5.2 The Integumentary System: Accessory Structures Of The Skin

Front 1

What is another name for hairs?

Back 1

pili

Front 2

What is the shaft of hair?

Back 2

The superficial portion of the hair, which projects above the surface of the skin.

Front 3

What is the root of hair?

Back 3

The portion of the hair deep to the shaft that penetrates into the dermis, and sometimes into the subcutaneous layer.

Front 4

The shaft and root of the hair both consist of three concentric layers of cells. What are they?

Back 4

1. Medulla

2. Cortex

3. Cuticle of Hair

Front 5

What does dark hair tell you about pigment in the medulla? Grey hair? White hair?

Back 5

Dark hair: large amounts of pigment granules

Grey hair: small amounts of pigment granules

White hair: lack of pigment granules and the presence of air bubbles

Front 6

Which layer consist of cells the most heavily keratinized?

Back 6

The cuticle of the hair.

Front 7

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

Back 7

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.

Front 8

What is the hair follicle?

Back 8

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

Front 9

What is the epithelial root sheath?

Back 9

An external root sheath and an internal root sheath, which make up the hair follicle.

Front 10

What is the dermal root sheath?

Back 10

The dense dermis surrounding the hair follicle.

Front 11

What is the bulb?

Back 11

The base of each hair follicle and its surrounding dermal root sheath.

Front 12

What is the papilla of the hair? What does it contain?

Back 12

A nipple-shaped indentation houses by the bulb.

Contains areolar connective tissue and many blood vessels that nourish the growing hair follicle.

Front 13

What is the hair matrix? Where does it arise from?

Back 13

A germinal layer of cells in the bulb. Arises from the stratum basale.

Front 14

What is a depilatory?

Back 14

A substance that removes hair.

Front 15

What is the arrector pili?

Back 15

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

Front 16

What is the hair root plexus?

Back 16

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.

Front 17

What makes up the growth cycle of a hair follicle?

Back 17

A growth stage, a regression stage, and a resting stage.

Front 18

What happens during the growth stage?

Back 18

Cells of the hair matrix divide. As new cells from the hair matrix are added to the base of the hair root, existing cells of the hair root are pushed upward and the hair grows longer. While the cells of the hair are being pushed upward, they become keratinized and die.

Front 19

What happens during the regression stage?

Back 19

The cells of the hair matrix stop dividing, the hair follicle atrophies (shrinks), and the hair stops growing.

Front 20

What happens during the resting stage?

Back 20

Nothing.

Front 21

What is alopecia?

Back 21

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

Front 22

What is hirsutism?

Back 22

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.

Front 23

What are lanugo?

Back 23

Fine downy hairs that cover the fetus.

Front 24

What are terminal hairs?

Back 24

Long, coarse, heavily pigmented hairs that replace lanugo of the eyebrows, eyelashes, and scalp prior to birth.

Front 25

What are vellus hairs?

Back 25

Short, fine, pale hairs that are barely visible to the naked eye, which replace lanugo on rest of body.

Front 26

What type of melanin is in brown to black hair? Yellow to red hair?

Back 26

Brown to black: Eumelanin

Yellow to red: Pheomelanin

Front 27

What are the exocrine glands associated with skin?

Back 27

Sebaceous (oil) glands, sudoriferous (sweat) glands, and ceruminous glands.

Front 28

Where are sebaceous glands distributed? Where is the secretory portion located? Where is it connected?

Back 28

Largely in lips, glans penis, labia minora, and tarsal glands; small in trunk and limbs; absent in palms and soles.

Location: Dermis

Mostly connected to hair follicle.

Front 29

What do sebaceous glands secrete?

Back 29

Sebum.

Front 30

What is sebum?

Back 30

Secretion of sebaceous (oil) glands.

Mixture of triglycerides, cholesterol, proteins, and inorganic salts.

Front 31

What are the functions of sebaceous glands?

Back 31

Prevent hairs from drying out, prevent water loss from skin, keep skin soft, inhibit growth of some bacteria.

Front 32

When is the onset of the function of sebaceous glands?

Back 32

Relatively inactive during childhood; activated during puberty.

Front 33

Where are eccrine sweat glands distributed? Location of secretory portion? Termination of excretory duct?

Back 33

Throughout skin of most regions of body, especially skin of forehead, palms, and soles.

Location: Mostly in deep dermis (sometimes in upper subcutaneous layer).

Termination: Surface of epidermis.

Front 34

What do eccrine sweat glands secrete? What is their function? When does the onset of their functions happen?

Back 34

Secrete perspiration, which consists of water, ions (Na+, Cl−), urea, uric acid, ammonia, amino acids, glucose, and lactic acid.

Function:Regulation of body temperature, waste removal, stimulated during emotional stress.

Onset: Soon after birth.

Front 35

Where are apocrine sweat glands distributed? Location of secretory portion? Termination of excretory duct?

Back 35

Skin of axillae, groin, areolae, bearded regions of face, clitoris, and labia minora.

Location: Mostly in deep dermis and upper subcutaneous layer.

Termination: Hair follicles.

Front 36

What do apocrine sweat glands secrete? What is their function? When is the onset of their function?

Back 36

Secretes perspiration, which consists of same components as eccrine sweat glands plus lipids and proteins.

Function: Stimulated during emotional stress and sexual excitement.

Onset: Puberty.

Front 37

Where are ceruminous glands distributed? Location of secretory portion? Termination of excretory duct?

Back 37

External auditory canal.

Location: Subcutaneous layer.

Termination: Surface of external auditory canal or into ducts of sebaceous glands.

Front 38

What do ceruminous glands secrete? What is their function? When is the onset of this function?

Back 38

Secrete cerumen, a waxy material.

Function: Impede entrance of foreign bodies and insects into external ear canal, waterproof canal, prevent microbes from entering cells.

Onset: Soon after birth.

Front 39

What is a sudoriferous gland?

Back 39

An apocrine or eccrine exocrine gland in the dermis or subcutaneous layer that produces perspiration. Also called a sweat gland.

Front 40

What is thermoregulation?

Back 40

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

Front 41

What are nails?

Back 41

A hard plate, composed largely of keratin, that develops from the epidermis of the skin to form a protective covering on the dorsal surface of the distal phalanges of the fingers and toes.

Front 42

What is the nail body (plate)?

Back 42

The visible portion of the nail.

Front 43

What is the free edge?

Back 43

The part of the nail body that may extend past the distal end of the digit.

Front 44

What is the lunula?

Back 44

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

Front 45

What is the hyponychium?

Back 45

Portion of the nail beneath the free edge composed of a thickened region of stratum corneum.

Front 46

What is the nail bed?

Back 46

The skin below the nail plate that extends from the lunula to the hyponychium.

Front 47

What is the eponychium?

Back 47

Narrow band of stratum corneum at the proximal border of a nail that extends from the margin of the nail wall. Also called the cuticle.

Front 48

What is the nail matrix?

Back 48

The portion of the epithelium proximal to the nail root.

Front 49

What are the functions of nails?

Back 49

1. They protect the distal end of the digits.

2. They provide support and counterpressure to the palmar surface of the fingers to enhance touch perception and manipulation.

3. They allow us to grasp and manipulate small objects, and they can be used to scratch and groom the body in various ways.