Components of Photosystems Answer Key

SH ORT A N SWER. Wri te the wor d or phrase that best compl etes each statement or answ ers the questi on. Fi gure 5.1 U sing Figure 5.1, match the following: 1) Site of the dermal ridges that produce epidermal ridges on the epidermal surfaces of the fingers. Answ er: E 2) Responsible for shock absorption and located in the hypodermis. Answ er: B 3) Pulls the hair follicle into an upright position. Answ er: A 1 4) Sudoriferous gland. Answ er: C 5) Dense irregularly arranged, fibrous connective tissue. Answ er: D 6) Region that thickens markedly when one gains w eight. Answ er: B 7) Where capillary loops are found. Answ er: E M A TCH IN G. Choose the item in column 2 that best matches each item i n col umn 1. M atch the following: 8) The most abundant cells of the epidermis. Answ er: E 9) Spider- shaped epithelial cells that synthesize the pigment melanin. Answ er: D 10) Cells plus a disc- like sensory nerve ending that functions as a sensory receptor for touch. A) M erkel cells B) Dendritic cells C) Keratin D) M elanocyte E) Keratinocytes Answ er: A 11) Skin macrophages that help activate the immune system. Answ er: B 12) The fibrous protein that helps give the epidermis its protective properties. Answ er: C M atch the following: 13) The layer of the epidermis where the cells are considered protective but nonviable. A) Stratum corneum Answ er: A 2 14) The layer of the epidermis that is several layers thick and contains pre- keratin. Answ er: A 15) The layer that contains the mitotic viable cells of the epidermis. A) Stratum spinosum B) Stratum granulosum C) Stratum basale Answ er: C 16) The layer of the epidermis that contains one to five layers of flattened cells and deteriorating organelles. Answ er: B M atch the following: 17) M ay indicate embarrassment, fever, hypertension, inflammation, anger, or allergy. Answ er: B 18) M ay indicate fear, anemia, or low blood pressure. Answ er: C 19) Usually indicates a liver disorder. A) A ddison's disease B) Erythema C) Pallor D) Jaundice E) Cyanosis Answ er: D 20) Appearance of a permanent tan; bronzing. Answ er: A 21) A bluish color in light- skinned individuals. Answ er: E 3 SHORT A N SWER. Write the word or phrase that best compl etes each statement or answ ers the question. Fi gure 5.2 Using Figure 5.2, match the following: 22) H ypodermis. Answ er: D 23) Epidermis. Answ er: A 24) Reticular layer of the dermis. Answ er: C 25) Papillary layer of the dermis. Answ er: B TRUE/FALSE. Write 'T' i f the statement is true and 'F' if the statement is false. 26) The eccrine sw eat glands are not the primary gland involved in thermoregulation. Answ er: True False 27) The dense fibrous connective tissue portion of the skin is located in the reticular region of the dermis. Answ er: True False 4 28) The protein found in large amounts in the superficial layer of epidermal cells is keratin. Answ er: True False 29) Joe just burned himself on a hot pot, and the burn is quite painful. Joe's burn would best be described as a third- degree burn. Answ er: True False 30) The reason that the nail bed appears pink is the presence of a large number of melanocytes in the underlying dermis. Answ er: True False 31) During the regressive phase of hair grow th, the matrix is inactive and the follicle atrophies. Answ er: True False 32) The skin cancer most likely to metastasize is cancer of the melanocytes. Answ er: True False 33) The skin is not able to receive stimuli because the cells of the epidermis are not living and therefore there are no sensory receptors in the skin. Answ er: True False 34) The dermis contains blood vessels and nerve fibers w hile the epidermis does not. Answ er: True False 35) For a doctor, simply looking at a patient's skin can help tow ards making a diagnosis. Answ er: True False 36) When an individual is exposed to extremely cold air the dermal blood vessels w ill dilate so that more blood will be brought closer to the outside surface of the skin. Answ er: True False 37) Regardless of race, all human beings have about the same number of melanocytes. Answ er: True False 38) Cells in the stratum corneum undergo mitosis to keep the layer thick and protective. Answ er: True False 39) The pinkish hue of individuals with fair skin is the result of the crimson color of oxygenated hemoglobin (contained in red blood cells) circulating in the dermal capillaries and reflecting through the epidermis. Answ er: True False 40) When a patient is said to have "third- degree burns," this indicates that the patient has burns that cover approximately one- third or more of the body. Answ er: True False 41) Thick skin has a more extensive dermal layer than thin skin. Answ er: True False 5 42) The action of the arrector pili muscle is very similar in humans as it is in other mammals but its beneficial functions differ. Answ er: True False M ULTI PLE CHOI CE. Choose the one alternati ve that best completes the statement or answ ers the question. 43) Select the most correct statement concerning skin cancer. A) M ost tumors that arise on the skin are malignant. B) Basal cell carcinomas are the least common but most malignant. C) M elanomas are rare but must be removed quickly to prevent them from metastasizing. D) Squamous cell carcinomas arise from the stratum corneum. Answ er: C 44) A needle w ould pierce the epidermal layers of the forearm in w hich order? A) corneum, granulosum, spinosum, basale B) basale, spinosum, granulosum, lucidum, corneum C) granulosum, basale, spinosum, corneum D) basale, spinosum, granulosum, corneum Answ er: A 45) The major regions of a hair shaft include all of the follow ing EXCEPT ________. A) cortex B) external root sheath C) cuticle D) medulla Answ er: B 46) The single most important risk for skin cancer is ________. A) genetics B) use of farm chemicals C) overexposure to UV radiation D) race Answ er: C 47) A splinter penetrated into the skin of the sole of the foot, almost to the papillary region of the dermis. Which layer of the epidermis would be the final layer injured? A) lucidum B) basale C) spinosum D) granulosum Answ er: B 48) Which of the following is a skin sensory receptor for touch? A) Pacinian corpuscle B) Ruffini body C) free nerve ending D) tactile cells Answ er: D 49) Which statement correctly explains why hair appears the w ay it does? A) Gray hair is the result of hormonal action altering the chemical composition of melanin. B) Perfectly round hair shafts result in wavy hair. C) A ir bubbles in the hair shaft cause straight hair. D) Kinky hair has flat, ribbonlike hair shafts. Answ er: D 6 50) The function of the root hair plexus is to ________. A) allow the hair to assist in touch sensation B) cause apocrine gland secretion into the hair follicle C) serve as a source for new epidermal cells for hair growth after the resting stage has passed D) bind the hair root to the dermis Answ er: A 51) Which of the following glands secrete sebum, an oily like substance? A) merocrine glands B) eccrine glands C) apocrine glands D) sebaceous glands Answ er: D 52) The reason the hypodermis acts as a shock absorber is that ________. A) the cells that make up the hypodermis secrete a protective mucus B) it is located just below the epidermis and protects the dermis from shock C) it has no delicate nerve endings and can therefore absorb more shock D) the major part of its makeup is adipose, w hich serves as an effective shock absorber Answ er: D 53) Which type of skin cancer is the most dangerous because it is highly metastatic and resistant to chemotherapy? A) melanoma B) squamous cell carcinoma C) adenoma D) basal cell carcinoma Answ er: A 54) Which of the follow ing cells and their function are correctly matched? A) dendritic cells – activate the immune system B) melanocytes – protects cells in the stratum corneum from damaging effects of sun's rays C) keratinocytes – provide sense of touch and pressure D) tactile cells – protection Answ er: A 55) Melanocytes and keratinocytes w ork together in protecting the skin from UV damage w hen keratinocytes ________. A) provide the melanocyte with nutrients necessary for melanin synthesis B) maintain the appropriate temperature so the product of the melanocyte will not denature C) accumulate the melanin granules on their superficial portion, forming a UV- blocking pigment layer D) maintain the appropriate pH in order for the melanocyte to synthesize melanin granules Answ er: C 56) The epidermis consists of five layers of cells, each layer with a distinct role to play in the health, well- being, and functioning of the skin. Which of the following layers is responsible for cell division and replacement? A) stratum granulosum B) stratum basale C) stratum corneum D) stratum lucidum Answ er: B 7 57) Water loss through the epidermis could cause a serious threat to health and well- being. Which of the following protects us against excessive water loss through the skin? A) Glycolipids that are secreted by keratinocytes into extracellular spaces. B) The dermis is the thickest portion of the skin and w ater cannot pass through it. C) Fat associated with skin prevents w ater loss. D) The size and shape of the cells that make up the stratum spinosum, as well as the thick bundles of intermediate filaments. Answ er: A 58) The dermis is a strong, flexible connective tissue layer. Which of the follow ing cell types are likely to be found in the dermis? A) osteoblasts, osteoclasts, and epithelial cells B) goblet cells, parietal cells, and chondrocytes C) monocytes, reticulocytes, and osteocytes D) fibroblasts, macrophages, and mast cells Answ er: D 59) The dermis has tw o major layers. Which layer constitutes 80% of the dermis and is responsible for the tension lines in the skin? A) the reticular layer B) the hypodermal layer C) the subcutaneous layer D) the papillary layer Answ er: A 60) Despite its apparent durability, the dermis is subject to tearing. How might a person know that the dermis has been previously stretched and/or torn? A) There is an episode of acute pain due to the large number of tactile corpuscles. B) The stretching causes the tension lines to disappear. C) The blood vessels in the dermis rupture and the blood passes through the tissue, causing permanent "black - and - blue marks." D) The appearance of visible, silvery- w hite scars is an indication of stretching of the dermis. Answ er: D 61) The papillary layer of the dermis is composed of loosely packed connective tissue w ith numerous peg- like projections that provide a great deal of surface area connecting the dermis to the epidermis. Which of the statements below do NOT represent benefits provided by the papillary layer's anatomy? A) The spaces in the connective tissue allow many small blood vessels to deliver nutrients and pick up waste diffusing from the superficial epidermal layers. B) The high surface area allow s for a stronger connection of dermis to epidermis. C) The looseness allow s for easy separation of the dead cell layer of epidermis to be shed. D) The looseness allows for phagocytes to roam through the tissue and search for infection. Answ er: C 62) The friction ridges seen in finger, palm and foot prints are different among various people but very similar betw een identical twins. This evidence suggests w hich of the follow ing? A) That friction ridges are genetically determined. B) That friction ridges change over time. C) That friction ridges aid in griping. D) That friction ridges allow for better tactile sensation. Answ er: A 8 63) Which of the follow ing statements indicates the w ay in which the body's natural defenses protect the skin from the effects of UV damage? A) Carotene, w hich accumulates in the stratum corneum and hypodermal adipose tissue, is synthesized in large amounts in the presence of sunlight. B) Prolonged exposure to the sun induces melanin dispersion, w hich in turn acts as a natural sunscreen. C) The skin is protected by increasing the number of epidermal dendritic cells, w hich help to activate the immune system. D) The skin is protected by the synthesis of three pigments that contribute to the skin's color. Answ er: B 64) Changes in the color of skin are often an indication of a homeostatic imbalance. Which of the follow ing would indicate a liver disease such as hepatitis resulting in elevated bilirubin? A) Black - and - blue marks become evident for no apparent cause. B) The skin takes on a bronze or metallic appearance. C) The skin and sclera of the eyes appears to have an abnormal, yellow ish tint. D) It is impossible to suggest Addison's disease from an inspection of a person's skin. Answ er: C 65) A dendritic or Langerhans cell is a specialized ________. A) squamous epithelial cell C) nerve cell B) melanocyte D) phagocytic cell Answ er: D 66) What are the most important factors influencing hair grow th? A) the size and number of hair follicles B) age and glandular products C) nutrition and hormones D) sex and hormones Answ er: C 67) Sudoriferous (sw eat) glands are categorized as tw o distinct types. Which of the following are the tw o types of sw eat glands? A) eccrine and apocrine B) holocrine and mammary C) sebaceous and merocrine D) mammary and ceruminous Answ er: A 68) The composition of the secretions of the eccrine glands is ________. A) primarily uric acid B) fatty substances, proteins, antibodies, and trace amounts of minerals and vitamins C) 99% water, sodium chloride, trace amounts of w astes, and vitamin C D) metabolic wastes Answ er: C 69) Apocrine glands, which begin to function at puberty under hormonal influence, seem to play little role in thermoregulation. Where would we find these glands in the human body? A) in the axillary and anogenital area B) in all body regions and buried deep in the dermis C) in the palms of the hands and soles of the feet D) beneath the flexure lines in the body Answ er: A 9 70) The sebaceous glands are simple alveolar glands that secrete a substance known as sebum. The secretion of sebum is stimulated ________. A) by high temperatures B) as a protective coating when one is sw imming C) w hen the air temperature drops D) by hormones, especially androgens Answ er: D 71) In addition to protection (physical and chemical barrier), the skin serves other functions. Which of the following is another vital function of the skin? A) The cells of the epidermis store glucose as glycogen for energy. B) It absorbs vitamin C so that the skin w ill not be subject to diseases. C) It converts modified epidermal cholesterol to a vitamin D precursor important to calcium metabolism. D) It aids in the transport of materials throughout the body. Answ er: C 72) Burns are devastating and debilitating because of loss of fluids and electrolytes from the body. H ow do physicians estimate the extent of burn damage associated with such dangerous fluid loss? A) by observing the tissues that are usually moist B) by measuring urinary output and fluid intake C) by using the "rule of nines" D) through blood analysis Answ er: C 73) Which layer of tissue is damaged in a first- degree burn? A) hypodermis C) dermis B) epidermis D) both the epidermis and dermis Answ er: B 74) Eyebrow hairs are always shorter than hairs on your head because ________. A) they grow much slower B) hormones in the eyebrow follicle switch the growth off after it has reached a predetermined length C) the vascular supply of the eyebrow follicle is one- tenth that of the head hair follicle D) eyebrow follicles are only active for a few months Answ er: D 75) Cells of the stratum spinosum have many interlocking desmosomes that will remain betw een the cells as they migrate to the stratum corneum. These cell junctions serve the body by ________. A) allowing secretions like sw eat or sebum to pass through B) stopping w ater loss and preventing dehydration C) preventing mechanical stress or trauma from damaging the epidermis D) preventing ultraviolet light from penetrating the deeper layers of the epidermis Answ er: C 76) Which of the follow ing examples listed below illustrates homeostasis maintained by a negative feedback? A) Production of vitamin D initiated by the suns UV light striking the skin. B) Formation of cerumen w ax to deter insects from entering the ear. C) Thickening of epidermis to form a callus in places where the skin is exposed to friction. D) Changes in the response of the hair follicle to dihydrotestosterone (DH T). Answ er: C 10 77) Which of the follow ing examples listed below illustrates homeostasis maintained by a negative feedback? A) Release of chemical signals by keratinocytes that have been damaged by UV light that will increase the production of melanin. B) Removal of nitrogenous compounds like urea within the sw eat. C) The near waterproof secretions of glycolipids that is released by cells in the stratum granulosum. D) The secretion of antibacterial compounds in sebum. Answ er: A 78) Which of the follow ing examples listed below illustrates homeostasis maintained by a negative feedback? A) Release of sw eat by eccrine glands in response to heat. B) An increase in sebum production in response to androgens (male sex hormones). C) Lack of pain in third- degree burns due to damage to sensory nerves in the dermis. D) Excretion of salts within the sweat. Answ er: A 79) Which layer of skin is LEA ST protected by melanin? A) stratum basale C) stratum spinosum B) stratum granulosum D) stratum corneum Answ er: D 80) Which layer of the epidermis will be supplied with the highest levels of oxygen from the blood? A) stratum granulosum B) stratum spinosum C) stratum basale D) stratum corneum Answ er: C 81) A patient has skin that is slightly blue in color. A likely treatment for this person might be ________. A) exposing the patient to more sunlight B) encouraging the patient to eat more orange colored vegetables (rich in beta carotene) C) giving the patient supplemental oxygen by mask D) increasing fluids through IV therapy Answ er: C 82) The arrector pili muscle's predominate, useful function in humans is to ________. A) provide warmth by making the hair stand on end B) assist in the release sebum from nearby sebaceous glands C) stimulate faster hair grow th D) prevent germs from entering the hair shaft Answ er: B 83) Which of the following is NOT one of the functions of the skin? A) Delivers important information about our environmental conditions to our brains. B) Gives the body its overall shape, loss of this function can be seen with the drooping of skin with age. C) Conducts endergonic metabolic chemical reactions using the suns energy to initiate vitamin D synthesis. D) Holds a portion of the bloods total volume to be shunted (diverted) to other organs when needed. Answ er: B 11 84) All of the follow ing will help the skin to fight infection but one. Which of the following will have little effect on the skin's ability to fight infection? A) Greater production of keratinocytes resulting in more layers of the stratum corneum. B) Greater production of melanin. C) Increased secretions of defensins from skin cells. D) More tight junctions between keratinocytes of the stratum corneum. Answ er: B 85) A light skinned person w ho is very cold may have a pale appearance. Which of the follow ing is the best explanation for w hy this might be so? A) The person's blood vessels in the dermis have undergone vasoconstriction (narrowing). B) The person's blood vessels in the epidermis have undergone vasodilation (widening). C) The person is in fear of hypothermia (sever cold exposure). D) The cold has slowed the movement of blood. Answ er: A 86) A surgeon opens her patient by cutting the integument parallel to the cleavage lines of the dermis (tension lines). This will result in ________. A) greater chance of infection B) faster healing of the skin and less scaring C) slowed healing and greater scaring D) less chance for infection Answ er: B 87) A light- skinned person may appear pink when they become over heated. The best explanation for this is ________. A) blood flow has increased to the sw eat glands in order to increase their metabolic activity B) the heart is pumping faster because the person was probably exercising C) the melanocytes are responding to the heat of the sun and change the appearance of the skin with increased production D) the blood vessels of the dermis have undergone vasodilation, bringing a greater volume of blood to the skin Answ er: D 88) William has a cut that is superficial, painful but not bleeding. Based on this information, you w ould predict that the cut has penetrated to ________. A) the stratum corneum but not the stratum granulosum B) the stratum basale but not the dermal layers C) the subcutaneous layer, but no deeper D) the papillary layer but not the reticular layer Answ er: B 89) The surge of sex hormones that accompanies puberty has a wide range of effects on the body. One of those effects is to enhance the activity of the sebaceous glands, increasing the production of sebum. Which of the following is the most likely to result from the increased sebaceous activity? A) Decreased vitamin D synthesis. B) Increased oily appearance and more acne. C) Increased hair grow th. D) Increased cooling of the skin. Answ er: B SHORT A N SWER. Write the word or phrase that best compl etes each statement or answ ers the question. 90) Cradle cap in infants is called ________. Answ er: seborrhea 12 91) The w hite crescent portion of the nail is called the ________. Answ er: lunula 92) The dermal folds that occur at or near joints where the dermis is tightly secured to deeper structures are called ________. Answ er: flexure lines 93) The ________ are the small muscles located in the dermis that cause goose bumps. Answ er: arrector pili 94) Tanning or darkening of the skin occurs as a defensive response to ________. Answ er: UV radiation 95) The coarse hair of the eyebrows and scalp is called ________ hair. Answ er: terminal 96) Burns that result in injury to the epidermis and the upper regions of the dermis is called a ________ burn. Answ er: second - degree 97) Pigment- producing cells in the epidermis are ________. Answ er: melanocytes 98) The only place you will find stratum ________ is in the skin that covers the palms, fingertips, and soles of the feet. Answ er: lucidum 99) List the layers of the dermis and describe the functions of the tissue that makes up each layer. Answ er: The papillary layer is composed of areolar connective tissue that allows phagocytes and other defensive cells to serve as a second line of defense against microbial invasion. The reticular layer is composed of dense irregular connective tissue that gives the skin strength and resiliency, maintains hydration, and provides elasticity to the skin. 100) There are several reasons other than genetics for hair loss. Identify some of these other factors. Answ er: Stressors such as acutely high fever, surgery, severe emotional trauma; drugs such as antidepressants and chemotherapy drugs; burns and radiation; lack of adequate nutrition due to poor skin circulation; and a protein- deficient diet can cause hair loss or thinning in our 4th decade of life and beyond. 101) In addition to the synthesis of vitamin D, keratinocytes are able to carry out some other biologically important functions. Name at least two of these other functions. Answ er: Keratinocyte enzymes can neutralize carcinogens that penetrate the epidermis. Keratinocytes are also able to convert topical cortisone to a more active anti- inflammatory form. 102) How are burns commonly classified? Give an example. Answ er: Burns are classified according to their severity or depth. For example, in first- degree burns, only the epidermis is damaged; in second- degree burns, the epidermis and upper dermis are damaged; in third- degree burns, there is widespread damage of epidermis and dermis. 13 103) What is vellus hair? Answ er: Vellus hair is pale, fine body hair associated w ith newborn children, women, and "peach fuzz" on all people. 104) Balding men have tried all kinds of remedies, including hair transplants, to restore their lost locks. Explain the cause of male pattern baldness. Answ er: It appears to be genetically determined and sex- linked, and is possibly caused by a delayed- action gene that responds to DH T and alters normal metabolism. 105) The skin protects, but how does it protect us and from w hat? Describe how the epidermal dendritic cells and melanocytes protect us. Describe what these cells protect us from. Answ er: The epidermal dendritic cells act as antigen- presenting cells (APC): They present part of the pathogens (fragments of pathogens called epitopes) to other immune system cells to trigger an immune response to an infection. The melanocytes produce melanin in response to exposure to cell damaging, ultraviolet light. UV light is converted to heat when it strikes melanin pigment. Unlike UV light, heat will not damage the cells, particularly the DN A w ithin the nucleus of the skin's cells. 106) Billions of consumer dollars are spent for deodorants and antiperspirants each year. Explain the production of body odors frequently associated w ith axillary skin. Answ er: Sw eat is mostly an odorless w atery secretion produced by eccrine and apocrine glands. The odor usually arises when bacteria break dow n lipids and proteins in the surface secretions. 107) What complications might be anticipated from the loss of large areas of skin surfaces? Answ er: Large losses of skin, as w ith severe burn injuries, allow excessive fluid loss and infection. Skin grafting or "synthetic skin" applications are usually necessary. 108) Why are the apocrine sweat glands fairly unimportant in thermal regulation? Answ er: They are largely confined to the axillary and anogenital regions rather than distributed on the body w here heat can be more readily dissipated. 109) Why is profuse sweating on a hot day good, and yet a potential problem? Answ er: Good because the sweat and evaporating of the sw eat causes cooling of the body. Bad because excessive w ater and salt loss may occur. Fluid and electrolyte imbalances may follow . 110) What is the function of skin dermal folds and deep skin creases? Answ er: Skin dermal folds and deep skin creases accommodate for joint movement. ESSA Y. Wri te your answ er in the space provi ded or on a separate sheet of paper. 111) We are told that every surface we touch is teeming with bacteria, and bacteria are found in the pools w e swim in, the w ater we wash with, and on the hands of friends. Why are we not inundated w ith bacterial infections on our skin? Answ er: The low pH of the skin secretions, otherw ise known as the acid mantle, retards the multiplication of bacteria on the skin. A lso, in areas w here sufficient sebum is produced regularly, many species of bacteria cannot exist. Beside the barrier qualities of the skin, it is also true that not all bacteria are harmful or thrive on skin. Skin is dry imparing bacteria to grow; Sweat contains high salt (N aCl) along w ith antimicrobial agents such as defensins and antibody: IgA . 14 112) The temperature yesterday was an uncomfortable 98°F. You unw isely chose to play tennis at noon, counting on your body's internal defenses to protect you against heat exhaustion. How did your body respond to this distress? Answ er: The thermoreceptors sense the temperature change, and neural stimulation responds by stimulating sweat glands. Their watery products evaporated at the skin surface and cooled the body. Blood vessels in the dermis also responded by dilating and releasing heat closer to the surface of the skin to allow greater heat dissipation. 113) M ary noticed a large, brow n spot on her skin. She has been playing tennis in the sun for several years without sun protection. She reported the discovery to a friend, w ho told her to apply the ABCD rule to determine whether or not she had malignant melanoma. H er friend told her that if her answer was "no" to the questions that w ere asked by the ABCD rule, she had nothing to w orry about. What is the A BCD rule and should she ignore the spot if her answ ers are negative? Answ er: The ABCD rule refers to the following: asymmetry–where the two sides of the spot do not match; border irregularity–the borders are not round and smooth; color–the pigmented spot contains shades of black, brown, tan, and sometimes blues and reds; and diameter–the spot is larger than 6 mm in diameter. It is imperative that M ary have a physician examine the spot immediately. A ny unusual lesion on the skin of a sun worshipper should be examined and the ABCD rule does not account for all possible factors, such as rapid growth, even if less than 6 mm. The fact that she has been exposed to the sun without protection itself would be a strong recommendation for her to see a dermatologist regardless of passing the A BCD rule. 114) The Waldorf family was caught in a fire but escaped. Unfortunately, the father and daughter suffered burns. The father had second- degree burns on his entire chest, abdomen, and both arms, and third- degree burns on his entire left low er extremity. The daughter suffered first- degree burns on her whole head and neck and second- degree burns throughout both lower extremities. a. What percentage of the father's body was covered by burns? b. What percentage of the daughter's body received first- degree burns? c. What part of the daughter's body has both the dermis and epidermis involved? d. The father experiences a good deal of pain in the area of the chest and abdomen, but little pain in the leg. Why Answ er: a. 45% (18% anterior torso + 9% both arms but not forearms + 18% low er extremity) b. 9% c. 36% d. N ormally, third- degree burns sear nerve endings off. When the tissue regenerates, pain will return. Second- degree burns are usually very painful because of the irritated but live nerve endings. 115) John, a younger teenager, notices that he is experiencing a lot of pimples and blackheads, w hich frequently become infected. What is causing this problem? Answ er: Because of hormonal changes, teenagers frequently have overactive sebaceous (oil) glands, which can clog and become infected or inflamed. Scratching, squeezing, or irritating the tissue can lead to infection. 116) Janet, a 28- year- old law yer, bought a brand new pair of shoes for her first court appearance. After w earing them for the first time, she noticed pain on her heel and a fluid- filled lesion. Explain what has happened. Answ er: A blister, a fluid- filled pocket that separates the epidermal and dermal layers, has formed due to her new shoes rubbing her heel. The repeated friction of the shoe rubbing her skin created the blister. 15 117) M elanoma is a form of skin cancer that arises from melanocytes. Melanoma is most common in Caucasians betw een 40 and 70 years of age. Explain why Caucasians would have a greater incidence of melanoma. Answ er: Melanoma has its beginnings in melanocytes, the skin pigment cells. These cells produce the dark protective pigment called melanin to protect against sun damage to DN A . Since the melanocytes in Caucasian people do not make as much melanin per cell as darker- skinned individuals, their melanocytes are more easily sun- damaged, resulting in damaged DN A cells that are more apt to lose genetic control of their own cell division. 118) The 68- year- old patient w as admitted to the hospital medical floor with a diagnosis of chronic bronchitis. His w ife asks the nurse why his skin looks blue. H ow would you explain cyanosis to the patient and his wife? Answ er: Cyanosis is a dusky bluish or grayish discoloration of the skin and mucous membranes that occurs with reduced oxygen levels. Without enough oxygen getting to the tissues the skin in Caucasians appears blue due to the color combination of dark maroon blood seen through the yellow ish tint of skin. A t close inspection of the conjunctiva and palms and soles may also show evidence of cyanosis. 119) Explain w hy soap that has an alkaline base may not be healthy for some patients to use daily. Answ er: The skin's acid mantle retards grow th of bacteria. Soap may destroy the acid mantle of the skin, causing it to lose its protective mechanism. Some soaps contain antibacterial agents, w hich can change the natural flora of the skin. 120) Robert, a surfer, has a mole that has changed its shape and size. His doctor, applying the ABCDE rule, diagnosed a melanoma. What do the letters ABCDE represent? Answ er: A = asymmetry B = border irregularity C = color D = diameter E = elevation 16