Quiz 9: Drugs for the Skin


Skin is the largest organ in the human body. It contains all four types of primary tissues. They are epithelial tissue, muscle tissue, connective tissue, and nervous. It can sense temperature and regulate the temperature of the body. The skin has two layers - epidermis and dermis. The outermost layer of skin is called epidermis. It consists of two types of cells, such as melanocytes and keratinocytes. The melanocytes define the skin tone. Keratinocytes produce keratin, which is a protein. It provides the waterproofing to the skin. The dermis is located just beneath the epidermis. It consists of connective tissue, lymphatic tissue, blood vessels, nerves, hair follicles, sebaceous glands, and sudoriferous glands. The tiny hairs grow from the hair follicles. They cover the body. The sebaceous glands secrete an oily type substance, sebum. It helps in lubricating the hairs. The sudoriferous glands (sweat glands) secrete fluid, which evaporates that helps to keep the body cool. Thus, it maintains the body temperature. The sense receptors of the skin can sense pressure, heat, touch, cold, etc.

1. A hair follicle is defined as a sac-like structure in the epidermis of the skin, from which hair grows. The hair follicles open into the sebaceous glands. Hair follicles go through an extensively regulated complex cycle of growth. The hair follicle is composed of papilla, hair matrix, root sheath, infundibulum, and the arrector pili muscles. Hence, the answer is (a) grows tiny hairs covering the body. 2. Epidermis is the outer most layer of the skin. It is the layer of the skin that is exposed to the external environment. It is composed of layers of keratinocytes with few melanocytes and Langerhans cells dispersed within them. The cells of the epidermis are tightly connected to each other. As a result, they form a physical barrier and do not allow materials through pass through the skin. Hence, the answer is (f) acts as waterproof covering. 3. Subcutaneous tissue is also called hypodermis. It is the inner most of the three layers of the skin. This layer is mainly composed of fat and connective tissue rich in collagen and elastin. The layer acts as an insulator due its abundance of fat. It also provides padding and protects the bone. Hence, the answer is (e) provides padding. 4. A sebaceous gland is a tiny sac-like structure that secrets the sebum. Sebum is an oily secretion that lubricates the skin and hair of animals. They generally open into the hair follicle at the skin where hair is present. Each hair follicle is surrounded by two or more sebaceous glands. Hence, the answer is (b) secretes oil. 5. Sense receptors or sensory receptors are found in both dermis and epidermis of the skin. There are three types of sensory receptors in the skin. They are thermoreceptors, nociceptors, and mechanoreceptors. The thermoreceptors sense temperature, nociceptors sense the feeling of pain, and mechanoreceptors sense pressure. Hence, the answer is (d) feels pressure or pain. 6. Sudoriferous glands are the glands that secrete sweat. Hence, they are also called sweat glands. There are two types of sweat glands. They are the eccrine and apocrine glands. Eccrine glands open directly into the skin surface whereas the apocrine glands open into the hair follicles. Hence, the answer is (c) secretes sweat.

The integumentary system is an organ system. It consists of the skin, hair, nails, and exocrine glands. The skin is the largest organ of the body. The integumentary system protects the body from the environment. The functions of the integumentary systems are, • To protect the body - The skin is a part of the integumentary system. It creates waterproofing protection by covering the whole body, for the body.  • To protect from micro-organisms - The skin covers the whole body with a hard surface. Thus, it is protecting the internal organs from infection. • To regulate body temperature - The skin can sense the temperature in the environment. It regulates body temperature accordingly. • To keep the body cool and eliminate waste from the body - The sudoriferous glands that are also called sweat glands, of the dermis layers of skin, secrets fluid which evaporates. It helps to keep the body cool. It eliminates waste products as sweat from the body.

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