Human Anatomy and Pathophysiology - Integumentary System PDF

HUMAN ANATOMY AND PATHOPHYSIOLOGY 1st Sem/ Module 5 A.Y. 2024-2025 Integumentary System MTHAPP LEC Topic Outline I. Definitions and functions of components...

HUMAN ANATOMY AND PATHOPHYSIOLOGY 1st Sem/ Module 5 A.Y. 2024-2025 Integumentary System MTHAPP LEC Topic Outline I. Definitions and functions of components SKIN II. Structure of the skin “Cutaneous membrane” A. Epidermis Largest organ of the body in weight B. Dermis Dermatology III. Appendages of the Integumentary system ○ medical specialty that deals with the A. Hair structure, function and disorders of the B. Nails integumentary system IV. Sweat glands 2 main parts: A. Eccrine B. Apocrine V. Sebaceous glands VI. Sensory receptor A. Mechanoreceptor B. Thermoreceptor VII. Immunological functions of the skin A. Langerhans cells B. Skin as barrier to pathogens VIII. Skin disorders and diseases A. Dermatitis and Eczema B. Skin Cancer Epidermis Dermis Functions of Integumentary System *Hypodermis Protection ○ Not part of the Skin ○ Acts as physical barrier. ○ Comprise of areolar and adipose tissue Regulation of Body Temperature ○ Sweat glands produce sweat that DEVELOPMENT: evaporate and cools the body down. Epidermis develops from ectoderm Sensation Dermis develops from mesoderm ○ Through sensory receptors Mechanoreceptor THREE PRIMARY DERM LAYERS Detects mechanical Ectoderm stimuli - Outermost ○ Ex. stretching - Nervous System and Epidermis and sensations Mesoderm Thermoreceptor - Middle Changes in Temperature - Muscle Cells and Connective Tissues Nociceptors Endoderm Detects pain sensations - Innermost Excretion - Gut and other internal organ ○ Excrete waste Immune Defense ○ Protects from foreign invaders Ex. Langerhans Cells (helps other cells detect foreign invaders so they can be destroyed) 1 ENRIQUE, BSMT-2B  Epidermis STRATUM SPINOSUM Superficial, thinner portion, Superficial to the stratum basale composed of epithelial tissue, Consists of numerous keratinocytes (8-10 avascular. layers) Keratinized stratified Coarser keratin squamous epithelium Provides both strength and flexibility to the Keratinocytes: skin ○ Produce the protein Melanocytes and Dendritic cells keratin & lamellar STRATUM GRANULOSUM granules Flattened keratinocytes that are undergoing ○ Keratin - Tough fibrous apoptosis (3-5 layers) protein (Helps Protect) Lamellar granules fuse with the plasma ○ Lamellar Granules - Forms Water membrane and release a lipid-rich- secretion- repellent sealant (Prevent water loss) acr as a water -repellent sealant. Cells Within Epidermis Transition between metabolically active Melanocytes strata and dead cells Pigment producing cells STRATUM LUCIDUM ○ Melanin (Yellow red or Present only in the thick skin (palms, soles, Brown black) palmar surface of the digits, plantar surface of Contribute to skin color and toes) absorbs damaging UV light Flattened clear, dead keratinocytes that contain large amounts of keratin and thickened Dendritic cells plasma membrane (4-6 layers) “Langerhans cells” STRATUM CORNEUM Immune response: recognize an 25 to 30 layers of extremely flattened dead invading microbe and keratinocytes destroy it Final product of the differentiation process of the keratinocytes Merkel cells Protect deeper layers from injury and microbial Tactile epithelial cells invasion Located in the deepest ○ Callus- abnormal thickening due to layer of the epidermis repeated friction Dermis Layers of the Epidermis Deeper, thicker connective tissue portion, vascular Dense irregular connective tissue containing collagen and elastic fibers- great tensile strength (resists pulling or stretching forces) Cells present ○ fibroblasts, macrophages, few adipocytes, blood vessels, nerves, glands, and hair follicles (epithelial invaginations of the epidermis) are embedded in the dermal layer Papillary Dermis Superficial portion of dermis (1⁄5) Consists of areolar connective tissue with thin collagen and fine elastic fibers: dermal ridges that house blood capillaries, tactile corpuscles and free nerve endings. Reticular Dermis Consists of dense irregular connective tissue with bundles of thick collagen and coarse elastic fibers; adipose cells, hair STRATUM BASALE follicles, nerves, sebaceous glands and Deepest layer sudoriferous glands. Composed of a single row of cuboidal or columnar keratinocytes & stem cells to continually produce new keratinocytes “Stratum germanativum” ○ “Germ”- Sprout Melanocytes and tactile epithelial cells 2 ENRIQUE, BSMT-2B  Structural Basis of Skin Color SKIN GLANDS Melanin, hemoglobin, carotene Feature Sebaceous Glands Influence the color of the skin Distribution Largely in lips, glans CONDITIONS penis, labia minora, and Freckles tarsal glands; small in genetically predisposed, melanin trunk and limbs; absent accumulates in patches in palms, palmar Nevus (Nunal) surfaces of the digits, round, flat or raised area, benign localized soles, and plantar overgrowth of melanocytes. surfaces of the toes. Albinism inherited inability of an individual to Location of secretory Dermis produce melanin/ unable to synthesize portion tyrosinase Vitiligo Termination of Mostly connected to hair autoimmune (antibody attacks melanocytes); excretory duct follicle. irregular white spots. Secretion Sebum (mixture of triglycerides, cholesterol, proteins, and inorganic salts). Function Prevent hairs from drying out, prevent water loss from skin, keep skin soft, inhibit growth of some bacteria. Onset of Function Relatively inactive during childhood; activated during puberty. Appendages of the Integumentary system Accessory Structures of the Skin | HAIR Hair Develop from the embryonic epidermis Present on most skin surfaces except the nipples, palms, palmar surfaces of the fingers, plantar surface of the toes, labia minora, prepuce of the penis Genetic and hormonal influences thickness and the pattern of hair distribution Growths of epidermis composed of dead keratinized epidermal cells Types of Hairs Lanugo Feature Eccrine Sweat Glands ○ very fine, nonpigmented, downy hairs, Distribution Throughout skin of most cover body of fetus regions of body, Terminal Hair especially skin of ○ long, coarse, heavily pigmented hairs forehead, palms, and Vellus Hair soles. ○ short, fine, pale hairs that are barely visible to the naked eye Location of secretory Mostly in reticular Alopecia portion dermis (sometimes in ○ partial or complete lack due to genetic upper subcutaneous factors, aging, endocrine disorders, tissue). chemotherapy, or skin disease Hirsutism Termination of Surface of epidermis ○ excessive amount of androgens= excretory duct excessive body hair in areas that usually not hairy Secretion Perspiration, which consists of water, ions 3 ENRIQUE, BSMT-2B  (Na*, CI), urea, uric acid, Accessory Structures of the Skin | NAILS ammonia, amino acids, Nails glucose, and lactic acid. Nails cells arise by transformation of superficial cells of the nail matrix Function Regulation of body Tightly packed, hard, dead, keratinized temperature, waste epidermal cells removal; stimulated Nail plate, a free edge, and a nail root during emotional stress. Onset of Function Soon after birth. Feature Apocrine Sweat Types of Skin Glands Thin Skin Distribution Skin of axillae, groin, areolae, bearded regions of face, clitoris, and labia minora. Location of secretory Mostly in reticular portion dermis and superficial subcutaneous tissue. Termination of Hair follicles. excretory duct Thick Skin Secretion Perspiration, which consists of same components as eccrine sweat glands plus lipids and proteins. Function Stimulated during emotional stress and sexual excitement. Onset of Function Puberty. Epidermal Wound Healing Restricted to the epidermis (abrasions, minor burns. 4 ENRIQUE, BSMT-2B  Deep Wound Healing Second- degree burn (partial thickness) Injury extends deep into dermis, and Destroy the epidermis & dermis subcutaneous tissue redness , blister formation, edema, pain Scar tissue is formed- FIBROSIS Third -degree burn (full thickness) The healed tissue loses some of its normal Destroys the epidermis, dermis subcutaneous function tissue HYPERTROPHIC SCAR Skin functions are lost (nerve endings) ○ elevated above the normal epidermal Systematic effects: shock, infection, decreased surface blood circulation, decreased production of KELOID SCAR urine & diminished immune response ○ extends beyond the boundaries into normal surrounding tissue. Pressure Ulcers Inflammatory Phase “Decubitus ulcers” Blood clot forms in the wound and loosely Shedding of epithelium caused by a constant unites the wound edges deficiency of blood flow to tissues Eliminate microbes, foreign material, and dying Affected tissue overlies a bony projection that tissue in preparation for repair has been subjected to prolonged pressure Vasodilation and increased permeability of against an object such as a bed, cast or splint blood vessels (bedridden patients). Migratory Phase Clot becomes a scab Medical Terminologies Fibroblasts migrate to begin scab tissue & regrow of blood vessels The tissue filling the wound is called granulation tissue Proliferative Phase Extensive growth of epithelial cells beneath the scab, deposition by fibroblasts of collagen fibers in random patterns, and continued growth of blood vessels Maturation Phase Scab sloughs off once the epidermis has been restored to normal thickness Collagen fibers become more organized, fibroblasts decrease in number, and blood vessels are restored to normal SKIN DISORDERS Skin Cancer Basal Cell Carcinoma ○ Most common ○ Tumor arise from stratum basale cells Squamous Cell Carcinoma ○ Arise from stratum spinosum Malignant Melanoma ○ Arise from melanocytes Risk factors for skin cancer Skin type Sun exposure Family history Age Immunological status Burns Tissue damage caused by agents that destroy the proteins in the skin (heat, electricity, radioactivity or corrosive chemicals) First- degree burn Involves only the epidermis Mild pain and erythema (redness) but no blisters (ex: sunburn) 5 ENRIQUE, BSMT-2B