A&p I: Ch 5 Notes

Front 1

What are the three major parts of the integumentary system?

Back 1

Epidermis
Dermis
Subcutaneous Layer (aka hypodermis)

Front 2

What are the two parts of the integument?

Back 2

cutaneous membrane
accessory structures

Front 3

What are the two components of the cutaneous membrane?

Back 3

outer epidermis (the superficial epithelium)
inner dermis (connective tissues)

Front 4

Where do accessory structures originate? What are the 5 most common accessory structures?

Back 4

* originate in the dermis, extend up through the epidermis to the skin surface
1) hair
2) hair follicles
3) sebaceous glands
4) sweat glands
5) nails

Front 5

What direct connections does the integument system have with other systems? (2 primary)

Back 5

* cardiovascular system -> blood vessels in the dermis
* nervous system -> sensory receptors for pain, touch and temperature

Front 6

What are the main functions of the skin?

Back 6

protect underlying tissues and organs
excrete salts, water and organic wastes (glands)
maintain body temperature (insulation/evaporation)
synthesize vitamin D3
store lipids
detect touch, pressure, pain and temperature

Front 7

What kind of tissue makes up the epidermis? What is its prominent characteristic?

Back 7

* stratified squamous epithelium
*avascular (nutrients and O2, diffues from capillaries in the dermis)

Front 8

What is the most abundant cell in the epidermis? What are some of its characteristics?

Back 8

* keratinocytes
* contain large amounts of keratin
* produce keratin (thick strong fibers)

Front 9

What are the two types of skin? Where is it found on the body? how many layers of keratinocytes does each contain?

Back 9

Thin skin
- covers most of the body
- 4 layers of keratinocytes
Thick skin
- covers palms of hands and soles of feet
- 5 layers of keratinocytes

Front 10

List the five strata of keratinocytes in thick skin, in order from the basal lamina to the free surface

Back 10

1) stratum basale (germinativum)
2) stratum spinosum
3) stratum granulosum
4) stratum lucidum (unique to thick skin)
5) stratum corneum

Front 11

What are some characteristics of the stratum basale? What are its 2 specialized cells and their purpose?

Back 11

* has many germinative (stem) cells or basal cells
* attached to basal lamina by hemidesmosomes
* forms strong bond between epidermis and dermis
* forms epidermal ridges
* dermal papillae -> increase area of basale lamina which strengthens attachment between epidermis and dermis
* Merkel cells - found in hairless skin, respond to touch (trigger nervous system)
* Melanocytes - contain pigment melanin, scattered thru out stratum basale

Front 12

What are some characteristics of the stratum spinosum?

Back 12

* the "spiny layer"
produced by division of stratum basale
contains 8-10 layers of keratinocytes bound by desmosomes
continues to divide, increasing thickness of epithelium
contains dendritic (Langerhans) cells - active in immune response

Front 13

What are some characteristics of the stratum granulosum? What do the cells of the stratum granulosum do?

Back 13

* the "grainy" layer
stops dividing, starts producing keratin (tough fibrous protein) and keratohaylin (dense granules, cross-linked keratin fibers)
* the cells produce protein fibers, then dehydrate and die
* the cells create tightly interlocked layer of keratin surrounded by keratohyalin

Front 14

What are some characteristics of the stratum lucidum?

Back 14

* the "clear" layer
*found only in thick skin*
covers stratum granulosum

Front 15

What are some characteritics of the stratum corneum?

Back 15

* the "horn layer"
exposed surface of the skin (dry layer)
15-30 layers of keratinized cells (cornification)
shed and replaced every 2 weeks
contains desmosomes
water resistant, but not waterproof

Front 16

What is keratinization?

Back 16

formation of a layer of dead, protective cells filled with keratin
occurs on all exposed skin surfaces except eyes

Front 17

How long does it take for the skin life cycle?

Back 17

15-30 days for a cell to move from stratum basale to stratum corneum

Front 18

What are the 2 kinds of perspiration?

Back 18

* insensible perspiration
* sensible perspiration

Front 19

Describe insensible perspiration

Back 19

when interstitial fluid is lost by evaporation through the stratum corneum

Front 20

Describe sensible perspiration

Back 20

When water is excreted by sweat glands
can lead to dehydration when there has been damage to the stratum corneum (burns and blisters) or from immersion to hypertonic solution (seawater)

Front 21

What 2 pigments influence skin color?

Back 21

* carotene
* melanin
* blood circulation also has an affect

Front 22

Briefly describe carotene

Back 22

orange-yellow pigment found in orange vegetables
accumulates in epidermal cells and fatty tissues of the dermis
can be converted to vitamin A

Front 23

Briefly describe melanin

Back 23

yellow-brown or black pigment
produced by melanocytes in stratum basale
transferred to keratinocytes

Front 24

What are the functions of melanocytes?

Back 24

melanin protects skin from sun damage
- UV radiation can cause DNA mutations and burns that lead to cancer and wrinkles
skin color depends on melanin production, not number of melanocytes

Front 25

What is the Epidermal Growth Factor (EFG)? Where is it produced? What is it used for? What are its functions?

Back 25

EFG is a powerful peptide growth factor
EFG is produced by glands (salivary and duodenum)
EFG is used in laboratories to grow skin grafts
Functions:
- promotes division of germinative cells
- accelerates keratin production
- stimulates epidermal repair
- stimulates glandular secretion

Front 26

Where do we primarily get vitamin D3 from? List some examples

Back 26

*sunlight
- UV radiation causes epidermal cells of stratum spinosum and basale to convert a steroid to cholecalciferol
- liver then creates intermediate product which is converted to calcitrol by the kidneys
- calcitrol allows calcium and phosphate absorption in the intestine
* diet
- naturally from fish, fish oils and shellfish
- from fortified food products

Front 27

Which primary hormones coordinate integumentary system function with other systems?

Back 27

steroid hormones (glucocorticoids)
thyroid hormones
sex hormones
growth hormone

Front 28

How do steroid hormones (glucocorticoids) affect the integumentary system?

Back 28

loosen intercellular connections and reduce epidermis effectiveness as a barrier to infection

Front 29

How do thyroid hormones affect the integumentary system?

Back 29

they maintain the normal blood flow to papillary plexus

Front 30

How do sex hormones affect the integumentary system?

Back 30

increase epidermal thickness
accelerate wound healing
increase number of dendritic cells protecting against cancer cells and pathogens

Front 31

How do growth hormones affect the integumentary system?

Back 31

stimulate fibroblast activity and collagen production
stimulate germinal cell division
- thickens epidermis
- promotes wound repair

Front 32

What are some characteristics of the papillary layer of the dermis?

Back 32

consists of areolar tissue (loose connective tissue)
contains smaller capillaries, lymphatics, and sensory neurons
has dermal papillae projecting between epidermal ridges

Front 33

What are some characteristics of the reticular layer of the dermis?

Back 33

consists of dense irregular connective tissue
contains larger blood vessels, lymph vessels and nerve fibers
contains collagen and elastic fibers
contains connective tissue proper

Front 34

What is dermatitis? What causes it? What is it characterized by?

Back 34

an inflammation of the papillary layer
caused by infection, radiation, mechanical irritation, or chemicals
characterized by itch or pain

Front 35

What provides dermal strength and elasticity?

Back 35

2 types of fibers
- collagen fibers (strong, resist stretching but bend easily - provide flexibility)
- elastic fibers (permit stretching then recoil to original length, limit flexibility of collagen fibers to prevent damage to tissue)
Skin Turgor
-properties of flexibility and resilience

Front 36

What makes up the Dermal Blood Supply?

Back 36

* The cutaneous plexus
- network of arteries along the reticular layer
* the papillary plexus
- capillary network from small arteries in papillary layer
*the venous plexus
- capillary return deep to the papillary plexus

Front 37

What is a contusion (in the dermis)?

Back 37

damage to blood vessels resulting in "black-and-blue" bruising

Front 38

What do nerve fibers in the skin control?

Back 38

blood flow
glandular secretions
sensory receptors

Front 39

What are tactile discs What do they monitor?

Back 39

sensory terminals
monitor Merkel cells

Front 40

What are some characteristics of the subcutaneous layer (hypodermis)?

Back 40

- lies below the integument
- stabilizes the skin
- allows separate movement
- made of elastic areolar and adipose tissues
- connected to the reticular layer of integument by connective tissue fibers
- has few capillaries and no vital organs
- site of subcutaneous injections using hypodermic needles

Front 41

What are some characteristics of subcutaneous fat deposits?

Back 41

- provides insulation for the body (helps maintain body temperature)
- have distribution patterns determined by hormones
- reduced by cosmetic liposuction

Front 42

What are the lines of cleavage?

Back 42

- formed by arrangement of collagen and elastin fibers in the skin
- clinically significant for surgery and wound healing (cut parallel -> better healing, less scarring, cut perpendicular -> remain open and more scarring)

Front 43

Where is the human body NOT covered with hair?

Back 43

palms
soles
lips
portions of external genitalia

Front 44

What are the functions of hair?

Back 44

protect and insulate
guard openings against particles and insects
sensitive to very light touch

Front 45

Describe the Hair follicle

Back 45

located deep in the dermis, produces nonliving hairs
wrapped in a dense connective tissue sheath
base is surrounded by sensory nerves (root hair plexus)

Front 46

Describe the accessory structures of hair

Back 46

Arrector Pili
-involuntary smooth muscle, causes hair to stand up ("goose bumps"
Sebaceous glands
- lubricate the hair/ skin surface
-control bacteria

Front 47

Describe the regions of the hair

Back 47

Hair Root
- lower part of the hair, attached to the integument
Hair Shaft
- upper part of the hair, not attached to the integument

Front 48

What are the three types of hairs?

Back 48

lanugo hairs
vellus hairs
terminal hairs

Front 49

What are lanugo hairs?

Back 49

hairs on an infant in utero, small tiny hairs that cover the surface of the body

Front 50

What are Vellus hairs?

Back 50

Soft, fine hairs that cover the body surface

Front 51

What are terminal hairs?

Back 51

Heavy, pigmented hairs
Located on the head, eyebrows, eyelashes and other parts of the body after puberty

Front 52

What affects hair color?

Back 52

produced by melanocytes at the hair papilla
determined by genes

Front 53

What are the two types of exocrine glands in the skin?

Back 53

Sebaceous glands
Sweat glands

Front 54

What are sebaceous glands? What are the two types of sebaceous glands?

Back 54

holocrine glands
secrete sebum (oil - lipids and other ingredients, lubricates and protects the epidermis and inhibits bacteria)
1) simple branched alveolar glands
- associated with hair follicles
2) sebaceous follicles
- discharge directly onto skin surface

Front 55

What are the two types of sweat glands? What is the main function of sweat glands?

Back 55

apocrine glands
merocrine glands
watery secretions

Front 56

Describe apocrine glands and state where they are found.

Back 56

Found in armpits, around nipples, and groin
secrete products into hair follicles
produce sticky, cloudy secretions
breakdown and cause odors
surrounded by myoepithelial cells which squeeze secretions onto skin surface in response to hormonal or nervous signal

Front 57

Describe Merocrine (Eccrine) sweat glands and state where they are found.

Back 57

Found widely distributed on body surface, especially on palms and soles
coiled, tubular glands
discharge directly onto skin surface
sensible perspiration
secrete water, salts, and organic compounds

Front 58

What are the functions of merocrine sweat gland activity?

Back 58

cool skin
excrete water and electrolytes
flush microorganisms and harmful chemicals from the skin

Front 59

What does the ceruminous gland do?

Back 59

produces cerumen (earwax)
protects the eardrum

Front 60

Which glands does the autonomic nervous system control? And where does it take place?

Back 60

-controls sebaceous and apocrine sweat glands
- works simultaneously over entire body

Front 61

How are merocrine sweat glands controlled? Where does sweating occur?

Back 61

- controlled independently
- sweating occurs locally

Front 62

What is the main function of sensible perspiration?

Back 62

Main function: thermoregulation - regulates body temperature -> works with the cardiovascular system

Front 63

What are nails made of?

Back 63

dead cells packed with keratin (strong protein fiber)

Front 64

What are the 6 primary parts of the visible nail?

Back 64

1) Nail body - visible portion
2) Lunula - pale crescent at the base of the nail
3) Sides of nails - lie in lateral nail grooves, surrounded by lateral nail folds
4) Hyponychium - skin beneath distal free edge of the nail
5) Eponychium - cuticle
6) Proximal nail fold

Front 65

Briefly describe the repair process of the integument..

Back 65

- bleeding occurs
- mast cells -> trigger inflammatory response
- scab stabilizes and protects the area
-germinative cells migrate around the wound
- macrophages clean the area
-fibroblasts and endothelial cells move in producing granulation tissue
-inflammation decreases
-clot disintegrates
- fibroblasts strengthen scar tissue

Front 66

What is granulation tissue?

Back 66

Scar tissue

Front 67

What is a keloid?

Back 67

When scar tissue is raised above the skin