chapter 5

Identify the two major components of the cutaneous membrane.

the two major components of the cutaneous membrane are the epidermis and dermis. The subcutaneous layer (hypodermis) is not part of the integuments.

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

Dandruff consists of cells from the stratum corneum.

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 glands secretions.

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

Identify the first step in skin repair

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

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

The five layers of the epidermis from deep to superficial are the stratum Basale, stratum lucidum, and stratum corneum.

Why does hair turn white or gray with age?

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

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 eccrine sweat glands become less active. Both changes make it more difficult for older people to cool themselves in hot weather.

Why is basal cell carcinoma considered less dangerous than malignant melanoma?

Cancerous basal cells rarely become malignant and metastasize , or spread, into other tissues throughout the body, as do melanoma cancer cells. Malignant melanoma is extremely dangerous because the cancerous melanocytes spread throughout the lymphatic system.

Where does nail production occur?

Contractile myoepithelial cells aid merocrine secretion discharge. They are found in apocrine and eccrine sweat glands, mammary glands, lacrimal (tear) glands, and salivary glands.

What are epidermal derivatives?

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

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 to synthesize the pigment melanin

Describe granulation tissue.

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

Describe the four phases of the hair growth cycle.

Hair follicles transition between 1. an active phase of continuous hair growth;2 regression;3 a resting phase, when the hair becomes a club hair; and reactivation of hair growth and shedding of club hair

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

Hormones that are necessary for maintain healthy skin include growth hormone, sex hormones, growth factors, glucocorticoids, and thyroid hormones.

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

In an autograft, the patient's undamaged skin 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 the best because they are not rejected by the patients' immune system.

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 a hair is painless because a hair shaft contains no sensory nerves.

Describe the secretory method and functions of sebum.

Sebum is secreted by holocrine secretion. Sebum lubricates and protects the keratin of the hair shaft, lubricates and conditions the surrounding skin, and inhibits 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. In response, to injury, cells of the stratum basal replace epithelial cells, and mesenchymal cells replace lost dermal cells.

Define and describe the lines of cleavage (tension lines). Predict the degree of scarring after the healing of a horizontal cut on the forehead just above the eyebrow.

Such a cut would cross the tension lines at a right angle, so a greater, rather than lesser, amount of scarring would be predicted.

Which exocrine glands are in the integument?

Sweat glands and sebaceous glands

Describe the layers of the dermis

The dermis is made up of two layers of connective tissues: a papillary layers and a reticular layer. The superficial papillary layer consists of areolar tissue containing capillaries, lymphatic vessels, and sensory neurons that supply the surface of the skin. The deeper reticular layer consists of dense irregular connective tissue containing collagen and elastic fibers.

Identify and describe the general functions of exocrine glands found in the skin.

The exocrine glands in the skin are sebaceous and sweat glands. Together, they assist in thermoregulation, excrete wastes, and lubricate hairs and the epidermis

In some cultures, female must be covered from heat 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 D) 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 bones become fragile.

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

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)

Distinguish among a first-degree, second-degree, and third-degree burn.

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

What happens when an arrector pili muscle contracts?

When arrector pili muscles contract, they pull the hair follicle erect. The overall effect is known as goose bumps.

Why does the skin appear red during exercise in hot weather?

When the skin gets warm, arriving oxygenated blood is diverted to the superficial dermis (papillary layer) to eliminate heat. The oxygenated blood imparts a reddish coloration to the light skin.