Exam 3: A & P 1

Age spots occur because of

an increase in the size of some melanocytes

Local destruction of skin and subcutaneous tissue on exposed surfaces as a result of extreme cold. In mild cases, the skin is blue and swollen and there is slight pain. In severe cases there is considerable swelling, some bleeding, no pain, and blistering. If untreated, gangrene may develop.

frostbite

What is responsible for the color of gray hair?

small amounts of pigment in the medulla

Mass produced by uncontrolled growth of epithellal skin cells; caused by a papillomavirus. Most are noncancerous.

wart

About ________ of water evaporates through the skin each day.

400mL

Structure composed of epithelium and surrounding the root of a hair from which hair develops.

Hair follicle

An excessive growth of hair in females and children, with a distribution similar to that in adult males, due to the conversion of vellus hairs into large terminal hairs in response to higher-than-normal levels of androgens.

Hirsutism

Which of the following is NOT one of the ways that the skin contributes to immunity?

It helps provide calcium ions.

What is the function of melanin

Melanin protects DNA of keratinocytes from the damaging effects of UV light.

Why does it hurt when you pluck out a hair but not when you have a haircut?

Plucking a hair stimulates hair root plexuses in the dermis, some of which are sensitive to pain. Because the cells of a hair shaft are already dead and the hair shaft lacks nerves, cutting hair is not painful.

Would you expect an epidermal wound to bleed? Why or why not?

Since the epidermis is avascular, an epidermal wound would not produce any bleeding.

Which epidermal layer includes stem cells that continually undergo cell division?

The stratum basale is the layer of the epidermis with stem cells that continually undergo cell division.

Which of the following is true when comparing thin and thick skin?

Thick skin has a higher density of sensory receptors than thin skin.

A fungal infection characterized by scaling, itching, and sometimes painful lesions that may appear on any part of the body; also known as Ringworm.

Tinea Corporis

Abnormal, nonpathological, partial, or total absence of pigment in skin, hair, and eyes.

albinism

Genetic factors, aging and endocrine disorders may contribute to the partial or complete lack of hair. This is called

alopecia

The partial or complete lack of hair as a result of factors such as genetics, aging, endocrine disorders, chemotherapy, and skin diseases.

alopecia

What is an abrasion?

an area where the skin has been scraped away.

A type of gland in which the secretory products gather at the free end of the secreting cell and are pinched off, along with some of the cytoplasm, to become the secretion, as in mammary glands.

apocrine sweat glands

Smooth muscles attached to hairs; contraction pulls the hairs into a vertical position, resulting in "goose bumps."

arrector pili

The most common form of skin cancer is

basal cell carcinoma

Proliferation of _________ forms all the layers of the epidermis.

basal cells

Which of the following is the very first step in epidermal wound healing?

basal cells lose contact with basement membrane

the deepest layer of the epiderimis is the stratum

basale

A collection of serous fluid within the epidermis or between the epidermis and dermis, due to short-term but severe friction. The term Bulla (BUL-a) refers to a large one.

blister

The skin synthesizes a precursor of ________ in response to UV radiation in sunlight.

calcitriol

An area of hardened and thickened skin that is usually seen in palms and soles and is due to persistent pressure and friction.

callus

Which of the following is NOT an organ system that the skin contributes to by helping activate vitamin D?

cardiovascular system

A lesion, usually in an oral mucous membrane, caused by type 1 herpes simplex virus (HSV) transmitted by oral or respiratory routes. The virus remains dormant until triggered by factors such as ultraviolet light, hormonal changes, and emotional stress. Also called a Fever blister.

cold sore

A collection of sebaceous material and dead cells in the hair follicle and excretory duct of the sebaceous (oil) gland. Usually found over the face, chest, and back, and more commonly during adolescence. Also called a Blackhead.

comedo

Condition in which tissue deep to the skin is damaged, but the epidermis is not broken.

contusion

A tactile receptor within the dermis that is sensitive to touch.

corpuscles of touch

The epidermis is derived from which developmental layer?

ectoderm

A disorder of the skin characterized by inflammation, red patches, blistering and itchy skin is

eczema

Which of the following is a redness of the skin due to engorgement of blood capillaries in the dermis?

erythema

The process by which fibroblasts synthesize collagen fibers and other extracellular matrix materials that aggregate to form scar tissue.

fibrosis

Which of the following is NOT typically considered a risk factor for skin cancer?

gender

A threadlike structure produced by hair follicles that develops in the dermis. Also called a pilus (Pī-lus); plural is pili (Pī -lī).

hair

A network of dendrites arranged around the root of a hair as free or naked nerve endings that are stimulated when a hair shaft is moved.

hair root plexus

Localized benign tumor of the skin and subcutaneous layer that results from an abnormal increase in the number of blood vessels. One type is a Portwine stain, a flat, pink, red, or purple lesion present at birth, usually at the nape of the neck.

hemanginome

Localized, protective response to tissue injury designed to destroy, dilute, or wall off the infecting agent or injured tissue; characterized by redness, pain, heat, swelling, and sometimes loss of function.

inflammation

Which of the following is a skin condition due to the buildup of the yellow pigment bilirubin in the skin?

jaundice

Oval-shaped pressure receptor located in the dermis or subcutaneous tissue and consisting of concentric layers of a connective tissue wrapped around the dendrites of a sensory neuron.

lamellated corpuscles

Fine downy hairs that cover the fetus.

lanugo

The moon-shaped white area at the base of a nail.

lanula

Contagious arthropods that include two basic forms.

lice

Which epidermal cells produce the pigment of the skin?

melanocytes

An embryonic connective tissue from which all other connective tissues arise.

mesenchyme

The neural structures located usually in the dermis that are sensitive to pressure are the

pacinian (lamellated) corpuscles

A common and chronic skin disorder in which keratinocytes divide and move more quickly than normal from the stratum basale to the stratum corneum. As a result, the surface cells never get a chance to cycle into the later keratinizing stages. The surface cells are shed immaturely and on the scalp are called dandruff.

psoriasis

An exocrine gland in the dermis of the skin, almost always associated with a hair follicle, that secretes sebum.

sebaceous gland

Older skin tends to be dry and broken because

sebaceous glands shrink in size

Which of the following contains bacteriacides?

sebum

secretion of sebaceous (oil) glands

sebum

Which of the following is the correct sequence of epidermal layers, from deepest to most superficial?

stratum basale, stratum spinosum, stratum granulosum, stratum corneum

The nail body is comparable to which layer of the general epithelium?

stratum corneum

Internal scarring due to overstretching of the skin in which collagen fibers and blood vessels in the dermis are damaged. Also called stretch marks.

striae

A continuous sheet of areolar connective tissue and adipose tissue between the dermis of the skin and the deep fascia of the muscles. Also called the hypodermis.

subcutaneous layer

Identify the layer located deep to the dermis but not a part of the skin.

subcutaneous layer

An apocrine or eccrine exocrine gland in the dermis or subcutaneous layer that produces perspiration

sudoriferous glands

Saucer-shaped free nerve endings that make contact with Merkel cells in the epidermis and function as touch receptors.

tactile discs

Thick skin is thicker than thin skin mostly because in thick skin

the stratum corneum is thicker

Homeostatic regulation of body temperature through sweating and adjustment of blood flow in the dermis.

thermoregulation

Cells in the stratum lucidum are dead and contain large amounts of keratin and thickened plasma membranes.

true