Chapter 5 The Integumentary System and Body Membranes Renita K Holmes msn rn Kaplan university

Integumentary system Unit 3 Activities Reading: Chapter 5 Discussion Questions Pre-Quiz Assignment Post-Quiz

Integumentary system This system is called the integumentary system. Integument is another name for the skin The skin itself is the principal organ of the integumentary system. The skin is the largest organ in the body The skin is one of a group of anatomically simple but functionally important sheet-like structures called membranes.

The skin Membranes Cover and protect the body surface Line body cavities Cover the inner surfaces of the hollow organs such as the digestive, reproductive, and respiratory passageways.

The skin Membranes Some membranes anchor organs to each other or to bones others cover the internal organs. In certain areas of the body, membranes secrete lubricating fluids that reduce friction during organ movements such as the beating of the heart or lung expansion and contraction. Membrane lubricants also decrease friction between bones in joints.

CLASSIFICATION OF BODY MEMBRANES Classification of body membranes There are 2 main types of membranes Epithelial membranes—composed of epithelial tissue and an underlying layer of connective tissue Connective tissue membranes—composed largely of various types of connective tissue

Types of body membranes Types of body membranes. A, Epithelial membranes, including cutaneous membrane (skin), serous membranes (parietal and visceral pleura and peritoneum), and mucous membranes. B, Connective tissue membranes, including synovial membranes.

CLASSIFICATION OF BODY MEMBRANES Epithelial membranes Cutaneous membrane—the skin Serous membranes—simple squamous epithelium on a connective tissue basement membrane Types Parietal—line walls of body cavities Visceral—cover organs found in body cavities Examples Pleura—parietal and visceral layers line walls of thoracic cavity and cover the lungs Peritoneum—parietal and visceral layers line walls of abdominal cavity and cover the organs in that cavity Diseases Pleurisy—inflammation of the serous membranes that line the chest cavity and cover the lungs Peritonitis—inflammation of the serous membranes in the abdominal cavity that line the walls and cover the abdominal organs

Serous membrane Serous Membrane Line ventral body cavities (pleural, peritoneum, pericardium); transparent, thin, prevents friction http://quizlet.com/2617801/classification-of-body-membranes-flash-cards/

The skin The skin; covers the outer surface of the body. Cutaneous Membrane The skin; covers the outer surface of the body. In contrast to serous or mucous membranes, the cutaneous membrane is thick, relatively waterproof, and usually dry. http://quizlet.com/2617801/classification-of-body-membranes-flash-cards/

CLASSIFICATION OF BODY MEMBRANES Epithelial membranes (cont.) Mucous membranes Line body surfaces that open directly to the exterior Produce mucus, a thick secretion that keeps the membranes soft and moist

Mucous membrane Mucous Membrane Mucous membranes are coated with the secretions of mucous glands. They line most of the digestive and respiratory tracts and portions of the urinary and reproductive tracts. Line passageways that communicate with exterior http://quizlet.com/2617801/classification-of-body-membranes-flash-cards/

CLASSIFICATION OF BODY MEMBRANES Connective tissue membranes Do not contain epithelial components Produce a lubricant called synovial fluid Examples are the synovial membranes in the spaces between joints and in the lining of bursal sacs

Synovial membrane Synovial Membrane Line join cavities (articulations) and produces the synovial fluid within the joint. The synovial fluid lubricates the cartilages in the joint, distributes oxygen and nutrients, and cushions shocks at the joint. http://quizlet.com/2617801/classification-of-body-membranes-flash-cards/

THE SKIN Structure: two primary layers called epidermis and dermis Outermost and thinnest primary layer of skin Composed of several layers of stratified squamous epithelium Stratum germinativum—innermost layer of cells that continually reproduce; new cells move toward the surface As cells approach the surface, they are filled with a tough, waterproof protein called keratin; eventually cells flake off of body Stratum corneum—outermost layer of keratin-filled cells

The skin Skin pigment—produced by deepest epidermal layer; gives color to the skin The brown pigment melanin is produced by specialized cells in deepest epidermal layer Blisters—caused by breakdown of union between cells or primary layers of skin Dermal-epidermal junction—specialized area between two primary skin layers

Microscopic view of the skin Microscopic view of the skin. The epidermis, shown in longitudinal section, is raised at one corner to reveal the ridges in the dermis.

THE SKIN Dermis Deeper and thicker of the two primary skin layers; composed largely of connective tissue Upper papillary layer of dermis characterized by parallel rows of tiny bumps called dermal papillae Ridges and grooves in dermis form pattern unique to each individual Basis of fingerprinting Improves grip for tool use and walking

The skin Deeper reticular layer of dermis filled with network of tough, interlacing, collagenous and stretchable elastic fibers Number of elastic fibers decreases with age and contributes to wrinkle formation Dermis also contains nerve endings, muscle fibers, hair follicles, sweat and sebaceous glands, and many blood vessels

THE SKIN Accessory structures of the skin Hair Lanugo soft hair of fetus and newborn Hair follicle epidermal tubelike structure required for hair growth Hair papilla structure from which hair growth begins Hair root lies hidden in follicle Hair shaft visible part of hair Arrector pili specialized smooth muscle that produces “goose bumps” and causes hair to stand up straight

Hair follicle. Relationship of a hair follicle and related structures to the epidermal and dermal layers of the skin.

THE SKIN Accessory structures of the skin (cont.) Receptors (Figure 5-2) Specialized nerve endings—make it possible for skin to act as a sense organ Meissner’s corpuscle—capable of detecting light touch Pacinian corpuscle—capable of detecting pressure

THE SKIN Accessory structures of the skin (cont.) Nails (Figure 5-6) Produced by epidermal cells over terminal ends of fingers and toes Nail body—visible part of nail Root—lies in a groove; hidden by cuticle Lunula—crescent-shaped area nearest root Nail bed may change color with change in blood flow

Structure of nails. Fingernail viewed from above.

Sagittal section of fingernail and associated structures

THE SKIN Accessory structures of the skin (cont.) Skin glands—two types Sweat, or sudoriferous, glands Eccrine sweat glands Most numerous, important, and wide-spread of the sweat glands Produce perspiration or sweat, which flows out through pores on skin surface Function throughout life and assist in body heat regulation Apocrine sweat glands Found primarily in axilla and around genitalia Secrete a thicker secretion quite different from eccrine perspiration Breakdown of secretion by skin bacteria produces odor

The skin Sebaceous glands Secrete oil or sebum for hair and skin Level of secretion increases during adolescence Amount of secretion is regulated by sex hormones Sebum in sebaceous gland ducts may darken to form a blackhead

THE SKIN Functions of the skin Protection—first line of defense against: Infection by microbes Ultraviolet rays from sun Harmful chemicals Cuts and tears

THE SKIN Functions of the skin (cont.) Temperature regulation Skin can release almost 3000 calories of body heat per day Mechanisms of temperature regulation Regulation of sweat secretion Regulation of blood flow close to the body surface Sense organ activity Skin functions as an enormous sense organ Receptors serve as receivers for the body, keeping it informed of changes in its environment

The skin Skin Cancer The three most common types of skin cancer are Squamous cell carcinoma, Basal cell carcinoma Malignant melanoma

The skin Exposure to the sun’s ultraviolet (UV) radiation is thought to be the most important factor in causing the common skin cancers. UV radiation damages the DNA in skin cells, causing the mistakes in mitosis that produce cancer. Skin cells have a natural ability to repair UV damage to the DNA, but in some people, this inherent mechanism may not be able to deal with a massive amount of damage.

Squamous Cell Carcinoma A common type of skin cancer, squamous cell carcinoma,is a slow-growing malignant tumor of the epidermis. Lesions begin as hard, raised nodules that are usually painless (Figure 5-7, A). If not treated, squamous cell carcinomas will grow in size and eventually metastasize or spread

The skin Squamous Cell Carcinoma

Basal Cell Carcinoma The most common type of skin cancer, Usually appears on the upper face Originating in cells at the base of the epidermis, Much less likely to metastasize It often appears first as a small, raised lesion that erodes in the center to form a bleeding, crusted crater

The skin Basal Cell Carcinoma

The skin Melanoma Malignant melanoma is the most serious form of skin cancer. This type of cancer sometimes develops from a benign or noncancerous pigmented mole, and then transforms into a dark, spreading cancerous lesion

The skin Malignant Melanoma

The skin Kaposi sarcoma is a rare form of skin cancer frequently associated with AIDS and other immune deficiencies.

The skin Warning Signs of Malignant Melanoma ABCD Rule Asymmetry Benign moles are usually symmetrical; their halves are mirror images of each other. Melanoma lesions are asymmetrical or lopsided. Border Benign moles are outlined by a distinct border, but malignant melanomal lesions are often irregular or indistinct in shape. Color Benign moles may be any shade of brown but are relatively evenly colored; melanoma lesions tend to be unevenly colored, exhibiting a mixture of shades or colors. Diameter By the time a melanoma lesion exhibits characteristics A, B, and C, it also is probably larger than 6 mm (14 inch).

THE SKIN Burns Treatment and recovery or survival depend on total area involved and severity or depth of the burn Body surface area is estimated using the “rule of nines” (Figure 5-8) in adults Body is divided into 11 areas of 9% each Additional 1% located around genitals

The “rule of nines.” Dividing the body into 11 areas of 9% each helps to estimate the amount of skin surface burned in an adult.

THE SKIN Burns (cont.) Classification of burns First-degree (partial-thickness) burns—only the surface layers of epidermis involved Second-degree (partial-thickness) burns—involve the deep epidermal layers and always cause injury to the upper layers of the dermis Third-degree (full-thickness) burns—characterized by complete destruction of the epidermis and dermis May involve underlying muscle and bone Lesion is insensitive to pain because of destruction of nerve endings immediately after injury—intense pain is soon experienced Risk of infection is increased

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