Skin

Front 1

Integumentary System

Back 1

consists of skin & its derivatives (sweat & oil glands, nails, hair) makeup a complex set of organs that serve several functions, mostly protective.

Front 2

3 major regions of Skin

Back 2

epidermis (outermost), dermis (middle), hypodermis (deepest/ adipose)

Front 3

Epidermis

Back 3

outermost region. It is a keartinized stratified squamous epithelium. Consists of 4 distinct cell types and 4 or 5 distinct layers. Functions as protection against bacteria and injury.

Front 4

Cells of Epidermis

Back 4

squamous keratinocytes , Melanocytes, Langerhans' (epidermal dendritic cells), occasional merkel cells

Front 5

keratinocytes

Back 5

produce keratin the fibrous protein that helps give the epidermis its protective properties (kera = horn in Greek). They arise from deepest part of epidermis from stratum basale. In Stratum basale they undergo almost constant mitosis they are pushed up by new cells. When they get to the top they are dead, scale like structures. Millions rub off everyday

Front 6

Melanocytes

Back 6

produce the brown pigment melanin. Spider-shaped cells found in the deepest layer of epidermis (10-25% of stratum basale cells)

Front 7

Langerhans' cells

Back 7

cells that help activate the immune system. Star shaped cells arise from bone marrow and migrate to the epidermis. Also called "epidermal dendritic cells"

Front 8

Merkel cells

Back 8

touch receptors associate w/ sensor nerve endings. Present at epidermal-dermal junction. Shaped like a spiky hemisphere each one is associated w/ a dislike sensory nerve ending. This combo is a Merkel disc.

Front 9

Thick skin

Back 9

covers palms, fingertips, and soles of feet. Consists of five layers (strata) from deep to superficial

Front 10

5 layers of skin

Back 10

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum

Front 11

thin skin

Back 11

all layers except stratum lucidium & other layers are thinner

Front 12

stratum basale

Back 12

"stratum germinativium" the deepest epidermal layer, attached to the underlying dermis along a wavy borderline that looks like corrugated cardboard. Mostly single layer of keratinocytes (youngest). Undergoing rapid mitosis. 10-25% of the cells are melanocytes & their branching processes extend among the surrounding cells and reach well into the more superficial stratum spinosum layer.

Front 13

stratum spinosum

Back 13

"prickly layer" several layers of live keratinocytes. Scattered among the keratinocyes are melanin granules & Langerhans' cells, wh/ are most abundant in this layer.

Front 14

stratum granulosum

Back 14

"granular layer" thin layer consists of 3-5 cell layers of live keratinocytes (this is the last live layer of keratinocytes). Here they change shape and flatten and accumulate keartohyaline granules and lamellated granules. Keratohyaline granules help to form keratin in the upper layers. The lamellated granules contain a waterproofing gycolipid.

Front 15

stratum lucidum

Back 15

"clear layer" appears as a thin transparent band. Consists of a few rows of flat, dead keartinocytes. Present only in thick skin (soles of feet, palms)

Front 16

stratum corneum

Back 16

"horny layer" outermost layer is a broad zone 20 to 30 cell layers thick of dead keratinized cells. Accounts for 3/4 of the epidermal thickness. Keratin & thickened plasma membranes of cells protect the skin against abrasion and penetration. Also, glycolipid between its cells waterproofs. Durable "overcoat for the body, protecting deeper cells from external environment (air), water loss, and rendering body relatively insensitive to biological, chemical, & physical assault.

Front 17

Dermis

Back 17

2nd major skin region: Composed of strong, flexible connective tissue.

Front 18

Dermis cell types

Back 18

Typical of cells found in any connective tissue proper: fibroblasts, macrophages, & occasional mast cells & white blood cells.

Front 19

Dermis Layers & contains?

Back 19

Richly supplied w/ blood and lymphatic vessels and nerve fibers. 2 Layers: papillary & reticular.

Front 20

superficial papillary layer

Back 20

vasuclar, areolar connective tissue. Contains peg like projections called dermal papillae that indent the epidermis. Dermal papillaie contain capillary loops, Meissners' corpuscles (touch receptors), & free nerve endings (pain receptors). Includes the makings of the markers called fingerprints.

Front 21

What makes fingerprints?

Back 21

In palms and soles of feet these dermal papillaie lie atop larger mounds called dermal ridges, wh/ cause the overlying epidermis to form epidermal ridges (wh/ increases friction and enhances grip ability). Combine this w/ the sweat from pores open along their crests on the fingertips is why we leave these individual marks.

Front 22

reticular layer

Back 22

Accounts for 80% of the dermis thickness. It is dense irregular connective tissue. Its extracellular matrix contains thick bundles of interlacing collagen fibers called cleavage, or tension lines. Also contains flexure lines.

Front 23

cleavage, or tension lines

Back 23

Its extracellular matrix of dermis: reticular layer contains thick bundles of interlacing collagen fibers that run in various planes (most run parallel to skin surface). Separations (or less dense regions) between bundles form _____, or _____ lines. Surgeons cut along these lines when possible wh/ leads the skin to heal better than when cut across them.

Front 24

flexure lines

Back 24

Dermal reticular layer folds that occur at or near joints, where the dermis is tightly secured to deeper structures (deep creases of your palms). Since the skin cannot slide easily to accommodate joint movement in such regions, the dermis folds and deep skin creases form. Also visible on the wrists, fingers, soles, and toes.

Front 25

Hypodermis

Back 25

Subcutaneous layer deep to the skin. Composed of adipose & areolar connective tissue. It acts as a shock absorber & insulator.

Front 26

Skin Color Pigments

Back 26

melanin, hemoglobin, & carotene

Front 27

melanin

Back 27

the only one made in the skin. A polymer made of tyrosine amino acids, ranges in color from yellow to reddish-brown to black.

Front 28

Melanin & the Sun

Back 28

Increased exposure to UV (DNA damage) leads to increased melanin production (skin gets tanner but is not more protected because damage is done). melanin protects by absorbing UV light & dissipating its heat. However, excessive sun damage can have other effects: clumping of elastin (leathery skin). Affecting the DNA leads to skin cancer.

Front 29

Carotene

Back 29

Yellow to orange pigment found in certain plant products such as carrots. Most obvious in palms and soles of feet.

Front 30

Hemoglobin

Back 30

Reddish pigment responsible for the pinkish hue of skin. Pinkish hue of fair skin reflects the crimson color of oxygenated hemoglobin in the red blood cells circulating through the dermal capillaries.

Front 31

Appendages of the Skin

Back 31

Sweat Glands, Sebaceous Glands (oil), Nails, Hair

Front 32

Sweat (Sudoriferous) Glands

Back 32

different types prevent overheating of the body. Sweat is 99% water, has antibodies, salt, microbicides & metabolic waste. 2 types.

Front 33

Types of Sweat Glands

Back 33

Eccrine (merocrine)& Apocrine

Front 34

Eccrine

Back 34

secrete sweat, prevents overheating. More numerous than apocrine. Found in abundance on the palms, feet, & forehead.

Front 35

Apocrine sweat glands

Back 35

Largely confined to the axillary and anogenital areas

Front 36

Ceruminous glands

Back 36

located in the ear canal, secrete cerumen (ear wax), block entry of foreign material.

Front 37

Mammary glands

Back 37

secrete milk

Front 38

Sebaceous (oil) glands

Back 38

Simple alveolar (one duct) glands that are found all over the body except on the palms and soles. Secrete sebum wh/ acts as lubrication and bactericide. They function as holocrine glands. Secretion is stimulated by hormones. (relatively inactive until puberty)

Front 39

Homeostatic imbalance in Sebaceous glands

Back 39

results in pimples (usually caused by bacteria)

Front 40

Nails

Back 40

A scalelike modification of the epidermis that contain hard keratin. Nail matrix is responsible for nail growth.

Front 41

Eponchium

Back 41

cuticle

Front 42

Hyponychium

Back 42

quick

Front 43

Hair or Pili

Back 43

Flexible Strands of dead keartinized cells produced by hair follicles

Front 44

How is hair pigmented

Back 44

By melanocytes at the base of the hair.

Front 45

Melanocytes at base of hair

Back 45

maintain warmth, alerting the body to the presence of insects on the skin, guarding the scalp.

Front 46

Main regions of hair

Back 46

shaft & root

Front 47

Hairs 3 Layers

Back 47

3 layers of keratinized cells: medulla, cortex and the cuticle

Front 48

Structure of Hair follicle

Back 48

root, bulb, sheath (inner & outer), hair follicle receptor, and pili muscle

Front 49

Hair follicle

Back 49

extend from the epidermis into the dermis and occasionally into the hypodermis.

Front 50

hair bulb

Back 50

deep end of the follicle located about 1/6" below the skin surface

Front 51

hair follicle receptor or root hair plexus

Back 51

a knot of nerve endings surrounding the hair bulb

Front 52

wall of hair follicle

Back 52

composed of an outer connective tissue root sheath derived from the dermis, a thickened basement membrane called the glassy membrane, and an inner epithelial root sheath.

Front 53

arrector pili muscle

Back 53

associated w/ each hair follicle is this bundle of smooth muscle cells called an ________. Smooth muscle, makes hair stand up straight "hair stands on end"

Front 54

Types of Hair Growth

Back 54

Classified as vellus or terminal

Front 55

vellus

Back 55

body hair of children and adult females, pale and fine

Front 56

terminal

Back 56

course, long hair of eyebrows, scalp, axillary & pubic regions

Front 57

Hair growth & density factors

Back 57

nutrition & hormones

Front 58

Hair thinning

Back 58

alopecia-in both sexes

Front 59

true baldness

Back 59

genetically determined & sex influenced condition. Male pattern baldness caused by follicular response to a metabolite of testosterone (shortening hair growth)

Front 60

Integumenatary System Functions

Back 60

Protection, Regulate Temp, Cutaneous Sensation, Metabolic, Blood Reservoir, Limited Excretion

Front 61

Protection

Back 61

Chemical & Physical & biological

Front 62

Chemical Protection Function

Back 62

Barriers include skin secretions and melanin

Front 63

Physical

Back 63

Barriers are provided by the continuity of the skin, and the harness of the keratinized cells

Front 64

Biological

Back 64

Barriers include the Langerhans' cells, the macrophages, and the DNA itself

Front 65

Regulation of Temp

Back 65

Skin reg. body temp by using the sweat glands of the skin to cool the body.

Front 66

Cutaneous Sensation

Back 66

made possible by the placement of cutaneous sensory receptors, wh/ are part of the nervous system, in the layers of the skin.

Front 67

Metabolic function

Back 67

skin makes vitamin D when exposed to sunlight

Front 68

Blood reservoir

Back 68

by holding up to 5% of the body's blood supply wh/ may be diverted to other areas of the body should the need arise.

Front 69

Limited excretion

Back 69

Limited amounts of nitrogenous wastes are excreted through the skin.

Front 70

Homeostatic Imbalances of Skin

Back 70

Aging, Skin Cancer, Burns, Tissue Trauma & Repair

Front 71

Aging

Back 71

decreasing regeneration, skin thins & less lubrication, more bruises & injury, decreasing elasticity leads to wrinkles, decreasing # of active hair follicles, decreasing melanocytes & immune cells enhances chances of getting skin cancer

Front 72

Skin Cancer

Back 72

Basal Cell Carcinoma, Squamous cell carcinoma, Melanoma

Front 73

basal cell carcinoma

Back 73

least malignant & most common. Stratum basale cells proliferate & invade the dermis & hypodermis. Slow growing & does not often metastasize. Can be cured by surgical excism in 99% of cases.

Front 74

Squamous Cell Carcinoma

Back 74

Arises from keartinocytes of stratum spinosum. Grows rapidly & metastasizes if not removed. Prognosis good if treated by radiation therapy or removed surgically.

Front 75

Melanoma

Back 75

Cancer of melanocytes is the most dangerous type of skin cancer because: Highly metastatitic, Resistant to chemotherapy. Chance of survival is poor if the lesion is over 4mm thick. Treated by wide surgical excision accompanied by immunotherapy.

Front 76

ABCDE rules for recognizing melanoma

Back 76

A-Asymmetry: The 2 sides of the pigmented spot or mole do not match. B-Border irregularity: the borders of the lesion exhibit indentations. C- Color: The pigmented spot contains several colors (blacks, browns, tans, & sometimes blues & reds). D-Diameter: The spot is larger than 6mm in diameter (the size of a pencil eraser). E-Elevation: Above the skin surface rule.

Front 77

Burns

Back 77

Classified according to severity: 1st, 2nd, 3rd.

Front 78

1st degree burn

Back 78

damage only to the epidermis

Front 79

2nd degree

Back 79

injure the epidermis and the upper region of the dermis. Blisters appear.

Front 80

3rd degree

Back 80

full thickness burns. Since nerve endings have been destroyed the burn area is not painful. Appears gray white, cherry red, or black

Front 81

Rule of Nines

Back 81

Estimates severity of burns. Burns considered critical if any of the following exists: over 25% of the body has 2nd degree burns. And/or over 10% of the body has 3rd degree burns. And or there are 3rd degree buns on face, hands, feet.

Front 82

Tissue Trauma & repair

Back 82

Body has many techniques for protecting itself from "uninvited guests" or injury. When tissue injury occurs these barriers are penetrated, this stimulates the body's inflammatory & immune responses, wh/ wage their battles largely in the connective tissues of the body.

Front 83

Inflammation

Back 83

Inflammatory chemicals released by injured cells and immune cells cause dilation of blood vessels. Redness, heat, swelling, & pain results. Clotting proteins construct a clot. Macrophage phagocytosize destroyed tissue.

Front 84

Organization

Back 84

Restores blood supply

Front 85

Regeneration & fibrosis

Back 85

Reg- Replacement of destroyed tissue. Fibrosis -proliferation of connective tissue. Fibrouse tissue begins to resemble the adjacent tissue. Surface Epithelium regenerates and the scab detaches. Results in a fully regenerated epithelium w/ underlying scar tissue.