B. Incorrect! The ectoderm does not produce the dermis. C. Incorrect! The dermis is derived from the mesoderm.

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1 Human Anatomy - Problem Drill 04: The Integumentary System Question No. 1 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as 1. From the inner cell mass of a blastocyst, the primary germ cell layers develop. Which of the following statements about the development of the integument is correct? Question #01 (A) The ectoderm produces the epidermis. (B) The ectoderm produces the epidermis and the dermis. (C) The dermis and the epidermis are produced by the endoderm. (D) The integumentary derivatives are produced by all three germ cell layers. (E) None of the answers is correct. A. Correct! The ectoderm does give rise to the epidermis and the integumentary derivatives. The ectoderm does not produce the dermis. The dermis is derived from the mesoderm. Only the ectoderm produces the 4 types of derivatives in the integument. One of the answers is correct. The integument develops from two of the three primary germ cell layers, the ectoderm and the mesoderm. The ectoderm produces the epidermis and the integumentary derivatives: hair, nails, sweat glands and sebaceous glands. The mesoderm produces the dermis. (A)The ectoderm produces the epidermis.

2 Question No. 2 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as 2. Which layer of the epidermis is labeled A in the image below? Cross- section of Epidermis A Question #02 (A) Stratum corneum. (B) Stratum basale. (C) Stratum reticulum. (D) Stratum granulosum. (E) Stratum lucidum. The stratum corneum is the upper most layer of the epidermis. B. Correct! The arrow labeled with the letter A is pointing to the stratum basale. The epidermis does not have a reticular layer. The stratum granulosum is the 3 rd layer from the surface of the epidermis, between the stratum lucidum and the stratum spinosum. The stratum lucidum is the 2 nd layer from the surface of the epidermis, between the stratum corneum and the stratum granulosum. The epidermis is made of differentiated squamous epithelium and is the first part of the skin barrier. There are a number of different cell types spread throughout the epidermis, the most predominant type being keratinocytes. The epidermis is divided into the following layers: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum and the stratum basale (basal layer). (B)Stratum basale.

3 Question No. 3 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as 3. The epidermis is made up of 5 layers; the fibrous protein keratin is present throughout the skin. The stratum granulosum is the key to the development of the upper layers of the epidermis. Which of the following statements about the stratum granulosum is correct? Question #03 (A) The stratum granulosum is present only in the thick skin of the palms of the hands and the soles of the feet. (B) The stratum granulosum is the 4 th layer from the surface of the epidermis. (C) Keratin is produced by keratinocytes that eventually disintegrate and die within this layer. (D) The stratum granulosum is attached to the basal lamina. (E) All the cells within this layer are viable and maintain a normal shape and size. The stratum lucidum is the layer of the epidermis that is present in the thick skin of the hands and feet. The stratum granulosum is the 3 rd layer from the surface of the epidermis. C. Correct! Keratin is produced by keratinocytes that eventually disintegrate and die within this layer. The stratum basale is attached to the basal lamina, in the deepest region of the epidermis. The keratinocytes in the stratum granulosum do eventually disintegrate, flatten and die. The stratum granulosum is the third layer in from the apical surface of the epidermis. This layer is the site of keratin formation; keratohyalin gives this layer its granular appearance. In this layer, the cells undergo degradation of their organelles and eventually die. (C) Keratin is produced by keratinocytes that eventually disintegrate and die within this layer.

4 Question No. 4 of The epidermis contains different cell types that perform a variety of functions. Which cell type produces the pigment that colors the skin? Question #04 (A) Melanocytes. (B) Langerhan cells. (C) Merkel cells. (D) Melanocytes and keratinocytes. (E) None of the cells in the epidermis produce pigment; cells in the subcutaneous layer produce the pigment and deliver it to the epidermal layers. A. Correct! Melanocytes produce melanin, which gives the skin its color. Langerhan cells initiate immune responses from the skin. Merkel cells are involved in the sensation of touch and pressure. While melanocytes do produce melanin, keratinocytes do not. The melanocytes in the epidermis produce melanin, which colors the skin. The different cell types of the epidermis contribute to the function of this portion of the skin, such as absorption of sunlight and UV rays, immune function to foreign organisms on the skin, and transmitting sensations of touch, pressure and heat Keratinocytes: produce keratin, which thickens the outer layers of the skin, making it more resistant to injury. Melanocytes: produce the brown pigment, melanin, which serves to protect the skin from the sun. Langerhans cells: initiate an immune response when the epidermis is injured. Merkel cells: participate in the sensation of touch and pressure. (A)Melanocytes.

5 Question No. 5 of Each human has unique fingerprints that do not change throughout life. Which of the following statements about fingerprints is correct? Question #05 (A) Fingerprints are made by dermal ridges; the epidermis plays no role in the formation of fingerprints. (B) Both the epidermis and the dermis contribute to the formation of fingerprints. (C) Epidermal ridges that extend from the stratum basal to the stratum corneum are part of the structure of a fingerprint. (D) Dermal papillae that extend from the dermis into the subcutaneous tissue make up the human fingerprint. (E) Fingerprints change and develop as we age. Both the epidermis and the dermis contribute to the friction ridges that make up fingerprints. B. Correct! Both the epidermis and the dermis contribute to the friction ridges that make up fingerprints. Epidermal ridges are part of the friction ridges; however, they extend into the dermis. Dermal papillae extend from the dermis into the epidermis and contribute to the formation of friction ridges. Fingerprints remain unchanged as we age. Fingerprints are unique friction ridges in the skin that are made of interactions between: (1) epidermal ridges that extend from the stratum basale into the dermis and (2) dermal papillae that extend towards the epidermis. The friction ridges assist in gripping objects with the hand. Fingerprints are unique and remain unchanged throughout life. (B)Both the epidermis and the dermis contribute to the formation of fingerprints.

6 Question No. 6 of Which statement is correct about the layer of the dermis labeled in the image below? A Question #06 Cross section of the Dermis (A) The letter A in the image identifies the papillary dermis. (B) This layer of the dermis contains blood vessels, sweat glands and sebaceous oil glands. (C) The letter A identifies the layer of the dermis that contains the dermal papillae. (D) Capillary loops, which supply the epidermis with oxygen and nutrients, are present in the layer identified with the letter A in the image. (E) The letter A identifies one of the 4 layers in the dermis. The letter A in the image labels the reticular layer of the dermis. B. Correct! The letter A labels the reticular layer of the dermis that does contain blood vessels, sweat glands and sebaceous oil glands. The dermal papillae are in the papillary dermis. The capillary loops that supply the epidermis with oxygen and nutrients are in the papillary dermis. There are only 2 layers in the dermis: papillary layer and the reticular layer. This dermis is the deep layer of the skin between the epidermis and the tissues under the skin (subcutaneous). The dermal layer is thicker than the epidermal layer and contains the blood vessels and innervation for both layers. The dermis is made up of two main components: the papillary layer and the reticular layer. The upper layer of the dermis is the papillary dermis. This layer projects derma papillae into the epidermis, which contributes to the ridges that produce a fingerprint. The reticular layer of the dermis is made of dense, irregular connective and adipose tissue. This layer of the dermis contains sweat glands, sebaceous (oil) glands and blood vessels. Capillary Loop Epidermal Ridges Cross section of the Dermis Dermal Papillae Papillary Dermis Reticular Dermis (B)This layer of the dermis contains blood vessels, sweat glands and sebaceous oil glands.

7 Question No. 7 of The integument has a number of derivatives or accessory structures. These derivatives form from infoldings of the epidermis during embryological development. Which of the following statements about the derivatives of the integument is correct? Question #07 (A) The integument has a total of 6 derivatives or accessory structures. (B) The arrector pili muscles are present in the first two layers of the epidermis. (C) The arrector pili muscle is attached to the hair and, when it raises the hair, the sebaceous gland is squeezed and empties its sebum. (D) Hair is a living structure from the hair papilla to the end of the hair shaft. (E) There are 3 different types of sweat glands. There are a total of 4 derivatives of the integument: hair, sweat glands, sebaceous glands, and nails. The arrector pili muscles are located in the dermis. C. Correct! The arrector pili muscle is attached to the hair and, when it raises the hair, the sebaceous gland is squeezed and empties its sebum. The hair is a nonliving structure made up of keratin produced from a hair follicle. There are two different types of sweat glands: apocrine and merocrine. The skin has a number of derivatives or accessory structures: hair follicles, sebaceous glands, sweat glands, and nails. These derivatives develop from infoldings of the epidermis during embryological development. The development of hair follicles can take up to 100 days or more during embryogenesis. The human body is covered with hair, from the hair on the scalp to the upper and lower limbs. Hair is a nonliving structure made up of keratin produced from a hair follicle. Hair functions by protecting the scalp from the sun, insulating the body, filtering the air in the nasal cavities, and sensing foreign particles or insects on the skin. (C)The arrector pili muscle is attached to the hair and, when it raises the hair, the sebaceous gland is squeezed and empties its sebum.

8 Question No. 8 of A 51-year-old male is diagnosed with a disorder of the skin in which there is almost a complete loss of sebum production. Which of the following statements about the consequences of this disorder is correct? Question #08 (A) The hair in this patient would be well-protected by the decrease in sebum production. (B) The patient would have an increased potential for developing acne, due to the decrease in sebum produced. (C) There would be a decrease in the potential bacterial growth on the patient s skin, due to the decrease in sebum. (D) Sebum undergoes holocrine secretion, as they are remnants of dead fat cells released simultaneously. (E) There would be no change in the health or function of the patient s skin. The hair would be more susceptible to damage because sebum protects the hair shaft. The likelihood of this patient developing acne would decrease with a decrease in sebum produced. There would be an increase in the potential for bacterial growth because sebum helps protect against this. D. Correct! Sebum undergoes holocrine secretion, as they are remnants of dead fat cells released simultaneously. Sebum protects the hair shaft, lubricates the skin, and limits the growth of bacteria. Therefore, a decrease in production would lead to dry skin with an increase in infection rates. Sebum is made up of lipids, wax, and components of dead, fat-producing cells. The release of sebum is known as holocrine secretion because sebum is released in conjunction with the remnants of dead fat cells. Sebum lubricates and protects the hair shaft, lubricates the skin, and limits the growth of bacteria. (D)Sebum undergoes holocrine secretion, as they are remnants of dead fat cells released simultaneously.

9 Question No. 9 of Which statement is correct about the part of the nail labeled with the letter A in the image below? A Question #09 (A) It appears white due to obscured blood vessels. (B) This is the nail free edge. (C) The letter A points to the eponychium. (D) The letter A points to the proximal nail fold, which functions to protect the underlying nail. (E) The lunula which is labeled in the image can extend beyond the end of the finger. A. Correct! The letter A points to the lunula, which appears white due to obscured blood vessels. The nail free edge is the white end that can extend beyond the end of the finger. The eponychium is a narrow band around the proximal edge of the nail; the letter A in the image points to the lunula. The proximal nail fold is an area of the skin adjacent to the proximal portion of the visible nail; the letter A points to the lunula. The lunula is crescent-shaped, and it does not extend beyond the end of the finger where the free edge is. Direction of Growth Nail Free Edge Lunula Proximal Nail Fold Eponychium The nail consists of the following: (1) nail root: the portion of the nail under the skin, (2) nail body: the visible pink portion of the nail, (3) Lunula: the white crescent at the base of the nail, which is made up of nail matrix and appears white because of obscured blood vessels, (4) Hyponychium: secures the nail to the finger, and the (5) Eponychium (cuticle): is a narrow band around the proximal edge of the nail, and the (6) Nail free edge: the white end that may extend beyond the finger. (A)It appears white due to obscured blood vessels.

10 Question No. 10 of A 71-year-old woman goes to her doctorʹs office because of a wound on her arm that is not healing. The doctor describes to the patient the skin healing process and the effects of aging on the skin. Based on this information, which of the following statements is true? Question #10 (A) There are a total of 4 steps in the repair of injury to the skin. (B) In step 1 of skin repair, the scab is replaced by epidermal cells. (C) During the aging process, the skin thickens and this leads to the formation of wrinkles. (D) During the 5 th step of skin repair, the scab falls off and the new skin is visible. (E) The formation of scar tissue at an injury site in the skin only occurs during severe damage to the skin. A. Correct! There are a total of 4 steps in the repair of injury to the skin. The scab is replaced with epidermal cells in step 3 of skin repair from an injury. During the aging process, the skin gets thinner and this leads to sagging and wrinkles. There are a total of 4 steps in the process of skin repair after injury. The formation of scar tissue after injury to the skin is a normal part of the process. If the skin receives only a very minor injury, scar tissue may not form. The skin is frequently damaged from scratches, cuts and burns. The skin has a strong ability to regenerate and repair itself from an injury. When the damage is large and spread over a wide area, there is an increased risk of infection and fluid loss. The skin repair processes can be divided into 4 steps: (1) Step 1 The damage and bleeding in the area lead to an inflammatory response locally, (2) Step 2 A few hours after the injury, bleeding is usually controlled (unless severe) and a scab has formed. During this step, phagocytes are removing debris from the area of the injury and the scab formation isolates the area, (3) Step 3 Approximately 1 week after the injury to the skin, the scab has been replaced by epidermal cells migrating into the area and the development of a fibroblast meshwork, (4) Step 4 Several weeks after the injury, the scab has dropped off and the repair of the epidermis is complete. The development of a scar is part of the repair process except for very minor injuries. The scar tissue is not the same as the original tissue, and there is a loss of elasticity and function in the scar tissue. (A)There are a total of 4 steps in the repair of injury to the skin.