BSC 2085 TEST Chapter 5
The peptide that is secreted by the pituitary gland and increases the rate of melanin production is __________.
MSH
A thick, flattened mass of scar tissue that grows into the tissue around an injury site is called __________.
a keloid
Hair production occurs in the __________.
reticular layers of the dermis
Approximately how long does it take for a cell to move from the stratum germinativum to the stratum corneum?
7-10 days
Why are lines of cleavage clinically significant?
A cut parallel to a cleavage line will remain closed.
Which of the following statements describes the immediate response by the skin to an injury?
Bleeding occurs, and mast cells trigger an inflammatory response.
How do third-degree burns differ from first- and second-degree burns?
In a third-degree burn, the epidermis, dermis, and hypodermis are destroyed.
A decrease in the number of __________ leads to increased damage and infection associated with age.
Langerhans cells
Why are malignant melanomas extremely dangerous and life-threatening?
The melanocytes grow rapidly and metastasize through the lymphatic system.
Sagging and wrinkling of the integument is due to __________.
a decrease in the elastic fiber network of the dermis
The hypodermis is useful for subcutaneous injection by hypodermic needle because it has __________.
a limited number of capillaries and no vital organs
When the body temperature becomes abnormally high, thermoregulatory homeostasis is maintained by __________.
an increase in sweat gland activity and an increase in blood flow to the skin
What are the primary tissues composing the hypodermis?
areolar and adipose
Where can you find an apocrine sweat gland?
armpits, nipples, and pubic region
Special smooth muscles in the dermis that, when contracted, produce "goose bumps" are called __________.
arrector pili
When ruptured dermal blood vessels leak into the dermis, a __________ may form.
bruise
Yellowing of the fingernails occurs in patients who have __________.
chronic respiratory disorders, thyroid gland disorders, or AIDS
What are the two basic factors interacting to produce skin color?
circulatory supply and pigment concentration
A hair at the end of the growth cycle is called __________.
club hair
The body of the nail __________.
consists of dead, tightly compacted cells
Skin exposure to small amounts of ultraviolet radiation serves to __________.
convert a steroid related to cholesterol into vitamin D
Sensible perspiration released by the eccrine sweat glands serves to __________.
cool the surface of the skin, reduce body temperature, and dilute harmful chemicals
When the skin is deprived of blood flow and oxygen, it takes on a bluish coloration called __________.
cyanosis
Hair turns gray or white because of __________.
decreased melanocyte activity
What condition causes inflammation in the papillary layer when a part of the skin is exposed to infection or an irritant?
dermatitis
What are the two layers of the cutaneous membrane (skin)?∙
dermis and epidermis
Differences in skin color among individuals are the result of __________.
differences in the number of melanocytes
Ceruminous glands are modified sweat glands located in the __________.
external auditory canal
The layers of the epidermis, beginning with the deepest layer and proceeding outward, include the strata __________.
germinativum, spinosum, granulosum, corneum
Accessory structures of the skin include the __________.
hair follicles and the sebaceous and sweat glands
What is the subcutaneous layer that separates the integument from the deep fascia around other organs?
hypodermis
What is the name of the pale, crescent-shaped area near the root of the nail?
lunula
The core of a hair is called the __________.
medulla
Nail production occurs at an epithelial fold NOT visible from the surface called the __________.
nail root
What are the two layers of the dermis?
papillary and reticular layers
The practical limit to the healing process of the skin is the formation of inflexible, fibrous, noncellular __________.
scar tissue
Sebaceous glands release which type of secretion?
sebum
The secretion that lubricates and inhibits growth of bacteria on the skin is called __________.
sebum
Excessive exposure of the skin to ultraviolet radiation may cause redness, edema, blisters, and pain. The presence of blisters classifies the burn as __________.
second -degree
An important function of the hypodermis is to __________.
stabilize the position of the skin in relation to underlying tissues
Epidermal cells in the stratum spinosum and stratum germinativum function as a chemical factory in that they can convert __________.
steroid precursors to vitamin D3 when exposed to sunlight
What is the most superficial layer of the epidermis?
stratum corneum
Psoriasis is a skin disorder in which there is abnormal increased mitotic activity in the __________.
stratum germinativum
In which layers of the epidermis do mitotic divisions occur?
stratum germinativum and stratum spinosum
Which epidermal layer is found only in thick skin?
stratum lucidum
Which of the following functions is NOT associated with the skin?
synthesis of B vitamins
What is the natural factor responsible for varying shades of hair color?
type of melanin present
Which of the following are benign tumors that occur in the skin?
warts
Because fresh water is hypotonic to body fluids, sitting in a freshwater bath causes __________.
water to enter the epidermis and cause the epithelial cells to swell