Skin MCQ Questions And Answers

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.

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.

The epidermis is the skin's outermost layer, acting as a protective barrier against harmful environmental factors such as bacteria, UV rays, and chemicals. It is composed of tightly packed cells but lacks blood vessels. Instead, it relies on the dermis, the underlying skin layer, for nutrients and oxygen through diffusion. The epidermis is responsible for producing keratin, a protein that strengthens the skin, and melanin, which gives skin its color and provides UV protection. Regular cell turnover in this layer helps to maintain skin health, repair damage, and shed dead cells, ensuring the skin remains resilient and functional.

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.

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.

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.

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.

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.

The sebaceous glands produce an oily secretion called sebum, which helps to lubricate and protect the skin. However, the waxy secretion in the external ear canal is produced by ceruminous glands, which are a type of modified sweat gland. This waxy secretion is commonly known as earwax or cerumen.

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.

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.

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.

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.

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.