5-1. The Skin

Question 1

Integumentary System

Answer 1

the skin and organs derived from it, including hair, nails, sweat and oil glands

Question 2

What are the 5 functions of the integumentary system?

Answer 2

1. protection
2. regulation of body temperature
3. cutaneous sensation
4. Vitamin D conversion
5. Excretion

Question 3

What does the integumentary system protect from?

Answer 3

protects underlying tissues from physical abrasion, bacterial invasion, and damaging UV radiation

Question 4

What does the integumentary system use to regulate body temperature?

Answer 4

sweat glands, shivering, blood flow to surface

Question 5

cutaneous sensation

Answer 5

special receptors that detect temperature, touch, pressure, and pain

Question 6

When skin is exposed to sunlight, __ in dermal blood vessels is converted to a __.

Answer 6

modified cholesterol; Vitamin D precurser

Question 7

What does the skin excrete?

Answer 7

small amounts of nitrogenous wastes (ammonia, urea, uric acid) are eliminated in sweat (though they are mostly excreted in urine)

Question 8

The skin is the __ organ in the body.

Answer 8

largest

Question 9

What are the two main layers to the skin?

Answer 9

epidermis (outer, thinner layer), dermis (inner thicker layer making up the bulk of the skin)

Question 10

outer, thinner layer of the skin

Answer 10

epidermis

Question 11

inner thicker layer of the skin, making up the bulk

Answer 11

dermis

Question 12

What are the functions of the epidermis?

Answer 12

protects, waterproofs, adds new cells, gives rise to hair, nails and glands

Question 13

What is the general structure of the epidermis?

Answer 13

keratinized, stratified squamos epithelium organized in 4-5 layers

Question 14

The epidermis is ___. (vascular/avascular)

Answer 14

avascular - nourishment comes from underlying dermis

Question 15

keratin

Answer 15

fibrous protein produced by keratinocytes that waterpoofs skin, resists abrasion, and acts as barrier to bacteria

Question 16

keratinocytes

Answer 16

special epidermial cells producing keratin

Question 17

What are the five epidermal layers, from deep to superficial?

Answer 17

stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum

“Bring Some Good Lotion to Cover”

Question 18

stratum basale

Answer 18

deepest layer of epidermis, attached to dermis. 1 layer of cells that keeps making new cells by mitosis

Question 19

What is the only layer of the epidermis that divides?

Answer 19

stratum basale

Question 20

Where is the stratum lucidum found?

Answer 20

thick skin of palms/soles

Question 21

stratum corneum

Answer 21

thick outer layer of flat dead cells filled with keratin and continuously shed

Question 22

keratinization

Answer 22

newly formed cells from basal layer are pushed to surface > filled with keratin and die (too far from blood vessels) > flake up and replaced from below

Question 23

We get a new epidermis every ___.

Answer 23

25-45 days

Question 24

callus

Answer 24

a thickening of the epidermis caused by persistent friction

Question 25

What are the functions of the dermis?

Answer 25

nourishes and supports epidermis, contains nerves for touch, gives skin strength, elasticity and extensibility

Question 26

What is the general structure of the dermis?

Answer 26

dense connective tissue containing collagen and elastic fibers. Permeated by many blood vessels, nerves, glands and hair follicles.

Question 27

What are the two layers of the dermis?

Answer 27

papillary and reticular

Question 28

The papillary layer is made of ___.

Answer 28

areolar connective tissue

Question 29

dermal papille

Answer 29

found on superior surface of the papillary layer; project into epidermis and contain capillaries or nerve endings. Increase friction and cause fingerprints.

Question 30

reticular layer

Answer 30

thick, deeper layer of the dermis (~80% of dermis), made of dense connective tissue

Question 31

hypodermis

Answer 31

subcutaneous layer of mostly adipose tissue, just deep to skin

Question 32

What are the functions of the hypodermis?

Answer 32

Attaches the dermis to underlying organs (muscle and bone), acts as a shock absorber, insulator and area of fat storage

Question 33

striae

Answer 33

stretch marks caused by extreme stretching of the skin

Question 34

blister

Answer 34

separation of dermal and epidermal layer by a fluid filled pocket, from short term acute trauma

Question 35

What determins skin color?

Answer 35

3 pigments: melanin, carotyne, and hemoglobin

Question 36

melanin

Answer 36

ranges in color from yellow to reddish brown to black. Absorbs UV radiation from sun. Racial differences due to type and amount of melanin.

Question 37

sun tan

Answer 37

prolonged sun exposure causes buildup of melanin to protect cell DNA from UV radiation

Question 38

albinism

Answer 38

inherited inability to make melanin

Question 39

Local accumulations of melanin are called __.

Answer 39

freckles (flat) or moles (raised)

Question 40

melanocytes

Answer 40

cells in epidermis that make melanin

Question 41

carotine

Answer 41

yellow-orange pigment in certain plants that tends to accumulate in the stratum corneum and hypodermis. Most obvious in palms and soles, varies with diet.

Question 42

hemoglobin

Answer 42

red pigment in blood cells circulating in capillaries of dermis

Question 43

cyanosis

Answer 43

blue; low oxygen

Question 44

erythema

Answer 44

red; inflammation, allergy, fever, emotion

Question 45

pallor

Answer 45

white; stress, low BP, anemia, fear or anger

Question 46

jaundice

Answer 46

yellow; liver disorder

Question 47

bruises

Answer 47

black and blue; blood escapes from damaged vessels and clots beneath skin

Question 48

vitiligo

Answer 48

loss of melanocytes (autoimmune)