5-2. Hair, Glands, and Nails; Skin Diseases

Question 1

hair

Answer 1

keratinized organ derived from epidermis; strongest material in the body

Question 2

Hair is found everywhere except __.

Answer 2

palms, nipples, soles, lips, and parts of genitals

Question 3

What are the functions of hair?

Answer 3

protection from heat loss and UV
Keep dirt and insects out of eyes, ears and nose
Eyelashes shield eyes
Sense insects on skin

Question 4

hair shaft

Answer 4

visible part projecting from the skin (shapes: round, oval, flat)

Question 5

hair root

Answer 5

part of hair embedded in skin

Question 6

hair follicle

Answer 6

structure that covers inner root sheaths extending from epidermal surface into dermis from which new hair develops.

Question 7

Hair follicles are active on the scalp for __, and eyelashes and brows ___.

Answer 7

scalp: 6-10 years

eyelashes and brows: 3-4 months

Question 8

hair bulb

Answer 8

lower, enlarged end of the follicle; contains a papilla providing nourishment; nerve ending wrapped around. acts as a very sensitive touch receptor.

Question 9

hair matrix

Answer 9

cells at base of bulb responsible for growth. Produce new hair by mitosis when old one is shed. Older cells pushed up root, become increasing keratinized and die.

Question 10

arrector pili

Answer 10

bundle of smooth muscle cells connected to each hair. Contraction pulls follicle upright and dimples skin (goose bumps) in response to cold or fear.

Question 11

sudoriferous glands

Answer 11

sweat glands distributed all over body except nipples and parts of genitals (each person has about 3 million)

Question 12

What are the two types of sudoriferous glands?

Answer 12

eccrine sweat gland and apocrine sweat gland

Question 13

eccrine sweat gland

Answer 13

coiled end deep in dermis, duct opens in a pore on surface. Most numerous on palms, soles and forehead. Secrete true sweat: 99% water with salt and traces of metabolic waste

Question 14

What is the function of the eccrine sweat glands?

Answer 14

prevent body from overheating

Question 15

apocrine sweat glands

Answer 15

found in axillary area and anogenital area. Larger glands empty into hair follicles. Has fat and proteins, when decomposed by bacteria, produces body odor

Question 16

ceruminous glands

Answer 16

modified sweat glands found lining external ear canals. secrete sticky, bitter substance called cerumen that deters insects and blocks entry of foreign materials

Question 17

sebacious glands

Answer 17

secrete oily substance called sebum; found all over body except places without hair (palms and soles). Small on trunk and limbs, large on face, neck and upper chest. Are connected to each hair follicle

Question 18

What are the functions of sebacious glands?

Answer 18

softens and lubricates skin, prevents brittle hair, slows water loss from skin

Question 19

nails

Answer 19

hard keratinized squamos epithelium cells that form a covering over the dorsal surface of the distal end of fingers and toes

Question 20

What are the functions of nails?

Answer 20

protect tips of fingers and toes
grasp and manipulate small objects
scratch an itch

Question 21

nail body

Answer 21

part of nail you see; pink because of underlying blood vessels

Question 22

free edge

Answer 22

part of the nail extending beyond the digit

Question 23

nail root

Answer 23

part hidden under skin

Question 24

lunula

Answer 24

white crescent at proximal border of nail body

Question 25

cuticule

Answer 25

narrow band of epidermis folded over proximal border of nail body

Question 26

nail matrix

Answer 26

epithelium under nail root, responsible for growth

Question 27

acne

Answer 27

active inflammation of sebacious glands, usually caused by bacterial infection (part. staphylococeus), and can be mild or severe

Question 28

What causes acne?

Answer 28

as white blood cells fight bacteria, pus (dead cells - bacteria and WBC) accumulate

Question 29

warts

Answer 29

viruses invade epithelial cells and cause them to multiply rapidly > benign tumors appear, often on hands/feet.

Question 30

How are warts spread?

Answer 30

direct contact with other humans with the papilloma virus

Question 31

ringworm

Answer 31

group of contageous fungal infections that may appear ring shaped. As fungi feed on skin cells, red scaly itchy lesions develop. Tend to grow on moist, damp areas (btwn toes - athlete’s foot; in groin - jock itch)

Question 32

skin cancer

Answer 32

malignant tumors arising in skin and invade other body areas

Question 33

What is the most common cause of skin cancer?

Answer 33

Overexposure to UV rays

Question 34

What are the two types of skin cancer?

Answer 34

basal cell carcinoma

melanoma

Question 35

basal cell carcinoma

Answer 35

least malignant but most common form of skin cancer. Cells of stratum basale proliferate to form shiny, dome shaped nodules. Full cure by surgical removal in 99% of cases

Question 36

melanoma

Answer 36

cancer of melanocytes, most dangerous but least common. Appears as a spreading brown/black patch that metasticizes rapidly to surrounding lymph/blood vessels.

Question 37

What is the primary treatment for melanoma?

Answer 37

wide surgical excision of tumor followed by chemo. Early detection is key to survival

Question 38

What is one rule for detecting melanoma?

Answer 38

ABCD Rule:

A - asymmetry (two sides do not match)
B - border irregularity (edges are indented, not smooth)
C - color (areas of different color)
D - diameter (larger than 6 mm across)

Question 39

burn

Answer 39

tissue damage from heat, electricity, radiation or chemicals

Question 40

What are the immediate dangers of burns?

Answer 40

loss of fluid and electrolytes > dehydration >shock and renal failure. Immediate replacement of lost fluids intravenously critical

Question 41

Rule of nines

Answer 41

way to assess % of body burned, used to estimate fluid loss

Question 42

After initial crisis has passed, the main threat of a burn is ___.

Answer 42

infection

Question 43

first degree burn

Answer 43

only epidermis is damaged, local redness and swelling (eg. sunburn)

Question 44

second degree burn

Answer 44

epidermis is destroyed, upper dermis injured. Local redness, swelling and blisters

Question 45

third degree burn

Answer 45

epidermis and dermis are destroyed; skin is gray, cherry red or black. Requires skin grafts