Essentials Of Human Anatomy & Physiology PDF - Chapter 4

Chapter 4 Skin and Body Membranes Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College © 2018 Pearson Education, I...

Chapter 4 Skin and Body Membranes Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College © 2018 Pearson Education, Inc. ◼ You must read the textbook. You cannot solely rely on my slides to study for the exams or quizzes. ◼ Make sure the PowerPoint is DOWNLOADED and not in review mode. ◼ For every video I posted, THE LINK IS found on the notes section of the slide. ◼ Click “enable slides” ◼ There is no voice recording for Chapter 4: Cells and Tissues. 11-2  Body Membranes: Classified according to tissue types Functions 1. Epithelial membranes 1. Cover surfaces A. Cutaneous 2. Line cavities B. Mucous 3. Organ protective sheets C. Serous 2. Connective tissue membranes A. Synovial  1. Epithelial Membranes A. Cutaneous membrane: Dry ❑ Outermost protective boundary: skin ❑ Construction ◼ Epidermis: keratinized stratified squamous epithelium ◼ Dermis: mostly dense (fibrous) connective tissue Figure 3.18e Types of epithelia and examples of common locations in the body. Figure 4.1a Classes of epithelial membranes.  1. Epithelial Membranes B. Mucous membranes (mucosae): Moist ❑ Line all body cavities that open to the exterior ◼ Locations: mouth, nostrils, esophagus, hollow organs of the digestive system, respiratory and urogenital tracts. ◼ Mucous secretion is not a requirement (urinary tract). ❑ Function: absorption or secretion ❑ Construction ◼ Epithelium type depends on site ◼ Loose connective tissue (lamina propria) Figure 4.1b Classes of epithelial membranes.  1. Epithelial Membranes C. Serous membranes (serosae) ❑ Line open body cavities that are closed to the exterior of the body ❑ Occur in pairs, separated by serous fluid, with a visceral and parietal layer ❑ Construction ◼ Simple squamous epithelium ◼ Areolar connective tissue Figure 4.1c Classes of epithelial membranes.  1. Epithelial Membranes ◼ Specific serous membranes ❑ Peritoneum ◼ Abdominal cavity ❑ Pleura ◼ Around the lungs ❑ Pericardium ◼ Around the heart Parietal Parietal pleura peritoneum Visceral pleura Visceral Visceral pericardium peritoneum Parietal pericardium Serous membranes line body cavities closed to the exterior. © 2018 Pearson Education, Inc. Figure 4.1d Classes of Epithelial Membranes 2. Connective Tissue Membranes A. Synovial membranes ❑ Loose areolar connective tissue ❑ Line fibrous capsules surrounding joints ❑ Secrete a lubricating fluid to cushion moving organs Figure 4.2 A typical synovial joint © 2018 Pearson Education, Inc. Integumentary System ◼ Integumentary system: 1. Skin (cutaneous membrane) 2. Skin appendages A. Sweat glands B. Oil glands C. Hair D. Nails  11 Video: The Integumentary System Structure Overview Functions of the Integumentary System 1. Insulates and cushion deeper body organs 2. Protects the entire body from: A. Mechanical damage (bumps and cuts) B. Chemical damage (acids and bases) C. Thermal damage (heat or cold) D. Ultraviolet radiation (sunlight) → melanin absorbs UV radiation E. Cells: microbes and phagocytes F. Desiccation (drying out) Prevent dehydration  Functions of the Integumentary System 3. Aids in loss or retention of body heat controlled by the nervous system 4. Aids in excretion of urea and uric acid 5. Synthesizes vitamin D Video: Functions of the Skin 14  Table 4.1 Functions of the Integumentary System Functions How accomplished Functions How accomplished Protects deeper tissues Physical barrier contains keratin, which from toughens cells; fat cells to cushion blows; Aids in body heat loss Heat loss: By activating sweat and both pressure and pain receptors, which or heat retention glands and by allowing blood to flush Mechanical damage alert the nervous system to possible (controlled by the into skin capillary beds so that heat (bumps) damage. nervous system) can radiate from the skin surface. Heat retention: By not allowing Chemical damage Has relatively impermeable keratinized cells; blood to flush into skin capillary beds. (acids and bases) contains pain receptors, which alert the nervous system to possible damage. Microbe damage Has an unbroken surface and “acid mantle” (skin secretions are acidic and thus inhibit microbes, such as bacteria). Phagocytes ingest foreign substances and pathogens, preventing them from penetrating into deeper body tissues. Aids in excretion of Contained in perspiration produced urea and uric acid by sweat glands. Ultraviolet (UV) Melanin produced by melanocytes offers radiation (damaging protection from UV damage. effects of sunlight or tanning beds) Synthesizes vitamin D Modified cholesterol molecules in Thermal (heat or cold) Contains heat/cold/pain receptors. skin converted to vitamin D in the damage presence of sunlight. Desiccation (drying out) Contains a water-resistant glycolipid and keratin. © 2018 Pearson Education, Inc.  Structure of the Skin 1. Epidermis—outer layer ❑ Hard and tough ❑ Stratified squamous epithelium ❑ Keratinocytes (most common) produce keratin ❑ Avascular ❑ Composed of five layers (strata) Epidermis: Composed of four to five layers of cells (strata) Figure 4.4 The main structural features of the epidermis. Structure of the Skin ◼ Summary of layers of the epidermis from deepest to most superficial ❑ Stratum basale ❑ Stratum spinosum ❑ Stratum granulosum ❑ Stratum lucidum: thick, hairless skin only (protects against damage) ❑ Stratum corneum  19 Video: Layers of the Epidermis Cells of the epidermis 1. Keratinocytes: keratin provides strength and acts as a water repellent sealant 2. Melanocytes: produce melanin, which contributes to skin color 3. Dendritic (Langerhans) cells: Alert and activate immune cells to a threat 4. Merkel cells: Associated with sensory nerve endings 20 Video: Cells of the Epidermis 21  Structure of the Skin 2. Dermis ❑ Underlies the epidermis ❑ Made of two layers 1. Papillary layer 2. Reticular layer ❑ Contains appendages of skin ❑ Composed of connective tissue Figure 4.3 Skin structure. 1. Papillary layer: areolar connective tissue ❑ contain projections called dermal papillae 2. Reticular layer: dense irregular connective tissue ❑ Blood vessels, sweat and oil glands ❑ Cutaneous sensory and deep pressure receptors (lamellar corpuscles) Figure 4.5 Light micrograph of the two layers of the dermis (100X). 23 ◼ Other dermal features ❑ Phagocytes (macrophages) ❑ Collagen and elastic fibers © 2018 Pearson Education, Inc. Video: The Dermis 25 Structure of the Skin ◼ Hypodermis (subcutaneous layer): ❑ Anchors the skin to underlying organs ❑ Mostly adipose tissue: shock absorption and insulation ❑ Not technically part of the integumentary system Figure 4.3 Skin structure.  Recap: Functions of the Skin 1) Protection: A. Chemical barriers: low pH of skin secretions prevents bacterial multiplication B. Biological barriers: dermal white blood cells C. Physical / mechanical barriers: protects against dehydration, abrasion or penetration of microorganisms; nails protect ends of digits 27 2. Body Temperature Regulation a) Sweat produced by sudoriferous glands causes evaporative cooling. b) Arterioles in dermis change diameter as temperature changes. 28 3. Cutaneous Sensation Exteroreceptors: Pressure, temperature, pain, touch 4. Metabolic Functions ◼ The precursor molecule of vitamin D is produced in the skin with the help of sunlight ◼ Vitamin D: aids in the absorption of calcium from the GI tract 5. Blood Reservoir: Makes blood available to body organs and working muscles 6. Excretion: Removal of waste products from the body: Sweat. Water, salt, urea, ammonia, uric acid 29  30 Video: Skin Functions Skin Color Pigments contribute to skin color 1. Melanin: Yellow, reddish brown, or black pigments 2. Carotene: Orange-yellow pigment from some vegetables 3. Hemoglobin: Red coloring from blood cells in dermal capillaries ◼ Oxygen content determines the extent of red coloring  32 Video: The Color of Skin Skin Color ◼ Redness (erythema): embarrassment, inflammation, hypertension, fever, or allergy ◼ Pallor (blanching): emotional stress, anemia, low blood pressure, impaired blood flow to an area ◼ Bruises: hematomas ◼ Jaundice: liver disorder Appendages of the Skin 1. Cutaneous glands are all exocrine glands A. Sebaceous glands B. Sweat glands 2. Hair 3. Hair follicles 4. Nails Figure 4.3 Skin Structure Appendages of the Skin ◼ Sebaceous (oil) glands ❑ Located all over the skin except for palms and soles ❑ Produce sebum (oil) ❑ Most have ducts that empty into hair follicles; others open directly onto skin surface Appendages of the Skin Sweat (sudoriferous) glands: 1. Eccrine: palms, soles of the feet and forehead o Activated shortly after birth o Open to sweat pores on the skin’s surface o Remove waste: acidic sweat (urea, uric acid, ammonia and lactic acid) o Thermoregulators: most widely distributed 2. Apocrine: empty into hair follicles in armpit and genitals o Activated at puberty o Odorless secretion. skin bacteria generates odor.  Appendages of the Skin ◼ Hair ❑ Produced by hair follicle ❑ Roots enclosed in follicles ❑ Keratinized epithelial cells ❑ Melanocytes provide pigment ❑ Hair grows in the hair bulb in stratum basale Figure 4.7a Structure of a Hair Root and Follicle Figure 4.7b Structure of a Hair Root and Follicle  Appendages of the Skin ◼ Nails ❑ Keratinized, scalelike modifications of the epidermis ❑ Stratum basale extends beneath the nail bed, which is responsible for growth ❑ Lack of pigment makes nails colorless ❑ Growth of the nail occurs from nail matrix Figure 4.8 Structure of a Nail  Homeostatic Imbalances of Skin ◼ Infections and allergies ❑ Athlete’s foot ◼ Caused by fungal infection (Tinea pedis) ◼ Itchy, red peeling skin between the toes ❑ Boils (furuncles) and carbuncles ◼ Caused by inflammation of hair follicles ◼ Carbuncles are clusters of boils caused by bacteria ❑ Cold sores (fever blisters) ◼ Caused by human herpesvirus 1 ◼ Blisters itch and sting Homeostatic Imbalances of Skin ❑ Contact dermatitis ◼ Chemicals provoke allergic responses ◼ Itching, redness, and swelling ❑ Impetigo ◼ Caused by bacterial infection ◼ Pink, fluid-filled raised lesions around mouth/nose ❑ Psoriasis ◼ Caused by trauma, infection, hormonal changes, or stress ◼ Red, epidermal lesions covered with dry, silvery scales that itch, burn, crack, or sometimes bleed Homeostatic Imbalances of Skin ❑ Burns damage tissue: heat, electricity, UV radiation, or chemicals ❑ Associated dangers ◼ Protein denaturation and cell death ◼ Dehydration and electrolyte imbalance ◼ Circulatory shock ❑ Result in loss of body fluids and infection from the invasion of bacteria Extent of a burn is estimated using the rule of nines ❑ 11 body areas for quick estimate ❑ Each area represents about 9% of total body surface area ◼ Genitals (perineum): 1 % Figure 4.10a Burns. © 2018 Pearson Education, Inc. Video: Rule of 9’s 43 First degree: (superficial burn) ◼ Damaged epidermis ◼ Redness, swelling and pain; heal in two to three days Figure 4.10b Burns. 44 Second degree (partial-thickness burn) ❑ Epidermis and superficial part of dermis are damaged ❑ Skin is red, painful, and blistered ❑ Regrowth of the epithelium can occur Figure 4.10b Burns. 45 Third degree (full thickness): entire thickness of the skin ◼ Destroys epidermis and dermis ◼ Gray-white, cherry red, or blackened ◼ Not painful due to the destruction of the nerve endings ◼ Requires skin grafts, as regeneration is not possible Figure 4.10b Burns. 46 ◼ Fourth-degree burn (full-thickness burn) ❑ Extends into deeper tissues (bone, muscle, tendons) ❑ Appears dry and leathery ❑ Requires surgery and grafting ❑ May require amputation Homeostatic Imbalances of Skin ◼ Criteria for deeming burns critical (if any one is met): ❑ Over 30 percent of body has second-degree burns ❑ Over 10 percent of the body has third- or fourth-degree burns ❑ Third- or fourth-degree burns of the face, hands, or feet, or genitals ❑ Burns affect the airways ❑ Circumferential (around the body or limb) burns have occurred  Homeostatic Imbalances of Skin ◼ Skin cancer: most common form of cancer in humans ❑ Risk factors: UV radiation ◼ Cancer classifications 1. Benign: neoplasm (tumor) has not spread 2. Malignant: neoplasm has invaded other body areas (metastasis) Homeostatic Imbalances of Skin Basal cell carcinoma: Least malignant and most common skin cancer ◼ Stratum basale cells are altered and can no longer make keratin ◼ 80% of skin cancers and develope relatively slowly (a) Basal cell carcinoma Squamous cell carcinoma: Second most common ◼ Stratum spinosum cells ◼ Scaly lesions, reddened papules, form shallow ulcers ◼ Early removal allows a good chance of cure Malignant melanoma: Most deadly but 5% of skin cancers ◼ Arises from melanocytes ◼ Metastasizes rapidly ◼ 1/3 develop from preexisting moles ◼ Highly resistant to chemotherapy ◼ Detection uses ABCDE rule for recognizing melanoma 52 ABCDE rule: 1) Asymmetry: two sides of the pigmented mole do not match 2) Border irregularity: Borders of mole are not smooth 3) Color: contains several colors 4) Diameter: the spot is larger than 6 mm in diameter 5) Evolution: One or more of the ABCD characteristics is evolving 53 54