1.
The layer of the epidermis that contains melanocytes is the
Correct Answer
A. Stratum basale
Explanation
The stratum basale is the layer of the epidermis that contains melanocytes. Melanocytes are specialized cells that produce melanin, the pigment responsible for skin, hair, and eye color. These cells are found in the deepest layer of the epidermis, the stratum basale, where they transfer melanin to nearby skin cells to protect them from UV radiation. The other layers mentioned in the options, such as the stratum lucidum, stratum spinosum, stratum corneum, and stratum granulosum, do not contain melanocytes.
2.
Most body odor is the result of bacterial metabolism of the secretions produced by _____ glands.
Correct Answer
A. Apocrine sweat
Explanation
Most body odor is the result of bacterial metabolism of the secretions produced by apocrine sweat glands. Apocrine sweat glands are found in areas such as the armpits and groin, and they produce a thicker and more oily type of sweat compared to the eccrine sweat glands found throughout the rest of the body. This thicker sweat provides a suitable environment for bacteria to thrive, and when these bacteria break down the sweat, it produces the characteristic body odor.
3.
The fibrous protein that is responsible for the strength and water resistance of the skin surface is
Correct Answer
E. Keratin
Explanation
Keratin is the correct answer because it is a fibrous protein that provides strength and water resistance to the skin surface. Keratin is a major component of the outermost layer of the skin, known as the epidermis, and it forms a protective barrier against environmental factors. It also helps to maintain the integrity and structure of the skin, making it strong and resistant to damage.
4.
The layer of the skin that provides protection against bacteria, as well as chemical and mechanical injuries is the
Correct Answer
A. Epidermis
Explanation
The epidermis is the outermost layer of the skin and serves as a protective barrier against bacteria, chemicals, and mechanical injuries. It is composed of multiple layers of cells, including keratinocytes, which produce a tough protein called keratin that helps to strengthen and protect the skin. The epidermis also contains melanocytes, which produce melanin, the pigment responsible for skin color and protection against UV radiation. Overall, the epidermis plays a crucial role in maintaining the integrity and health of the skin.
5.
When the body temperature rises above normal
Correct Answer
D. Blood flow to the skin increases
Explanation
When the body temperature rises above normal, the body initiates a response to cool down. One of the ways it does this is by increasing blood flow to the skin. This allows heat to be transferred from the core of the body to the skin surface, where it can be dissipated into the surrounding environment. By increasing blood flow to the skin, the body can effectively release excess heat and regulate its temperature.
6.
The macrophages found in the epidermis are the
Correct Answer
D. Langerhans cells
Explanation
Langerhans cells are a type of macrophage found in the epidermis. They play a crucial role in the immune response by capturing and presenting antigens to activate T cells. Unlike other macrophages, Langerhans cells have a dendritic shape and are involved in the initiation of immune responses against pathogens that penetrate the skin. This makes them distinct from squamous cells, Merkel cells, basal cells, and melanocytes, which have different functions and locations within the epidermis.
7.
_________ glands discharge an oily secretion into fair follicles.
Correct Answer
E. Sebaceous
Explanation
Sebaceous glands discharge an oily secretion into hair follicles. These glands are responsible for producing sebum, which helps to moisturize and protect the skin and hair. The sebum produced by sebaceous glands helps to keep the skin and hair lubricated, preventing dryness and providing a natural barrier against bacteria and other harmful substances.
8.
The _____ are the most abundant cells in the epidermis
Correct Answer
B. Keratinocytes
Explanation
Keratinocytes are the most abundant cells in the epidermis. These cells are responsible for producing keratin, a tough protein that provides structural support and protection to the skin. Keratinocytes also play a role in the immune response of the skin and are involved in the process of wound healing. Langerhans cells, melanocytes, adipocytes, and Merkel cells are all present in the epidermis, but they are not as abundant as keratinocytes.
9.
Contraction of the arrector pili muscles cause
Correct Answer
A. "goose bumps"
Explanation
When the arrector pili muscles contract, it causes the hair follicles to stand upright, resulting in the appearance of "goose bumps" on the skin. This response is triggered by various factors such as cold temperatures, fear, or emotional arousal. The contraction of these muscles does not directly affect sweat release, hair shedding, or skin color change.
10.
The _______ contains the cells that are undergoing mitosis.
Correct Answer
E. Stratum basale
Explanation
The stratum basale is the correct answer because it is the deepest layer of the epidermis where cell division occurs. This layer contains cells that are actively undergoing mitosis, which is the process of cell division. The other layers mentioned in the options, such as the stratum granulosum, stratum corneum, stratum spinosum, and stratum lucidum, do not contain cells that are actively undergoing mitosis.
11.
Protective functions of the skin include all of the following except protection
Correct Answer
A. Of the joints
Explanation
The skin has various protective functions, including protecting against infections, harmful chemicals, and water loss. However, it does not provide direct protection to the joints. The joints are primarily protected by other structures such as ligaments, tendons, and cartilage. While the skin does cover the joints, its main function is not specifically to protect them.
12.
Hair follicles and fingernails originate in the _____ but are actually derived from ______ tissue.
Correct Answer
C. Dermis; spidermal
Explanation
Hair follicles and fingernails originate in the dermis but are actually derived from epidermal tissue. The dermis is the layer of skin that lies beneath the epidermis, and it contains the hair follicles. The epidermis is the outermost layer of the skin and is responsible for the production of hair and nails. Therefore, the hair follicles and fingernails are derived from the epidermal tissue within the dermis.
13.
Most of the body heat is produced by
Correct Answer
C. Contraction of skeletal muscles
Explanation
The correct answer is contraction of skeletal muscles. Skeletal muscles are responsible for generating body heat through their contractions. When these muscles contract, they produce heat as a byproduct of the energy being used. This heat helps to regulate body temperature and keep it within a normal range. The hypothalamus plays a role in regulating body temperature, but it does not directly produce heat. Similarly, blood vessels and contraction of cardiac muscles do not generate as much heat as skeletal muscles.
14.
Usually a decrease in the amount of oxygen in the blood will result in ____ of the skin
Correct Answer
A. Cyanosis
Explanation
A decrease in the amount of oxygen in the blood can lead to cyanosis, which is a bluish discoloration of the skin. This occurs because when there is inadequate oxygen in the blood, the skin and mucous membranes do not receive enough oxygen, causing them to appear blue. Cyanosis is a sign of poor oxygenation and can indicate a serious medical condition. It is not related to jaundice, paleness, or flushing, which have different causes and symptoms.
15.
The skin is able to synthesize Vitamin D when exposed to sunlight.
Correct Answer
A. True
Explanation
The skin is able to synthesize Vitamin D when exposed to sunlight because sunlight contains ultraviolet B (UVB) rays that interact with a type of cholesterol in the skin called 7-dehydrocholesterol. This interaction converts 7-dehydrocholesterol into previtamin D3, which is then converted into active vitamin D3 in the liver and kidneys. Vitamin D is important for calcium absorption, bone health, and immune function.
16.
Keratin is the skin pigment that protects it against ultraviolet light.
Correct Answer
B. False
Explanation
The statement is false because keratin is not a skin pigment. Keratin is a protein that is found in the outer layer of the skin, hair, and nails. It provides strength and protection to these structures, but it does not protect against ultraviolet light. The pigment responsible for protecting the skin against ultraviolet light is melanin. Melanin is produced by cells called melanocytes and gives color to the skin, hair, and eyes.
17.
Both the epidermis and the dermis are continually shed and regenerated.
Correct Answer
B. False
Explanation
The statement is false because while the epidermis is constantly shedding and regenerating, the dermis is not. The dermis is a deeper layer of the skin that provides structural support and contains blood vessels, nerves, and other important structures. It does not go through the same shedding and regeneration process as the outer layer, the epidermis.
18.
The epidermis contains sensory receptors.
Correct Answer
B. False
Explanation
The epidermis is the outermost layer of the skin and its main function is to protect the underlying tissues. It does not contain sensory receptors. Sensory receptors are located in the dermis, which is the layer beneath the epidermis. Therefore, the statement that the epidermis contains sensory receptors is false.
19.
Skin color is basically determined by the amount of melanin in the skin.
Correct Answer
A. True
Explanation
Melanin is the pigment responsible for the color of our skin, hair, and eyes. It is produced by special cells called melanocytes. The more melanin present in the skin, the darker the skin color. This is why people with darker skin have more melanin compared to those with lighter skin. Therefore, it is correct to say that skin color is determined by the amount of melanin in the skin.
20.
The sebaceous gland produces a waxy secretion in the external ear canal.
Correct Answer
B. False
Explanation
The sebaceous gland does not produce a waxy secretion in the external ear canal. The correct answer is False.
21.
The most numerous and widespread sweat glands in the body are the apocrine sweat glands.
Correct Answer
B. False
Explanation
The given statement is false. The most numerous and widespread sweat glands in the body are actually the eccrine sweat glands. These glands are found all over the body and are responsible for regulating body temperature by producing sweat. Apocrine sweat glands, on the other hand, are found in specific areas such as the armpits and groin, and they produce a different type of sweat that is odorless but can develop an odor when it comes into contact with bacteria on the skin.
22.
The blood vessels in the skin dilate when the body needs to conserve heat to maintain the body temperature.
Correct Answer
B. False
Explanation
When the body needs to conserve heat to maintain body temperature, the blood vessels in the skin actually constrict, not dilate. This constriction helps to reduce blood flow to the skin, which in turn reduces heat loss from the body. By reducing blood flow to the skin, the body can conserve heat and maintain its temperature. Therefore, the correct answer is false.
23.
Second-degree burns are less severe than first-degree burns and are not as painful.
Correct Answer
B. False
Explanation
This statement is incorrect. Second-degree burns are more severe than first-degree burns and are typically more painful. Second-degree burns affect both the outer layer of skin (epidermis) and the underlying layer of skin (dermis), while first-degree burns only affect the outer layer. Second-degree burns can cause blistering, redness, and swelling, while first-degree burns usually only cause redness and mild pain.
24.
The amount of blood flow through the skin can influence skin color.
Correct Answer
A. True
Explanation
The statement is true because the amount of blood flow through the skin can affect its color. When blood flow increases, the skin appears redder or flushed, while decreased blood flow can make the skin appear paler. This is because blood carries oxygen and nutrients to the skin cells, and changes in blood flow can alter the amount of oxygen and nutrients reaching the skin. Additionally, blood vessels near the surface of the skin can dilate or constrict, further influencing skin color.