Ch05 module review of anatomy and physiology by Math Your Way

5.2a Identify the layers of the epidermis (from deep to superficial).

The layers of the epidermis from deep to superficial are the stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.

5.1c Identify the major functions of the integumentary system.

The major functions of the integumentary system are to protect underlying tissues and organs, excrete wastes by integumentary glands, maintain body temperature, produce melanin and keratin, synthesize vitamin D3, store lipids, and detect touch, pressure, pain, and temperature.

5.7c Why is pulling a hair painful, yet cutting a hair is not?

Pulling a hair is painful because its root is attached deep within the hair follicle, the base of which is surrounded by a root hair plexus consisting of sensory nerves. Cutting a hair is painless because a hair shaft contains no sensory nerves.

5.9a Describe a typical fingernail.

A fingernail is a keratinous structure that is produced by epithelial cells of the nail root and protects the underlying fingertip. Structures of the nail include a distal free edge, lateral nail fold, lunula, proximal nail fold, eponychium, nail root, nail body, and hyponychium.

5.5a Distinguish between a first-degree, second-degree, and third degree burn.

A first-degree burn affects only the surface of the skin. This would include most sunburns. A second-degree burn damages the entire epidermis and perhaps some of the dermis. Although blistering occurs, accessory structures such as haw follicles and glands are generally not affected. Third-degree burns, also called full-thickness burns, destroy the epidermis and dermis, and extend into the hypodermis.

5.2c A splinter that penetrates to the third layer of the epidermis of the palm is lodged in which layer?

A splinter that penetrates to the third epidermal layer of the palm is lodged in the stratum granulosum.

5.7a Describe a typical strand of hair.

A typical hair is a keratinous strand produced by basal cells within a hair follicle.

5.10c Why do people tolerate summer heat less well and become more susceptible to heat-related illness when they become older?

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

5.10a Identify some common effects of the aging process on skin.

Common effects of the aging process on the skin include epidermal thinning due to declining basal cell activity, fewer melanocytes, reduced sebaceous gland secretion, declining dendritic cell numbers, reduced vitamin D3 production, declining glandular activity, reduced blood flow to the dermis, cessation of hair follicle functioning, and slower skin repair.

5.2b Dandruff is caused by excessive shedding of cells from the outer skin layers of the scalp. Thus, dandruff is composed of cells from which epidermal layer?

Dandruff consists of cells from the stratum corneum.

5.8c Deodorants are used to mask the effects of secretions from which type of skin gland?

Deodorants are used to mask the odor of apocrine sweat gland secretions.

5.6a What are epidermal derivatives?

Epidermal derivatives are accessory structures that originate from the epidermis during embryological development. They include hair follicles, sebaceous and sweat glands, and nails.

5.3b Why does exposure to sunlight or sunlamps darken skin?

Exposure to sunlight or sunlamps darkens skin because the ultraviolet radiation they emit stimulates melanocytes in the epidermis and dermis to synthesize the pigment melanin.

5.12b Describe granulation tissue.

Granulation tissue is the combination of fibrin clots, fibroblasts, and the extensive network of capillaries in healing tissue.

5.5c Describe the three types of skin grafts. Which one is best? Why?

In an autograft, the undamaged skin of a patient is used as a graft source. An allograft uses skin from a donor, and a xenograft uses skin from an animal such as a pig. Autografts are best because they are not rejected by the patient's immune system.

5.11b Explain the relationship between sunlight exposure and vitamin D3.

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

5.9b Where does nail production occur?

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

5.8b What are the functions of sebaceous secretions?

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

5.12c 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. In response to injury, cells of the stratum basale replace epithelial cells while mesenchymal cells replace lost dermal cells.

5.11a List some hormones that are necessary for maintaining a healthy integument.

Some hormones that are necessary for maintaining healthy skin are growth hormone, sex hormones, growth factors (including epidermal growth factor [EGF]), steroid hormones (glucocorticoids), and thyroid hormones.

5.6b What are the two examples of exocrine glands in the integument?

Sweat glands and sebaceous glands are exocrine glands in the integument.

5.6c Describe the functions of the integument's accessory structures.

The accessory structures protect the integument (as in the case of hair and nails), provide sensations, assist in thermoregulation, and excrete wastes.

5.4c Where are the capillaries and sensory receptors that supply the epidermis located?

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

5.4a Describe the location of the dermis.

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

5.12a Identify the first step in skin repair.

The first step in tissue repair is inflammation. Inflammation produces swelling, redness, heat, and pain.

5.11c In some cultures, females must be covered from head to toe when they go outdoors. Explain why these women are at increased risk of developing 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 radiation cannot reach the skin to stimulate cholecalciferol (vitamin D3) production, so fragile bones can develop.

5.9c Define hyponychium.

The hyponychium is the thickened stratum corneum underlying the free edge of a nail.

5.4b What accounts for the ability of the dermis to undergo repeated stretching?

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

5.1a Identify the two major components of the cutaneous membrane.

The two major components of the cutaneous membrane are the epidermis and the dermis. The hypodermis is not part of the integument.

5.3a Name the two pigments contained in the epidermis.

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

5.1b List the various accessory structures of the integument.

The various accessory structures of the integument are hairs, nails, and exocrine glands (sebaceous glands and sweat glands). Supporting structures include blood vessels and nerve fibers.

5.5b Which type of burn usually requires skin grafting? Why?

Third-degree burns often require skin grafting because the tissue damage is so great it cannot repair itself.

5.8a 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.

5.7b What happens when an errector pili muscle contracts?

When an arrector pili muscle contracts, it pulls the hair follicle erect. The overall effect is known as "goose bumps" or "chicken skin."

5.3c Why does the skin of a fair-skinned person appear red during exercise in hot weather?

When 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.

5.10b Why does hair turn white or gray with age?

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