Ch. 5 Intergumentary System

Question 1

Skin has appendages of

Answer 1

Sweat (sudoriferous) glands
Sebaceous (oil) glands
Hairs and hair follicles
Nails

Question 2

Skin functions

Answer 2

Protect 
Regulate body temperature
Cutaneous sensation
Metabolic function (synthesize V-D precursor)
Blood reservoir
Excretion

Question 3

Skin function: Protection

Answer 3

It has 3 types of protective barriers
1 chemical
2 physical
3 biological

It protects deeper tissue from
Mechanical damage: falling, adipose padding
Chemical damage: secretions+ melanin keratin
Bacterial damage: acidic pH on skin stop bacteria
Thermal damage: receptors hot, cold to brain
Ultraviolet radiation: (carcinogen) melanin prevents DNA mutation from the top.
Desiccation: (drying out) prevents loss of fluid, may leak if burned.

Question 4

Skin Function: Body temp regulation

Answer 4

Negative Feedback:

Too hot start to sweat, too cold erector pili muscle stands up to warm up

Question 5

Skin Function: Cutaneous Sensation

Answer 5

Receptors for pain, pressure, vibrations, signaling the control center.

Question 6

Skin function: Metabolic function

Answer 6

Synthesize vitamin precursor

But too much direct sunlight can cause cancer.

Question 7

Skin Function: Blood reservoir

Answer 7

Holds up to 5% body’s total blood volume, then shunted in circulation used by working muscles and body organs

Question 8

Skin function: Excretion

Answer 8

Excrete and eliminate sweat and nitrogen-containing wastes (ammonia;due to protein breakdown, urea, uric acid), NaCl, H2O, etc.

Question 9

Skin structures 3

Answer 9

Epidermis
Dermis
Hypodermis

Question 10

Skin structure: Epidermis 5

Answer 10

Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale

Question 11

Epidermis 5 strata

Answer 11

1. Stratified squamous epithelium w/ keratin
2. cells tightly connected by Desmosomes
3. Keratinocytes form several layers
4. layers of the epidermis ***
5. Melanin

Question 12

Layers of epidermis: Stratum Corneum

Answer 12

20-30 cell layers thick and accounts for 3/4 of epidermal thickness.

Located at exposed surface of skin

Protective barrier of dead, durable, and expendable cells. (Cells are plasma membrane filled with keratin that is protective.

Thickness will vary depending on use, (calluses can develop on palms of hands and soles of feet.

Glycolipids secreted between cells provides waterproofing and preserves some permeability characteristics of the skin.

Allows for transdermal medications like nicotine patches.

Question 13

Layers of epidermis:

Answer 13

Stratum Corneum 
Stratum Lucidum (keratin soles)
Stratum Granulosum 
Stratum Spinosum
Stratum Basale

Question 14

Layers of epidermis: Stratum Basale

Answer 14

Single row of cells that serve as origin of keratinocytes for all superficial strata.

High mitotic activity

Contains melanocytes )accounts for 10-25 of stratum basale cells.

Question 15

Melanin

Answer 15

Pigment produced by melanocytes

Gets packaged in melanosomes
And then deposited into the keratinocytes in more superficial layers.

Melanin granules then position themselves on superficial or sunny side of keratinocytes nucleus to protect against UV radiation.

Amount produced depends on den ethics and exposure to sunlight.

Cell production of tyrosinase )acts on the amino acid tyrosine) is critical for melanin production.

Albinism; commonly failure to produce tyrosinase

Question 16

Dermis

2 layers

Answer 16

Strong collagen, flexible (elastic)connective tissue,
Papillary layer: 20%, Thin superficial layer of areolar connective tissue, supports and nourishes overlying epidermis, projections called dermal papillae, pain receptors, capillary loops, rise SA and serves as basis for friction ridges and fingerprints.

Reticular layer: 80%, dense irregular connective tissue and mesh work of collagen and elastic fibers , blood vessels, glands, nerve receptors.

Question 17

Hypodermis (subcutaneous)

Answer 17

1. Not part of the skin
2. Anchors skin to underlying organs
3. Composed mostly of adipose tissue (half of body’s stored fat)

Question 18

Appendages of the skin

Answer 18

Sebaceous glands
Sweat (sudoriferous) glands
Hair
Nails

Question 19

Appendages of the skin: Sebaceous glands

Answer 19

Produce oil (sebum): Softens and lubricates the hair and skin.

Most with ducts that empty into hair follicles.

Distributed body wide except for palms of hands and soles of the feet.

Glands are activated at puberty (under hormonal control) Clinical: acne- accutane is teratogenic

Question 20

Appendages of the skin: Sweat Glands

Answer 20

Widely distributed 3 million in the body.

Eccrine
Apocrine
Ceruminous Glands
Mammary glands

Question 21

Eccrine Sweat Gland

Answer 21

Coiled, tubular portion in dermis with opening via duct to pore on the skin surface.

Distributed body wide (most numerous)

Helps dissipate excess heat through evaporative cooling.

Question 22

Apocrine Sweat Gland

Answer 22

Ducts empty into hair follicles

Localized to axillary and pubic (anogenital) areas only 2000 in number

Activated by stress, pain, & sexual excitement; not temp.

Fatty acid and protein secretion. Bacteria breakdown produces body odor.

Question 23

Ceruminous Modified Sweat glands

Answer 23

Found in lining of external ear canal

Secretion mixes with sebum to produce cerumen or earwax.

Question 24

Mammary Modified sweat glands

Answer 24

Not discussed

Question 25

Appendages of the skin: Hair

Answer 25

1. Distributed body wide except palms, soles, lips, nipple, external genitalia 2. Strand of dead , hard keratinized epithelial cells projecting from an invaginated tunnel in the epidermal and dermal layers called the hair follicle 3. Hair follicle: A. Tubular invaginations of the epidermis B. Formed by mitotically active stratum Basale cells C. Melanocytes provide pigment for hair color D. Dermal capillaries provide blood supply Four parts: Shaft-visible part of hair; projects from surface Root- part of the hair enclosed in hair follicle Bulb- growth zone at inferior end of hair follicle 5. Arrector pili muscle (smooth muscle) 6. Clinical:minoxidal (rogaine)

Question 26

Appendages of the skin: Nails structure

Answer 26

Nail fold (lateral and proximal skin coverings) Eponychium (cuticle) Nail body: sheet of hard keratin attached to nail bed. Lanula -crescent shaped vascular area at proximal end of the nail bed and visible through the nail. Used for visual check of oxygen status in patients. Clinical: eponychiitis, ingrown toenail

Question 27

Injection sites

Answer 27

Intradermal (ID): Tb test Subcutaneous ("subcue" or SQ): Hypodrms adipose. Intramuscular (IM): in muscle below hypodermis Intravenous (IV): in vein.

Question 28

Blisters

Answer 28

Fluid filled pocket between epidermis and dermis. Tissue damage by friction.

Question 29

Lines of Cleavage | 5.4b

Answer 29

Formed by uniform alignment of collagen and elastic fibers

Question 30

Stretch Marks

Answer 30

Collagen stretched beyond their capability

Question 31

Decubitus ulcers "Bed Sores"

Answer 31

Blood supply is restricted -> ischemia (O2 reduced) -> necrosis (tissue death) Bacterial infections result, difficult to heal, secondary intention. Areas of highest risk are least padded (elbow, heels, backbone) little fat over them Patients of high risk: elderly in care homes, less fat Importance of rotating patient positions, artificial padding and clean bedding.

Question 32

Burns

Answer 32

Tissue damage inflicted by heat, electricity, UV radiation, or chemicals that denature proteins and cause cell death in affected areas. Dangers associated are loss of fluids lead to: Dehydration Electrolyte imbalance (muscle contractions) Renal failure Circulatory Shock*

Question 33

Burns: circulatory shock

Answer 33

Loose interstitial fluid, plasma, blood plasma, is going into tissue, gets thick hard to pump.

Question 34

Burns: Infection

Answer 34

Sepsis (widespread bacterial infection) is leading cause of death in burn victims.

Question 35

Burns: Rule of Nines

Answer 35

Way to approximate the extent of burns Special tables are used when greater accuracy is desired Head 4.5% 4.5%. 4.5% 18% 1% 9%. 9% 9,9,9,36, 18, 18

Question 36

Severity of Burns | 1st degree burn

Answer 36

Only epidermis is damaged Redness, pain, swelling (inflammation) heat Heals 2-3 days.

Question 37

Severity of Burns | 2nd degree burns

Answer 37

Damage to Epidermis and Dermis Redness, pain, swelling (inflammation), heat + Blistering (fluid) Heals 3-4 weeks

Question 38

Severity of Burns | 3rd degree burns

Answer 38

Total tissue destruction of epidermis, dermis, hypodermis. Tissue becomes dis colored, but no edema, or pain, no nerves, Usually requires skin graft.

Question 39

Skin Cancer | Most common types

Answer 39

Basal cell carcinoma Squamous cell carcinoma Malignant melanoma

Question 40

Clinal Applications

Answer 40

``` Injection sites Blisters Lines of cleavage Stretch marks Decubitus ulcers "bed sores" Burns Skin cancer ```

Question 41

Skin Cancer: Basal cell carcinoma

Answer 41

Bubble growth Least malignant bit most common type 80% of all skin cancers Arises from stratum Basale cells that then go and invade the underlying dermis and hypodermis. Results in a shiny, dome shaped nodule most commonly found in Sun-exposed regions of the face Slow growing and therefore metastasizes seldom Full cure by surgical excision in 99% of cases

Question 42

Skin Cancer: Squamous cell carcinoma

Answer 42

Arises from stratum Spinosum Results in a scaly reddened papule most commonly on the head (scalp, ears, and lower lip and hands) Tends to grow rapidly and will metastasize if not removed Chance of complete cure is good if caught early and removed by surgery or radiation.

Question 43

Skin Cancer: Malignant Melanoma

Answer 43

Most deadly, but Rare Accounts for only 5% of all skin cancers but 90% of skin cancer deaths due to metastasis and resistance to chemotherapy Cancer of melanocytes Metastasizes rapidly to lymph and blood vessels Can occur body wide Most appear spontaneously, but about 1/3 from pre existing moles (wherever there is pigment)

Question 44

Skin cancer: ABCDE early mole detection

Answer 44

``` A : asymmetry B : irregular border C : color D : diameter larger than 6mm pencil eraser E : elevation above skin surface evolution Changes over time ```