chapter 5 the integumentary system and body membranes renita k holmes msn rn kaplan university

CHAPTER 5THE INTEGUMENTARY SYSTEM

AND BODY MEMBRANES

RENITA K HOLMES MSN RNKAPLAN UNIVERSITY

Elsevier items and derived items © 2008, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.

INTEGUMENTARY SYSTEM

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

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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.

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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.

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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.

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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

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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.



• 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

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SEROUS MEMBRANE

Serous Membrane

Line ventral body cavities (pleural, peritoneum, pericardium); transparent, thin, prevents friction

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THE SKIN

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.

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• 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

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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

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• 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

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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.

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THE SKIN

• Structure: two primary layers called epidermis and dermis• Epidermis

• 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

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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

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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

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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

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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

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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

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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

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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

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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

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THE SKIN

oFunctions of the skin• Protection—first line of defense against:

• Infection by microbes• Ultraviolet rays from sun• Harmful chemicals• Cuts and tears

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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

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THE SKIN

Skin CancerThe three most common types of skin cancer

are• Squamous cell carcinoma, • Basal cell carcinoma • Malignant melanoma

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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.

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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

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THE SKIN

• Squamous Cell Carcinoma

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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

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THE SKIN

• Basal Cell Carcinoma

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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

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THE SKIN

• Malignant Melanoma

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THE SKIN

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

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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 oftenirregular or indistinct in shape.

Color Benign moles may be any shade of brown but are relatively evenly colored; melanoma lesionstend 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 largerthan 6 mm (14 inch).

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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

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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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QUESTIONS

Questions?

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chapter 5 the integumentary system and body membranes renita k holmes msn rn kaplan university

Documents

derived items

affiliate of elsevier

types of body membranes

frictionelsevier items

connective tissue membranes

mucous membranes

synovial membranes

body membranesrenita