Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
THE INTEGUMENTARY SYSTEM I. Introduction A. Basics 1. Consists of skin, hair, nails, and cutaneous glands. 2. Largest organ of body • 15-25 sq. ft • 9 lbs • 0.5-4.00 mm thick • Lose ~ 40# skin in lifetime B. Layers 1. Epidermis • Epithelial t. 2. Dermis • Connective t. 3. Hypodermis (subcutaneous t.) • Loose connective t. (fat) • Not part of the skin • Anchors the skin to bone and muscle tissue C. Functions protection provides a barrier against microorganisms, water, solar radiation, etc. Vitamin D Production Synthesizes an inactive form of vitamin D Sensation Receives incoming messages/stimuli Thermoregulation Acts to maintain constant internal body temperature Excretion (small amount) Acts to excrete sweat, oil & milk II. Epidermis A.General 1.Keratinized, stratified, squamous epithelium 2.New epidermis every 35-45 days II. Epidermis A. General 3. Callus – gross thickening due to friction 4. Blister – acute trauma leads to separation of dermis and epidermis II. Epidermis B. Cell types II. Epidermis B. Cell types 1. Keratinocytes cells that produce fibrous protein keratin. 2.Keratin is a sulfur rich,tough, water repellant protein (the sulfur gives a distinct odor when hair, fur, skin or leather burns) 3.protects the skin and the underlying tissues from heat, microbes, abrasion and chemicals 4.Produced in deepest layer II. Epidermis B. Cell types B. Cell types 2. Melanocytes •Produce pigment melanin •Pigment is phagocytized by keratinocytes •Melanin protect keratinocytes from UV radiation yet Excessive sun exposure causes elastic fibers to clump leading to leathery skin & depresses skin immunity. Normal skin color determinants Melanin Yellow, brown or black pigments Carotene Orange-yellow pigment from some vegetables Hemoglobin Red coloring from blood cells in dermis capillaries Oxygen content determines the extent of red coloring B. Cell types 3. Merkel’s cells • Associated w/nerve cell endings – touch reception in fingertips 4. Langerhans’ cells • Macrophage-like • Defend against microorganisms • Found in Stratum Spinosum II. Epidermis C. 5 Layers Hint to remember the layers: Can Little Girls Speak German or British • Can • Little • GiRls • SPeak • GERMan/ • British Corneum Lucidum GRanulosum SPinosum GERMinativum or Basale II. Epidermis 1. Stratum Basalis • AKA:Stratum Germinativum • Single layer of cuboidal cells • Mitotic •10-25% melanocytes deposited here. •Responsible for generating the layers above it 1. Stratum Basalis • Receive nutrients by diffusion from dermis • Contains keratinocytes melanocytes & Merkel’s cells/disks (light touch receptors) •It takes 60-75 days for cells in this layer to reach the outermost surface 2. Stratum Spinosum • Called the “Spiny or prickly Layer” (8-10 layers thick) • Less mitotic ~ less nutrition received. • Cells are many sided keratinocytes often called “Prickle Cells” 2. Stratum Spinosum • Scattered among keratinocytes are Langerhans’ cells (immunity cells) Note: The Stratum Basalis and Stratum Spinosum •contain the only epidermal cells that receive adequate nourishment by way of diffusion. •As the daughter cells are pushed upward, away from the source of nutrition, they gradually die and their soft protoplasm becomes keratinized (hard). • • • • 3. Stratum Granulosum Layer has granules w/i it’s cytoplasm Keratinization begins Cells begin to die Thin layer 3-5 cell layers 4. Stratum Lucidum • Clear layer • Found in thick skin only as palms and soles of feet • Contain Keratin fibrils • Cells begin to degenerate 5. Stratum Corneum • • • Horny Layer 20-30 cell = ¾of thickness. Keratin in this layer prevents water loss due to lipids in surrounding cells, adds strength due to keratinization & exfoliaiton prevents abrasion of cells. 5. Stratum Corneum • Consists of dead flat keratinized cells being sloughed off • Forms from the embryological ectoderm germ layer. (stratified squamous) (conreum means horn) II. Epidermis III. Dermis skin’s body functions occur here Known as the “true skin” because most of the III. Dermis aka: hide A. General 1. Strong, flexible, connective tissue 2. Thickness: 0.6 – 3 mm III. Dermis A. Has collagen gives skin toughness & plumpness due to water attraction, elastic & reticular fibers give skin an elastic quality (as we age, a decrease in collagen & elastic fibers allows skin to sag) B. Develops from the mesoderm of the embryological germ layer. A. General Contains • • • • • • • Blood vessels Nerves Hair follicles Sebaceous Oil glands Sudiferous Sweat glands Nail roots Skin Appendages A. General Epidermis projects into dermis to form dermal Papillae. Touch Receptors Hair follicles III. Dermis B. 2 Layers: Papillary & Reticular B. Layers 1. Papillary Layer a. Closest to epiderms b. Made of areolar, loose con. t. c. Has Dermal Papillae • Finger-like projects that indent into the epidermis c. Has Dermal Papillae • Contain Capillaries pain receptors Meisner corpuscles: sensitive to light touch, discriminative touch, & low vibrations. Allows you to gather information about objects shape, texture, & density, so your brain can identify the object Finger prints III. Dermis B. Layers 2. Reticular layer a.Deepest layer b.Comprises 4/5 of dermis c.Made of dense irregular connective tissue III. Dermis B. Layers 2. Reticular layer d.Rich in blood vessels and nerve e. Pacinian corpuscles (Lamellated Corpuscles) – (egg shaped) sensitive to deep tactile pressure & high frequency vibration. Adapt rapidly. act as intestinal & joint proprioceptors & enable you to detect the object due to its weight III. Dermis B. Layers 2. Reticular layer d.Ruffini’s corpuscle senses heat found skin & mouth e.Krause’s End Bulb senses cold found in mucus membrane of mouth III. Dermis B. Layers 2. Reticular layer f. Tension lines or cleavage – separation of collagen bundles g. Flexure line – folding of dermis at joints of wrists, palms, fingers toes Homeostatic Imbalance • A decubitus ulcer (bed sore) can occur in bedridden patients who are not turned regularly or who are dragged across the bed repeatedly due to their own body weight restricting the normal flow of blood to the skin. IV. Hypodermis aka superficial fascia 1. Areolar and adipose tissue 2. Contains lots of Elastic fibers that attach the skin to the muscle below 3. Insulates, absorbs shock, stores fat, ½ of body’s stored fat is here. IV. Hypodermis 1. Is absent or very thin in the eyelids, penis, scrotum & nipples True or False? 1. The dermis is the superficial layer of the skin. 2. The skin helps regulate body temperature. 3. The epidermis has three layers. 4. The hypodermis is above the dermis. 5. The skin protects against UV radiation. Functions of Skin? • The four main functions of the integumentary system are: (Waste Excretion, Movement, Thermoregulation, Protection, Sensation, Immunity) 1. Which function acts as a barrier against chemical, mechanical, and microbial damage? 2. Which function acts to maintain constant internal temperature? 3. Which function acts to receive stimuli from the environment? 4. Which function acts to release sweat contains organic chemicals, salts, and urea? V. Skin Appendages A.General (4 embryonic categories: hair, nails, nerves, & glands) 1. Organs that develop from the embryonic epidermis 2. Also called epidermal derivatives V. Skin Appendages 3.Includes a.Hair b.Sweat , sudoriferous, glands c.Sebaceous, oil, glands d.Finger nails e.Tooth enamel V. Skin Appendages B. Hair 1. Is fused keratinized cells 2. Protects against • Scalp injury • Sun • Heat loss 3. Blonds have more hair than dark haired people. 3. Hair • Hair is a slender filament of mostly dead keratinized epithelial cells that grow from a follicle • Is a derative of the modified stratum corneum • The hair consists of the medulla, a core of loose cells and air spaces, surrounded by a cortex, which is densely packed keratinized cells. • The cortex is covered by the cuticle. 3. Hair •The bulb is a swelling at the base where the hair originates; the root is the remainder of the hair within the follicle; and the shaft is the portion of the hair above the skin surface. •Erector pili muscles are smooth muscle V. Skin Appendages B. Hair 1. Is fused keratinized cells 2. Protects against • Scalp injury • Sun • Heat loss B. Hair 3. Structure a. Shaft • Above surface • Shape determines curliness – Round = straight – Oval = wavy – Flat = kinky Note: The root and shaft are made of 3 tubes Note: 3 tubes • cuticle: outer tube 1 layer of heavily keratinized cells. • cortex: middle tube several layers of cells w/ pigments in dark hair and air bubbles in white hair. • medulla: inner tube made of 2 -3 rows of cells with pigments and air spaces. B. Hair Follicle • Hair Bulb Matrix produces hair • Inner epidermal sheath made of epithelial tissue • Outer dermal sheath made of dermal connective tissue. • Arrector pili muscle – goose bumps V. Skin Appendages B.Hair 4. Split ends – cuticle wears away 5. Color results from melanin (black, brown, yellow) 6. Hair growth/loss – depends on genes, stress, illness, malnutrition, hormone levels, some hair styles (ie tight braids), excessive combing, & styling (w/use of hair chemicals) & Excessive exercise Cycle of Hair Growth • Newly formed hair cells move up the follicle as newer cells form beneath. • As the cells dry out & fill w/keratin the hair cells begin to harden & die. V. Skin Appendages/ Hair B. Kinds of hair Lanugo – fine downy hair present in fetus and replaced at birth. Vellus hair: fine pale body hair of women and children. Approx 2/3 of hair in ♀ and 1/10 in ♂ and all hair in children, except eyebrows, eyelashes and scalp hair. Terminal hair: coarse, pigmented male body hair. Forms eyebrows, eyelashes, scalp and pubic, axillary, and facial hair after puberty. V. Skin Appendages C.Nails 1. Scale-like epidermal derivatives 2. Pink due to capillaries in dermis 3. Fingernails grow faster than toenails C. Nails 3. Nail plate is heavily karantinized 4. Nail body or matrix is the nail itself where mitosis occurs. 5. Nail root is responsible for growth C. Nails C. Nails Stratum basale extends beneath the nail bed The nail contains a free edge, a body, & nail root. Eponchium (cuticle) is the proximal nail fold that projects onto the nail body. Lunula is the half moon shaped portion of the nail that lacks pigmentation. Subungal Hematoma: blood clot beneath the nail. V. Skin Appendages/Exocrine Glands D. Sudoriferous Glands = Sweat Glands 1. Two types: Eccrine or Merocrine & Apocrine 2. Both secrete sweat, which evaporates & cools the body. 3. Sweat is odorless but when it mixes w/the skin’s natural bacterial, sweat’s proteins & fats feed the bacteria causing a musky, unpleasant odor. 4. Merocrine/Eccrine Glands–are the most numerous & located all over the body especially in palms of the hands & soles of the feet. (Mainly produce sweat which is mostly water plus some salts, Vit. C, traces of metabolic wastes like ammonia & urea, & lactic acid therefore it’s acidic.) V. Skin Appendages/ Exocrine Glands D. Sudoriferous Glands : Sweat glands 5. Apocrine Glands: located mostly in axillary & the genital regions & around the anus. Secrete sweat that contains fatty acids, proteins, which can give it a milky or yellowish color. Usually begin functioning during puberty & quit working in old age. 6. Mammary Glands are considered modified apocrine sweat glands. V. Composition & Function of Sweat Glands Made mostly of water, some metabolic wastes & fatty acids & proteins (apocrine) Function Helps dissipate excess heat Excretes waste products Acidic nature inhibits bacteria growth Odor is from associated bacteria D. Sudoriferous Glands 4. Function • Assists in maintaining normal body temp. D. Sudoriferous Glands 5. specialized sudoriferous glands • Mammary glands • Ceruminous glands Cerum = earwax D. Sebaceous Glands Sebaceous glands Produce oil Lubricant for skin Kills bacteria Most with ducts that empty into hair follicles Glands are activated at puberty V. Skin Appendages E. Ceruminous Glands 1. Produce Sebum • Oil • Prevents skin from drying out • Protects against bacteria 2. Exocrine Fill in the blanks with: hypodermis, keratinocytes, sweat, or papillary. 1. Eccrine is a type of _______________ gland. 2. _______________ produce keratin. 3. Adipose tissue is found in the _______________. 4. The _______________ of the dermis forms fingerprints. V. Skin Appendages E. Tooth Enamel 1. the hard outer layer of the tooth. VI. Skin Color A.Melanin 1. Made by • melanocytes • transferred to keratinocytes 2. Yellow to brown to black 3. Racial differences result of kind and amount of melanin A. Melanin 4.Builds up with sun exposure protects • Over exposure alters DNA cancer and/or leathery skin Not enough UV to break down of folic acid (vit. B) anemia or neural tube defects A. Melanin 4.Builds up with sun exposure protects • Under exposure MS Rickets Osteoporosis B. Carotene 1.Yellow to orange 2.Found mainly in Corneum Layer, soles, palms C. Hemoglobin 1.In red blood cells in capillaries 2.Gives pinkish hue to Caucasian skin Note: Caucasian’s have less melanin VII. Other A. Regulation of Body Temp. 1. Negative feedback system 2. Excessive Heat • Vessels dilate • Sweat evaporates from skin 3. Prevent heat loss • Vessels constrict • Arrector pili muscles cause hair to stand on end VII. Other Infections Athletes foot Caused by fungal infection Boils and carbuncles Caused by bacterial infection Cold sores Caused by virus VII. Other Infections and allergies Contact dermatitis Exposures cause allergic reaction Impetigo Caused by bacterial infection Psoriasis Cause is unknown Triggered by trauma, infection, stress VII. Other B. Aging 1. Blood flow to skin reduced • Thins skin/ more easily damaged • Repair is slower 2. Sagging results from • Elastic fibers reduce in number & diameter • Loss of subcutaneous tissue VII. Other B. Aging 3. Age Spots • Localized areas of increased # of melanocytes 4. Gray hair • Decrease or lack of melanin production VII. Other C. Skin Cancer 1.The most common type of cancer 2. It occurs more often in people with light colored skin who have had a high exposure to sunlight. Skin Cancer Cancer – abnormal cell mass Suffix “-oma” means tumor Two types Benign Does not spread (encapsulated) Malignant Metastasized (moves) to other parts of the body Skin cancer is the most common type of cancer Skin Cancer Moles VII. Other C. Skin Cancer 3. Signs of skin cancer a. growth or a sore that won't heal b. a small lump. • smooth, shiny and waxy • or it can be red or reddish brown. c. a flat red spot that is rough or scaly. Skin cancers VII. Other C. Skin Cancer Most common type yet least malignant: a.Basal Cell Carcinomas b.Caused by exposure to the sun Basal Cell Carcinoma VII. Other C. Skin Cancer 3. Frequent type: b.Squamous Cell Carcinoma Metastasizes to lymph nodes Sun exposure Lips of smokers Early removal allows for good chance of survival Squamous Cell Carcinoma VII. Other C. Skin Cancer 3. Most deadly type: c.Melanoma • Most malignant • Caused by sun exposure • Metastasizes rapidly to lymph and blood vessels Melanoma IV. Other C.Skin Cancer 4. ABCD Rule to distinguish a normal mole from a melanoma • A ... Asymmetrical halves the different halves of the mole don't look like each other • B ... Border irregularity the edges of the mole are indented or notched. • C ... Color variation different colors in pigmented area • D ... Diameter greater than the size of a pencil eraser tip or 6mm VII. Other Burns Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals Associated dangers Dehydration Electrolyte imbalance Circulatory shock Severity of a Burn • Severity of a thermal wound correlates directly with: – Temperature – Concentration – Amount of heat energy possessed by the object or substance – Duration of exposure Burn severity depends on: 1. Depth of burn 2. Extent of burn 3. Critical areas involved • Face, upper airway, hands, feet, genitalia 4. Preexisting medical conditions 5. Patient younger than 5 or older than 55 VII. Other D. Burns 1. st 1 • • • • • Degree, Mild, Superficial Minor epithelial damage Red, tender Dry No blisters Mild Edema Mild Burn VII. Burns 2nd Degree, Moderate, Partial Thickness • Damage to epidermis and superficial (papillary) dermis • Pink, exquisitely tender • Moist • Blisters • Heals in 2-3 wks w/o scarring. Partial Thickness Burns Partial Thickness Burns VII. Burns D. 3rd Degree, Severe, Full-thickness • Involves all 3 skin layers • Color variable: white, waxy, red, brown, red (scalds) • Destroys elasticity • Dry • Painless • Does not heal Third Degree Burn Rule of 9’s – Used to estimate surface area affected by the burn. • Divide body into 9% sections D. Burns 3. Rule of 9’s • • • • • • Torso: 18% Leg: 18% Head: 9% Arm: 9% Genitalia: 1% Palm: 1% Critical Burns Burns are considered critical if: Over 25% of body has second degree burns Over 10% of the body has third degree burns There are third degree burns of the face, hands, or feet VII. HOMEOSTASIS & TISSUES A. Inflammatory Response 1.Inflammation produces swelling, redness, heat, tenderness, and a loss of function at the inflamed site. VII. HOMEOSTASIS & TISSUES A. Inflammatory Response An infection is an inflammation produced by an invading organism, such as a bacterium. B. Inflammatory Response 2. Sequence of Events homeostasis disturbed mast cells release chemicals blood flow and permeability increases clot formation isolates area phagocytes remove debris and microorganisms homeostasis returns Injury and Repair • • The skin can regenerate after injury. After injury there are four stages of healing: 1. 2. 3. 4. After injury bleeding usually occurs into the site. Clot or scab forms at the surface of the epidermis. Granulation occurs and the clot dissolves. Scar tissue forms and the extent of scarring depends on the degree of the injury. 2 types of Tissue Repair 1. Regeneration Replacement of destroyed tissue by the same kind of cells 2. Fibrosis Repair by dense fibrous connective tissue (scar tissue) Determination method for repair type: Type of tissue damaged Severity of the injury Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.69 Events in Tissue Repair Capillaries become very permeable Introduce clotting proteins Wall off injured area Formation of granulation tissue Regeneration of surface epithelium Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.70 Regeneration of Tissues Tissues that regenerate easily Epithelial tissue Fibrous connective tissue and bone Tissues that regenerate poorly Skeletal muscle Tissues that are replaced largely with scar tissue Cardiac muscle Nervous tissue within the brain and spinal cord Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.71 Developmental Aspects of Tissue Epithelial tissue arises from all three primary germ layers Muscle and connective tissue arise from the mesoderm Nervous tissue arises from the ectoderm With old age there is a decrease in mass and viabililty in most tissues Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.72 THE END