Chapter 4 - Anatomy And Physiology

Keratinocytes are the most abundant cell type in the epidermis.

The stratum basale produces new epidermal cells.

The stratum corneum is the name of the skin layer that causes dandruff.

1) Serous membranes line ventral body cavities closed to the exterior. 2) Mucous membranes line body cavities open to the exterior. Examples are the respiratory, digestive, urinary, and reproductive organ cavities.

Lining a fibrous capsule surrounding a joint.

1) The skin is the epithelial membrane that covers the surface of the body. 2) Cutaneous membrane is a synonym for skin, as is integument, which means covering. 3) The integumentary system is the skin and its derivatives (nails, hair, and glands).

Important functions of the integumentary system are (choose any three): 1) It protects deeper tissues from mechanical damage such as bumps, chemical damage due to acids and bases, bacterial damage, UV radiation from the damaging effects of sunlight, thermal damage (heat or cold), and desiccation (drying out). 2) It aids in body heat loss or heat retention (controlled by the nervous system). 3) It aids in excretion of urea and uric acid. and 4) It synthesizes vitamin D.

Just the epidermis.

Melanin, carotene, and hemoglobin all contribute to skin color.

The sebaceous glands, which produce oily secretions.

Cuticle, cortex, and medulla.

Sebum is an oily secretion of the sebaceous glands.

Both are dilute salt solutions containing vitamins and wastes. Apocrine secretion also contains proteins and fatty acids.

No, the nail won't regrow because the growth region (nail matrix) is torn off.

Loss of body fluids containing needed proteins and electrolytes, resulting in circulatory shock, and overwhelming infection.

1) First-degree burns are red and swollen but usually heal within 2-3 days; there is only epidermal damage. 2) Second-degree burns damage the epidermis and some of the dermis; blisters appear but epithelial regeneration can occur. 3) Third-degree burns destroy the entire skin thickness. The burn is gray and painless; must graft.

The ABCD rule.

Sun exposure.

Because stratum corneum cells are dead.

Loss of subcutaneous fat.

The sebaceous glands of the baby.

1) The epithelial type is the same in all serous membranes, but there are different epithelial types in different mucous membranes. 2) Serous membranes line closed body cavities, whereas mucous membranes line body cavities open to the outside. 3) Both membranes contain an epithelium plus a layer of loose connective tissue.

1) Have parietal and visceral layers; and 2) Secrete a lubricating fluid.

Water, ammonia, and sodium chloride.

1) Shaft; 2) Cortex; 3) Cuticle; and 4) Lunule.

1) Is the diet deficient in proteins? 2) Has the person been exposed to excessive radiation? 3) Has the person recently suffered severe emotional trauma?

1) Nail bed; 2) Lunule; and 3) Nail folds.

1) Sweat glands; 2) Sweat pores; 3) Eccrine gland; and 4) Apocrine gland.

Hair, hair papilla, and nail.

1) Melanocytes protect from UV radiation. 2) Hypodermis insulates and is used for energy storage. 3) Stratum corneum is for waterproofing and preventing water loss. 4) Dermal blood supply - temperature regulation. 5) Eccrine sweat glands - excretion of water, urea, and salts. 6) Papillary layer of the dermis - produces the patterns for fingerprints.

Synovial membrane.

1) Mechanical damage, such as bumps; 2) Chemical damage, such as acids and bases; 3) Ultraviolet radiation (damaging effects of sunlight); 4) Thermal damage (heat or cold); 5) Desiccation (drying out)

When the skin is exposed to sunlight, the melanocytes are stimulated and produce more of the melanin pigment, and tanning occurs.

Decubitus ulcers (bedsores) occur in bedridden patients who are not turned regularly or who are dragged or pulled across the bed repeatedly. The weight of the body puts pressure on the skin, especially over bony projections. Because this restricts the blood supply, the skin becomes pale or blanched at pressure points. At first, the skin reddens when pressure is released, but if the situation is not corrected, the cells begin to die, and small cracks or breaks in the skin appear at compressed sites. Permanent damage to the superficial blood vessels and tissue eventually results in degeneration and ulceration of the skin.

Two categories of skin secretions are: 1) Sebum - an oily secretion produced by the sebaceous glands. Sebum is a mixture of oily substances and fragmented cells. It keeps the skin soft and moist and prevents the hair from becoming brittle. Sebum also contains chemicals that kill bacteria. 2) Sweat - produced by the sudoriferous glands (sweat glands). Sweat travels to the skin's surface via pores in the skin.

Your skin regulates your body temperature through blood vessels and through the process of sweating. The skin is your body's thermostat. When you're out in cold weather, your skin triggers shivering so the blood vessels will contract and keep you as warm as possible. But if there's a heat wave, you'll sweat to increase the blood flow to the capillaries, which in turn increases sweating. This process cools you off as the water evaporates from your skin.

If a sebaceous gland's duct is blocked by sebum, a whitehead appears on the skin surface. If the accumulated material oxidizes and dries, it darkens, forming a blackhead.

Arrector pili are small bands of smooth muscle cells. They connect each side of the hair follicle to the dermal tissue.

Basal cell carcinoma develops from the youngest epidermal cells.

Like balding, this is usually genetically controlled by a "delayed-action" gene. Once the gene takes effect, the amount of melanin deposited in the hair decreases or becomes entirely absent, which results in gray-to-white hair.

Three changes that occur in the skin as you age are: 1) The amount of subcutaneous tissue decreases, leading to the intolerance of cold that is so common in older adults; 2) The skin also becomes drier (because of decreased oil production), and as a result, it may become itchy and bothersome; 3) The skin thins, which makes it more susceptible to bruising and other types of injuries.

A bald man is not really hairless - he does have hairs in the bald area. But, because those hair follicles have begun to degenerate, the hairs are colorless and very tiny (and may not even emerge from the follicle). Such hairs are called vellus (vell = wool) hairs.