1. The Integumentary System

2. Organs are two or more tissues which together perform a specialized function.
Epithelial membranes are thin structures that usually contain both epithelial and connective tissue.

3. Three types of epithelial membranes
Serous Membranes
Line cavities and cover organs
Simple squamous epi. over loose connective tissue
Parietal and visceral portions
Secrete a serous (watery) fluid for lubrication

4. Cutaneous membrane is the skin
Mucous membranes
Line cavities that open to the exterior
Layer of epithelium over connective tissue; epithelium varies with location
Tight junctions and goblet cells
Cutaneous membrane is the skin
the major organ of the integumentary system

5. One of the largest organs
Integumentary system is the skin and the organs derived from it (hair, glands, nails)
One of the largest organs
2 square meters; lbs.
Largest sense organ in the body
The study of the skin is Dermatology

6. Functions: 1. Regulation of body temperature
Cellular metabolism produces heat as a waste product .
High temperature
Dilate surface blood vessels
Sweating
Low temperature
Surface vessels constrict
shivering

8. 2. Protection
physical abrasion
dehydration
ultraviolet radiation
3. Sensation
touch
vibration
pain
temperature

9. 4. Excretion
5. Immunity/ Resistance
6. Blood Reservoir
8-10 % in a resting adult
7. Synthesis of vitamin D uv light
aids absorption of calcium

10. Anatomy
Epidermis Skin
Dermis
Subcutaneous layer or hypodermis

16. Epidermis Stratum basale (stratum germinativum)
Single layer of cuboidal to columnar cells
Stem cells that produce keratinocytes
Melanocytes - # the same for all races
Melanin produced in a melanosome

17. Stratum spinosum (thorn-like, prickly)
8-10 layers attached by desmosomes
See spines when cell is stained for microscopy
Keratinocytes take in melanin by cytocrine secretion

20. Stratum granulosum 3-5 layers Keratinization begins here
Keratohyalin found in granules
Cells beginning to die

21. Stratum lucidum (lucid = clear)
More apparent in thick skin
3-5 layers of clear cells
Eleidin
Stratum corneum (corneum means horny)
Dead, flat cells full of keratin
Keratin is waterproof
Cells are shed
Basal cell to surface – about 2-4 weeks

22. Dermis Connective tissue layer
Collagen and elastic fibers, nerves, blood vessels, muscle fibers, adipose cells, hair follicles and glands.
Papillary layer
1/5 of dermis – loose areolar connective tissue
Highly vascular
Dermal papillae - fingerprints

23. Reticular (net) layer Dense irregular connective tissue
Sebaceous (oil) glands
Hair follicles
Ducts of sudoriferous (sweat) glands
Striae or stretch marks
Meissner’s corpuscles and Pacinian corpuscles

24. Hypodermis Attaches the reticular layer to the underlying organs
Loose connective tissue and adipose tissue
Major blood vessels – rete cutaneum

25. Accessory organs or epidermal derivatives
Hairs
Epidermal growths that function in protection
Shaft, root, and folllicle
Sebaceous glands, arrector pili muscle, and hair root plexus (touch)
Hair growth and replacement have a cyclical pattern
‘male-pattern’ baldness

29. Nails Plates of highly packed, keratinized cells
Protection, scratching, & manipulation
Formed by cells in nail bed called the matrix ( in area of lunula)
1 mm / week
Eponychium - cuticle

32. Skin Glands Sebaceous (oil) glands Usually connected to hair follicles
Holocrine glands
Fats, cholesterol, proteins, salts, and cell debris
Moistens hair and waterproofs skin

33. Sweat (sudoriferous) glands
Eccrine sweat glands
Merocrine glands
Water, salt, wastes
Function is to cool the body (also nervous)
Apocrine sweat glands
Larger, merocrine glands
Associated with hair follicles
More viscous – fatty acids and proteins
Odor occurs when broken down by bacteria

34. Ceruminous glands Mammary glands Modified sudoriferous glands
Secrete cerumen (ear wax)
Mammary glands
Secrete milk

37. Skin color Genetic factors Environmental factors
Same number of melanocytes
Albinism
Environmental factors
Uv light or x-rays

39. Physiological factors
Amount of blood
Amount of oxygen
Cyanosis
Carotene accumulation
Jaundice – liver disorder

40. Wound healing Inflammation Shallow cuts
Blood vessels dilate and become permeable
Heat, redness, swelling and pain
Shallow cuts
Epithelial cells migrate
Contact inhibition

42. Deeper wounds Inflammatory phase Migratory phase Proliferative phase
Fibrin forms clot
Migratory phase
Fibroblasts make granulation tissue
Proliferative phase
Maturation phase
Scars – hypertrophic scar
keloid

47. Burns First degree or partial thickness burn Only epidermis is damaged
Erythema, mild edema, surface layer shed
Healing – a few days to two weeks
No scarring

48. Second degree- deep partial-layer burn
Destroys epidermis
Blisters form
Healing depends on survival of accessory organs
No scars unless infected

49. Third degree or full-thickness burn
Destroys epidermis, dermis and accessory organs of the skin
Healing occurs from margins inward
Skin grafting may be needed
Autograft
Homograft
Rule of Nines