Porth Chapter 60

Question 1

functions of the skin

Answer 1

prevent body fluids from leaving the body; protect the body from potentially damaging environmental agents, serve as an area for heat exchange; provide protection against invading microorganisms

Question 2

role of receptors in the skin

Answer 2

relay the following sensations to the CNS for localization and discrimination:
pressure, temperature, pain

Question 3

outer epidermis

Answer 3

avascular layer composed of four to five layers of stratified squamous keratinized epithelial cells formed in the deepest layer of the epidermis; these cells migrate to the skin surface to replace cells lost during normal shedding

Question 4

basement membrane (skin)

Answer 4

thin adhesive layer cementing the epidermis to the dermis; layer involved in blister formation

Question 5

inner dermis

Answer 5

connective tissue layer that separates the epidermis from the underlying subcutaneous fat layer; contains blood vessels and nerve fibers that supply the epidermis

Question 6

keratinocyte

Answer 6

major cell of epidermis, 95% of this layer, five layers that represent a progressive differentiation or maturation of the keratinocytes, originate in basal layer and change morphically as they are pushed to outer layer of the epidermis, migration time is 20-30 days, rate of production needs to be consistent with rate of shedding

Question 7

papillary dermis

Answer 7

A thin, superficial layer that lies adjacent to the epidermis; Consists of collagen fibers and ground substance; this layer is densely covered with conical projections called dermal papillae; Minimize the separation of the dermis and the epidermis; Nourish the epidermal layers of the skin

Question 8

reticular dermis

Answer 8

The thicker area of the dermis that forms the bulk of the dermal layer​; Complex meshwork of three-dimensional collagen bundles interconnected with large elastic fibers and ground substance​; A viscid gel that is rich in mucopolysaccharides

Question 9

skin appendages

Answer 9

hair, nails, sebaceous glands, eccrine glands, apocrine glands

Question 10

eccrine sweat glands

Answer 10

Simple tubular structures that originate in the dermis and open directly to the skin surface​; Numerous (several million) and vary in density​; Located over the entire body surface; Transport sweat to the outer skin surface to regulate body temperature

Question 11

apocrine sweat glands

Answer 11

Less numerous than eccrine sweat glands; Larger and located deep in the dermal layer​; Open through a hair follicle, even though a hair may not be present​; Found primarily in the axillae and groin

Question 12

secretions of the sebaceous glands

Answer 12

Lipids, including triglycerides​; Cholesterol; Wax

Question 13

secretions of the sebaceous glands

Answer 13

Lipids, including triglycerides​; Cholesterol; Wax

Question 14

nails

Answer 14

Hardened keratinized plates​; Protect the fingers and toes and enhance dexterity

Question 15

immune cells found in dermis

Answer 15

Macrophages​; T cells​; Mast cells​; Fibroblasts

Question 16

pruritus

Answer 16

Originates in free nerve endings in the skin​; Carried by small myelinated type C nerve fibers; Itch and pain are antagonistic; Causes​: Histamine​, Tryptase, Opioids, Neuropeptides, Substance P​, Bile salts, Bradykinin

Question 17

xerosis

Answer 17

Dry skin​; Dehydration of the stratum corneum; Aging skin will be dry due to a change in the composition of sebaceous gland secretions and a decrease in the secretion of moisture from the sweat glands; Moisturizing agents are the cornerstone of treatment for dry skin: Emollients, Humectants, Occlusives

Question 18

dark skin variations

Answer 18

Because of their skin color, dark-skinned persons are better protected against skin cancer, premature wrinkling, and aging of the skin that occurs with sun exposure. (Ashy skin​, Hypo- and hyperpigmentation)