Chapter 5 questions

The hair matrix contains ________.

A layer of basal cells

Why do teenagers often experience acne?

Acne results from a blockage of sebaceous glands by sebum.

Sebaceous glands ________.

Are associated with hair follicles

Eccrine sweat glands ________.

Are present in the skin throughout the body and produce watery sweat

In response to stimuli from the sympathetic nervous system, the arrector pili ________.

Are responsible for goose bumps

The papillary and reticular layers of the dermis are composed mainly of ________.

Connective tissue

Explain the differences between eccrine and apocrine sweat glands.

Eccrine sweat glands are all over the body, especially the forehead and palms of the hand. They release a watery sweat, mixed with some metabolic waste and antibodies. Apocrine glands are associated with hair follicles. They are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis. They release a thicker sweat that is often decomposed by bacteria on the skin, resulting in an unpleasant odor.

One of the functions of the integumentary system is protection. Which of the following does not directly contribute to that function?

Folic acid synthesis

Similar to the hair, nails grow continuously throughout our lives. Which of the following is furthest from the nail growth center?

Hyponychium

If you cut yourself and bacteria enter the wound, which of the following cells would help get rid of the bacteria?

Langerhans cells

Describe the structure and composition of nails.

Nails are composed of densely packed dead keratinocytes. They protect the fingers and toes from mechanical stress. The nail body is formed on the nail bed, which is at the nail root. Nail folds, folds of skin that overlap the nail on its side, secure the nail to the body. The crescent-shaped region at the base of the nail is the lunula.

An individual using a sharp knife notices a small amount of blood where he just cut himself. Which of the following layers of skin did he have to cut into in order to bleed?

Papillary dermis

Why do scars look different from surrounding skin?

Scars are made of collagen and do not have the cellular structure of normal skin.

The papillary layer of the dermis is most closely associated with which layer of the epidrmis?

Stratum basale

As you are walking down the beach, you see a dead, dry, shriveled-up fish. Which layer of your epidermis keeps you from drying out?

Stratum corneum

Langerhans cells are commonly found in the ________?

Stratum spinosum

Collagen lends ________ to the skin.

Structure

Why do people sweat excessively when exercising outside on a hot day?

Sweating cools the body when it becomes warm.

The skin consists of two layers and a closely associated layer. What are the basic functions of each of these layers?

The epidermis provides protection, the dermis provides support and flexibility, and the hypodermis (fat layer) provides insulation and padding.

In humans, exposure of the skin to sunlight is required for ________.

Vitamin D synthesis

Explain your skin's response to a drop in body core temperature.

When the core body temperature drops, the body switches to heat-conservation mode. This can include an inhibition to excessive sweating and a decrease of blood flow to the papillary layers of the skin. This reduction of blood flow helps conserve body heat.

Bedsores ________.

are preventable by eliminating pressure points

In general, skin cancers ________.

can be reduced by limiting exposure to the sun

An individual has spent too much time sun bathing. Not only is his skin painful to touch, but small blisters have appeared in the affected area. This indicates that he has damaged which layers of his skin?

epidermis and dermis

After a skin injury, the body initiates a wound-healing response. The first step of this response is the formation of a blood clot to stop bleeding. Which of the following would be the next response?

increased production of connective tissue

Squamous cell carcinomas are the second most common of the skin cancers and are capable of metastasizing if not treated. This cancer affects which cells?

keratinocytes of the stratum spinosum