3. integumentary system

Credits: Ed Cabalang Jr

1. Integumentary system ~Skin and its Derivatives~

2. Skin ( cutaneous membrane) largest organ of the human body with a surface area of 1.5-2.0 square meters in an average adult. Each 5 square cm may have up to: 600 sweat glands 20 blood vessels 60,000 melanocytes and over a thousand nerve endings . “A waterproof, stretchable, washable and permanent-pressed coat of the human body that is guaranteed to last a lifetime with reasonable care”

3. Protection Integument (“covering”) Functions tight cell junctions prevent bacterial invasion lipids released retard evaporation pigment protects somewhat against UV light Langerhans cells alert immune system

4. 2. Thermoregulation How does it regulate temperature? Sweating Dilate/constrict of blood vessels Goose bumps High temperature Dilate surface blood vessels Sweating Low temperature Surface vessels constrict shivering Functions

5. Shivering and constriction of surface vessels raise internal body temperature as needed Exercise in moderate exercise, more blood brought to surface helps lower temperature with extreme exercise, blood is shunted to muscles and body temperature rises

6. 3. Excretes Waste The skin removes the excess of water, pigments and salts from the blood through the sweat glands. subcutaneous Functions

7. 4. Reduces water loss The uppermost layer of the skin, a thick impermeable membrane, is full of Keratin and is “cornified” or hardened Functions

8. 5. Houses sensory receptors Functions touch, pressure, vibration, tickle, heat, cold, and pain arise in the skin

9. 6.Synthesis of Vit . D Functions activation of a precursor molecule in the skin by UV light enzymes in the liver and kidneys modify the activated molecule to produce calcitriol , the most active form of vitamin D. necessary vitamin for absorption of calcium from food in the gastrointestinal tract

10. Structure of the Skin

11. Cutaneous membrane Protects tissues from physical trauma, biological pathogens, and chemical trauma Provides sensations Accessory Structures Provides sensations Produces secretions Protects epidermal surfaces Integumentary System

12. Keratinized stratified squamous epithelium

13. Stratum Basale: Mitotic layer, continuously replaces epidermal cells, turnover rate between 25 to 50 days Stratum Spinosum: Cells are pushed upward and flatten out Stratum Granulosum: Cells contain granules of Keratin Layers of the Epidermis

14. Stratum Lucidum: Observed only in non-hairy or thick skin. Several layers of dead cells with indistinct boundaries Stratum Corneum: Composed of 25 or more layers of dead squamous cells still joined by desmosomes. Eventually desmosomes break and cells flake off in a process called desquamation Layers of the Epidermis

15. Keratinocytes: Most common cells of the epidermis. Provides protection and waterproofing sealant Melanocytes: Produces and transfer the protein melanin to Keratinocytes. Melanin is a brown/black pigment that absorbs UV-light. Cells of the Epidermis

16. Langerhans cells: Arise from red bone marrow and migrate to the epidermis. They participate in immune responses against bacteria and viruses. Easily damaged by UV Merkel Cells: Found in the Stratum Basale, they contact the flattened process of sensory neuron. They respond to touch sensations Cells of the Epidermis

17. Melanin produced in epidermis by melanocytes melanocytes convert tyrosine to melanin UV in sunlight increases melanin production same number of melanocytes in everyone, but differing amounts of pigment produced results vary from yellow to tan to black color Skin Color Pigments

18. Clinical observations freckles or liver spots = melanocytes in a patch albinism = inherited lack of tyrosinase ; no pigment vitiligo = autoimmune loss of melanocytes in areas of the skin produces white patches The wide variety of colors in skin is due to three pigments - melanin, carotene, and hemoglobin (in blood in capillaries) - in the dermis.

19. Carotene in dermis: yellow-orange pigment (precursor of vitamin A) found in stratum corneum & dermis Hemoglobin in dermis: red, oxygen-carrying pigment in blood cells if other pigments are not present, epidermis is translucent so pinkness will be evident Skin Color Pigments

20. Deeper layers of skin 10-20 times thicker than epidermis. Top layer arranged In ridges. Why are there ridges? Dermis

21. Ridges help the epidermis bind to the dermis. The uneven ridges create fingerprints Dermis

22. Dermis Reticular region: consists of dense irregular CT Contain most of the accessory Structures Papillary Region: Consist of areolar Tissue Dermal Papilla: Fingerlike projections that greatly increase surface area 1 2 3 4 Layers of the Dermis

23. Apocrine sweat glands: Found in the Axillae, nipples, labia, and glans penis. Begin to function at puberty and are affected by hormones Produce odorous thick secretion Possible pheromone function Sudoriferous (eccrine) Sweat Gland: Widespread (3,000/sq. in.) Produce thin watery secretion Controlled by nervous system Thermoregulation Excretion of urea Antibacterial action Accessory Structures of the Dermis

24. Sebaceous “Oil” gland: Secrete sebum Coats hair shaft and lubricates the epidermis Secreted to hair follicles Not associated with hair on the labia, glans penis, and lips Activity controlled by sex-hormones Modified in external ear canal to produce cerumen or ear wax (ceruminous glands) Accessory Structures of the Dermis

25. Mammary Glands: Anatomically related to apocrine sweat glands Development controls by sex hormones and pituitary hormones Produce milk Accessory Structures of the Dermis

26. Ceruminous Glands: Modified sweat glands found in the external auditory canal Produce cerumen or ear wax Helps trap foreign particles from reaching the eardrum Accessory Structures of the Dermis

27. Hair: Present on most skin except palmer surface, and plantar surface Growth controlled by genetics and sex hormones Provides protection and sensory input Each hair has an arrector pili muscle Accessory Structures of the Dermis

28. Split ends

29. Nails – protective covers of ends of fingers and toes.

30. Meissner’s Corpuscles: Present in dermal papilla Specialized sensory neuron nerve endings Respond to touch ( tactile) Most numerous in thick or non-hairy skin of the palmar and plantar surfaces Special Sensory Apparatus

31. Pacinian Corpuscle: Encapsulated sensory nerve ending Located at the hypodermis/dermis junction Respond to pressure Special Sensory Apparatus

32. The hair growth cycle consists of a growing stage and a resting stage. Growth cycle = growth stage & resting stage Growth stage lasts for 2 to 6 years matrix cells at base of hair root producing length Resting stage lasts for 3 months matrix cells inactive & follicle atrophies Old hair falls out as growth stage begins again normal hair loss is 70 to 100 hairs per day Both rate of growth and the replacement cycle can be altered by illness, diet, high fever, surgery, blood loss, severe emotional stress, and gender. Chemotherapeutic agents affect the rapidly dividing matrix hair cells resulting in hair loss. Hair Growth

33. Hair color is due primarily to the amount and type of melanin. Graying of hair occurs because of a progressive decline in tyrosinase . Dark hair contains true melanin Blond and red hair contain melanin with iron and sulfur added Graying hair is result of decline in melanin production White hair has air bubbles in the medullary shaft Hormones influence the growth and loss of hair (Clinical applications). Hair Color

34. Acne – infection of sebaceous gland Skin Diseases

35. Whitehead-sebum lodges in ducts bec of improper discharging blackhead- whitehead blackened by oxidation

36. Furuncles and carbuncles

37. Benign tumor – fleshy growths on neck, armpits and body. Harmless! Tumor Skin Diseases

38. Vascular Birthmarks – Blood vessel abnormality affecting .5% of population – darkens skin Skin Diseases

39. Dermatitis – dry, sensitive skin Skin Diseases

40. Athlete’s Foot Ring Worm Fungal Infection Skin Diseases

41. Impetigo – bacterial infection Skin Diseases

42. Disorders of the Skin Psoriasis – chronic inflammation

43. SkinCancer: three common types Melanoma Squamous cell Carcinoma Basal cell carcinoma

44. ABCD Rule for Detection

45. Warts- viral infection Plane warts Common wart Plantar wart Skin Diseases

46. VAMPIRES AND WEREWOLVES Porphyria- rare skin condition; genetic - can not make the iron-containing heme part of hemoglobin -accumulation of porphyrins; lesions appear when exposed to the sun -fingers, toes, nose become mutilated, degeneration of gums, rampant hair growth -symptoms become aggravated by exposure to some chemicals including garlic

47. Characteristics of Porphyria ( 5Ps) Puberty Psychiatric abnormality Pain Polyneuropathy Photosensitivity Treatments: Injection of heme molecules from healthy rbcs Middle ages ( no injections)- drank blood

48. Touch me Nots- Epidermolysis bullosa Hereditary Lack of keratin in basal cells of epidermis A simple touch can cause layers to separate and blister

49. SKIN SIGNS Red skin- HBP, polycythemia, allergy, blushing Pale ( pallor)- anemia, LBP, fear and anger Purplish/bluish- severe heart disease, pneumonia Yellow-jaundice Bronze – addison’s disease Moist/hot- hyperthyroidism Rashes- measles, chicken pox and infectious dss Vitamin deficiency- rough, cracked scaly around corners of mouth Black/bluish marks- hematoma (clots)

50. Burns

51. When an injury extends to tissues deep to the epidermis, the repair process is more complex than epidermal healing, and scar formation results. Healing occurs in 4 phases inflammatory phase has clot unite wound edges and WBCs arrive from dilated and more permeable blood vessels migratory phase begins the regrowth of epithelial cells and the formation of scar tissue by the fibroblasts proliferative phase is a completion of tissue formation maturation phase sees the scab fall off Scar formation hypertrophic scar remains within the boundaries of the original wound keloid scar extends into previously normal tissue collagen fibers are very dense and fewer blood vessels are present so the tissue is lighter in color Deep Wound Healing

52. Inflammatory stage: a. Blood clot forms b. Inflammation is the result of vasodilation which helps deliver WBC’s to help eliminate microbes Migratory Phase: a. Clot becomes a scab b. Epithelial cells migrate beneath scab to repair epithelium c. Fibroblast migrate into the area to repair connective tissue d. New tissue is called granulation tissue

53. 3. Proliferative phase: a. Extensive growth of epithelial cells b. Deposition of collagen fibers by fibroblasts c. Continued growth of vascular network 4. Maturation phase: a. Scab sloughs off b. Collagen fibers become more organized c. Fibroblasts decrease in number

54. Collagen fibers decrease in number & stiffen Elastic fibers become less elastic Fibroblasts decrease in number decrease in number of melanocytes (gray hair, blotching) decrease in Langerhans cells (decreased immune responsiveness) reduced number and less-efficient phagocytes Age-related Structural Changes

55. Your body is composed of approximately 100 Trillion cells About 16% of your body weight is skin The skin is completely renewed every 27 days You will make almost 1000 new skins in a lifetime If all the layers of your skin were laid out on the ground, it would cover about 20 m 2 or 2 parking spaces FYI !

56. A fingernail or toenail takes about 6 months to grow from base to tip Fingernails grow faster than toenails An average human scalp has 100,000 hairs We lose between 40 and 100 hairs per day Blondes have more hair than brunettes FYI !

57. Fingerprints provide traction for grasping objects Even identical twins have different fingerprints Every square inch of dermis contains twenty feet of blood vessels Skin on our hands and feet is thicker. When we bathe, skin takes on water and swells slightly. In the thicker areas, increased surface area creates crowding. The skin must wrinkle to accommodate the changes FYI !

58. Friction of the epidermis causes cell division to increase. This outward thickening is called a callus. Sometimes growth is inward, creating a corn. Humans shed about 600,000 particles of skin per hour – about 1.5 pounds per year. At age 70, you will have lost about 105 lbs. of skin. FYI !