Chapter Quiz 5.1 Flashcards
Which epidermal layer is unique to the skin of the palms and soles?
stratum basale
*stratum lucidum
stratum corneum
stratum granulosum
(Recall the layers of the epidermis, focusing on the clear layer, which has cells that are flattened, densely packed, largely devoid of organelles, and filled with keratin and keratohyalin.)
Which statement regarding epidermal pigmentation is FALSE?
Melanocytes manufacture melanin from the amino acid tyrosine.
Carotene pigment is most apparent in the stratum corneum cells of light-skinned individuals.
Melanocytes are found in the stratum basale, either nestled between or deep to the epithelial cells.
(The primary pigments involved in skin coloration are carotene and melanin, which are two of the factors that influence skin color.)
Which of the following consists of an interwoven meshwork of dense irregular connective tissue containing both collagen and elastic fibers?
stratum spinosum
hypodermis
*reticular layer of the dermis
papillary layer of the dermis
(The dermis supports the epidermis, and the hypodermis stabilizes the position of the skin in relation to underlying tissues.)
Functions of the integumentary system do NOT include which of the following?
excretion of salts, water, and organic wastes
maintenance of normal body temperature
*production of vitamin A, which is important for normal calcium metabolism
storage of lipids
Aging, hormonal changes, and ultraviolet radiation permanently reduces the amount of ______.
collagen in the epidermis
*elastin in the dermis
collagen in the dermis
the thickness of the stratum basale
Which structural feature of hair consists of germinative cells that produce the hair?
root hair plexus
*hair matrix
hair papilla
cortex
(Hair production begins at the base of a hair follicle, which is a complex structure composed of epithelial and connective tissues.)
Which exocrine glands, found in most areas of the skin, produce watery secretions containing electrolytes?
*merocrine sweat glands
apocrine sweat glands
sebaceous follicles
oil glands
(Determine which glands are also controlled primarily by the nervous system, are important in thermoregulation and excretion, and perform some antibacterial action.)
Nail production occurs at the ________.
eponychium
lunula
hyponychium
*nail root
Nails are composed of stratified keratinized epidermal cells, which are produced at an epithelial fold not visible from the surface, the deepest portion of which lies close to the distal phalanx (fingertip bone).
Which age-related integumentary change results in skin cooling that can make an individual feel cold, even in a warm room?
fewer active follicles
thinning dermis
decreased perspiration
*reduced blood supply
Which hormone, synthesized by the kidneys, is required for normal bone growth and maintenance?
cholecalciferol
growth hormone (GH)
epidermal growth factor (EGF)
*calcitriol
(Limited exposure to sunlight is beneficial due to the synthesis of vitamin D3, which is converted by the liver into an intermediate product used by the kidneys for hormone production.)
Why is a diagnosis of basal cell carcinoma so much easier for a patient and their family to receive than one of malignant melanoma?
Mestasasis virtually never occurs in basal cell carcinoma; in malignant melanoma cancerous melanocytes grow rapidly and metastasize through the lymphatic system.
Most people survive the first; malignant melanoma depends on when diagnosed - early = 99% 5 yr survival rate; late = 14%…
What are the factors involved in influencing skin coloration?
presence of pigments (primarily melanin and carotene) in the skin/skin pigmentation, degree of dermal circulation, and degree of keratinization in the epidermis.
Describe lines of cleavage and discuss their clinical significance.
aka tension lines - a pattern of fiber bundles (collagen and elastic) oriented to resist forces applied to the skin.
A cut parallel to the cleavage will remain closed and heal with little scarring. A cut at right angles to a tension line will be pulled open as severed elastic fibers recoil, resulting in greater scarring.
Compare and contrast apocrine and merocrine sweat glands.
Apocrine - secrete into hair follicles; sticky, cloudy, and potentially odorous secretion; strongly influenced by hormones.
Location - armpits, nipples, pubic region
Structure - rings that surround hair follicle lumen
Function - olfactory communication
(also includes ceruminous glands in ears and mammary glands)
Merocrine (eccrine) - secrete directly onto skin; controlled primarily by nervous system
Location - most areas of skin (palms and soles have a high concentration)
Structure -
Function - thermoregulation and excretion (and some antibacterial properties)
Both squeezed by myoepithelial cells to discharge secretion; both flush the epidural surface; BOTH RELY ON MEROCRINE SECRETION
How do the nails of an individual provide useful diagnostic information? Cite one or more example(s).
Cells producing the nails can be affected by conditions that alter body metabolism, so changes to shape, structure, or appearance can provide useful diagnostic information.
Ex. psoriasis = pitted and distorted due to rapid cell division in the stratum basale
Ex. blood disorders = concave
