Integumentary System.pdf

Membranes ~ thin sheet or layer of tissue that covers a structure or lines a cavity 2 Major Categories: 1. Mucous membrane – consists of epithelium & CT lining the cavities that opens to the outside of the body (digestive, respiratory, excretory & reproductive system...

Membranes ~ thin sheet or layer of tissue that covers a structure or lines a cavity 2 Major Categories: 1. Mucous membrane – consists of epithelium & CT lining the cavities that opens to the outside of the body (digestive, respiratory, excretory & reproductive systems) 2. Serous membranes – consists of epithelium & CT lining the cavities not open to the outside of the body (pleural membranes & peritoneal membranes) Other membranes: 1. skin/cutaneous membrane 2.Synovial membranes – line the inside of the joint cavity 3.Periosteum – CT membrane surrounding a bone  Inflammation 5 Major Symptoms: Mediators 1.Redness 2.Heat 1. Histamine 3.Swelling 2. Kinins 4.Pain 3. Prostaglandins 5.Disturbance of 4. leukotrienes function Inflammation 1. A splinter in the skin causes damage & introduces bacteria Mediators of inflammation are released/ activated in injured tissues & adjacent BV Some BV’s are ruptured causing bleeding 2. Mediators of inflammation cause capillaries to dilate (redness) Mediators of inflammation also increases capillary permeability, fluid leaves the capillaries (edema) Inflammation 3. WBC leaves the dilated BV & move to the site of bacterial infection, where they begin to phagocytize bacteria & other debris  Tissue Repair Fresh wound cuts through the epthelium (epidermis) & underlying CT (dermis), and a clot forms  Tissue Repair Approximately 1 week after the injury, a scab is present, & epithelium (new epidermis) is growing into the wound.  Tissue Repair Approximately 2 wks after the injury, the epithelium has grown completely into the wound, & fibroblastshave formed granulation tissue.  Tissue Repair Approximately 1 month after the injury, the wound has completely closed, the scab has been sloughed, & the granulation tissue is being replaced by new CT Integumentary System Functions of the Integumentary System 1. Protection 2.Sensation 3.Vitamin D production 4.Temperature regulation 5.Excretion Hypodermis (subcutaneous tissue) ❖ attaches the skin to the underlying bone & muscle ❖ supplies the skin w/ blood vessels & nerves ❖ consists mostly of loose connective & adipose tissue that contains half of the body’s stored fats Skin  Dermis ❖ strong, flexible connective tissue ❖ gives skin its strength & resilience ❖ contains collagen, elastic & reticular fibers ❖ rich in nerves, receptors, blood vessels, lymph vessels, hair follicles & sweat glands extend to it ❖ 10-20 times thicker than the epidermis  Dermal Layer 1. Papillary layer ▪ Meissner’s corpuscles ▪ Mainly areolar CT ▪ Lots of BV ▪ Dermal papillae ~ w/ BVs to supply the overlying epidermis w/ nutrients, remove waste products & aid in regulation of body temperature ✓ Produce finger prints ~ increases friction & enhances gripping ability  Dermal Layer 2. Reticular layer ▪ Mainly dense (irregular CT) ▪ Pacinian corpuscles ▪ Lots of collagen fibers ▪ Lines of cleavage (tension lines) between collagen bundles ✓ longitudinal in limbs ✓ circular around trunk ▪ Dermal tearing (stretch marks)  Epidermis ❖ stratified squamous epithelium ❖ upper layers ~ dead, filled w/ keratin (waxy protein) ❖ lower layers ~ living cells ❖ replaced every 35-45 days ❖ prevents water loss & resists abrasion  Epidermal Layer 1. Stratum basale Deepest stratum Consists of columnar or cuboidal cells Actively dividing cells (every 19 days) Only cells that get adequate nutrition & oxygen by diffusion from tissues below Bordered below by basement membrane  Epidermal Layer 2. Stratum spinosum several layers thick flattened, irregular, spinelike projections less mitosis ❖ S. basale + S. spinosum = Stratum germinativum ~ growing layers  Epidermal Layer 3.Stratum granulosum very thin; 2-3 cell layers thick as cells move up from s. basale they die & get flatter & thinner keratinization begins here  Epidermal Layer 4. Stratum lucidum thin transluscent band only found in thick areas of the epidermis *soles of feet *palms of hand  Epidermal Layer 5. Stratum corneum thickest of all layers; ¾’s the thickness of epidermis 20-30 cell layers thick dead cells completely filled w/ keratin water resistant main protection against biological assault  Cells of the Epidermis 1. Stem cells ~ undifferentiated cells found only in deepest layer 2. Keratinocytes ~ synthesize keratin 3. Melanocytes ~ synthesize melanin 4. Merkel cells ~ touch receptors attached to nerve cell 5. Langerhans cells ~ macrophages that stand guard against toxins, microbes & other pathogens that penetrate the skin  Skin Color 1. melanin ❖ group of pigments (yellow, orange, brown or black) responsible for skin, hair & eye color ❖ Provides protection against UV radiation from the sun Albinism  Skin Color 2. Carotene ❖yellow pigment in plants such as squash & carrots ❖ lipid soluble; accumulates in the lipids of S. corneum, fat cell of dermis & hypodermis ❖ gives the skin slight yellowish tint 3. Hemoglobin  Skin Color & Texture in Diagnosis 1. Cyanosis ~ bluish cast; poor oxygenation 2. Erythema ~ redness; emotional, hypertension, inflammation 3. Pallor ~ paleness; emotion, anemia, low blood pressure  Skin Color & Texture in Diagnosis 4. Jaundice ~ yellowing; liver disorder ~ bile pigments in blood 5. Hematoma ~ escaped blood has clotted; deficiency in Vit. C or hemophilia 6. Leathery skin ~ overexposure; clumping of elastin fibers; depressed immune system  Skin Markings 1. Friction ridges ❖ Markings on fingertips ❖ Allow us to manipulate objects more easily 2. Flexion lines ❖ Flexor surfaces of digits, palms, wrists, elbow etc.  Skin Markings 3. Freckles ❖ flat melanized patches ❖ vary w/ heredity or exposure to sun 4. Moles ❖ elevated patch of melanized skin  Accessory Skin Structures 1. Hair ❖ Covers the entire body except the palms, soles, lips, nipples & parts of the external genitals ❖ Hormones account for the development of “hairy regions” (head, axillary & pubic areas  Accessory Skin Structures ❖ heavily keratinized ❖ consists of : a. shaft – visible part b. follicle – sheath surrounding the root c. papillae – growing part; vascularized d. arrector pili muscles  Accessory Skin Structures ❖ hair color depends on the amount of melanin on the cortex of the shaft ❖ hair texture related to differences in cross sectional shape e.g. straight hair – round; wavy – oval; curly- flat  Accessory Skin Structures 2. Nails ❖ plates of hard, tightly packed keratinized cells of epidermis. ❖ composed of three principal parts: ✓Nail body- The visible portion of the nail. ✓Free edge- The aspect of the nail that may extend past the distal end of the digit. ✓Nail root- The aspect of the nail that is buried underneath a fold of skin.  Accessory Skin Structures ✓Lunula- The whitish semilunar area of the proximal end of the nail body. ✓Eponychium- Also known as the cuticle. This is a narrow band of epidermis which extends from the lateral border of the nail wall. ✓Nail matrix- Epithelial tissue deep to the nail root where actual nail growth occurs. Nail Function ❖nails allow us to grasp and manipulate small objects. ❖nails also provide protection against trauma to the distal ends of the digits.  Glands 1. Sebaceous glands /oil ❖ located in the dermis and are usually connected to hair follicles. ❖ produce an oily, white substance “sebum” which oils the hair and skin and thus prevents drying and also provides protection against some bacteria. ❖ located on the lips, on the eyelids and on the genitalia  Glands 2. Sweat glands /sudoriferous ❖ approximately 3 to 4 million sweat glands in the human body ❖ divided into two types, eccrine & apocrine, based on their structure and location a. Eccrine /merocrine Sweat Glands ✓ most common type of sweat glands. ✓ composed of simple coiled tubular glands that opens directly onto the surface of the skin through sweat pores. ✓most numerous on the palms of the hands & the soles of the feet  Glands b. Apocrine Sweat Glands ✓ composed of compound coiled tubular glands that usually opens into hair follicles superficial to the opening of sebaceous glands. ✓ typically found in the axillae, genitalia and around the anus.  Glands 3. Mammary glands ❖ modified sweat glands ❖ produce milk 4. Ceruminous glands ❖ modified sweat glands in the external ear canal ❖ secrete cerumen (ear wax) for protection  Skin Imbalances & Aging 1. Allergies a. contact dermatitis ~ allergic response 2. Infections a. viral (cold sores, herpes simplex, warts, Rubeola (measles), Rubella (german measles), chickenpox) b. fungal (ringworm, athlete’s foot) c. bacterial (boils & carbuncles, impetigo)) Impetigo Herpes Simplex Warts Shingles Rubella/German Measles Rubeolla/Measles Ringworm  Skin Imbalances & Aging 3. Genetic Diseases a. psoriasis ✓ chronic, noninfectious skin disease ✓ skin becomes dry & scaly ✓ cycle of skin cell production increases by 3-4x’s normal ✓ S. corneum gets thick as dead cells accumulate ✓ often triggered by trauma, infection, hormonal changes or stress Psoriasis  Skin Imbalances & Aging 4. Burns a. 1st degree burns ✓ skin is inflamed, red ✓ surface layer of skin is shed ✓ affect the epidermis only b. 2nd degree burns ✓ deeper injury ✓ blister formation ✓ entire epidermis is affected & part of dermis  Skin Imbalances & Aging c. 3rd degree burns ✓ entire skin is destroyed ✓ sometimes affecting the subcutaneous tissue ✓ may result in dehydration & electrolyte imbalances ✓ may require skin grafting ✓ extent of damage assessed/estimated by the “rule of 9” ~ head, arms- 9% of skin surface ~ front & back of torso, each leg – 18% ~ groin – 1%  Skin Imbalances & Aging 5. Skin Cancer a. Basal cell carcinoma ✓ most common ✓ least malignant ✓ S. basale cannot form keratin ✓ result in tissue erosion & ulceration ✓ 99% is fully cured  Skin Imbalances & Aging b. Squamous cell carcinoma ✓ cancer of the cells in S. spinosum ✓ usually induced by sun ✓ cells grow rapidly & grow into the lymphatic tissue c. Malignant melanoma ✓ cancer of melanocytes ✓ deadly, often begins w/ moles