Integumentary System

Question 1

The skin has two distinct layers.

The superficial layer is a sheet of keratinized stratihed squamous epithelium called the

Answer 1

epidermis

Question 2

The epidermis is itself divided into distinct histological regions or strata (meaning “layers”):

Answer 2

Stratum basale
Stratum spinosum
Stratum granulosum
Stratum lucidum
Stratum corneum

Question 3

is the deepest stratum of the epidermis. It consists of a single sheet of columnar cells that continue to divide. As the daughter cells are formed, they are pushed upward, becoming part of the next stratum.

Answer 3

Stratum Basale

Question 4

is noted for its multilayer of distorted (“spined”) cells. The cells become distorted as they are pushed up from the deeper stratum basale.

Answer 4

Stratum spinosum

Question 5

Stratum Basale & stratum spinosum together are often called

Answer 5

stratum germinativum.

Question 6

is superficial to stratum spinosum.

It contains flattened cells pushed up from the deeper strata.

As the cells are pushed up through this stratum, they form the protein granules that give it the name ___. By the time the cells leave this stratum, they have died.

Answer 6

Stratum granulosum

Question 7

(meaning “light layer”) is a very thin layer present only in thick skin.

Thick skin is found only in high-wear areas such as the palms and soles.

The more flexible thin skin is found over most other areas of the body.

This stratum’s name comes about because it is translucent, allowing light to pass through it easily.

Answer 7

Stratum lucidum

Question 8

is the layer of dead, keratinized tissue already

is extremely thick in thick skin, providing a great deal of protection.

It protects deeper tissues from mechanical injury, from inward or outward diffusion of water and other molecules, and from invasion by microorganisms.

Answer 8

Stratum corneum

Question 9

The layer of skin deep to the epidermis is a sheet of irregular fibrous connective tissue called the

Answer 9

dermis

Question 10

has a scattering of blood vessels and nerves. The blood vessels supply both the dermis and epidermis.

Because blood cools when it travels through the skin, the body varies the amount of blood sent to the skin to regulate loss of heat by the entire body.

Answer 10

Dermis

Question 11

There are two regions of the dermis:

Answer 11

Reticular layer
Papillary layer

Question 12

The ___ of the dermis is a thick region of irregularly arranged protein fibers. Most of the fibers are collagenous, but a few are made of elastin.

Answer 12

reticular layer

Question 13

The ____ is the bumpy superficial portion of the dermis attached to the epidermis.

The bumps, called ___ (meaning “nipples”), form regular rows in thick skin but are rather irregularly arranged in thin skin. For this reason, thick skin can be observed to have distinct ridges, such as fingerprints. These ridges give the hands and feet better gripping ability.

Answer 13

papillary layer

papillac

Question 14

Deep to the skin is a layer of subcutaneous tissue, sometimes called the ____ or ___. Although not a part of the skin, it is often studied along with skin.

Answer 14

hypodermis, superficial fascia

Question 15

is loose, fibrous (areolar) connective tissue that connects the skin to underlying muscles and bone. Some of the areolar tissue has been modified to become adipose tissue. Adipose tissue’s protective and insulating characteristics complement the protection and temperature regulation roles of the skin.

Answer 15

Subcutaneous tissue

Question 16

The skin has a variety of accessory structures, including ?

Answer 16

Hair & nails

Question 17

Both hair and nails are modified forms of _____ or keratinized tissue.

Answer 17

stratum corneum

Question 18

is a cylinder of compact keratinized material

Answer 18

hair

Question 19

is a plate of compact keratinized material

Answer 19

nail

Question 20

Each hair is formed within a separate.

The ____ is a sheath-like indentation of the epidermis

Answer 20

hair follicle

Question 21

At the bottom of the follicle, a ___ covered with stratum germinativum produces the hair.

Answer 21

Hair papilla

Question 22

The portion of each hair within the follicle is called the

Answer 22

hair root

Question 23

the portion that has been pushed out of the follicle is called the

Answer 23

hair shaft.

Question 24

The hair has a very dense ___ and a less dense __.

Answer 24

cortex, medulla

Question 25

Attached to each follicle is an

This gland produces the fatty substance, sebum, that coats the hair and skin.

Answer 25

exocrine (ducted) sebaceous gland

Question 26

prevents moisture loss and conditions the hair and skin so that they do not become brittle and easily broken.

Answer 26

Sebum

Question 27

The ___ is a strap of smooth muscle tissue connecting the side of a follicle to the superficial surface of the dermis.

When contracted, the muscle pulls the follicle so that it is nearly perpendicular to the skin’s surface. This increases the air spaces among the hairs, improving their insulation quality.

Contraction of this also dimples the epidermis, raising a ridge at the edge of the follicle (a “goose pimple” or “goose bump”).

Answer 27

arrector pili muscle

Question 28

The toenail or fingernail is also formed by a modified portion

Answer 28

stratum germinativum

Question 29

In the case of either hair or nail, this modified tissue is often called

Answer 29

matrix

Question 30

A portion of the nail bed (skin under the nail) is matrix that produces the

Answer 30

nail plate

Question 31

Part of the matrix may be visible through the nail as a pale crescent, or ___.

Answer 31

lunula

Question 32

Nail formation begins under a fold of

The portion of the nail under the fold is the root, and the visible portion is the nail body.

Answer 32

epidermis

Question 33

A ___ may extend from the fold onto the nail body

Answer 33

cuticle, or eponychium

Question 34

They are exocrine glands that produce a watery solution, sweat, that coats the skin.

Answer 34

Sweat glands

Question 35

serves primarily to improve heat loss by the skin through evaporation.

Answer 35

Sweat

Question 36

____ produce thin, watery sweat in many areas of the body.

Answer 36

Eccrine sweat glands

Question 37

found in the axillary and pubic regions, and starting at puberty, secrete a thicker sweat that is rich in complex organic molecules.

Answer 37

Apocrine sweat glands