Ch 5 HW

Vitamin D, following activation in the skin, is converted to the hormone calcitriol by enzymes in the liver and kidneys. People in northern climates who may not get adequate sun exposure can become deficient in vitamin D. What mineral would be especially affected by this?

Calcium

Which of the following statements about hair are true?

Consists of a shaft, root and a hair follicle The arrector pili muscle is responsible for "goose bumps". The root of a hair penetrates the dermis

The skin is also known as the

Cutaneous membrane

Which of the below structures are sweat glands that do not become active until puberty and whose secretions can create body odor when it is metabolized by bacteria on the skin?

D

What factors contribute to the susceptibility of aging skin to infection?

Decrease in Langerhans cell number Decrease in macrophage number Decrease in size of sebaceous glands resulting in dry broken skin.

Differences in skin pigmentation are due to the number of melanocytes in the basal layer of the skin. People with darker skin have many more melanocytes than people with paler skin.

False

This is the junction between the free edge and the skin of the fingertip and secures the nail to the fingertip

Hyponychium

Which statement are correct about the dermis

It is thinner in men than in women It contains collagen and elastin fibers It provides the blood supply and many sensory receptors for the epidermis It has a smaller papillary layer, and a thicker reticular layer

As newly formed cells of the stratum basale are pushed to the surface, they accumulate keratin and undergo apoptosis. This process is referred to as _______.

Keratinization

Which type of epithelium makes up the epidermis?

Keratinized stratified squamous

About 90% of the cells of the epidermis are which type of cell?

Keratinocytes

Actual growth of the nail occurs in the

Nail matrix

What criteria are used to distinguish thick and thin skin?

Presence of epidermal ridges, the number and types of glands present. The Thickness and number of layers of epidermis along with the distribution on your body.

The pigment producing cells of the epidermis are located in which layer?

Stratum basale

Which layer has stem cells that undergo cell division to continually produce new keratinocytes?

Stratum basale

This skin layer is only present in places subjected to high levels of mechanical wear and tear, and provide an additional protective layer where it occurs, such as in the soles of the feet, palms, and fingertips.

Stratum lucidum

Which is not true about melanocytes?

They undergo rapid mitosis to regenerate skin

In addition to a thicker stratum corneum and the presence of a stratum lucidum, the thick skin of the palms and fingertips of the hands and of the soles of the feet have a denser array of sense receptors than thinner skin found elsewhere on the body, and also is hairless.

True

In deep wound healing, an injury has penetrated through to the dermis or even the hypodermis. In this type of wound, the healing process will leave a scar and could involve a loss of some functionality of the area of the wound

True

The cells of the stratum basale become more metabolically active and increase their rate of cell division when upper layers of the epidermis are stripped away due to abrasions or burns.

True

The skin helps to regulate body temperature by producing perspiration and adjusting blood flow to the dermis

True

Wounds that only damage the epidermis won't bleed because the epidermis is avascular

True

The amount and kind of melanin present in the cortex and medulla of a hair shaft determines hair color. When ,leaning is replaced by air bubbles in the shaft, which is the resulting hair color?

White

Along with sweating, which other responses by skin assists with thermoregulation?

blood vessels near the skin can dilate, increasing blood flow and heat loss

When an epidermal wound begins the healing process, basal cells migrate away from the basement membrane, enlarge, and migrate to fill in the wounded area. As these cells migrate from different sides of the wound, and reach each other, they stop migrating. This process is called

contact inhibition

Which might be due to a decrease in the amount of oxygen in the blood

cyanosis

Which is the correct sequence of phases for deep wound healing?

inflammation, migration, proliferation, maturation

Which of the following is a tumor that arises from melanocytes?

malignant melanoma

Which layer consists on average of 25 to 30 layers of flattened dead keratinocytes

stratum corneum

Which epidermal layer marks the transition between metabolically active cells of lower layers and the dead layers of keratinocytes of the upper layers?

stratum granulosum