Anatomy and Physiology Module 4 - Skin and Body Membranes PDF

Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Anatomy and Physiology Modul...

Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Anatomy and Physiology Module 4 – Skin and Body Membranes Skin and Body Membranes Body membranes cover surfaces, line body cavities, and form protective (and often lubricating) sheets around organs. 2 major groups: Epithelial membranes Cutaneous membrane - generally called the skin or integumentary system, is the outer covering that we all rely on for protection. Mucus Membrane - this membrane type lines all body cavities that open to the exterior, such as those of the hollow organs of the respiratory, digestive, urinary, and reproductive tracts. Serous Membrane - it lines body cavities that are closed to the exterior (except for the dorsal body cavity and joint cavities). Connective tissue membranes - represented by synovial membranes. These membranes line the fibrous capsules surrounding joints, where they provide a smooth surface and secrete a lubricating fluid. Functions of the Integumentary System - Protects deeper tissues from: Mechanical damage (bumps) Chemical damage (acids and bases) Microbe damage Ultraviolet (UV) radiation Thermal (heat or cold) damage Desiccation (drying out) 1  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing The Integumentary System (Skin) - keeps water and other precious molecules in the body. Epidermis - Most cells of the epidermis are keratinocytes (keratin cells), which produce keratin, the fibrous protein that makes the epidermis a tough protective layer in a process called keratinization. Like all other epithelial tissues, the epidermis is avascular; that is, it has no blood supply of its own. 5 Layers of the epidermis (strata): Stratum Basale - The deepest cell layer of the epidermis which lies closest to the dermis and is connected to it along a wavy border that resembles corrugated cardboard. Stratum Spinosum - Resulting stage of the continuous and rapid cell reproduction. Stratum Lucisum - This latter epidermal layer is not present in all skin regions. It occurs only where the skin is hairless and extra thick, that is, on the palms of the hands and soles of the feet. 2 Stratum Granulosum - Cells become flatter and increasingly keratinized.  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Stratum Granulosum - Cells become flatter and increasingly keratinized. Stratum Corneum - The outermost layer consists of 20 to 30 cell layers thick, but it accounts for about three-quarters of the epidermal thickness. Desmosomes – connect keratinocytes throughout the epidermis. Melanocyte - Produces Melanin (mel’ah- nin), a pigment that ranges in color from yellow to brown to black. Melanin Granules - is the cytoplasmic structure of the melanocyte which carries the melanin pigment. Merkel Cell - are associated with sensory nerve endings and serve as touch receptors called Merkel discs. Nerve Ending - The nerve endings sense pain, touch, pressure, and temperature. Epidermal dendritic cell - important “sentries” that alert and activate immune system cells to a threat such as bacterial or viral invasion. 3  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Dermis - The dermis is the “hide.” It is a strong, stretchy envelope that helps to bind the body together. 2 major regions: Papillary Layer - Is the superficial dermal region. On the palms of the hands and soles of the feet, the papillae are arranged in definite patterns that form looped and whorled ridges on the epidermal surface that increase friction and enhance the gripping ability of the fingers and feet. Reticular Layer - Is the deepest skin layer. ^It contains dense irregular connective tissue, as well as blood vessels, sweat and oil glands, and deep pressure receptors called lamellar corpuscles. Cutaneous Sensory Receptors 4  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Elastic fibers - give the skin its elasticity when we are young. The dermis is abundantly supplied with blood vessels that play a role in maintaining body temperature homeostasis. 5  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Skin Color - Three pigments contribute to skin color: melanin, carotene, and hemoglobin. Melanin (yellow, reddish brown, or black) - Skin exposure to sunlight stimulates melanocytes to produce more melanin pigment, resulting in tanning of the skin. People who produce a lot of melanin have brown-toned skin, whereas people with less melanin are light skinned. Carotene - orange-yellow pigment plentiful in carrots and other orange, deep yellow or leafy green vegetables. In people who eat large amounts of carotene-rich foods, the skin tends to take on a yellow-orange cast. Hemoglobin - (pigment in red blood cells) In light-skinned people, the crimson color of oxygen- rich hemoglobin in the dermal blood supply flushes through the transparent cell layers above and gives the skin a rosy glow. Cyanosis - When hemoglobin is poorly oxygenated, both the blood and the skin of light-skinned people appear blue. Jaundice is a condition produced when excess amounts of bilirubin circulating in the blood stream dissolve in the subcutaneous fat (the layer of fat just beneath the skin), causing a yellowish appearance of the skin and the whites of the eyes. Appendages of the Skin 6  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Cutaneous Glands - The cutaneous glands are all exocrine glands that release their secretions to the skin surface via ducts. 2 groups: Sebaceous (oil) glands - are found all over the skin, except on the palms of the hands and the soles of the feet. Their ducts usually empty into a hair follicle, but some open directly onto the skin surface. Sweat glands - also called sudoriferous (su”do-rif’er-us; sudor = sweat) glands, are widely distributed in the skin. 2 types: ❖ Eccrine (ek’rin) glands - produce sweat, a clear secretion that is primarily water plus some salts (sodium chloride), vitamin C, traces of metabolic wastes (ammonia, urea, uric acid), and lactic acid (a chemical that accumulates during vigorous muscle activity). ❖ Apocrine glands - are largely confined to the axillary (armpit) and genital areas of the body. Hair and hair follicles Hair Follicles - (folli = bag) are actually compound structures. Hair serves a few minor protective functions, such as guarding the head against bumps, shielding the eyes (via eyelashes), and helping to keep foreign particles out of the respiratory tract (via nose hairs). 7  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Nails - is a scalelike modification of the epidermis that corresponds to the hoof or claw of other animals. Burns – is caused by denatured proteins that cause damage and cell death to the affected area. Causes: Intense heat UV radiation (sunburn) Electricity Certain chemicals (such as acids) Life threatening problems: Dehydration and electrolyte imbalance Infection Classification: Burns are classified according to their severity (depth): First-degree burns, only the superficial epidermis is damaged. Sunburn without blistering is a first-degree burn. Second-degree burns involve injury to the epidermis and the superficial part of the dermis. The skin is red, painful, and blistered. Third-degree burns destroy both the epidermis and the dermis and often extend into the subcutaneous tissue, reflecting their categorization as full thickness burns. Blisters are usually present, and the burned area appears blanched (gray - white) or blackened - charred. Because the nerve endings in the area are destroyed, the burned area is not 8  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing painful. Fourth-degree burns are also full-thickness burns, but they extend into deeper tissues such as bone, muscle, or tendons. These burns appear dry and leathery, and they require surgery and grafting to cover exposed tissue. Rule of nines - This method divides the body into 11areas, each accounting for 9 percent of the total body surface area, plus an additional area surrounding the genitals (the perineum) representing 1 percent of body surface area. This is the basis for fluid resuscitation. 9  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Pressure Ulcers - consist of injury to the skin and/or underlying tissue, usually over a bony prominence, as a result of force alone or in combination with movement. Previously called decubitus ulcers, pressure sores, or bedsores. Risk Factors Friction and shearing force Immobility inadequate nutrition Fecal and Urinary Incontinence Excessive Body Heat Diminished Sensation Decreased Mental Status Advanced Age ▪ Loss of lean body mass ▪ Generalized thinning of the epidermis ▪ Decreased strength and elasticity of the skin due to changes in the collagen fibers of the dermis ▪ Increased dryness due to a decrease in the amount of oil produced by the sebaceous glands. ▪ Diminished pain perception due to a reduction in the number of cutaneous end organs responsible for the sensation of pressure and light touch ▪ Diminished venous and arterial flow due to aging vascular walls. Chronic Medical Conditions 10  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Common Pressure Sites Common Pressure Sites 11  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing Norton’s Pressure Area Risk Assessment Form (Scoring System) This tool can be used to identify patients at-risk for pressure ulcers. The five subscale scores of the Norton Scale are added together for a total score that ranges from 5-20. A lower Norton score indicates higher levels of risk for pressure ulcer development. Generally, a score of 14 or less indicates at-risk status. Braden Scale for Predicting Pressure Sore Risk. The scale consists of six subscales and the total scores range from 6-23. A lower Braden score indicates higher levels of risk for pressure ulcer development. Generally, a score of 18 or less indicates at-risk status. 12  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing 13  Far Eastern University Institute of Health Sciences and Nursing Department of Nursing How do the body locations of serous and mucous membranes differ? A scalpel penetrates the left lung and enters the heart. Name the six serous membrane layers the blade passes through as it moves from the body surface into the heart. Where would you find a synovial membrane? REFERENCES: Berman, A., & Snyder, S. (2012). Kozier & Erb’s Fundamentals of Nursing: Concepts, Process, and Practice. Prentice Hall. Marieb, E. N., & Keller, S. M. (2017). Essentials of human anatomy and physiology. Pearson. VanPutte, C., Russo, A., Regan, J., & Russo, A. F. (2018). Seeleys Essentials of Anatomy and Physiology. 14