Integumentary System A&P PDF

INTEGUMENTARY SYSTEM A&P PRESENTED BY: ALARZAR PRE-TEST 1. Which epidermal cell type is most numerous? a) Keratinocyte b) Melanocyte c) Dendritic cell d) Tactile epithelial cell PRE-TEST 2. The order in which a needle would pierce the epidermal layer of the forearm? a) Basale, spinosum, gran...

INTEGUMENTARY SYSTEM A&P PRESENTED BY: ALARZAR PRE-TEST 1. Which epidermal cell type is most numerous? a) Keratinocyte b) Melanocyte c) Dendritic cell d) Tactile epithelial cell PRE-TEST 2. The order in which a needle would pierce the epidermal layer of the forearm? a) Basale, spinosum, granulosum, corneum b) Basale, spinosum, granulosum, lucidum, corneum c) Granulosum, basale, spinosum, corneum d) Corneum, granulosum, spinosum, basale PRE-TEST 3. Which cell functions as part of the immune system? (a) keratinocyte, (b) melanocyte, (c) dendritic cell, (d) tactile epithelial cell. PRE-TEST 4. The outermost epidermal layer is the (a) stratum spinosum, (b) stratum granulosum, (c) stratum corneum, (d) stratum basale. 5. Which of the following is not an epidermal derivative? (a) hair, (b) sweat gland, (c) sensory receptor, (d) sebaceous gland. 7. An arrector pili muscle: (a) is associated with each sweat gland, (b) can cause a hair to stand up straight, (c) enables each hair to be stretched when wet, (d) provides new cells for continued growth of its associated hair. 8. Sebaceous glands: (a) are holocrine glands, (b) are found in the palms and soles, (c) have antibacterial properties, (d) accelerate water loss from the skin. 9. Which of the following structures is a part of the follicle wall of a hair? (a) cortex, (b) external root sheath, (c) medulla, (d) hair papilla. 10. What is the first threat to life from a massive third-degree burn? (a) infection, (b) catastrophic fluid loss, (c) unbearable pain, (d) loss of immune function. OBJECTIVES: THE INTEGUMENTARY SYSTEM INCLUDES THE SKIN AND ACCESSORY STRUCTURES SUCH AS HAIR, GLANDS AND NAILS FUNCTIONS OF THE INTEGUMENTARY SYSTEM PROTECTION reduces the negative and harmful effects of the UV light acting as a barrier and keeps MOs from entering the body prevents dehydration by reducing water loss SENSATION contains sensory receptors that detect heat, cold, touch, pressure and pain FUNCTIONS OF THE INTEGUMENTARY SYSTEM TEMPERATURE REGULATION modulation of blood flow through skin and sweat glands VITAMIN D PRODUCTION produces cholecalciferol and interacts with UVB to form Vit D for regulation of calcium homeostasis EXCRETION Waste products removal through skin and glands THE INTEGUMENTARY SYSTEM INCLUDES THE SKIN AND ACCESSORY STRUCTURES SUCH AS HAIR, GLANDS AND NAILS SKIN ¡ Composed of 2 layers, EPIDERMIS and DERMIS ¡ Epidermis – superficial layer of the skin with stratified squamous epithelial tissue ¡ Dermis – layer of connective tissue, responsible for the strength of the skin SUBCUTANEOUS TISSUE (hypodermis) – layer of loose connective tissue and not part of the skin. Connects the skin to the bone or muscle EPIDERMIS ¡ Contains no blood vessels ¡ Receive nutrients and excrete waste products by the diffusion of substances between the epidermis and the capillaries of the dermis ¡ Composed of: ¡ Keratinocytes – cells that produce a protein mixture called keratin which makes cells more durable, constantly lost at the surface ¡ Melanocytes – produce the pigment melanin that contributes to skin color ¡ Langerhans cells/Dendritic Cells – part of the immune system ¡ Merkel cells/ tactile epithelial cells – specialized epidermal cells associated with the nerve endings responsible for detecting light touch and pressure ¡ Keratinization - cells accumulate keratin and produce an outer layer of dead, hard cells that resists abrasion and forms a permeability barrier  EPIDERMIS ¡ Keratinization - cells accumulate keratin and produce an outer layer of dead, hard cells that resists abrasion and forms a permeability barrier EPIDERMAL STRATA THICK AND THIN SKIN ¡ Thick skin (palms of the hands, soles of the feet and fingertips) – with five epithelial strata and multiple strata corneum layers ¡ Thin skin (covers the rest of the body) – lucidum is generally absent, with each strata usually with fewer layers, where hair is found SKIN COLOR ¡ FACTORS THAT DETERMINE SKIN COLOR: ¡ Pigments in the skin ¡ Blood circulating through the skin ¡ Thickness of the stratum corneum ¡ Melanin – group of pigments responsible for hair, skin and eye color, protection against UVL, produced by melanocytes SKIN COLOR DERMIS ¡ Composed of cells such as fibroblasts, adipocytes, macrophages ¡ Collagen – type of protein fibers of ECM ¡ Contains blood vessels that allow for nutrient and waste exchange to the cells of the dermis and the living cells of the epidermis ¡ Contains nerve endings, hair follicles, smooth muscles, glands and lymphatic vessels ¡ Free nerve endings for pain, itch, temperature sensations ¡ Meissner corpuscles for simultaneous stimulation ¡ Ruffini end organs for sensing continuous touch or pressure DERMAL LAYERS RETICULAR LAYER’S CLEAVAGE LINE SUBCUTANEOUS TISSUE ¡ Attaches the skin to underlying bone and muscle and supplies the skin with blood vessels and nerves ¡ Loose connective tissue with collagen and elastic fibers ¡ Where half of the body’s lipids are stored that act as insulation and padding and source of energy TRICEPS SKINFOLDING TEST ACCESSORY SKIN STRUCTURES: HAIR ¡ Found everywhere except for palms, soles, lips, nipples, parts of the external genitalia and distal segments of fingers and toes ¡ 5-6th month of fetal life – delicate, unpigmented hair called lanugo cover the fetus ¡ Time of birth- long, course and pigmented hair called terminal hair replace lanugo on the head and vellus hair on the rest of the body ¡ Puberty – terminal hair replaces vellus hair on the pubic and axillary regions (for males, in the face to form the beard) which is a sign of sexual maturity  HAIR STRUCTURE ¡ Shaft – above the surface ¡ Root – below the surface with the base called bulb ¡ Composed of dead, keratinized epithelial cells ¡ Hair follicle – tubelike invagination of the epidermis into the dermis, where hair develops and grows ¡ Inside the bulb are undifferentiated epithelial cells called matrix HAIR STRUCTURE HAIR GROWTH 1. Anagen (Growth) – active phase in which hair follicles takes on its onion like shape and works to produce hair fiber 2. Catagen (Transition) – follicles undergoes apoptosis-driven regression and loses 1/6th of its standard diameter 3. Telogen (Resting) – follicle becomes dormant and growth of hair shaft does not occur 4. Exogen (Shedding) – extension of the telogen phase (losing 50-100 hairs/day is normal) INFLUENCE OF HORMONES ON THE HAIR CYCLE OF FEMALES HAIR COLOR, MUSCLES AND GLANDS ¡ Melanin production and distribution of melanin to the cells affect hair color ¡ Arrector Pili – smooth muscle cells associated with each hair follicle ¡ Positioned at an oblique angle to the surface of the skin so when the muscle contracts, the follicle is pulled into a perpendicular position ¡ Sebaceous Glands – alveolar glands that produce sebum (rich in lipids) and classified as holocrine glands; prevents drying and protects against some bacteria HAIR COLOR, MUSCLES AND GLANDS ¡ Sweat Glands ¡ Eccrine – simple, coiled, tubular that open directly onto the surface through sweat pores ¡ Apocrine – found in the axillae, genitalia and around the anus, do not help with thermoregulation, secrete organic substances that are metabolized by bacteria that produces body odor ¡ Ceruminous glands – eccrine glands found in the ear canal. Cerumen protects the ear drum from dirt and insects ¡ Mammary Glands – modified apocrine located in the breast, produces milk CUTANEOUS GLANDS  ACCESSORY SKIN STRUCTURES: NAILS ¡ Thin plate consisting of layers of dead stratum corneum cells with hard keratin ¡ Located on the distal ends of the digits ¡ Consists of nail root (covered by the skin) and nail body )visible portion) ¡ Cuticle/ Eponychium – where the nail fold grows into the nail body ¡ Hyponychium – located beneath the free edge of the nail body ¡ Nail matrix and bed – composed of epithelial tissue that gives rise to the cells that form the nail PHYSIOLOGY: PROTECTION 1. Protection from mechanical damage 2. First line of defense against microorganisms 3. Melanin absorbs UVL 4. Hair as a heat insulator, prevents against UVL and abrasion, prevents dusts and foreign objects from entering the nose, ear and eyes 5. Nails protect ends of the digits from damage and can be used in defense 6. Reduces water loss PROTECTION: PHYSICAL AND IMMUNE BARRIERS 1. Due to the stratum corneum provides outstanding barrier capacity 2. Water resistant glycolipids block most diffusion of water and substances to prevent loss and entry into the body 3. Self-repairing ability 4. Dendritic cells engulf foreign invaders and migrate to lymph nodes and triggers an immune response 5. Dermal macrophages dispose of viruses and bacteria that penetrate the epidermis  PROTECTION: CHEMICAL BARRIER 1. Skin secretions creates an acid mantle (low pH property) 2. Contains dermcidin in sebum that kills many bacteria outright 3. Has defensins that punch holes in bacteria making them leak 4. Cathelicidins that are effective in in preventing GABHS 5. Melanin provides a chemical pigment to shield from UV damage PHYSIOLOGY: SENSATION PHYSIOLOGY: TEMPERATURE REGULATION PHYSIOLOGY: TEMPERATURE REGULATION  PHYSIOLOGY: VITAMIN D PRODUCTION ¡ Vitamin D – stimulates the uptake of calcium and phosphate from the small intestine ¡ Precursor molecule (7,d) is stored in the skin ¡ After exposure to UVL, it is converted to cholecalciferol then released to the bloo and modified by liver and kidneys ¡ Becomes a hormone, calcitriol for calcium homeostasis PHYSIOLOGY: EXCRETION EFFECTS OF AGING 1. Epidermis thins and decreased collagen = skin is more easily damaged, likely skin infections and skin repair slows down 2. Sebaceous gland activity decreases = skin becomes drier 3. Decreased activity of sweat glands + decreased blood supply – reduced ability for thermoregulation 4. Decreased functional melanocytes – age spots, white/ gray hair * Skin exposed to sunlight age more rapidly than nonexposed skin