Exercise 7: The Integumentary System PDF

7 E X E R C I S E The Integumentary System Learning Outcomes Go to Mas...

7 E X E R C I S E The Integumentary System Learning Outcomes Go to Mastering A&P™ > Study Area to improve your performance ▶ List several important functions of the skin, or integumentary system. in A&P Lab. ▶ Identify the following skin structures on a model, image, or microscope slide: epidermis, dermis (papillary and reticular layers), hair follicles and hair, sebaceous glands, and sweat glands. ▶ Name and describe the layers of the epidermis. ▶ List the factors that determine skin color, and describe the function of melanin. ▶ Identify the major regions of nails. ▶ Describe the distribution and function of hairs, sebaceous glands, and sweat glands. ▶ Discuss the difference between eccrine and apocrine sweat glands. > Lab Tools > Practice Anatomy Lab ▶ Compare and contrast the structure and functions of the epidermis and > Histology the dermis. Instructors may assign new Building Vocabulary coaching activities, Pre-Lab Quiz questions, Art Instructors may assign these and other Pre-Lab Pre-Lab Quiz Quiz questions using Mastering A&P™ Labeling activities, Practice Anatomy Lab Practical questions (PAL) for Histology of the Integumentary System, 1. All the following are functions of the skin except: and more using the Mastering A&P™ a. excretion of body wastes Item Library. b. insulation c. protection from mechanical damage d. site of vitamin A synthesis Materials 2. Immune cells found in the epidermis are ▶ Skin model (three-dimensional, if a. dendritic cells c. melanocytes available) b. tactile epithelial cells d. keratinocytes ▶ Compound microscope 3. These cells produce a brown-to-black pigment that colors the skin ▶ Prepared slide of human scalp and protects DNA from ultraviolet radiation damage. The cells are: ▶ Prepared slide of skin of palm or sole a. dendritic cells c. melanocytes ▶ Sheet of 20# bond paper ruled to mark b. keratinocytes d. tactile cells off cm2 areas 4. The portion of a hair that projects from the surface of the skin is ▶ Scissors known as the: ▶ Povidone-iodine swabs, or Lugol’s iodine a. bulb b. matrix c. root d. shaft and cotton swabs 5. Circle the correct underlined term. The epidermis / hypodermis largely ▶ Adhesive tape consists of fat and insulates the integument. ▶ Disposable gloves ▶ Data collection sheet for plotting distribution of sweat glands T he integument is considered an organ system because it consists of multiple ▶ Porelon® fingerprint pad or portable organs, the skin and its accessory organs. It is much more than an external inking foils body covering; architecturally, the skin is a marvel. It is tough yet pliable, ▶ Ink cleaner towelettes a characteristic that enables it to withstand constant insult from outside agents. ▶ Index cards (4 in. 3 6 in.) The skin has many functions, most concerned with protection. It insulates and ▶ Magnifying glasses cushions the underlying body tissues and protects the entire body from abrasion, exposure to harmful chemicals, temperature extremes, and bacterial invasion. The hardened uppermost layer of the skin prevents water loss from the body surface. 107 M07_MARI2259_12_GE_C07.indd 107 12/07/2022 17:51  108 Exercise 7 The skin’s abundant capillary network plays an important role the skin pores in sweat. The skin also has important metabolic in temperature regulation by regulating heat loss from the body duties. For example, it is the site of vitamin D synthesis for the surface. body. Vitamin D plays a role in calcium absorption in the diges- The skin has other functions as well. For example, it acts tive system. Finally, the sense organs for touch, pressure, pain, as an excretory system; urea, salts, and water are lost through and temperature are located here. Basic Structure of the Skin The skin has two distinct regions—the superficial epidermis in a blister. Immediately deep to the dermis is the subcutaneous composed of epithelium and an underlying connective tissue, layer, or hypodermis, which is not considered part of the skin. the dermis (Figure 7.1). These layers are firmly “cemented” It consists primarily of adipose tissue. The main skin areas and together along a wavy border. But friction, such as the rubbing structures are described below. of a poorly fitting shoe, may cause them to separate, resulting Epidermis Structurally, the avascular epidermis is a keratinized stratified Activity 1 squamous epithelium consisting of four distinct cell types and four or five distinct layers. Locating Structures on a Skin Model 7 Cells of the Epidermis As you read, locate the following structures in the diagram Keratinocytes (literally, keratin cells): The most abundant (Figure 7.1) and on a skin model. epidermal cells, their main function is to produce keratin Hair shaft Dermal papillae Epidermis Papillary layer Sweat pore Dermis Appendages of skin Reticular layer Eccrine sweat gland Arrector pili muscle Sebaceous (oil) gland Hair follicle Hair root Subcutaneous layer (hypodermis; not part of skin) Nervous structures Sensory nerve fiber with Dermal vascular plexus free nerve endings Tactile corpuscle Adipose tissue Lamellar corpuscle Hair follicle receptor (root hair plexus) Figure 7.1 Skin structure. Three-dimensional view of the skin and the underlying tissue. The Instructors may assign this figure epidermis and dermis have been pulled apart at the right corner to reveal the dermal papillae. as an Art Labeling Activity using Mastering A&P™ Tactile corpuscles are not common in hairy skin but are included here for illustrative purposes. M07_MARI2259_12_GE_C07.indd 108 12/07/2022 17:51  The Integumentary System 109 Figure 7.2 The main structural features in the epidermis of thin skin. (a) Photomicrograph depicting the four major epidermal layers (4303). (b) Diagram showing the layers and relative distribution of the different cell types. Notice that the keratinocytes are joined by numerous desmosomes. The stratum lucidum, present in thick skin, is not illustrated here. Instructors may assign this figure as an Art Labeling Activity using Mastering A&P™ Keratinocytes Dendritic cell Stratum corneum Most superficial layer; 20–30 layers of dead keratinocytes, essentially flat membranous sacs filled with keratin. Glycolipids in extracellular space. Stratum granulosum One to five layers of flattened cells, 7 organelles deteriorating; cytoplasm full of lamellar granules (release lipids) and keratohyaline granules. Stratum spinosum Several layers of keratinocytes joined by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin. Stratum basale Deepest epidermal layer; one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers. Dermis (a) Dermis Melanin Tactile Sensory granule epithelial nerve cell ending Desmosomes Melanocyte fibrils. Keratin is a fibrous protein that gives the epidermis its durability and protective capabilities. Keratinocytes are (b) tightly connected to each other by desmosomes. Far less numerous are the following types of epidermal cells Dendritic cells: Also called Langerhans cells, these cells (Figure 7.2): arise from the bone marrow and migrate to the epidermis. They ingest foreign substances and play a key role in acti- Melanocytes: Spidery black cells that produce the brown- vating the immune response. to-black pigment called melanin. The skin tans because Tactile epithelial cells: Occasional spiky hemispheres that, melanin production increases when the skin is exposed in combination with sensory nerve endings, form sensitive to ultraviolet radiation (UVR) in sunlight. The melanin touch receptors located at the epidermal-dermal junction. provides a protective pigment umbrella over the nuclei of the cells in the deeper epidermal layers, thus shielding their Layers of the Epidermis genetic material (DNA) from the damaging effects of ultra- The epidermis consists of four layers in thin skin, which covers violet radiation. Freckles and moles (nevi) are areas where most of the body. Thick skin, found on the palms of the hands melanin is more concentrated. and soles of the feet, contains an additional layer, the stratum M07_MARI2259_12_GE_C07.indd 109 12/07/2022 17:51  110 Exercise 7 Table 7.1 Layers of the Epidermis (from superficial to deep) Epidermal layer Description Stratum corneum (horny layer) The outermost layer consisting of 20–30 layers of dead, scalelike keratinocytes. They are constantly being exfoliated and replaced by the division of the deeper cells. Stratum lucidum (clear layer) Present only in thick skin. A very thin transparent band of flattened, dead keratinocytes with indistinct boundaries. Stratum granulosum (granular layer) A thin layer named for the abundant granules its cells contain. These granules are (1) lamellar granules, which contain a waterproofing glycolipid that is secreted into the extracellular space; and (2) keratohyaline granules, which help to form keratin in the more superficial layers. At the upper border of this layer, the cells are beginning to die. Stratum spinosum (spiny layer) Several layers of cells that contain thick, weblike bundles of intermediate filaments made of a pre-keratin protein. The cells in this layer appear spiky because when the tissue is prepared, the cells shrink, but their desmosomes hold tight to adjacent cells. Cells in this layer and the basal layer are the only ones to receive adequate nourishment from diffusion of nutrients from the dermis. Stratum basale (basal layer) A single row of cells immediately above the dermis. Its cells are constantly undergoing mitosis to form new cells, hence its alternate name, stratum germinativum. Some 10–25% of the cells in this layer are melanocytes, which thread their processes through this and adjacent layers of keratinocytes. Occasional tactile epithelial cells are also present in this layer. 7 lucidum. From deep to superficial, the layers of the epidermis Skin Color are the stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum (Figure 7.2). The layers Skin color is a result of the relative amount of melanin in skin, the of the epidermis are summarized in Table 7.1. relative amount of carotene in skin, and the degree of oxygen- ation of the blood. Carotene is a yellow-orange pigment present primarily in the stratum corneum and in the adipose tissue of the Dermis hypodermis. Its presence is most noticeable when large amounts The connective tissue proper making up the dermis consists of carotene-rich foods (carrots, for instance) are eaten. of two principal regions—the papillary and reticular areas Skin color may be an important diagnostic tool. For ­(Figure 7.1). Like the epidermis, the dermis varies in thickness. example, flushed skin may indicate hypertension or fever, whereas pale skin is typically seen in anemic individuals. Papillary dermis: The more superficial dermal region com- When the blood is inadequately oxygenated, as during asphyx- posed of areolar connective tissue. It is very uneven and has iation and serious lung disease, both the blood and the skin take fingerlike projections from its superior surface, the dermal on a bluish cast, a condition called cyanosis. Jaundice, in which papillae, which attach it to the epidermis above. These the tissues become yellowed, is almost always diagnostic for projections lie on top of the larger dermal ridges. In the liver disease, whereas a bronzing of the skin hints that a person’s palms of the hands and soles of the feet, they produce the adrenal cortex is hypoactive (Addison’s disease). + fingerprints, unique patterns of epidermal ridges that remain unchanged throughout life. Abundant capillary networks in the papillary layer furnish nutrients for the ­epidermal layers and allow heat to radiate to the skin surface. The pain Accessory Organs of the Skin receptors (free nerve endings) and touch receptors (tactile corpuscles in hairless skin) are also found here. The accessory organs of the skin—cutaneous glands, hair, and Reticular dermis: The deepest skin layer. It is composed of nails—are all derivatives of the epidermis, but they reside pri- dense irregular connective tissue and contains many arter- marily in the dermis. They originate from the stratum basale ies and veins, sweat and sebaceous glands, and pressure and extend into the dermis. receptors (lamellar corpuscles). Nails The abundant dermal blood supply allows the skin to play a Nails are hornlike derivatives of the epidermis (Figure 7.3). role in the regulation of body temperature. When body tempera- Their named parts are: ture is high, the arterioles serving the skin dilate, and the capillary network of the dermis becomes engorged with the heated blood. Nail plate: The visible attached portion. Thus body heat is allowed to radiate from the skin surface. Free edge: The portion of the nail that grows out away from The dermis is also richly provided with lymphatic vessels and the body. nerve fibers. Many of the nerve endings bear highly specialized Hyponychium: The region beneath the free edge of the nail. receptor organs that, when stimulated by environmental changes, transmit messages to the central nervous system for interpreta- Nail root: The part that is embedded in the skin and adheres tion. Some of these receptors—free nerve endings (pain recep- to an epithelial nail bed. tors), a lamellar corpuscle, a tactile corpuscle, and a hair follicle Nail folds: Skin folds that overlap the borders of the nail. receptor (also called a root hair plexus)—are shown in Figure 7.1. Eponychium: Projection of the thick proximal nail fold (These receptors are discussed in depth in Exercise 22.) commonly called the cuticle. M07_MARI2259_12_GE_C07.indd 110 12/07/2022 17:51  The Integumentary System 111 Lateral Lunule Hair follicle wall nail fold Peripheral connective tissue (fibrous) sheath Glassy membrane Epithelial root sheath External root sheath Internal root sheath Hair root (a) Cuticle Free edge Nail Eponychium Nail root Cortex of nail plate (cuticle) Medulla Proximal Nail (a) nail fold matrix Hair shaft Arrector pili muscle 7 Sebaceous gland Hair root Hair bulb Hyponychium Nail bed Phalanx (bone of fingertip) Hair follicle wall (b) Peripheral connective tissue Figure 7.3 Structure of a nail. (a) Surface view of the distal (fibrous) sheath part of a finger. The nail matrix that forms the nail lies beneath Glassy membrane the lunule; the epidermis of the nail bed underlies the nail. Epithelial root (b) Sagittal section of the fingertip. sheath External root sheath Internal root Nail bed: Extension of the stratum basale beneath the nail. sheath Nail matrix: The thickened proximal part of the nail bed Hair root containing germinal cells responsible for nail growth. As Cuticle the matrix produces the nail cells, they become heavily Cortex keratinized and die. Thus nails, like hairs, are mostly non- Medulla living material. Hair matrix Lunule: The proximal region of the thickened nail matrix, which appears as a white crescent moon. Everywhere else, Hair papilla nails are transparent and nearly colorless, but they appear Melanocyte pink because of the blood supply in the underlying dermis. Subcutaneous When someone is cyanotic because of a lack of oxygen in adipose tissue the blood, the nail beds take on a blue cast. (b) Activity 2 Figure 7.4 Structure of a hair and hair follicle. (a) Diagram of a cross section of a hair within its follicle. Identifying Nail Structures (b) Diagram of a longitudinal view of the hair bulb of the hair Identify the parts of a nail (as shown in Figure 7.3) on yourself follicle, which encloses the hair matrix, the actively dividing or your lab partner. epithelial cells that produce the hair. Hair consists of two primary regions: the hair shaft, the Hairs and Associated Structures region projecting from the surface of the skin, and the hair root, Hairs, enclosed in hair follicles, are found all over the entire which is beneath the surface of the skin and is embedded within body surface, except for thick-skinned areas (the palms of the the hair follicle. The hair bulb is a collection of well-nourished hands and the soles of the feet), parts of the external genitalia, epithelial cells at the base of the hair follicle (Figure 7.4). the nipples, and the lips. M07_MARI2259_12_GE_C07.indd 111 12/07/2022 17:51  112 Exercise 7 The hair shaft and the hair root have three layers of keratin- tissue sheath and provides nutrition to the growing hair. It ized cells: the medulla in the center, surrounded by the cortex, is called the hair papilla. A layer of actively dividing epi- and the protective cuticle. Abrasion of the cuticle at the tip of thelial cells called the hair matrix is located on top of the the hair shaft results in split ends. Hair color depends on the hair papilla. amount and type of melanin pigment found in the hair cortex. Arrector pili muscle: Small bands of smooth muscle Hair follicle: A structure formed from both epidermal and cells connect each hair follicle to the papillary layer of dermal cells (Figure 7.4). Its epithelial root sheath, with the dermis (Figures 7.1 and 7.4). When these muscles two parts (internal and external), is enclosed by a thick- contract (during cold or fright), the slanted hair follicle ened basement membrane, the glassy membrane, and by is pulled upright, dimpling the skin surface with goose a peripheral connective tissue (or fibrous) sheath, which is bumps. This phenomenon is especially dramatic in a essentially dermal tissue. A small nipple of dermal tissue scared cat, whose fur actually stands on end to increase protrudes into the hair bulb from the peripheral ­connective its apparent size. Activity 3 Comparing Hairy and Relatively Hair-Free Skin Microscopically Whereas thick skin has no hair follicles or sebaceous (oil) How is this stratified squamous epithelium different from that glands, thin skin usually has both. The scalp, of course, has the observed in the esophagus (Exercise 6)? 7 highest density of hair follicles. 1. Obtain a prepared slide of the human scalp, and study it _____________________________________________________ carefully under the microscope. Compare your tissue slide to Figure 7.5a, and identify as many as possible of the dia- _____________________________________________________ grammed structures in Figure 7.1. Hair follicle Sebaceous gland Epidermis Dermis Epidermis Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale Dermis (a) (b) Figure 7.5 Photomicrographs of skin. (a) Thin skin with hairs (403). (b) Thick skin (753). M07_MARI2259_12_GE_C07.indd 112 12/07/2022 17:52  The Integumentary System 113 How do these differences relate to the functions of these two 2. Obtain a prepared slide of hairless skin of the palm or sole similar epithelia? (Figure 7.5b). Compare the slide to the photomicrograph in Figure 7.5a. In what ways does the thick skin of the palm or _____________________________________________________ sole differ from the thin skin of the scalp? _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ Cutaneous Glands Sweat (Sudoriferous) Glands The cutaneous glands fall primarily into two categories: Sweat, or sudoriferous, glands are exocrine glands that are the sebaceous glands and the sweat glands (Figure 7.1 and widely distributed all over the skin. Outlets for the glands are Figure 7.6). epithelial openings called pores. Sweat glands are categorized by the composition of their secretions. Sebaceous (Oil) Glands Eccrine sweat glands: Also called merocrine sweat glands, The sebaceous glands are found nearly all over the skin, except these glands are distributed all over the body. They pro- for the palms of the hands and the soles of the feet. Their ducts duce a clear secretion consisting primarily of water, salts usually empty into a hair follicle, but some open directly on the (mostly NaCl), and urea. Eccrine sweat glands, under the 7 skin surface. control of the nervous system, are an important part of the Sebum is the product of sebaceous glands. It is a mixture of body’s heat-regulating apparatus. They secrete sweat when oily substances and fragmented cells that acts as a lubricant to the external temperature or body temperature is high. keep the skin soft and moist (a natural skin cream) and keeps When sweat evaporates, it carries excess body heat with it. the hair from becoming brittle. The sebaceous glands become particularly active during puberty, when more male hormones Apocrine sweat glands: Found predominantly in the axil- (androgens) begin to be produced for both genders; thus the lary and genital areas, these glands secrete the basic compo- skin tends to become oilier during this period of life. nents of eccrine sweat plus proteins and fat-rich substances. Blackheads are accumulations of dried sebum, bacte- Apocrine sweat is an excellent nutrient medium for the ria, and melanin from epithelial cells in the oil duct. microorganisms typically found on the skin. This sweat is Acne is an active infection of the sebaceous glands. + initially odorless, but when bacteria break down its organic components, it begins to smell unpleasant. Sweat pore Sebaceous gland Dermal connective Sebaceous Hair root in tissue gland duct hair follicle Eccrine sweat gland Duct Dermal connective tissue Secretory cells (a) Photomicrograph of a sectioned (b) Photomicrograph of a sectioned sebaceous gland (1003) eccrine sweat gland (1453) Figure 7.6 Cutaneous glands. M07_MARI2259_12_GE_C07.indd 113 12/07/2022 17:52  114 Exercise 7 Activity 4 8. Once all the data have been collected, review the class results. 9. Prepare a lab report for the experiment. (See Getting Differentiating Sebaceous and Started, on Mastering A&P). Sweat Glands Microscopically Using the slide thin skin with hairs and the photomicrographs of cutaneous glands (Figure 7.6) as a guide, identify sebaceous Dermography: Fingerprinting and eccrine sweat glands. What characteristics relating to loca- Each of us has a unique genetically determined set of finger- tion or gland structure allow you to differentiate these glands? prints. Because fingerprinting is useful for identifying and appre- hending criminals, most people associate this craft solely with _____________________________________________________ criminal investigations. However, fingerprints are also invalu- able for quick identification of amnesia victims, missing persons, _____________________________________________________ and unknown deceased, such as people killed in major disasters. The friction ridges responsible for fingerprints appear in _____________________________________________________ several patterns, which are clearest when the fingertips are inked and then pressed against white paper. Impressions are also made when perspiration or any foreign material such as blood, dirt, or grease adheres to the ridges and the fingers are then pressed 7 Activity 5 against a smooth, nonabsorbent surface. The three most com- mon patterns are arches, loops, and whorls (Figure 7.7). Plotting the Distribution of Sweat Glands 1. Form a hypothesis about the relative distribution of sweat glands on the palm and forearm. Justify your hypothesis. 2. The bond paper for this simple experiment has been pre­ ruled in cm2—put on disposable gloves, and cut along the lines to obtain the required squares. You will need two squares of bond paper (each 1 cm 3 1 cm), adhesive tape, and a ­povidone- iodine swab or Lugol’s iodine and a cotton-tipped swab. 3. Paint an area of the medial aspect of your left palm (avoid the deep crease lines) and a region of your left forearm with the iodine solution, and allow it to dry thoroughly. The painted (a) Plain arch (b) Tented arch area in each case should be slightly larger than the paper squares to be used. 4. Have your lab partner securely tape a square of bond paper over each iodine-painted area, and leave the paper squares in place for 20 minutes. (If it is very warm in the laboratory while this test is being conducted, you can obtain good results within 10 to 15 minutes.) 5. After 20 minutes, remove the paper squares, and count the number of blue-black dots on each square. The presence of a blue-black dot on the paper indicates an active sweat gland. The iodine in the pore is dissolved in the sweat and reacts chemically with the starch in the bond paper to produce the blue-black (c) Loop (d) Loop color. You have produced “sweat maps” for the two skin areas. 6. Which skin area tested has the greater density of sweat glands? _____________________________________________________ _____________________________________________________ _____________________________________________________ 7. Tape your results (bond paper squares) to a data collection sheet labeled “palm” and “forearm” at the front of the lab. Be (e) Plain whorl (f) Double loop whorl sure to put your paper squares in the correct columns on the data sheet. Figure 7.7 Main types of fingerprint patterns. (a, b) Arches. (c, d) Loops. (e, f) Whorls. M07_MARI2259_12_GE_C07.indd 114 12/07/2022 17:52  The Integumentary System 115 Activity 6 Taking and Identifying Inked Fingerprints For this activity, you will be working as a group with your lab Bulb of finger partners. Though the equipment for professional fingerprint- ing is fairly basic, consisting of a glass or metal inking plate, printer’s ink (a heavy black paste), ink roller, and standard 8 in. 3 8 in. cards, you will be using supplies that are even Start roll here Start roll here Roll Roll easier to handle. Each student will prepare two index cards, Ink Ink each bearing his or her thumbprint and index fingerprint of the right hand. 1. Obtain the following supplies and bring them to your bench: two 4 in. 3 6 in. index cards per student, Porelon® fingerprint pad or portable inking foils, ink cleaner towelettes, and a magnifying glass. (a) (b) 2. The subject should wash and dry the hands. Open the ink Figure 7.8 Fingerprinting. Method of inking and printing pad or peel back the covering over the ink foil, and position it (a) the thumb and (b) the index finger of the right hand. close to the edge of the laboratory bench. The subject should 7 position himself or herself at arm’s length from the bench edge and inking object. 7. When all group members at a bench have completed the above steps, they are to write their names on the backs of their 3. A second student, called the operator, stands to the left of index cards. The students combine their cards, shuffle them, the subject and with two hands holds and directs movement of and transfer them to the opposite bench. Finally, students clas- the subject’s fingertip. During this process, the subject should sify the patterns and identify which prints were made by the look away, try to relax, and refrain from trying to help the same individuals. operator. 4. The thumbprint is to be placed on the left side of the index How difficult was it to classify the prints into one of the three card, the index fingerprint on the right. The operator should categories given? position the subject’s right thumb or index finger on the side of the bulb of the finger in such a way that the area to be inked ______________________________________________________ spans the distance from the fingertip to just beyond the first joint, and then roll the finger lightly across the inked surface Why do you think this is so? until its bulb faces in the opposite direction. To prevent smear- ing, the thumb is rolled away from the body midline (from left ______________________________________________________ to right as the subject sees it; see Figure 7.8), and the index finger is rolled toward the body midline (from right to left). The same ink foil can be reused for all the students at the bench; the Was it easy or difficult to identify the prints made by the same ink pad is good for thousands of prints. Repeat the procedure individual? (still using the subject’s right hand) on the second index card. ______________________________________________________ 5. If the prints are too light, too dark, or smeary, repeat the procedure. Why do you think this was so? 6. While other students in the group are making clear prints of their thumb and index finger, those who have completed that ______________________________________________________ activity should clean their inked fingers with a towelette and attempt to classify their own prints as arches, loops, or whorls. Use the magnifying glass as necessary to see ridge details. M07_MARI2259_12_GE_C07.indd 115 12/07/2022 17:52  This page is intentionally left blank M07_MARI2259_12_GE_C07.indd 116 12/07/2022 17:52  Instructors may assign a portion 7 of the Review Sheet questions using Mastering A&P™ REVIEW SHEET E X E R C I S E The Integumentary System Name _______________________________________________________ Lab Time/Date_____________________________________ Basic Structure of the Skin 1. Complete the following statements by writing the appropriate word or phrase on the blank line: 1. Epidermis The superficial region of the skin is the_____________________, composed of _________________________ _________________________ _________________________ (3 words) tissue. 2. Hypodermis The deeper region tissue is the __________________________, composed of connective tissue. 3. The most numerous cell of the epidermis is the ________________________________. Keratinocytes 4. The two primary layers of the dermis are the ________________________________ Papillary dermis dermis, composed of areolar connective Reticular dermis tissue, and the _______________________________ dermis, composed of dense irregular connective tissue. 2. Four protective functions of the skin are: It insulates and cushions the body' s tissues. a. __________________________________________ c. __________________________________________ defends the entire body from abrasion, chemical b. __________________________________________ d. __________________________________________ exposure, temperature fluctuations, and bacterial invasion. 3. Using the key choices, choose all responses that apply to the following descriptions. Some terms are used more than once. Key: a. stratum basale d. stratum lucidum g. reticular dermis b. stratum corneum e. stratum spinosum c. stratum granulosum f. papillary dermis _____________ 1. layer of translucent cells in thick skin containing dead keratinocytes _____________ 2. two layers containing dead cells _____________ 3. dermal layer responsible for fingerprints _____________ 4. epidermal layer exhibiting the most rapid cell division _____________ 5. layer including scalelike dead cells, full of keratin, that constantly slough off _____________ 6. layer named for the numerous granules present _____________ 7. location of melanocytes and tactile epithelial cells _____________ 8. area where weblike pre-keratin filaments first appear _____________ 9. deep layer of the dermis _____________ 10. layer that secretes a glycolipid that prevents water loss from the skin 117 M07_MARI2259_12_GE_C07.indd 117 12/07/2022 17:52  118 Review Sheet 7 4. Label the integumentary structures and areas indicated in the diagram. 5. Label the layers of the epidermis in thick skin. Then, complete the statements that follow. a. Glands that respond to rising androgen levels are the _______________________ glands. b. ___________________ ___________________ are epidermal cells that play a role in the immune response. c. Tactile corpuscles are located in the ____________________________________ ____________________________________. d. ___________________________ corpuscles are located deep in the dermis. 6. Which skin lubricant is secreted by sebaceous glands? ____________________________________________________________________________________________________________ M07_MARI2259_12_GE_C07.indd 118 12/07/2022 17:52  Review Sheet 7 119 7. List the three major types of glands in the epidermis. _______________________________________________________________ ____________________________________________________________________________________________________________ ____________________________________________________________________________________________________________ Accessory Organs of the Skin 8. Match the key choices with the appropriate descriptions. Some terms are used more than once. Key: a. arrector pili d. hair follicle g. sweat gland—apocrine b. cutaneous receptors e. nail h. sweat gland—eccrine c. hair f. sebaceous gland _____________ 1. tiny muscles, attached to hair follicles, that pull the hair upright during fright or cold _____________ 2. sweat gland with a role in temperature control _____________ 3. sheath formed of both epithelial and connective tissues _____________ 4. less numerous type of sweat-producing gland; found mainly in the pubic and axillary regions _____________ 5. primarily dead/keratinized cells (two responses from key) _____________ 6. specialized nerve endings that respond to temperature, touch, etc. _____________ 7. secretes a lubricant for hair and skin 9. Describe two integumentary system mechanisms that help regulate body temperature. __________________________________ ____________________________________________________________________________________________________________ ____________________________________________________________________________________________________________ 10. Several structures of the hair are listed below. Identify each by matching its letter with the appropriate area on the­ photomicrograph. a. cortex b. cuticle c. hair matrix d. hair papilla e. medulla M07_MARI2259_12_GE_C07.indd 119 12/07/2022 17:52  120 Review Sheet 7 Plotting the Distribution of Sweat Glands 11. With what substance in the bond paper does the iodine painted on the skin react? ______________________________________ 12. Which skin type has more sweat glands, thin or thick skin? Explain.___________________________________________________ 13. What type of sweat glands are widely distributed in the body? _______________________________________________________ Dermography: Fingerprinting 14. Why can fingerprints be used to identify individuals? _______________________________________________________________ ____________________________________________________________________________________________________________ 15. Name the three common fingerprint patterns. __________________________________ , __________________________________ and __________________________________ 16. Henna tattoos are temporary tattoos that last about 2 weeks. Hypothesize why henna tattoos do not last as long as permanent tattoos. ___________________________________________________________________________________________ ____________________________________________________________________________________________________________ ____________________________________________________________________________________________________________ 17. + Albinism is a rare type of genetic disorder. Which layer of the skin is affected in albinism? _____________________________ ____________________________________________________________________________________________________________ ____________________________________________________________________________________________________________ 18. + Tyrosinase is an enzyme found in melanocytes, and its reduced activity is linked to albinism. Explain why. _______________ ___________________________________________________________________________________________________________ ____________________________________________________________________________________________________________ M07_MARI2259_12_GE_C07.indd 120 12/07/2022 17:52