NURSING 101Chapter 46: Structure, Function, and Disorders of the Integument

1. Which component of the epidermis initiates immune responses and provides a defense against environmental antigens? a. Langerhans cells c. Keratinocytes b. Merkel cells d. Melanocytes ANS: A 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. This function is not true of the other options. PTS: 1 REF: Page 1617 2. Which cells of the dermis release histamine and play a role in the hypersensitivity reactions of the skin? a. Histiocytes c. Mast cells b. Fibroblasts d. Macrophages ANS: C Only mast cells release histamine and play a role in hypersensitivity reactions in the skin. PTS: 1 REF: Page 1618 3. Which cells of the dermis secrete connective tissue matrix? a. Macrophages c. Fibroblasts b. Mast cells d. Histiocytes ANS: C Only fibroblasts secrete the connective tissue matrix and collagen. PTS: 1 REF: Page 1618