calories of heat a day (controlled by hypothalamus) 1. Too cold sweat glands are inactive and dermal blood vessels constrict, involuntary arrector pili muscles contract 2. Too hot sweat glands become active and dermal blood vessels dilate C. Healing 1. Inflammation swelling due to dilated and broken blood vessels decreases osmolality. 2. Epidermis is wounded, basal cell mitosis s stimulated at a faster rate. 3. Dermis wound will form scab, which fibroblasts will replace with CT fibers and produce scar

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19 A. Causes: UV Light, Fire, Electricity, Acid B. Total area involved rules of nine C. 1 st degree minor discomfort reddening of skin only epidermis D. 2 nd degree deep epidermal and some, dermal blistering, damage sweat glands, oil glands, hair E. 3 rd complete destruction of the dermis insensitive to pain. VIII. Burns

20 1 st Degree 1 st degree minor discomfort reddening of skin only epidermis

21 2 nd Degree 2 nd degree deep epidermal and some, dermal blistering, damage sweat glands, oil glands, hair

22 3 rd Degree 3 rd complete destruction of the dermis insensitive to pain. Scarring and lesions