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N106 > Chapter 5 > Flashcards

Chapter 5 Flashcards

1
Q

What are the 2 major parts of the integumentary system?

A
  1. Cutaneous membrane, or skin
  2. Accessory structures
    - Hair
    - Exocrine glands
    - Nails
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2
Q

What are the 2 layer of the Cutaneous layers

A
  1. Superficial epithelium, or epidermis

2. Underlying connective tissues of the dermis

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3
Q

Hypodermis, or subcutaneous layer

A
  • Loose connective tissue beneath the dermis
  • Separates integument from deeper tissues
  • Not part of the integumentary system, yet interwoven with connective tissue of the dermis
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4
Q

5 General Functions of the integument

A
  1. Protection
    - Skin covers and protects underlying tissues
    - Prevents fluid loss
  2. Temperature maintenance
    - Skin regulates heat exchange with the environment
  3. Synthesis and storage of nutrients
    - Epidermis synthesizes vitamin D3
    - Dermis stores lipids in adipose tissue
  4. Sensory reception
    - Receptors detect touch, pressure, pain, and temperature and relay information to nervous system
  5. Excretion and secretion
    - Glands excrete salts, water, and organic wastes
    - Specialized integumentary (mammary) glands secrete milk
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5
Q

Epidermis

A
  • Composed of layered epithelial tissue
  • Avascular (contains no blood vessels)
  • Relies on diffusion from underlying connective tissue for nutrients and oxygen
  • Deepest cells (closest to the dermis) are most active
  • Cells in outer, superficial layers are dead
  • Majority of the cells are keratinocytes
  • Contain the protein keratin
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6
Q

Thick and Thin skin

A
  • Terms “thick” and “thin” refer to thickness of epidermis (not whole integument)
  • Thick skin – five layers of cells
  • Found on palms of hands and soles of feet
  • Very thick stratum corenum
  • Total thickness about 0.5 mm (standard paper towel)
  • Thin skin – four layers of cells
  • Covers the rest of the body
  • Total thickness about 0.08 mm (plastic sandwich bag)
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7
Q

What are the 5 Layers of thick skin form deep to superficial

A
  1. Stratum basale
  2. Stratum spinosum
  3. Stratum granulosum
  4. Stratum lucidum
  5. Stratum corneum
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8
Q

Stratum Basale

A
  • Deepest layer of the epidermis
  • Also called stratum germinativum
  • Attached to basement membrane by hemidesmosomes
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9
Q

Cells in the Stratum Basale

A
  • Stem cells that continually divide to replace cells lost at the surface
  • Merkel cells (sensitive to touch)
  • Melanocytes (synthesize melanin, a pigment)
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10
Q

Epidermal Ridges

A
  • Formed by cells of the stratum basale extending down into dermis
  • Dermal projections (dermal papillae) extend up into epidermis between ridges
  • Ridges and papillae interlock
  • Increasing surface area for diffusion
  • Strengthening bond between layers
  • Contours of skin surface follow ridge patterns
  • Basis for fingerprints
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11
Q

Intermediate Strata

A
  • New daughter cells formed in stratum basale migrate upward toward skin surface
  • Cells progress through three intermediate layers
    1. Stratum spinosum
    2. Stratum granulosum
    3. Stratum lucidum
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12
Q

Stratum Spinosum (spiny layer)

A
  • Cells may continue to divide
  • Consists of keratinocytes held together by desmosomes
  • Contains branched dendritic cells (involved in the immune response)
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13
Q

Stratum Granulosum and Stratum Lucidum

A

Stratum granulosum (grainy layer)
-Cells have stopped dividing
-Cells have started making keratin
-Durable, water-resistant protein
-Coats surface of skin and forms hair and nails
Stratum lucidum (clear layer)
-Composed of flattened, densely packed cells filled with keratin

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14
Q

Stratum Corneum

A
  • Contains 15–30 layers of flattened, dead cells packed with keratin
  • Called keratinized or cornified cells
  • Cells tightly connected by desmosomes
  • Because of connections, are generally shed in large groups or sheets
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15
Q

Cell Progression in the Epidermis

A
  • Generally, takes 7–10 days for cell to move from stratum basale to stratum corneum
  • In the process, cells fill with keratin and die
  • Dead cells stay in the stratum corneum for two more weeks before being shed or washed away
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16
Q

Skin color- Pigmentation

A

Carotene and melanin are the two pigments that influence skin color

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17
Q

Carotene

A
  • Orange-yellow pigment
  • Accumulates in epidermal cells
  • Found in orange-colored foods (carrots, squashes)
  • Two types of melanin, red-yellow and brown-black
  • Made by melanocytes
  • Store melanin in vesicles called melanosomes
  • Activity increases in response to sunlight (ultraviolet radiation) exposure
  • Melanin absorbs UV radiation, protecting deeper layers of epidermis and dermis
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18
Q

Dermal Circulation and Skin Color

A
  • Oxygenated blood is bright red
  • Increase in body temperature dilates superficial blood vessels in dermis
  • Result is a flushed, red skin color
  • Temporary constriction of the same vessels results in pale skin
  • Cyanosis, a bluish coloration, occurs when blood oxygen supplies are diminished
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19
Q

Vitamin D3

A
  • Formed by epidermal cells
  • Converted from a cholesterol-related steroid when epidermal cells exposed to sunlight
  • Liver and kidneys convert vitamin D3 into calcitriol
  • Essential for absorption of calcium and phosphorus
  • Inadequate vitamin D3 can lead to weak and flexible bones
  • Detrimental Effects of Sunlight on Skin
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20
Q

Skin cancers

A
  • Any cancer of epithelial tissue is a carcinoma
  • Basal cell carcinoma is most common skin cancer
  • Originates in stratum basale
  • Squamous cell carcinoma found in more superficial layers
  • Malignant melanoma is most dangerous
  • Usually begins from a mole
  • Can metastasize through the lymphatic system
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21
Q

The Dermis

A
  • Lies between the epidermis and hypodermis
  • Contains two major layers
  • Superficial papillary layer
  • Deeper reticular layer
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22
Q

Dermal Papillary Layer

A
  • Named after the dermal papillae
  • Consists of areolar tissue
  • Supports and nourishes epidermis
  • Contains capillaries, lymphatic vessels, and sensory neurons supplying skin surface
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23
Q

Dermal Reticular Layer

A
  • Interwoven meshwork of dense irregular connective tissue
  • Elastic fibers provide flexibility
  • Collagen fibers limit flexibility and so prevent damage to tissue
  • Dominant cell type is fibroblast
  • Accessory organs derived from epidermis (hair follicles, sweat glands) extend into this layer
  • Also contains: blood vessels, lymphatic vessels, nerve fibers, and sensory receptors
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24
Q

Blood supply in the Dermis

A

Networks of arteries called plexuses

25
Q

Cutaneous Plexus

A
  • Lies along border of hypodermis

- Supplies adipose tissue in hypodermis and tissues of the integument

26
Q

Subpapillary plexus

A

Provides blood to capillary loops along epidermis-dermis boundary

27
Q

Hypodermis

A
  • Also called the subcutaneous layer
  • Deep to the dermis
  • Fibers intermixed with dermis, so no clear delineation
  • Not actually part of the integument
  • But stabilizes position of the skin relative to underlying tissues
  • Consists of areolar tissue with many fat cells
  • No vital organs in area make it an ideal site for subcutaneous injections
28
Q

Hair and Hair Follicles

A

Accessory structures of the integumentary system

29
Q

Hairs

A
  • Nonliving, keratinized structures
  • Produced by hair follicles
  • Project above the skin surface everywhere except:
  • The sides and soles of the feet, palms of the hands, sides of the fingers and toes, the lips, and portions of the external genitalia
30
Q

Hair Follicle Structure

A
  • Project into dermis and usually into hypodermis
  • Walls contain all cell layers found in epidermis
  • Epithelium at the base of follicle forms cap over the hair papilla
  • Connective tissue that contains capillaries and nerves
31
Q

Hair Matrix

A
  • surrounds hair papilla
  • Contains epithelial stem cells
  • Cells divide and push daughter cells toward surface
32
Q

Hair Structure

A
  • As hair cells move toward surface, they become keratinized and die
  • Point of keratinization is about halfway to skin surface and marks boundary between hair root and shaft
  • Hair root – portion that anchors hair into skin
  • Hair shaft – hair part we see on the surface
33
Q

Hair Shaft Structure

A 
-Three layers of dead, keratinized cells
Cuticle (surface layer)
-Made of an overlapping shingle-like layer of cells
-Contains hard keratin, giving hair stiffness
Cortex – also contains hard keratin
Medulla
-Makes up the core
-Contains flexible soft keratin
34
Q

Hair Growth

A

-Hair growth cycle
Grows for two to five years
-Follicle becomes inactive for same time frame
-When new growth cycle begins, follicle produces new hair
-Old hair gets pushed to surface and shed

35
Q

Functions of Hair

A
  • Protects the scalp from UV light
  • Provides insulation for the skull
  • Prevents entry of foreign particles into nose, eyes, and ears
  • Provides early-warning system to prevent injury due to sensory fibers at base of hair follicles
  • Expresses emotional state by hair standing up due to contraction of arrector pili muscle
  • Produces “goose bumps”
36
Q

Hair Color

A
  • Differences due to type and amount of melanin from melanocytes
  • Hair color varies from black to blond
  • Genetically determined and influenced by hormones and environmental factors
  • Pigment production declines with age causing gray or white hair
  • Exocrine Glands of the Skin
37
Q

Two types of exocrine glands in the integument

A

Sebaceous glands

Sweat glands

38
Q

Sebaceous Glands

A
  • Also called oil glands
  • Discharge oily lipid secretion (sebum) into hair follicles through holocrine secretion
  • Sebum inhibits growth of bacteria, lubricates the hair, and conditions surrounding skin
  • Sebaceous follicles discharge sebum directly onto skin of face, back, chest, nipples, and external genitalia
39
Q

Sebaceous Glands and Acne

A
  • Sebaceous glands are sensitive to changes in concentrations of sex hormones
  • Secretions accelerate at puberty
40
Q

Acne

A

Blocked sebaceous ducts causes inflammation and raised “pimple”

41
Q

Sweat Glands

A

Also called sudoriferous glands
Include two types
1. Apocrine sweat glands
2. Merocrine sweat glands

42
Q

Apocrine Sweat Glands

A
  • Become active at puberty
  • Secrete into hair follicles in armpits, around nipples, and in pubic region
  • Secretion is sticky, cloudy, and potentially odorous
  • Sweat is food source for bacteria on skin, increasing odor
  • Deodorants are used to mask this odor
43
Q

Merocrine Sweat Glands

A
  • Also called eccrine sweat glands
  • Coiled tubular structure secretes watery perspiration directly onto surface of skin
  • Very numerous with high numbers on soles and palms
  • Sweat is 99 percent water with electrolytes, urea, and organic nutrients
  • Sodium chloride gives it the salty taste
  • Function is to cool body through evaporation
44
Q

Modified Sweat Glands

A

-Mammary glands
-Structurally related to apocrine sweat glands
Secrete milk

45
Q

Ceruminous glands

A
  • Located in passageway of external ear

- Secretions combine with sebaceous gland secretions to form cerumen, or earwax

46
Q

Nails

A
  • Protect dorsal surfaces of tips of fingers and toes
  • Visible nail body
  • Made of dense, keratinized cells
  • Recessed beneath surrounding epithelium
  • Bordered by lateral nail folds
47
Q

Nail Bed

A

Deeper level of epidermis covered by nail body

48
Q

Nail Root

A
  • Epithelial fold not visible from the surface
  • Site of nail production
  • Covered by the cuticle, or eponychium
  • Portion of the stratum corneum
49
Q

Lunula

A

Pale crescent near nail root

50
Q

Repair of the Integument

A 
Skin regeneration occurs because:
-Stem cells of epithelium and connective tissue undergo cell division
-Replacing lost or damaged tissue
Four phases of skin regeneration
1.   Inflammatory phase
2.   Migratory phase
3.   Proliferation phase
4.   Scarring phase
51
Q

Inflammatory Phase

A
  • Mast cells released at bleeding injury site trigger inflammatory response
  • Result is increased blood flow to region and increased numbers of phagocytes
52
Q

Migratory Phase

A
  • Blood clot or scab forms at surface
  • Stratum basale cells migrate along wound edges to replace missing cells
  • More phagocytes clear debris and pathogens
  • If wound covers extensive area or involves a region of thin skin:
  • Granulation tissue forms in deeper tissue
  • Combination of blood clot, fibroblasts, and extensive capillary network
53
Q

Proliferation Phase

A
  • Deeper parts of the clot dissolve
  • Number of capillaries declines
  • Fibroblasts have formed extensive mesh work of collagen fibers
54
Q

Scarring Phase

A
  • Scab is shed and epidermis is complete
  • Shallow depression marks injury site
  • Fibroblasts create fibrous, noncellular scar tissue to elevate epidermis
  • Degree of scar formation dependent on severity and location of injury and age of patient
  • Keloids are thickened areas of scar tissue covered by shiny, smooth epidermal surface
55
Q

Effects of burns

A
  • Burns result from exposure of skin to heat, radiation, electrical shock, or strong chemicals
  • Severity depends on depth into the tissues and the total area affected
  • Skin functions affected by burns
  • Fluid and electrolyte balance
  • Thermoregulation
  • Protection from infection
  • Classification by Depth of Burn
  • Partial-thickness burns
56
Q

First-degree Burn

A

-Only the epidermis is affected
-Causes erythema or redness from inflammation
Example: sunburn

57
Q

Second-degree Burn

A
  • Entire epidermis and part of the dermis damaged
  • Causes blistering, pain, and swelling
  • Some scar tissue may form
  • Full-thickness burns
58
Q

Third-degree burn

A
  • Epidermis and dermis are destroyed
  • Damage may extend into the hypodermis
  • Sensory nerves destroyed
  • Cannot repair themselves and usually require skin grafting
59
Q

Effects of Aging on the Integument

A

-Skin injuries and infections are more common
-Likely due to a thinning of the epidermis as stem cells become less active
-Sensitivity of immune system is reduced mainly due to a decrease of macrophages residing in the skin
-Muscles become weaker and bone strength decreases
due to a decline in vitamin D3
-Sensitivity to sun exposure increases
due to lower amount of melanin production
-Skin becomes dryer and often scaly due to reduction in glandular secretions
-Hair thins and changes color due to low-functioning follicles and decreased melanocyte activity
-Sagging and wrinkling of the skin occurs due to decrease in elastic network, more noticeable when skin has been exposed to a lot of sunlight
-Ability to lose heat is reduced due to reduced dermal blood supply and less active sweat glands
-Skin repairs take place more slowly due to slower stem cell division, increasing the threat of infection in cuts

N106 (6 decks)

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