Chapter 11, Problem 1PL

Which of the following is not a function of the integumentary system?

1. protection
2. excrete small amounts of waste
3. movement
4. aid in regulating body temperature

Summary Introduction

Introduction :

The integumentary system is an organ system consisting of the skin, cutaneous glands, hair, and nails. These structures provide a protective covering for deeper tissues, retard water loss, house sensory receptors, aid in regulating body temperature and excrete small quantities of waste.

Answer to Problem 1PL

Correct answer :

The correct answer is option (c) Movement.

Explanation of Solution

Explanation/justification for the correct answer :

Option (c) Movement.The skeletal system provides the body with physical support and helps in Movement. Skeletal muscles are attached to bones and have the ability to move them, thus facilitating movement. So, the correct answer is option (c).

Explanation for incorrect answer :

Option (a) Protection. Skin has a protective acidic film called the acid mantle (pH 4−6). It helps to keep the number of bacteria and fungi colonizing the surface under control. Protection against the pathogens that intrude the surface is provided by immune cells called dendritic cells in the epidermis. The epidermal cells of the skin are packed with the tough protein keratin and linked by strong desmosomes that give the epithelium its durability. So, this is an incorrect option.

Option (b) Excrete a small amount of waste. Sweat glands secrete sweat which contains mostly water but also contains wastes such as; sodium chloride, ammonia, urea, and uric acid. Sebaceous glands produce an oily secretion called sebum. Sebum consists of broken-down cells that are replaced by mitosis at the base of the gland. Ceruminous glands are found only in the auditory canal, where their secretion combines with sebum and dead epidermal cells to form earwax. So, this is an incorrect answer.

Option (d) Aid in regulating body temperature. Skin helps in thermoregulation. During cold times, thermoreceptors present in the dermis transmit signals to the brain, and the brain sends signals back to the dermal blood vessels. Vasoconstriction is the blood vessels that reduces the flow of blood close to the skin surface and thus reduces heat loss. When one is overheated, the vasodilation of the dermal blood vessels increases cutaneous blood flow and increases heat loss. So, this is an incorrect answer.