Question 1

Tinea (e.g., ringworm) and candidiasis are caused by fungi.

Accepted Answer

Tinea infections are fungal infections of the skin and are classified according to their location on the body. Candidiasis is caused by the yeastlike fungus Candida albicans and normally can be found on mucous membranes, on the skin, in the gastrointestinal tract, and in the vagina.

Question 2

Kaposi sarcoma is a vascular malignancy that occurs only in people with AIDS.

Accepted Answer

Kaposi sarcoma (KS) is a vascular malignancy with four different presentations: in association with drug-induced immunosuppressions, for example, after kidney transplantation, an endemic form in equatorial Africa, a classic form presenting on the lower legs of older men, and in association with AIDS.

Question 3

Which cells of the dermis release histamine and play a role in the hypersensitivity reactions of the skin?

Accepted Answer

Mast cells release histamine and play a role in hypersensitivity reactions in the skin.

Question 4

When pressure on capillaries is unrelieved, the endothelial cells lining those capillaries become disrupted with platelet aggregation forming microthrombi.

Accepted Answer

Continuous pressure on tissue between the bony prominence and a resistant outside surface distorts capillaries and occludes the blood flow and oxygen supply. If the pressure continues unrelieved, the endothelial cells lining the capillaries become disrupted with platelet aggregation, forming microthrombi that block blood flow and cause anoxic necrosis of surrounding tissues.

Question 5

_____ of the epidermis initiate immune responses and provide defense against environmental antigens.

Accepted Answer

Langerhans cells (a type of dendritic cell) and dermal dendritic cells initiate an immune response by presenting processed antigen to T cells, thus providing a defense against environmental antigens.

Question 6

Pain experienced by patients during the thawing period after frostbite is mild because the nerve endings are anesthetized by the cold.

Accepted Answer

The mechanism of injury is complex but appears to be related to direct cold injury to cells, indirect injury and cell death from extracellular and intracellular ice crystal formation, and impaired circulation with anoxia because of thrombosis in the exposed area.

Question 7

Warts are benign lesions of the skin caused by human papillomavirus (HPV).

Accepted Answer

Warts (verrucae) are benign lesions of the skin caused by HPV.

Question 8

Merkel cells are associated with touch receptors and function as slowly adapting mechanoreceptors when stimulated.

Accepted Answer

Merkel cells are associated with touch receptors and function as slowly adapting mechanoreceptors when stimulated by deformation of the epidermis.

Question 9

Which gland releases secretions that are important in thermoregulation and cooling of the body through evaporation?

Accepted Answer

The eccrine sweat glands are distributed over the body, with the greatest numbers in the palms of the hands, soles of the feet, and forehead. These secretions are important in thermoregulation and cooling of the body through evaporation.

Question 10

Psoriasis is an inflammatory skin condition.

Accepted Answer

Inflammatory cytokines (i.e., TNF, IFN-g, IL-6, IL-12, IL-15, IL-17, IL-22, IL-23) from activated T cells, B cells, and macrophages cause the skin changes and comorbidities occurring in psoriasis.

Question 11

The relationship between nevi and melanoma has been found to be insignificant.

Accepted Answer

A nevus, or mole, is an aggregation of melanocytes . These clusters of cells may not be apparent until puberty, when the pigmentation process is initiated by steroid hormones. The relationship between nevi and melanoma makes it important for the clinician to understand the various neval forms (Table 44-8). Most nevi never become suspicious; however, suspicious pigmented nevi should be removed.

Question 12

Which receptors of the autonomic nervous system regulate heat loss through the skin?

Accepted Answer

Heat loss can be regulated by varying blood flow through the skin by opening and closing the arteriovenous anastomoses in conjunction with evaporative heat loss of sweat. The sympathetic nervous system regulates vasoconstriction and vasodilation through a-adrenergic receptors.

Question 13

Cytomegalovirus is a type of herpesvirus.

Accepted Answer

There are eight types of herpes simplex virus (HSV), a group of DNA viruses: HSV-1 (type 1), HSV-2 (type 2), cytomegalovirus (CMV), varicella-zoster virus (VZV; type 3), Epstein-Barr virus, and human herpesviruses 6, 7, and 8 (Kaposi sarcoma-associated) that cause substantial neurologic morbidity among infants and children.

Question 14

Shingles and chickenpox are both caused by the same herpesvirus.

Accepted Answer

Herpes zoster (shingles) and varicella (chickenpox) are caused by the same herpesvirus-VZV.

Question 15

The initiating site of inflammation in vasculitis may be blood, vessel wall, or adjacent tissue.

Accepted Answer

Vasculitis (angiitis) is an inflammation of the blood vessels. The initiating site of inflammation may be the blood, the vessel wall, or the adjacent tissue.

Question 16

Melanoma is a malignant tumor of the skin originating from keratinocytes, the cells of the skin that synthesize the pigment melanin.

Accepted Answer

Melanoma is a malignant tumor of the skin originating from melanocytes, or cells that synthesize the pigment melanin.

Question 17

Which cells of the dermis secrete connective tissue matrix?

Accepted Answer

Fibroblasts secrete the connective tissue matrix and collagen.

Question 18

A furuncle may be a folliculitis that has spread through the follicular wall to the dermis.

Accepted Answer

A furuncle, or "boil," is an inflammation of the hair follicles that may develop from a preceding folliculitis and spread through the follicular wall into the surrounding dermis.

Question 19

Older adults have impaired wound healing because of a decreased blood supply and depressed immune system.

Accepted Answer

Decreased cell proliferation, decreased blood supply, and depressed immune responses delay wound healing in aging skin.

Question 20

Erysipelas is an acute infection of the skin most often caused by group A streptococci.

Accepted Answer

Erysipelas is an acute superficial infection of the upper dermis (a superficial form of cellulitis) most often caused by group A streptococci.

Quiz 44: Structure, Function, and Disorders of the Integument