Chapter 6 Questions

What layer listed here contains areolar connective tissue and dermal papilae? A. papillary layer of dermis B. subcutaneous layer C. reticular layer of dermis D. epidermis

A. papillary layer of dermis

Which statement is FALSE about sebaceous glands? A. They release their secretion onto a hair follicle. B. They release their product by apocrine secretion. C. They are located in the dermis. D. The product they secrete acts as a lubricant and waterproofer.

B. They release their product by apocrine secretion

Melanin is: A. an orange-yellow pigment that strengthens the epidermis B. a pigment that accumulates inside keratinocytes C. a protein fiber that is found in the dermis D. a pigment that gives the characteristic color to hemoglobin

B. a pigment that accumulates inside keratinocytes

The cells in a hair follicle that are responsible for forming hair are the: A. hair papilla cells B. matrix cells C. medullary cells D. cortex cells

B. matrix cells

The sweat glands that communicate with skin surfaces throughout the body, producing a secretion that is primarily water, are: A. apocrine glands B. merocrine glands C. sebaceous glands D. all of these are correct

B. merocrine glands

A _____ degree burn typically involves the epidermis and part of the dermis. The subcutaneous layer is not affected. A. first- B. second- C. third- D. fourth-

B. second-

Which of the following is NOT a function of the integument? A. acts as a physical barrier B. stores calcium in the dermis C. regulates temperature through vasoconstriction and dilation of dermal blood vessels D. participates in immune defense

B. stores calcium in the dermis

The layer of the epidermis in which cells begin the process of keratinization is the: A. stratum corneum B. stratum basale C. stratum lucidum D. stratum granulosum

B. stratum basale

Which epidermal cell type is responsible for detecting touch sensations? A. keratinocyte B. melanocyte C. tactile cell D. epidermal dendritic cell

C. tactile cell

Where are the ceruminous glands located and what do they secrete?

Ceruminous glands are located in the ear canal and they secrete waterproof earwax called cerumen.

At what stage of wound healing does granulation tissue first form? A. after scar tissue forms along the wound B. before the blood completely clots C. before leukocytes enter the site and clean the wound D. after a blood clot forms and prior to scar tissue forming

D. after a blood clot forms and prior to scar tissue forming

List the four main cell types in the epidermis, their function and the layer(s) of the integument in which they reside.

Keratinocytes: these cells synthesize keratin, which strengthens the epidermis. They are found in all of the epidermal strata. Melanocytes: these cells produce and store melanin in response to UV light and transfer the pigment granules (melanosomes) into keratinocytes to protect DNA from UV radiation. They are found in the Stratum Basale. Tactile cells: these cells are sensitive to touch and release chemicals that stimulate nerve ending to provide sensory information about the objects we touch. They are found in the Stratum Basale. Epidermal Dendritic cells: these are immune cells that help fight infections in the epidermis. They are found in the Stratum Spinosum.

What are the three types of hair?

Lanugo, vellus, and terminal hair

Describe the tissue type and structure of the two specific layers of the dermis.

Papillary Layer of the Dermis: The superficial region of the dermis that is found directly internal to the epidermis. It is composed of areolar connective tissue, and it derives its name from the projections of the dermis called dermal papilae. They interact with deep projection called epidermal ridges and increases the area of contact between the two layers and interlocks them. Reticular Layer of the Dermis: This forms the deeper, major portion of the dermis that extends all the way to the underlying subcutaneous layer. Consists of primarily dense irregular connective tissue with large bundles of collagen fibers that surrounds and structures the dermis.

Describe the composition of the layers of the epidermis.

Stratum Basale: The deepest epidermal layer. Its a single layer of cuboidal to low columnar cells that is tightly attached to a basement membrane. It is composed of three cell types: keratinocytes, melanocytes, and tactile cells. Stratum Spinosum: Made up of several layers of polygonal keratinocytes. These nondividing keratinocytes are connected to each other by desmosomes. This layer is also composed of epidermal dendritic cells. These are immune cells that help fight infection in the epidermis. Stratum Granulosum: This layer contains up to 3-5 layers of keratinocytes. This stratum begins a process called keratinization. This is a process where the cells fill with keratin and the nucleus and organelles begin to disintegrate, killing the cells. Full keratinization is not completed in this layer. Stratum Lucidum: A thin translucent region of about 2-3 cell layers. This stratum is only found in thick skin. Cells in this layer are pale and featureless. The keratinocytes are flattened and filled with eleidin (a translucent protein). This layer helps in protecting the skin from UV light. Stratum Corneum: This is the most superficial layer of the epidermis. This is the layer you see when you look at your skin. This stratum is made up of about 20-30 layers of dead, scaly, interlocking keratinized cells. They are anucleate and tightly packed together.

Discuss the steps involved in wound repair of the integument.

The first step of wound repair consists of cut blood vessels bleeding into the wound and carrying clotting proteins, white blood cells and antibodies in with the blood. In step two blood clotting begins and patches together the edges of the wound to keep pathogens out. Inside the wound, leukocytes begin cleaning the wound of debris. Step three involves the cut blood vessels regenerating and granulation tissue forms. Leukocytes remove the clotted blood and fibroblasts produce new collagen fibers. The final step of wound repair consists of epithelial regeneration at the edges of the wound and connective tissue being replaced by fibrosis.

Compare the structure and composition of the following nail parts: nail body, nail bed, eponchyium, and lunula.

The nail body is the middle part of the actual nail that lies between the nail root and the free edge. The nail bed is the layer of epidermis that lies underneath the nail body. The eponchyium is the nail cuticle, a narrow band of epidermis that extends from the margin of the nail wall onto the nail body. The lunula is the whitish semilunar area of the proximal end of the nail body.

What are some effects of aging on the integument?

The skin repair process takes longer because of reduced stem cell activity. The skin becomes thinner. Collagen fibers become less in number and elastic fibers lose elasticity. Wrinkles become prominent. The skins immune responsiveness decreases because there are less epidermal dendritic cells. Finally, hair follicles produce thinner hairs or no hairs at all.

Describe how the skin is involved in vitamin D production.

Vitamin D is synthesized from a steroid precursor by the keratinocytes when they are exposed to UV radiation. Vitamin D is then released into the blood and taken to the liver where it is converted to an intermediate molecule and taken to the kidneys to be converted into the active form of Vitamin D (calcitriol).

What embryonic tissues form the integument?

ectoderm and mesoderm