Anatomy and Physiology chapter 5 checkpoint questions

What accounts for the ability of the dermis to undergo repeated stretching?

The presence of elastic fibers and the resilience of skin turgor allow the dermis to undergo repeated cycles of stretching and recoil (returning to its original shape).

Where are the capillaries and sensory neurons that supply the epidermis located?

The capillaries and sensory neurons that supply the epidermis are located in the papillary layer of the dermis.

What term describes the combination of fibrin clots, fibroblasts, and the extensive network of capillaries in healing tissue?

The combination of fibrin clots, fibroblasts, and the extensive network of capillaries in tissue that is healing is called granulation tissue.

What happens when the arrector pili muscle contracts?

The contraction of the arrector pili muscle pulls the hair follicle erect, depressing the area at the base of the hair and making the surrounding skin appear higher. The result is known as "goose bumps."

Describe the location of the dermis.

The dermis (a connective tissue layer) lies between the epidermis and the hypodermis.

In some cultures, women must be covered completely, except for their eyes, when they go outside. Explain why these women may develop bone problems later in life.

The hormone cholecalciferol (vitamin D3) is needed to form strong bones and teeth. When the body surface is covered, UV light cannot penetrate to the blood in the skin to begin vitamin D3 production, resulting in fragile bones.

Describe the hypodermis.

The hypodermis is a layer of loose connective tissue below the dermis; it is also called the subcutaneous layer or superficial fascia. 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.

Identify the common purpose that the integumentary system serves for all body systems.

The integumentary system provides the whole body, and thus all its systems, mechanical protection against environmental hazards.

Identify the layers of the epidermis

The layer of the epidermis are the stratum germinativum, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneun.

Describe a typical strand of hair.

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

Which type of skin gland is most affected by the hormonal changes that occur during puberty?

Apocrine sweat glands enlarge and increase secretory activity in response to the increase in sex hormones that occurs at puberty.

Older individuals do not tolerate the summer heat as well as they did when they were young, and they are more prone to heat-related illness. What accounts for these changes?

As a persons ages, the blood supply to the dermis decreases and merocrine sweat glands become less active, These changes make it more difficult for the elderly to cool themselves in hot weather.

Name the sources of epidermal growth factor in the body.

Salivary glands and duodenal glands epidermal growth factor (EGF).

Some criminals sand the tips of their fingers so as not to leave 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 the fingerprints are formed in layers of the skin that are constantly regenerated, so these ridges will eventually reappear. The pattern of the ridges is determined by the arrangement of tissue in the dermis, which is not affected by sanding.

Describe a typical fingernail.

A fingernail is a keratinous structure produced by epithelial cells of the nail root that protects the fingertip.

Deodorants are used to mask the effects of secretions from which type of skin gland?

Deodorants are used to mask the order of apocrine sweat gland secretions, which contain several kinds of organic compounds have an odor, and others produce an oder when metabolized by skin bacteria.

Identify some roles of epidermal growth factor pertaining to the epidermis.

Epidermal growth factor (EGF) promotes the divisions of germinative cells in the stratum germinativum and stratum spinosum, accelerates the production of keratin in differentiating keratinocytes, stimulates epidermal development and epidermal repair after injury and stimulates synthetic activity and secretion by epithelial glands.

Once a burn on the forearm that destroys the epidermis and extensive areas of the deep dermis heals, will hair grow again in the affected area?

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

Why does swimming in fresh water for an extended period cause epidermal swelling?

Fresh water is hypotonic with respect to skin cells, so water moves into the cells by osmosis, causing them to swell.

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 germinativum convert a cholesterol-related steroid into cholecalciferol, also known as vitamin D3.

Where does nail growth occur?

Nail growth occurs at the nail root, an epidermal fold that is not visible from the surface.

What are the functions of sebaceous secretions?

Sebaceous secretions (called sebum) lubricate and protect the keratin of the hair shaft, lubricate and condition the surrounding skin, and inhibit the growth of bacteria.

Why can skin regenerate effectively even after considerable damage?

Skin can regenerate effectively even after undergoing considerable damage because stem cells persist in both the epithelial and connective tissue components of skin. When injury occurs, cells of the stratum germinativum replace epithelial cella while mesenchymal cells replace cells lost from the dermis.

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

Stratum Corneum

A splinter that penetrates to the third layer of the epidermis of the palm is lodged in which layer?

Stratum Granulosum

Identify several functions of subcutaneous fat.

Subcutaneous fat provides insulation to help reduce heat loss, serves as an energy reserve, and acts a shock absorber for the body.

What term is used to describe the thickened stratum corneum underlaying the free edge of a nail?

The area of thickened stratum corneum under the free edge of a nail is called the hyponychium.

Why is the skin important to muscular system activity?

The skin synthesizes vitamin D3, which is essential for normal calcium absorption, Calcium ions play a key role in muscle contraction.

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 hypodermis or subcutaneous layer.

Name the two pigments contained in the epidermis.

The two pigments contained in the epidermis are carotene, an orange-yellow pigment, and melanin, a brown, yellow-brown, or black pigment.

Identify two types of exocrine glands found in the skin.

Two types of exocrine glands found in the skin are sebaceous (oil) glands and sweat glands.

Why does exposure to sunlight or sunlamps darken skin?

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

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

When the skin gets warm, arriving oxygenated blood is diverted to the superficial dermis for the purpose of eliminating heat. The oxygenated blood imparts a reddish coloration to the skin.

Why does hair turn white or grey with age?

With advancing age, melanocyte activity decreases, leading to gray or white hair.