Classification of Body 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

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

Serous Membranes, cont Pleura- thoracic cavity Peritoneum- abdominal cavity Serous membranes secrete thin, watery fluid that helps reduce friction

Pleurisy inflammation of the pleura that line the chest walls and cover the lungs Pain is caused by friction of the lungs rubbing against the chest walls

Periotonitis Inflammation of the serous membranes in the abdominal cavity

Mucous Membranes Line body surfaces opening directly to the exterior Respiratory Digestive Urinary Reproduction Produce mucous to keep membranes moist and soft

Mucocutaneous Junction The point where skin and mucous membranes meet Lack hair or sweat glands that characterize skin Can be common sites for infection Examples: Eyelids Nasal openings Vulva anus

Classification of Body Membranes Connective tissue membranes Do not contain epithelial components Produce a thick, colorless lubricant called synovial fluid line spaces between bones and joints Also line bursae- small, cushion-like sacs found between moving body parts

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, and new cells move toward the surface

The Skin Epidermis As cells approach surface, they are filled with a tough, waterproof protein called keratin and eventually flake off Stratum corneum—outermost layer of keratin-filled cells

The Skin Epidermis Pigment-containing layer—epidermal layer that contains pigment cells called melanocytes, which produce the brown pigment melanin

Melanin What gives color to the skin Melanocytes- pigment producting cells Skin color genes are inherited Other factors that effect skin color Cyanosis- bluish gray- decreased bloodflow Vitiligo- patchy looking areas of light skin- due to loss of melanocytes Albinism- partial or total lack of melanin pigment in the skin

Variations of skin pigment continued Freckles Most occur due to a genetic trait in light skinned people chronically in sun exposed areas

Blisters Cells of the epidermis are packed tightly together When these links are weakened or destroyed due to burns, friction, or irritants blisters form Blisters can also occur at the Dermal- epidermal junction- area of contact between the two that “glues” them together

The Skin Dermis Deeper and thicker of the two primary skin layers and composed largely of connective tissue Upper area of dermis characterized by parallel rows of peg-like dermal papillae Ridges and grooves in dermis form pattern unique to each individual (basis of fingerprinting) Deeper areas of dermis filled with network of tough collagenous and stretchable elastic fibers

Striae- are stretch marks Occur when the connective and elastic tissues are stretched beyond their ability to rebound Wrinkles occur because the amount of elastic fibers in the dermis decrease, and the amount of fat in the subcutaneous tissue is reduced                                                              

The Skin Dermis Dermis also contains nerve endings, muscle fibers, hair follicles, sweat and sebaceous glands, and many blood vessels

Problems with development of the dermis blood vessels can cause birthmarks Strawberry hemangioma Port-wine stain “stork bite”

Nails Nail body is the visible part of the nail Produced by epidermal cells over terminal ends of fingers and toes Nail body is the visible part of the nail Nail Root is the rest of the nail that in a groove and is hidden by the cuticle

Lunula “little moon” is the nail body closest to the root; crescent shaped white area Nail Bed is the layer of epithelium under the nail. Because it has a large blood supply it appears pink under a clear nail If blood oxygen levels drop the nail bed appears blue

Age and race can influence normal shape and appearance of nails Light skinned- longitudinal lines Dark skin- pigmented bands Onycholysis “nail pitting” separation of nail from nail bed starting at the distal end; common in patients with psoriasis

The Skin Appendages of the skin Hair Soft hair of fetus and newborn called lanugo Hair growth requires epidermal tube-like structure called hair follicle Hair growth begins from hair papilla

Hair Follicle- small tube located in the dermis where hair growth begins Papilla- cluster of cells at the base of the follicle “hair root” is hidden in follicle “shaft” is the visible part of the hair As long as the cells in the papilla are alive new hair will grow to replace plucked or cut hair Cutting or shaving hair DOES NOT make it grow faster or become coarser because neither effects the cells in the papilla

Alopecia (hair loss) Male pattern baldness Hereditary Result of aging Alopecia areata Last 1-3 months Round or oval sudden hair loss Chemotherapy Radiation Extreme stress Certain metabolic or endocrine diseases Reaction to certain drugs Postpardum alopecia 1-4 months post giving birth Front and sides of scalp <one year Alopecia totalis Complete loss of scalp hair with no apparent reason May experience periods of re- growth and then loss again

Goose Bumps Arrector pili muscle Attached to the base of the papilla and to the side of the hair follicle Involuntary muscle contraction; usually when we are frightened or cold

The Skin Appendages of the skin Receptors 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 Skin glands Types Sweat or sudoriferous Sebaceous

Sweat (sudoriferous) glands Two types Eccrine More numerous Cover most of body surface Secrete transparent, watery liquid 1 inch of skin contain approx. 3000! Produce perspiration or sweat, which flows out through pores on skin surface Function throughout life and assist in body heat regulation Apocrine Found primarily in the axilla and pigmented skin around the genitals Thicker, milky secretions Odor is caused by the secretion mixing with bacteria on the skin, not the secretion itself Enlarge and begin to function at puberty

Sebaceous gland Secrete oil or sebum for hair and skin Level of secretion increases during adolescence Amount of secretion regulated by sex hormones Acne vulgaris inflammation of sebaceous gland ducts Grow where hair grows, have ducts that open into the hair follicles Often sebum accumulates in the ducts forming white pimples or darkens and forms blackheads Secretions decrease with age which contributes to wrinkles and cracking of skin

Functions of the Skin Protection—first line of defense Against infection by microbes Against ultraviolet rays from sun Against harmful chemicals Against cuts and tears Skin grafts

Functions of the Skin Temperature regulation Skin can release almost 3000 calories of body heat per day Mechanisms of temperature regulation Regulation of sweat secretion Regulation of flow of blood close to the body surface

Functions of the Skin 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—disorders of the skin (dermatomes)

Subcutaneous Injections Carries major blood vessels and nerves Spongy texture Allows for rapid, relatively pain-free absorption Liquid medicine and pelleted implant materials

Disorders of the Skin

Acne Acne vulgaris Most common kind Occurs mostly in adolescents Caused by increased sebum production between ages 10-19 Papules are inflammed lesions Pustules are pus filled pimples that rupture Treatment Proper cleaning Topical medications Oral antibiotics and other drugs

ATHLETE’S FOOT Contagious fungal infection Usually contracted in public baths and showers Rx – antifungal agents

Skin Lesions Elevated lesions -cast a shadow outside their edges Papule—small, firm raised lesion Plaque—large raised lesion Vesicle—blister Pustule—pus-filled lesion Crust—scab Wheal (hive)—raised, firm lesion with a light center

Flat lesions —do not cast a shadow Skin Lesions Flat lesions —do not cast a shadow Macule—flat, discolored region Ex. Freckle Copyright © 2005, 2002, 1997, 1992 by Mosby, Inc. All rights reserved.

Copyright © 2005, 2002, 1997, 1992 by Mosby, Inc. All rights reserved. Skin Lesions Depressed lesions cast a shadow within their edges Excoriation—missing epidermis, as in a scratch wound Ulcer—craterlike lesion Fissure—deep crack or break Copyright © 2005, 2002, 1997, 1992 by Mosby, Inc. All rights reserved.

DERMATITIS Non-specific inflammation of skin Can be rash – reaction to soap, plants, etc. Can be emotional – stress can cause skin blotches

SKIN CANCER Associated with exposure to sun (UV rays) Most common type of cancer in people

Skin Cancer Three common types Squamous cell carcinoma—the most common type, characterized by hard, raised tumors Basal cell carcinoma—characterized by papules with a central crater; rarely spreads Melanoma—malignancy in a nevus (mole); the most serious type

MALIGNANT MELANOMA Occurs in melanocytes Metastasizes to other areas quickly Appears as brown or black irregular patch that occurs suddenly A change in an existing wart or mole may indicate melanoma Rx – surgical removal of melanoma and surrounding area and chemotherapy

GENITAL HERPES Viral Blister in genital area Spread through sexual contact Periods of remission and exacerbation Rx – Acyclovir Can be passed to newborn during vaginal delivery

BURNS Caused by radiation, sun, boiling water, chemicals, fire or electricity RULE OF NINES – Measures percent of body burned. Body divided into 11 area, each is 9% of body surface.

BURNS FIRST DEGREE Superficial Skin red and dry Involves only epidermis Rx – cold water

BURNS SECOND DEGREE Epidermis and dermis Pain, swelling, redness and blistering Skin may be exposed to infection Rx – pain medication, dry sterile dressing

Burns Third-degree (full-thickness) burns characterized by complete destruction of the epidermis and dermis May involve underlying muscle and bone (fourth-degree) Lesion is insensitive to pain because of destruction of nerve endings immediately after injury—intense pain is soon experienced Symptoms – loss of skin, blackened skin May be life threatening

RULE OF NINES The volume of fluid lost can be estimated indirectly by determining how much of the body surface is burned (extent of burns), using the rule of nines. Body divided into 11 areas of 9% each Additional 1% of body surface area around genitals

Copyright © 2005, 2002, 1997, 1992 by Mosby, Inc. All rights reserved. Skin Infections -Impetigo—highly contagious staphylococcal infection Tinea—fungal infection (mycosis) of the skin; Boils—furuncles; staphylococcal infection in hair follicles Scabies—parasitic infection Copyright © 2005, 2002, 1997, 1992 by Mosby, Inc. All rights reserved.

Vascular and Inflammatory Skin Disorders Decubitus ulcers Urticaria or hives Scleroderma Psoriasis Eczema Copyright © 2005, 2002, 1997, 1992 by Mosby, Inc. All rights reserved.