Anatomy & Physiology Chapter 5

Front 1

Two major regions of the skin

Back 1

- epidermis
- dermis

Front 2

- keratinized stratified squamous epithelium.

Back 2

The epidermis is composed of

Front 3

- They are the most common (90%) of the epidermal cells- produce keratin protein
– produce lamellar granules

Back 3

Keratinocytes

Front 4

- makes skin tough and provides protection

Back 4

keratin

Front 5

- release a lipid-based, water repellant, sealant

Back 5

lamellar granules

Front 6

- these produce the pigment melanin, which moves to the keratinocytes and absorbs damaging U.V. rays of the sun.

Back 6

Melanocytes

Front 7

- arise from red bone marrow and participate in the immune response against invading microbes.

Back 7

Langerhans cells

Front 8

- serve in the sensation of touch.

Back 8

Merkel cells

Front 9

Strata (layers) of the epidermis

Back 9

- corneum
– lucidum
– granulosum
– spinosum
- basale

Front 10

- is the deepest layer of epidermis
-contains keratinocytes and stem cells that divide to produce new keratinocytes
-hemidesmosomes bind keratinocytes to the basement membrane.

Back 10

Stratum basale

Front 11

-is where cells begin to become flattened.

Back 11

Stratum spinosum

Front 12

-in the middle and is where cells undergo apoptosis – contains keratohyalin Lamellar granules

Back 12

Stratum granulosum

Front 13

- cell death

Back 13

Apoptosis

Front 14

- is a distinctive protein the stratum granulosum, which converts intermediate filaments called tonofilaments into keratin

Back 14

keratohyalin

Front 15

- occurs only in thick skin and contains flattened, clear, dead, keratinocytes.

Back 15

Stratum lucidum

Front 16

-Is the outer most stratum and is made of 25-30 layers of dead flat keratinocytes.

Back 16

Stratum corneum

Front 17

On average it takes ___________ for a cell produced in the stratum basale to rise to the surface and be sloughed off.

Back 17

one month

Front 18

- the second, deeper layer of the skin
- mainly composed of C.T. w/ relatively few cells.
– papillary region
– reticular region

Back 18

Dermis

Front 19

- is more superficial and consists of areolar C.T. in projections called dermal papillae.

Back 19

Papillary region

Front 20

- These projections contain blood vessels that nourish the epidermis, and nervous tissue for various sensations.

Back 20

dermal papillae

Front 21

- consists of dense irregular C.T. w/ lots of collagen fibers that form a net.

Back 21

Reticular region

Front 22

-are small tears in the dermis caused by extensive stretching in pregnancy or obesity.

Back 22

Striae (stretch marks)

Front 23

- is the major body pigment and it varies the skin color from yellow to black.
- The number of melanocytes does not vary between the races but the amount of _______ produced does.
U.V. exposure increase enzyme activity in melanosomes which increase ______ production resulting in a suntan.
This protects skin from UV light.

Back 23

Melanin

Front 24

- in cells called melanocytes
– produce melanin

Back 24

melanosomes

Front 25

- a foreign pigment is inserted into the dermis. These can be removed with lasers but this is expensive and can be painful.

Back 25

tattooing

Front 26

- hair is composed of columns of keratinized, dead cells connected together by

Back 26

Structure

Front 27

- the part of the hair that projects from the skin.

Back 27

Shaft

Front 28

- the part of the hair below skin surface.

Back 28

Root

Front 29

- surrounds the root as an internal and external root sheath (epidermal root sheath).

Back 29

Hair follicle

Front 30

- an enlarged structure at the base of the hair follicle. It contains:

Back 30

Bulb

Front 31

- contains blood vessels that nourish hair.

Back 31

Papilla of hair

Front 32

- a ring of cells which divide to form new hair.

Back 32

Matrix

Front 33

- muscle that contracts to raise hair on skin. (Causes goose bumps)

Back 33

Arrector pili

Front 34

Function of hair: on the head

Back 34

- protects from UV rays and from injury.

Front 35

Function of hair: on the eyebrow and eyelashes

Back 35

- protects eyes from debris.

Front 36

Function of hair: -in nostrils and ear canal

Back 36

- prevents taking in of insects and particles.

Front 37

Function of hair:_______ heat loss.

Back 37

decreases

Front 38

- slight movement of hairs stimulates neurons called hair root plexuses surrounding the follicles.

Back 38

Touch reception

Front 39

- tightly packed keratinized epidermal cells and they normally grow Approx. 1 mm per week.

Back 39

Nail Structure

Front 40

Each nail consists of:

Back 40

nail root
nail body
free edge
eponychium (cuticle)
lunula
hypochium

Front 41

- the part of the nail underneath the skin.

Back 41

Nail root

Front 42

- the visible part up to the distal end of the finger.

Back 42

Nail body

Front 43

- the part of the nail that extends past the distal end of the digit.

Back 43

Free edge

Front 44

- the narrow band of epidermis above the proximal border of the visible nail.

Back 44

Eponychium (cuticle)

Front 45

- the part moon-shaped area at the base of the nail. It is white because it lies above a thick stratum basale in the nail matrix

Back 45

Lunula

Front 46

- where new cells are produced for nail growth.

Back 46

nail matrix

Front 47

- is the thickened stratum corneum below the free edge and it secures the nail to the finger tip

Back 47

Hyponychium

Front 48

Nail Function:

Back 48

-Protect against trauma to ends of digits.
- For scratching.
- For manipulating small objects.

Front 49

- are usually associated with hair and occur everywhere except for palms and soles of feet. They secrete an oily substance called sebum.

Back 49

Sebaceous glands

Front 50

-Keeps hair and skin from drying out.
- Keeps skin soft.
- inhibits bacterial growth.

Back 50

Sebum

Front 51

2 types of Sudoriferous (sweat) glands:

Back 51

eccrine
aprocrine

Front 52

- are more common
- occur everywhere except for lips, nail beds, genitalia, and eardrums.
- produce common sweat, which serves to regulate body temperature and eliminate a little waste.

Back 52

Eccrine (ordinary sweat) glands

Front 53

- occur mainly in the skin of the armpit, pubic region, areolae, and beard of males.
- During sexual excitement and emotional stress, they produce a more viscous secretion known as a “cold sweat”.

Back 53

Apocrine glands

Front 54

- occur in skin of auditory canal and secrete wax (cerumen) to trap foreign particles.

Back 54

Ceruminous glands

Front 55

Five major functions of skin

Back 55

-Thermoregulation
-protection
-sense various physical stimuli
– extretion and absorption
– synthesis of vitamin D

Front 56

- if the body temperature is too high, the skin releases sweat to cool the body.
- the blood vessels dilate (widen) to deliver more heat to the skin (vasodilatation).
-If the body temperature is too low, vasoconstriction works to conserve more body heat.

Back 56

functions of skin:
Thermoregulation

Hint 56

functions of skin:

Front 57

abrasion, microbes, dehydration, and UV radiation.

Back 57

functions of skin: Protection

Hint 57

functions of skin

Front 58

- some waste ions and organic molecules are released through skin. Topical drugs are absorbed through the skin because they are lipid-soluble.

Back 58

functions of skin: Excretion and absorption

Hint 58

functions of skin:

Front 59

-In skin, sunlight (UV) activates a chemical that later becomes Vitamin D (calcitriol) which aids in the absorption of calcium from food.

Back 59

functions of skin: Synthesis of Vitamin D

Hint 59

functions of skin:

Front 60

1. Basal epidermal cells begin to migrate (move) across the wounded area in sheets until they have contacted other cells on all sides. (contact inhibition)
2. Other basal cells divide to replace those that have left, to fill in.
3. Then all basal cells will divide to form new layers.

Back 60

Epidermal wound healing:

Front 61

1. Inflammatory phase
2. Migratory phase
3. Proliferative phase
4. Maturation phase

Back 61

Deep wound healing (cut extends into the dermal tissue):

Front 62

- Blood clot forms
- Vasodilatation and increased vessel permeability deliver pathogen fighting cells and wound healing cells to the wound.

Back 62

Inflammatory phase

Front 63

Clot becomes a scab
- Epithelial cells move (migrate) across to form a bridge
- Fibroblasts synthesize scar tissue called granulation tissue
- Damaged blood vessels grow back

Back 63

Migratory phase

Front 64

- growth of epithelial cells and deposition of collagen by fibroblasts and continued growth of blood vessels below the scab.

Back 64

Proliferative phase

Front 65

- Scab sloughs off
- Collagen fibers become organized
- Blood vessels are restored
- Fibroblasts decrease in number

Back 65

Maturation phase

Front 66

-develops from ectoderm tissue.

Back 66

epidermis

Front 67

-grows as keratinized epithelium from it‘s base. It does not reach the tip of the digit until the 9th month.

Back 67

nail

Front 68

-begin as down growths of stratum basale into the dermis. They produce a delicate fetal hair called lanugo.

Back 68

Hair follicles

Front 69

- develop as down growths of stratum basale.

Back 69

Sudoriferous (sweat) glands

Front 70

-develops from mesoderm tissue.

Back 70

dermis

Front 71

- Collagen fibers decrease in number and break.
- elastic fibers become less elastic. These changes produce wrinkles.
- Hair and nails grow more slowly.
- Pathogen fighting cells decrease in number.
- Dry and broken skin is caused by a decrease in the size of sebaceous glands.
- More susceptibility to heat strokes since sweat production is decreased.
- Pigment blotching (age spots) occur because of an increase in the size of melanocytes.
- Skin is thinner and heals more slowly.

Back 71

Describe the effects of aging on the integumentary system.

Front 72

Burns: Causes

Back 72

- excessive heat, electricity, radioactivity, or caustic chemicals, these will destroy (denature) proteins in the skin.

Front 73

Burns: Effects

Back 73

- skin looses thermoregulation and protection from pathogens and desiccation. These vary by type of burn.

Front 74

First- degree burn:

Back 74

affects only epidermis (e.g. mild sunburn)

Front 75

Second- degree burn:

Back 75

destroys part of dermis (blisters)

Front 76

Third degree (full-thickness) burn:

Back 76

extends into subcutaneous layer.

Front 77

Skin Cancer

Back 77

-the primary cause is excessive sun exposure.

Front 78

Basal cell carcinomas

Back 78

- make up 78% of all skin cancers and rarely metastasize.

Front 79

Squamous cell carcinomas

Back 79

- most arise from epidermis in preexisting skin lesions on sun-exposed skin. Have a variable tendency to metastasize

Front 80

Watch for the ABCD’s of cancer

Back 80

-Asymmetry
-Border irregular
-Color is uneven
-Diameter is greater than an eraser on a pencil

Front 81

- caused by a constant cut-off of blood supply because of bone pressing against an object. (E.g. bed) Can produce ulceration of tissue, skin breaks, and become infected.

Back 81

Pressure ulcers (bedsores, decubitus ulcers)

Front 82

an area where skin has been scraped away

Back 82

abrasion

Front 83

a superficial fungal infection of the skin of the foot

Back 83

athlete's foot

Front 84

a collections of serous fluid within the epidermis or between the epidermis and dermis, due to short term but severe friction

Back 84

blister

Front 85

refers to a large blister

Back 85

bulla

Front 86

an area of hardened and thickened skin that is usually seen in palms and sole and is due to persistant pressure and friction

Back 86

callus

Front 87

a lesion, usually in oral mucoius membrane caused by the Type 1 herpes simples 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

Back 87

cold sore
also called a fever blister

Front 88

a collectoin of sebaceous material and dead cells in the hair follicle and excretary duct of the secaceous gland. Usually found over the face, chest, and back

Back 88

comedo also known as a blackhead

Front 89

inflammation of the skin characterized by redness, itching, and swelling and caused by exposure of the skin to chemicals that bring about an allergic reacton, such as poison ivy toxins

Back 89

contact dermatitis

Front 90

a painful conical thickening of the stratum corneum of the epidermis found principally over over toe joints and between the toes, often caused by friction or pressure.

Back 90

Corn

Front 91

a sac with a distinct connective tissue wall, containing a fluid or other material

Back 91

cyst

Front 92

an inflammation of the skin characterized by patches of red, blistering, dry, extremely itchy skin. It occusrs mostly in skin creased in the wrist, backs of knees, and fronst of the elbows. It typically begins in infancy and many children outgrow the condition

Back 92

eczema

Front 93

local destruction of skin and subcutaneous tissue on exposed surfaces as a result of extreme cold.
In mild cases, the skin is wollen and there slight pain.
In severe cases there is considerable swelling, some bleeding, no pain, and blistering.
If left untreated gangrene may develop.
Treated by rapid rewarming

Back 93

frostbite

Front 94

localized tumor of the skin and subcutaneous layer that results from an abnormal increase in blood vessels.

Back 94

hemangioma

Front 95

One type of hemangioma that is present at birth
- flat, pink, red, or purple lesion
- usually at the nape of the neck

Back 95

portwine stain

Front 96

reddened elevated patches of skin that are often itchy.
Most commenly caused by infections, physical trauma, medications, emotional stress, food additived, and certian food allergies

Back 96

Hives - also called urticaria

Front 97

formation of hardened growth of epidermal tissue

Back 97

keratosis

Front 98

premalignant lesion of the sun-exposed skin of the face and hands

Back 98

solar keratosis

Front 99

an irregular tear of the skin

Back 99

laceration

Front 100

a small, round skin elevaton less than 1 cm in diameter. ex: pimple

Back 100

papule

Front 101

itching, on of the most common dermatoligical disorders.
it may be caused by skin disorders (infections), systemic disorders (cancer, kidney failure) psycogenic factors (stress) or allergic reactions

Back 101

puritis

Front 102

in reference to a medication - applied to the skin surface rather than injested or injected

Back 102

topical

Front 103

mass produced by uncontrolled growth of epithelial skin cells caused by a papillomavirus.
most are noncancerous

Back 103

wart