Skin and body membranes
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Skin and body membranes

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  • The epidermis layer is the stratified squamous layer. The dermis is dense connective tissue. The hypodermis is not technically part of the skin, but anchors it to underlying organs.
  • Name the body cavities open to the exterior: Respiratory, digestive, urinary
  • Which body cavities are closed to the exterior? Thoracic, abdominopelvic.
  • Get picture of peritoneum. Check Marieb site for interactives.
  • So what kind of membrane is this? Cutaneous
  • .5 to 4mm thick Dermis and epidermis are firmly attached to each other. Divided by wavy (undulating) borderline. A blister occurs when dermis separates from the epidermis. Callus is a gross thickening of the epidermis. Hypodermis is not technically part of the skin.
  • 5 layers in thick skin like palms and soles of feet. 4 layers elsewhere Basale: Usually made up of columnar cells. Mostly keratinocytes, 25% melanocytes and some Merkel’s cells (touch receptors). Melanocytes have projections (fingers) that touch all keratinocytes. Keratinocytes then phagocytize ends of melaninocyte “fingers” and get melanin. Melanin then coats the “sunny” side of the keratinocytes, protecting them from UV damage to DNA. Click to next slide for illustration. Stratum Spinosum- spiny layer. Mitotic cells pushed upward from stratum basale. Stratum granulosum: production of keratin begins as cells enter this layer. Stratum lucidum: Clear, flat layer full of keratin. Found only in the palms of hands and soles of feet. Stratum Corneum: 20-30 layers thick: ¾ of epidermal thickness. Shingle-like, dead cells full of keratin. Rubs and flakes off every 25-45 days. Friction causes the stratum corneum to add even more layers forming a callus or, over a bone projection, called a corn.
  • Change answer at school.
  • Connective tissue with a gel-like matrix of collagen and elastic fibers. Cells are fibroblasts, macrophages, mast cells, WBCs. Loss of collagen and elastin fibers are products of ageing.
  • Between fibers are less dense regions called lines of cleavage or tension lines. Usually run longitudinally on limbs and circularly in neck and trunk. Surgeons try to cut with lines of cleavage so incisions gape less, heal more quickly. Flexure lines (dermal folds) result from dermis being secured to deeper structures by hypodermis. Wrists, palms, solds of feet, fingers and toes. When skin cannot slide to accommodate bending of joint, thus folds are needed.
  • Another note on melanin. Though melanin offers protection, too much sun exposure causes clumping of elastin fibers leading to leathery skin (solar elastosis).
  • Another note on melanin. Though melanin offers protection, too much sun exposure causes clumping of elastin fibers leading to leathery skin (solar elsastosis) Also too much UV can depress immune system (cold sores outbreak) as well as alter DNA. Melanin: color can range from yellow to orange to brown. Carotene: orange-yellow pigment. More prominent in Asians. Adipose also looks yellow. Prominent in palms and soles. Hemoglobin: responsible for pinkish color in caucasians.
  • Add picture of bruise, cyanosis, or jaundice
  • Go over and describe different structures. Point out that sweat glands go directly to surface. Sebaceous gland empties into hair follicle. Show how epidermis wraps around hair follicle. Show arrector pili muscle, nerve, artery, vein. Point out nerve endings—pacinian corpuscle or merkels. Note page 103 after bold word “hair follicle” that the follicle is an extension of epidermis deep into dermis and that it plays a part in tissue repair. If surface epidermis is damaged in burn or otherwise the epidermal cells can divide and serve as a source of new epithelial cells in the region.
  • Exocrine—what other kind of glands have you heard of? Endocrine. What do the terms tell you about where the two types of glands might secrete their products?
  • Small on body trunk and limbs, but large on face, neck and upper chest. Central cells accumulate triglycerides, cholesterol and other lipids, become engorged then fragment. Ducted into hair follicle. Also impedes water loss from skin.
  • 2.5 million on body
  • Minor protection functions: guarding head from trauma, heat loss and sunlight. Eyelashes shield eyes. Nasal hair keeps dust out of respiratory tract. Hair made of fused, keratinized cells. 100,000 hairs in scalp. 30,000 hairs in man’s beard. Velus hair: pale, fine hair on womens’ and children’s bodies. Terminal hair-coarser, darker hair on head, eyebrows.
  • Medulla large cells partially separated by air spaces. Cortex several layers of flattened cells Cuticle single layer of overlapping cells. Overlap from below like shingles on a roof. Split ends: abrasion of cuticle causes cuticle to wear away at tip allowing keratin fibrils in cortex and medulla to frizz out.
  • Top to bottom: Caucasian, Negroid, Mongoloid
  • Get picture of hair follicle
  • Exocrine—what other kind of glands have you heard of? Endocrine. What do the terms tell you about where the two types of glands might secrete their products?
  • Hoof or claw in animals, non-living Nail folds: borders of nail include cuticle. Nail bed: epithelial cells underlaying nail. Thickened portion at proximal end of nail is the matrix from which the cells arise. Nail is keratinzed cells that move forward as new cells are made at the matrix. Pink in nail is from blood supply in dermis Lanula: this is the area where the stratum basale (germinativum) cells are dividing.
  • Chemicals can be acids or bases. All of these denature cell proteins (enzymes and others) and cause cell death. Burned skin is sterile for 24 hours then bacteria, fungi & viruses can invade since the mechanical barrier is damaged. These pathogens grow quickly in the rich environment of dead tissue. Metabolism is affected: burn patients need 1000s of extra calories to repair tissue. They can’t eat enough, so they get IV feedings.
  • Regeneration occurs because epithelial cells are still present.
  • Coppertone ad has changed. Baby has no tan or burn.
  • Put picture of people on beach or in sun
  • Insert picture of basal cell carcinoma

Skin and body membranes Skin and body membranes Presentation Transcript

  • Skin and Body Membranes
  • Body Membrane Types
    • Epithelial Membranes
      • Cutaneous
      • Mucous
      • Serous
    • Connective Tissue Membranes
      • Synovial membranes
  • Which of these is not an epithelial membrane?
    • Serous
    • Synovial
    • Mucous
    • Cutaneous
  • Cutaneous Membranes: Skin
    • Composed of keratinizing stratified squamous epithelium with an underlying layer of dense connective tissue.
    • Is exposed to air
    • Is a dry membrane
  • Mucous Membrane: Mucosa
    • Consists of epithelium lying on connective tissue membrane know as lamina propria
    • Lines all body cavities open to the exterior
    • Are moist membranes continuously bathed in secretions or urine.
    • Are adapted for absorption and secretion
  • Serous Membranes: Serosa
    • Consists of simple squamous epithelial layer resting on areolar connective tissue.
    • Line all ventral body cavities closed to the exterior.
    • Is a double lined membrane consisting of a parietal and visceral layer.
  • Serous Membranes
    • Parietal layer touches the wall of the ventral body cavity.
    • Visceral layer covers the outside of the organ
    • Serous fluid is secreted by both layers and separates the layers.
    • Three locations: pericardium around heart; pleura around lungs; peritoneum in abdominal cavity around abdominal organs
  • Which epithelial membrane surrounds organs in the ventral body cavity?
    • Cutaneous
    • Mucous
    • Serous
  • Which epithelial membrane is dry?
    • Cutaneous
    • Mucous
    • Serous
  • Which epithelial membrane is adapted for absorption and secretion?
    • Cutaneous
    • Mucous
    • Serous
  • Which epithelial membrane is a two-layer membrane?
    • Cutaneous
    • Mucous
    • Serous
  • Which epithelial membrane is continuously bathed in secretions or urine?
    • Cutaneous
    • Mucous
    • Serous
  • Which epithelial membrane contains keratin and is formed of stratified squamous epithelium?
    • Cutaneous
    • Mucous
    • Serous
  • Which epithelial membrane has three locations and is designated either pericardial, pleural or peritoneal?
    • Cutaneous
    • Mucous
    • Serous
  • Connective Tissue Membrane: Synovial Membranes
    • Line the fibrous capsules surrounding joints
    • All connective tissue; no epithelial layer
    • Provide a smooth surface and a lubricating fluid
    • Line bursae and tendon sheaths which cushion joints.
  •  
  • Which of the following relationships is INCORRECT?
    • Visceral peritoneum/outer surface of the small intestine
    • Parietal peritoneum/outer surface of the heart
    • Parietal pleura/wall of the thoracic cavity
    • Visceral pleura/outer surface of the lung
  • Which does not belong?
    • Serous
    • Cutaneous
    • Synovial
    • Mucous
  • Vocabulary
    • Roots
    • Hypo
    • Sub
    • Derm-
    • Melano-
    • Somato, -some
    • Words
    • Hypodermis
    • Dermis
    • Epidermis
    • Striae
    • Keratin
    • Stratum
    • Melanin
    • Cyanosis
    • Carotene
    • Pallor
    • Jaundice
  • Integumentary System: Skin
    • Functions
      • Protection against these damaging forces
        • Mechanical
        • Chemical
        • Thermal
        • UV
        • Bacterial
    • Functions
      • Insulation
      • Waterproofing: keratin
      • Regulate heat loss: capillaries and sweat glands
      • Excretion: urea, salts, water
      • Synthesis of Vitamin D with the aid of UV
      • Sensation: touch, pressure, temperature and pain receptors
    Integumentary System: Skin
  • Structure of Skin: Layers
    • Epidermis: outer layer made of stratified squamous, keratinized epithelial cells
    • Dermis: under layer made of dense collagenous connective tissue
    • Hypodermis (subcutaneous tissue) made of adipose and areolar connective tissue types. Anchors skin to underlying organs and acts as shock absorber.
  • Which integumentary layer consists of dense connective tissue?
    • Epidermis
    • Dermis
    • Hypodermis
  • Which integumentary layer consists of adipose and areolar connective tissue?
    • Epidermis
    • Dermis
    • Hypodermis
  • Which integumentary layer provides insulation and shock absorption?
    • Epidermis
    • Dermis
    • Hypodermis
  • Which integumentary layer consists of stratified squamous epithelial cells?
    • Epidermis
    • Dermis
    • Hypodermis
  • Epidermis
    • Avascular
    • Keratinocytes: produce keratin
    • Melanocytes: produce melanin
      • Melanin protects DNA from UV
      • Freckles and moles: concentrated melanin
  • Layers of epidermis from the bottom up
    • Stratum corneum
    • Intermediate strata
    • Stratum basale
  • Keratinocytes and Melanocytes
  • Which layer lies closest to the dermis?
    • Stratum corneum
    • Intermediate strata
    • Stratum basale
  • Which is the most superior layer containing dead cells full of keratin?
    • Stratum corneum
    • Intermediate strata
    • Stratum basale
  • Dermis
    • Strong stretchy layer that holds body together
    • Leather is treated animal dermis
    • Two major regions: Papillary region and Reticular Region
  • Dermal Regions
    • Papillary Region
    • Upper dermal layer with projections from its surface that indent epidermis above
    • Furnish nutrients to epidermis via capillaries
    • House pain and touch receptors
    • These ridges form fingerprints which help us grip.
  • Dermal Regions
    • Reticular layer: deepest skin layer
    • Contains blood vessels, sweat and oil glands, deep pressure receptors and phagocytes.
    • Collagen fibers toughen dermis; attract and bind water to hydrate skin
    • Elastic Fibers give skin elasticity
    • Wrinkles: decrease in elastic fibers, collagen fibers and subcutaneous fat.
  • Which dermal component toughens the dermis and binds water?
    • Collagen
    • Elastin (elastic fibers)
    • Phagocytes
    • Papillary ridges
  • The loss of which leads to wrinkles?
    • Collagen
    • Elastin (elastic fibers)
    • Subcutaneous fat
    • All of the above
  • Which dermal component is responsible for fingerprints?
    • Collagen
    • Elastin (elastic fibers)
    • Phagocytes
    • Papillary ridges
  • Skin Color
    • Three pigments involved
      • Amount and kind of melanin
      • Carotene in stratum corneum and subcutaneous tissue.
      • Amount of oxygen bound to hemoglobin
    Hints for skin color in Photoshop
  • All but the following are involved in skin pigmentation
    • Melanin
    • Keratin
    • Carotene
    • Hemoglobin
  • Skin color descriptions
    • Cyanosis: blue color due to lack of oxygen
    • Erythema: reddened skin from embarrassment, fever, hypertension, inflammation or allergy.
    • Pallor: pale skin due to anemia, low blood pressure, or impaired blood flow.
    • Jaundice: yellow skin from a liver disorder.
    • Bruises: clotted blood masses under skin
  • Skin Appendages
    • Are derived from epidermis though they reside primarily in dermis.
    • Include hair, nails, sweat glands, and sebaceous glands.
  • http://wps.aw.com/bc_marieb_ehap_8/0,9797,1670743-,00.html
  • Skin Appendages Exocrine glands Nails Sebaceous glands Sweat glands Merocrine glands Apocrine glands Heat regulating Stress stimulated which include are either which are Hair which are Produce oil Empty into hair follicle Open to skin surface
  • Exocrine Glands
    • Release secretions to skin surface via ducts
    • Two groups: sebaceous and sweat glands
  • Sebaceous glands: oil glands
    • Not on palms or soles
    • Usually empty into a hair follicle
    • Contains chemicals to kill bacteria
    • Keeps skin soft and prevents brittle hair
    • Sebum: mix of oily substances and fragmented cells.
    • Increased quantities during adolescence
  • When sebaceous glands cause problems:
    • Whitehead: sebaceous gland is blocked
    • Blackhead: accumulated material dries and darkens
    • Acne: active infection of sebaceous gland
    • Seborrhea: occurs in infants; overactive sebaceous glands
  • Sweat glands: Merocrine
    • Produce sweat
    • Acidity inhibits growth of bacteria
    • Reaches skin surface via a pore
    • Sweat: 99% water, NaCl, Vit. C and metabolic wastes
    • Heat regulating to maintain body temp.
  • Apocrine Glands
    • Found in axillary and genital areas
    • Ducts empty into hair follicles
    • Contains all merocrine fluids do, plus fatty acids and proteins. May have milky or yellow color
    • Odorless fluid, but bacteria feeding on fatty acids and proteins may cause odor.
    • Puberty stimulates glands.
    • Not for heat regulation. Activated by stress, fear and sexual activity.
  • Which kind of exocrine gland is responsible for keeping skin soft and preventing hair from becoming brittle?
    • sebaceous
    • meroccrine
    • apocrine
  • Which kind of exocrine gland is stimulated at puberty?
    • sebaceous
    • merocrine
    • apocrine
  • Which kind of exocrine gland regulates heat?
    • sebaceous
    • merocrine
    • apocrine
  • Hair and hair follicles
    • Protect head, eyes, and nasal passageways
  • Hair structure
    • Produced by hair bulb
    • Root: enclosed hair in the follicle
    • Shaft: hair projecting from the scalp or skin. This part is dead.
    • Medulla: central core of hair surrounded by cortex.
    • Cortex enclosed by cuticle
    • Cuticle: outer section that prevents matting of hair, protects from abrasion and give strength and color to hair.
  • Pigment distribution in hair Human Caucasian hair Human red hair Human Mongoloid hair Dog hair
  • Hair types
    • Wavy hair: hair follicle is oval
    • Curly hair: hair follicle is flat and ribbon like
    • Straight hair: hair follicle is round
  • Hair Follicles
    • Epidermal sheath: forms hair
    • Dermal sheath: supplies blood vessels, reinforce hair
    • Arrector pili: smooth muscle that pulls hair upright during times of fright or cold.
  •  
  • Skin Appendages 87 88 89 90 92 93 91 94 95 which include are either which are 86 which are
  • Stratum basale 53 52 55 54 56 epidermis dermis hypodermis Nerve Root sheath
  • Nails
    • Structure: free edge, body and root
    • Nail folds: borders of nail
    • Nail bed: stratum basale.
    • Pink in nail comes from blood supply in dermis
    • Lanula: white crescent-shaped area showing thick nail matrix.
  • Homeostatic Imbalances of Skin
    • Infections and allergies
    • Athlete’s foot: fungus infection between toes
    • Boils/Carbuncles: bacterial infection causes inflammation of hair follicles and sebaceous glands
    • Cold Sores: herpes simplex infection on lips or oral mucosa, virus localizes in cutaneous nerve.
  • Homeostatic Imbalances of Skin
    • More infections and allergies
    • Contact dermititis: exposure to chemicals that invoke an allergic response
    • Impetigo: bacterial infection causes blisters (more common in children)
    • Psoriasis: reddened epidermial lesions. Auto-immune; can be triggered by stress, infection, hormonal changes.
  • Burns
    • Tissue damage and cell death due to heat, electricity, UV or other radiation, or chemicals.
    • Life-threatening consequences of burns
      • Fluid loss, electrolyte loss from seeping. Causes dehydration and circulatory shock.
      • Depressed immune system; pathogens eat dead tissue.
    • Rule of nines helps estimate volume of fluid loss to gauge fluid replacement.
  • Types of Burns
    • Partial thickness burns
      • 1 st degree: only epidermis is damaged. Not serious.
      • 2 nd degree: injury to epidermis and upper dermis
        • Blisters, red, painful
        • Regeneration occurs
  • 1 st and 2 nd degree burns
  • Types of Burns
    • Full thickness burn
      • 3 rd degree burns destroy entire thickness of skin.
      • Initially not painful as nerve endings are destroyed.
      • Regeneration not possible; skin grafts required.
      • Deadly if over 10% of body.
  • Skin cancer
    • Caused by UV radiation exposure and/or frequent irritations by chemicals or infections.
  • Basal cell Carcinoma
    • Least malignant, most common type.
    • Stratum basale cells proliferate invading dermis and hypodermis.
    • Most often on sun-exposed areas
    • Slow growing; rarely metastasize; surgical removal for full cure.
  • Squamous Cell Carcinoma
    • Arises from keratinocytes of stratum spinosum
    • Grows rapidly and may metastasize to lymph nodes.
    • Sun-induced.
    • Cured by surgery and/or radiation.
  • Malignant Melanoma
    • Cancer of melanocytes
    • 5% of skin cancers, survival ration is 50%
    • Spreading brown to black patch that metastasizes to blood or lymph nodes
    • Treated by surgery and immunotherapy
    • Recognized by ABCD rule
      • Asymmetry
      • Border irregularity
      • Color variation
      • Diameter greater than 6mm