A membrane is a thin, sheetlike structure that covers and protects the body’s surface, lines body cavities, and covers the inner surfaces of hollow organs, such as the digestive, reproductive, and respiratory passageways.What are some of the other functions performed by membranes? Some membranes anchor organs to each other or to bones, membranes secrete lubricating fluids that reduce friction during organ movements (beating heart or lung expansion and contraction), membrane lubricants also decrease friction between bones in joints.
What are the three types of epithelial membranes? cutaneous, serous, and mucousThe cutaneous membrane is the primary organ of the integumentary system. It has a superficial layer of epithelial cells and an underlying layer of supportive connective tissue.The serous membrane that lines body cavities and covers the surfaces of organs is a single, continuous sheet of tissue.The name of the serous membrane is determined by its location.What are some examples of serous membranes? What are their functions? Serous membranes are found only on surfaces within closed cavities. Parietal membranes line the walls of cavities like wallpaper in a room. Visceral membranes cover the surface of organs within body cavities.
Serous membranes secrete a thin, watery fluid that helps to reduce friction and serves as a lubricant when organs rub against one another and against the walls of the cavities that contain them.
Pleurisy is also known as “pleuritis.”Why might peritonitis sometimes be a serious complication of an infected appendix? An infected appendix that ruptures will allow the contents of the gastrointestinal tract to enter the peritoneal cavity.
What are some examples of mucous membranes in the body? Mucous membranes line body surfaces that open directly to the exterior such as those lining the respiratory, digestive, urinary, and reproductive tracts.What is the mucocutaneous junction? The transitional area that serves as the point of fusion where skin and mucous membranes meetThe epithelial component of a mucous membrane varies depending on location and function.The esophagus has a tough, abrasion-resistant stratified squamous epithelium.The lower segment of the digestive tract has a simple, columnar epithelium.
What are some examples of connective tissue membranes, and what are the functions that they serve? Synovial membranes line the spaces between bones and joints; they also line the cushion-like sacs called bursae.In figure 6-2 the various types of epithelial and connective tissue membranes are shown.What are the functions performed by each of the membranes in figure 6-2?
One square inch of skin contains: 500 sweat glands, 1000 nerve endings, yards of blood vessels, 100 oil (sebaceous) glands, 150 sensors for pressure, 75 sensors for heat, and 10 sensors for cold.What type of membrane is the skin? CutaneousDescribe the process of cell reproduction performed by the stratum germinativum. Mitosis; then they move toward the surface and specialize in ways that increase their ability to provide protection for the body tissues that lie below them.What purposes does this process serve? It enables the skin to repair itself if injured.
What is keratin and what purpose does it serve? Keratin is a tough, waterproof material that provides cells in the outer layer of the skin with a horny, abrasion-resistant, and protective quality.
Pigment—comes from Latin term meaning “paint.”The higher the concentration of melanin, the deeper the color of skin.What is the primary function of melanin? Melanin determines skin color.How is the amount of melanin in the skin determined? Heredity and exposure to sunlight affect amount of melanin.Cyanosis: change in skin color (bluish tinge in light-skinned individuals) if blood oxygen levels or blood flow is reduced.
Cells of the dermis are scattered far apart, with many fibers in between.What types of fibers are in the dermis, and what are their characteristics? Dermis is composed largely of connective tissue with tough, strong fibers (collagen or white fibers) and stretchable and elastic (yellow).
The dermis contains a specialized network of nerves and nerve endings to process sensory information such as pain, pressure, touch, and temperature.What results from the elastic fibers in the dermis decreasing with age? Why would this happen? The number of elastic fibers decreases with age and wrinkles develop as the skin loses elasticity, sags, and becomes less soft and pliant.
Are there any parts of the body that are hairless? If so, which? The lips, palms of the hands, and soles of the feet are hairless.What is lanugo? Lanugo is the downy, soft hair of a newborn.
What is the arrector pili? What function does it perform and why? The arrector pili is a tiny, smooth (involuntary) muscle attached to the base of a dermal papilla above and the side of a hair follicle below. When it contracts, it simultaneously pulls on its two points of attachment to create goose pimples or goose flesh.What parts of the hair are in the dermis? What parts are in the epidermis? See Figure 6-2.
Receptors are widely distributed over the skin.
How are nails formed?What purposes might the nails serve? See Figure 6-9 and Figure 6-10
What might cause the nail bed to change colors? Decrease in blood oxygen level
A single square inch of skin on the palms contains about 3000 eccrine sweat glands.What is the difference between eccrine and apocrine glands? Eccrine sweat glands are more numerous and widespread over the body. They produce a transparent, thin, watery liquid. Apocrine glands are found primarily in the axilla and genital areas. They secrete a thicker, milky secretion that produces odor when skin bacteria decompose the secretion. Apocrine glands become active at puberty.
Apocrine glands enlarge and begin to function at puberty.What causes the odor sometimes associated with secretions of the apocrine glands?
Sebum secretion decreases in late adulthood, contributing to increased wrinkling and cracking of the skin.Why would sebum be referred to as “nature’s skin cream”? It prevents drying and cracking of the skin.
How does the skin protect the body against the potential hazards listed in this slide? Intact skin prevents damage from external forces; waterproof skin products are best treatment for skin maintenance.What are the defensive properties of keratin? Keratin is waterproof, which prevents fluid from entering or leaving through the skinWhat are the defensive properties of melanin? Protects body against ultraviolet rays of the sun
How is heat lost through the skin? By regulation of the blood flow through capillaries in the skin; dilation will cause heat loss.Blood supply to the skin far exceeds the amount needed by the skin.
How do receptors respond to environmental changes? There are receptors for light touch (Meissner corpuscles), pressure (Pacini corpuscles), pain, heat and cold.
Skin lesions can be benign or malignant or might not indicate a disorder at all.What are some examples of benign lesions and malignant lesions? See Table 6-1, Figure 6-15What are some examples of lesions that do not indicate a disorder?
In what ways can the skin be burned? Burns can occur from a fire, contact of the skin with a hot surface, exposure to ultraviolet light. Burns can also occur when skin contacts an electric current or harmful chemical.
The classification system used to describe the severity of burns is based on the number of tissue layers involved.The most severe burns destroy not only layers of skin and subcutaneous tissue but underlying tissues as well.What are some examples of how one might receive first-, second-, and third-degree burns? What are the symptoms, and what tissues are damaged? See Figure 6-16, Figure 6-17, A, Figure 6-17, B
What are the 11 body areas defined by the “rule of nines”? See Figure 6-18What percentage of the body is injured if a person has burns to the face and both arms? 27%
Skin infections are common because the skin is the body’s first line of defense against microbes.Can skin infections be life threatening? Provide an example. Yes, infections with staphylococcal or streptococcal bacteria that begin in the skin and become systemic.Give examples of skin infections that are caused by a virus, a fungus, and an itch mite.
Skin disorders can be caused by a lack of blood flow, allergic reactions, inflammatory reactions, or autoimmune diseases that attack the skin.
What are the warning signs of malignant melanoma? Asymmetrical, irregular, or indistinct in shape, unevenly colored, larger than 6 mmWhat does ABCD stand for in evaluation of a mole? Asymmetry, Border, Color, Diameter
Adults who have had more than two blistering sunburns before the age of 20 years have a much greater risk for development of melanoma than someone who has had no such burns.