005 Integumentary
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Transcript of 005 Integumentary
• Protection- mechanical, chemical, bacterial
• Body temperature regulation• Prevent water loss• Metabolic- synthesize vitamin D• Cutaneous Sensation• Blood reservoir• Excretion• Prevent UV damage
An organ, cells constantly dying and being replaced
Facts:• Weighs 9-11 lbs• s.a. = 1.5-2m2
• 1 cm2 has 70 cm blood vessels, 55 cm nerves, 100 sweat glands, 15 oil
glands, 230 sensory receptors• New skin produced in 25-45 days
• Keratinocytes (90%)- waterproofs & protects
skin, nails, hair, stratum corneum
• Melanocytes (8%)- produce melanin
• Merkel Cells- slow mechanoreceptors
• Langerhans’ Cells- immunological defense
• Stratum Corneum
• Stratum Lucidum
• Stratum Granulosum
• Stratum Spinosum
• Stratum Basale-
(Germinativum)
Dermis
papillary dermis
reticular dermis
a. Cellular
Fibroblasts (synthesize collagen, elastin, and reticulin), histiocytes, endothelial cells, perivascular macrophages and dendritic cells, mast cells, smooth muscle, and cells of peripheral nerves and their end-organ receptors.
b. Fibrous
Collagen & reticulin - provide tensile strength
Elastic fibers- provide for restoration of shape after a deformation
c. Ground substance
glycosaminoglycans: hyaluronic acid, chondroitin sulfate, and dermatan sulfate.
This layer contains adipose tissue and serves to attach the dermis to its underlying tissues.
Hypodermis
Some variations in human skin color(Sub-Saharan African, Indian, Southern European, and Northwest European)
Melanin Pigments:• Eumelanin: • Phaeomelanin
> Eumelanin:Phaeomalanin- darker skin and hair color;< Eumelanin:Phaeomalanin- lighter skin and hair color
Skin color due to: Melanin, Carotene & Hemoglobin
I -light skinned, burns easily, never tans
II - light skinned, burns easily, tans some
III - light skinned, burns occasionally, tans well
IV - light skinned, tans well, rarely burns
V - brown skinned (Asian, Indo-Asian, Chinese, Japanese), tans well, burns rarely, can sunburn after prolonged exposure to UVR
VI - black skinned (Afro-Caribbean), deeply pigmented, can burn after prolonged exposure to UVR
25% US pop
Human complexions are generally classified into six skin types:
• Cyanotic• Jaundice• Erythema• Pallor
• Pigmentation levels usually increase with age.
- exception: premature graying• Normal pigmentation may be altered by
genetic defects or by acquired diseases. -Hyperpigmentation- age spots -Hypopigmentation- vitiligo, albinism
External agents can also alter skin color.
• lightening agents
• carotene
• dyes
• Some internal compounds--such as the byproducts of hemoglobin metabolism--may color the skin.
Sunless tanning
Malignant melanoma
• 2% of all cancers
Risks:
1. Skin type
2. Sun exposure
3. Family history
4. Age
5. Immunological status
• A= asymmetry
• B= border
• C= color
• D= diameter
Normal mole Melanoma
Sweat Glands
• Eccrine (merocrine) glands- sweat• Apocrine glands- axillary & anogenital areas• Ceruminous glands- ears canal• Mammary glands- female reproductive glands
Ceruminous glands
Sweatglands
Sebaceous
Hair
Sebaceous gland
Hair shaft
Hair root
Hair bulb in follicle
Nail
1st Degree: epidermal damageEx. sunburn
2nd Degree: epidermis & upper dermis
Ex. blisters
3rd Degree: entire thickness of skin
Skin replacement: http://www.youtube.com/watch?v=eXO_ApjKPaI
• Blood vessels dilate• WBC & clotting agents released• Scab forms
• Granulation tissue forms• Capillary beds invade clot• Clean up begins
• Scar area has contracted • Epithelium regeneration begins
1. In which lay of skin are blood vessels located? 2. Where does epithelium regeneration begin?3. What color is a persons skin if they are cyanotic?4. List the layer of the epidermis in order from top to
bottom.5. What is the primary tissue of the hypodermis?