chapter 5 review questions

Describe a typical strand of hair.

A typical hair is a keratinous strand produced by epithelial cells of a hair follicle.

Why does exposure to sunlight or sunlamps darken skin?

When exposed to the ultraviolet radiation in sunlight or tanning lamps, melanocytes in the epidermis (and dermis) synthesize the pigment melanin, darkening the skin.

The fibrous protein that forms the basic structural component of hair and nails is a) collagen. b) melanin. c) elastin. d) keratin.

d) keratin.

Why does the skin of a light-skinned person appear red during exercise in hot weather?

When skin gets warm, arriving oxygenated blood is diverted to superficial blood vessels to eliminate heat. The oxygenated blood imparts a reddish coloration to the skin.

What happens when the arrector pili muscle contracts?

Contraction of the arrector pili muscle pulls on the hair follicle, making the hair stand erect. The result is sometimes known as "goose bumps."

Dandruff is caused by excessive shedding of cells from the outer layer of skin in the scalp. Thus, dandruff is composed of cells from which epidermal layer?

Dandruff consists of cells from the stratum corneum.

If a burn on the forearm destroys the epidermis and the deep dermis and then heals, will hair grow again in the affected area?

Even though hair is a structure derived from the epidermis, the follicles are in the dermis. Where the epidermis and deep dermis are destroyed, new hair will not grow.

List five major functions of the integumentary system.

Five major functions of the integumentary system include protection, temperature maintenance, synthesis and storage of nutrients, sensory reception, and excretion and secretion.

Explain the relationship between sunlight exposure and vitamin D3 synthesis.

In the presence of ultraviolet radiation in sunlight, epidermal cells in the stratum spinosum and stratum basale convert a cholesterol-related steroid into vitamin D3.

The following events are part of the skin repair process. In which order do they occur? 1) Phagocytosis of pathogens and debris 2) Formation of scar tissue 3) Inflammatory response 4) Formation of scab a) 1,3,2,4 b) 3,1,2,4 c) 3,1,4,2 d) 3,4,1,2

d) 3,4,1,2

Some criminals sand their fingertips to avoid leaving recognizable fingerprints. Would this practice permanently remove fingerprints? Why or why not?

Sanding the tips of the fingers will not permanently remove fingerprints. The ridges of fingerprints are formed in skin layers that are constantly regenerated, so these ridges will eventually reappear.

Where are the capillaries that supply the epidermis located?

The capillaries that supply the epidermis are located in the papillary layer of the dermis, where they follow the contours of the epidermis-dermis boundary.

Describe the location of the dermis.

The dermis (a connective tissue layer) lies immediately deep to the epidermis.

Identify the five layers of the epidermis.

The five layers of the epidermis are the stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.

What is the most common skin cancer?

The most common skin cancer is basal cell carcinoma.

Describe the subcutaneous layer.

The subcutaneous layer is a layer of areolar tissue containing many adipose (fat) cells, which lies below the dermis. It is not considered a part of the integument, but it is important in stabilizing the position of the skin in relation to underlying tissues.

List the two terms for the tissue that connects the dermis to underlying tissues.

The tissue that connects the dermis to underlying tissues is the subcutaneous layer or hypodermis.

The lipid in oil glands is released through which type of secretion? a) endocrine b) holocrine c) merocrine d) apocrine e) eccrine

b) holocrine

The two types of exocrine glands in the skin are a) merocrine and sweat glands. b) sebaceous and sweat glands. c) apocrine and sweat glands. d) eccrine and sweat glands.

b) sebaceous and sweat glands.

The two major components of the integument are a) the cutaneous membrane and the accessory structures. b) the epidermis and the subcutaneous layer. c) the hair and the nails. d) the dermis and the subcutaneous layer.

b) the epidermis and the subcutaneous layer.

What is the composition of the papillary layer of the dermis? a) reticular connective tissue b) stratified squamous epithelium c) areolar connective tissue d) dense, irregular connective tissue e) dense, regular connective tissue

c) areolar connective tissue

The blood supply to the skin arises from a network of blood vessels called the ________ plexus in the hypodermis, at its border with the reticular layer of the dermis. a) cervical b) mesenteric c) cutaneous d) celiac e) brachial

c) cutaneous

All of the following are accessory structures of the integumentary system except a) nails. b) hair. c) dermal papillae. d) sweat glands.

c) dermal papillae.

A burn that destroys only the superficial cells of the epidermis, such as a mild sunburn, is classified as a) full-thickness b) fourth-degree c) first-degree d) second-degree e) third-degree.

c) first-degree

The type of burn that injures the hypodermis, deeper tissues, and organs is a a) first-degree burn b) second-degree burn c) third-degree burn d) semi-partial-thickness burn e) partial-thickness burn.

c) third-degree burn

Name the two pigments in the epidermis.

carotene and melanin