integumentary system

inflammatory response

inflammatory response

Mobilize immune defenses, destroy infection, remove

foreign materials and damaged cells, and initiate tissue

repair

redness, calor, tumor, dolor, functional impairment

Redness, heat, swelling, pain, disturbed function

Chemical mediators.

Include histamine, kinins, prostaglandins, leukotrienes.

• Stimulate pain receptor and increase blood vessel

permeability as well movement of WBCs to affected area.

• Tissue swells, called edema

Stages of the Inflammatory Response

A splinter in the skin causes damage and

introduces bacteria. Chemical mediators of

inflammation (histamine, kinins, prostaglandins,

leukotrienes, and others) are released or activated

in injured tissues and adjacent blood vessels.

Some blood vessels rupture, causing bleeding.

2. Chemical mediators cause capillaries to dilate and

the skin to become red and warm. Speeds the

arrival of white blood cells and other infection

fighting and repair chemicals.

3. Chemical mediators also increase capillary

permeability, allowing clotting proteins, white blood

cells, and fluid to leave the capillaries, producing

swelling and pain. Clotting proteins will diffuse into

the interstitial spaces and for a clot. White blood

cells (For example, neutrophils) leave the dilated

blood vessels and move to the site of bacterial

infection, where they begin to phagocytize bacteria

and other debris

4.9 Tissue Repair

Regeneration

Replacement

new cells of same type are produced; function is

restored.

new type of tissue develops, resulting in scar

and loss of some function

Classification of cells based on ability to regenerate.

labile, stable, permanent

capable of mitosis through life; skin, mucous

membranes, hematopoietic tissue, lymphatic tissue, adult stem cells, bone marrow, ca be repaired by regen.,

: no mitosis after growth ends, but can divide after injury;

liver, pancreas, endocrine cells, CT, liver, endocrine,

not divide after growth, smooth muscles

:

///

,Ages skin more rapidly.

• Normal elastic fibers replaced by interwoven mat of

elastic-like material.

• Number of collagen fibers decreases.

• Impaired ability for keratinocytes to divide,

if killed, replaced by a different type of cell; limited

regenerative ability; nervous, skeletal and cardiac muscle.

neurons, skeletal, cardiac muscle, no replication,

Skin Repair

Primary union

edge of wound close together.

Wound fills with blood.

clot forms: fibrin threads start to contract; pull edges

together.

Scab.

• Inflammatory response; pus forms as white cells die.

• Granulation tissue. Replaces clot, delicate C.T.

composed of fibroblasts, collagen fibers, capillaries.

• Scar. Formed from granulation tissue. Tissue turns

from red to white as capillaries are forced out

for skin repair During the first week, the inflammatory response

Blood vessels…

Fibrin and blood cells role

Phagocytic

white cells called neutrophils

Fibroblasts from…

Capillaries

fibrin in clot

induces vasodilation and takes more blood cells and

other substances to the area

permeability

increases, resulting in edema.

move into the wounded tissue because of the increased

permeability. Fibrin isolates and walls off

microorganisms and other foreign matter

then move into the tissue

to help fight the infection. They ingest bacteria and

tissue debris to clear the area for repair. Neutrophils

killed through this process creates pus

surrounding CT migrate into the clot and produce

collagen and other extracellular matrix components

grow from blood vessels at the edge of the

wound and revascularize the area

broken down and removed

By two weeks

granulation tissue

the clot has been replaced

by granulation tissue that will eventually

form a scar at the wound site

tissue is a delicate, granular-appearing

connective tissue that consists of

fibroblasts, collagen, and capillaries

By a month

a large amount of granulation

tissue is converted to a scar, which

consists of dense irregular collagenous CT.

At first, the scar is bright red because

numerous blood vessels are present.

Later, the scar becomes white as collagen

accumulated and the vascular channels are

compressed

Repair by secondary union is similar, but with some

differences

The clot may not completely close the gap

• It takes longer for epithelial tissue to regenerate and cover

the wound.

• Generally, more inflammation, more risk of infection, and

more pus.

• More granulation tissue forms, and contraction of the

fibroblasts leads to wound contracture that results in

disfiguring scars.

• It is advisable to suture a large wound so it can heal by

primary union instead of secondary union

The most common types of cancer are from

adeno tissue with more rapid cell division

Carcinomas

cancers of epithelial tissue; include nearly

all lung, breast, colon, prostate, and skin cancers, basal cell and squamous cell

_adeno___carcinomas

derived from glandular epithelium, most breast cancers

Sarcomas

relatively rare cancers of mesodermal tissue

(connective and muscular, osteo or chondro sarcoma

ex: muscles, fat, blood vessels, nerves

molecule markers for cancer

keratin filaments

Effects of Aging on Tissues

what becomes more elastic?

Cells divide more slowly.

Rate of blood cell synthesis declines in the elderly.

Injuries don’t heal as readily.

Collagen fibers become more irregular in structure, though they

may increase in number; tendons and ligaments become less

flexible and more fragile.

Elastic fibers become less elastic.

Changes in collagen and elastin result in.

• Arterial walls and elastic ligaments become less elastic.

• Atherosclerosis and reduced blood supply to tissues.

• Wrinkling of the skin.

• Increased tendency for bones to break

mucous

serous

synovial

composed of an epithelium and underlying

layer of connective tissue

Organs

skin and accessory

structures such as hair,

____sweat, oil___, and nails

Structures that are part of the integument.

Skin.

• Hair.

• Nails.

• Glands

Functions

Protection

Sensation

Temperature regulation

Vitamin D production

Excretion

Protection – protects against U V light, microorganisms, water loss.

• Sensation – sensory receptors for heat, cold, touch, pressure, pain.

• Temperature regulation – modulation of __blood_____ flow through the skin

and activity of sweat glands.

• Vitamin D production from a molecule made in the skin when exposed

to U V light.

• Excretion – small amounts of waste products eliminated

Epidermis

Dermis

Subcutaneous tissue.

Superficial layer of

stratified squamous epithelial tissue.

fed by diffusion of capillaries through papillary

Protection and reduces water loss.

//

Deep layer of connective

tissue.

• Structural strength

//

____not_ part of skin.

• Loose connective tissue that

connects skin to underlying

structures

Avascular

Epidermis

nourished by diffusion from capillaries of the

papillary layer of the dermis

Epidermis

Composed of epithelial cells arranged into layers or strata

Epidermis

Separated from dermis by basement membrane

Epidermis

Epidermal Cells

Keratinocytes

Melanocytes

Langerhans cells

Merkel cells

Keratinization

Keratinocytes: most cells. Produce keratin for strength.

• Melanocytes: contribute to skin color. melanin_______ produced

by these cells then transferred to keratinocytes. Same

number of melanocytes in all people.

• Langerhans cells: part of the immune system.

dendritic cells found primarily in the epidermis of the skin, as well as in the lining of the oral cavity, foreskin, and vagina

• Merkel cells: detect light touch and superficial pressure.

Keratinization: as cells move outward through the layers

they fill with keratin, die, and serve as a layer that resists

abrasion and forms permeability layer

Epidermal Strata:

Stratum basale (germinativum).

Deepest portion of epidermis and single layer of cuboidal or columnar

cells.

• High ____mitotic___ activity; keratinocyte stem cells undergo mitosis about

every 19 days; one daughter cell remains in the stratum basale to

divide again, while the other daughter cell is pushed to the surface and

becomes keratinized.

• Desmosomes hold the keratinocytes together and provide structural

strength.

• It takes 40 to 56 days to move from the stratum basale to the surface

and be sloughed off

Stratum spinosum

Eight to ten layers of many-sided cells that flatten as they are pushed

upward.

• Contain new desmosomes, lipid-filled lamellar bodies, and additional

keratin fibers

cells shrink from desmosomes, causes cells to be shiny causing lamellar bodies

Stratum granulosum.

Two to five layers of flattened, diamond-shaped cells.

• Contains protein granules of keratohyalin that accumulate in the cytoplasm.

• Lamellar bodies move to the plasma membrane and release their lipid

contents into the extracellular space.

• In superficial layers, nucleus and other organelles degenerate and cell dies;

the keratin fibers and keratohyalin granules do not degenerate

lipid content in extracellular space

protein envelope,

Stratum lucidum

Thin, clear zone of dead keratinocytes with indistinct boundaries.

• Found only in palms and soles,

keratohyalin dispersed around keratin fibers,, transparent cells,

Stratum corneum.

Most superficial and consists of 25 or more layers of dead, overlapping

squamous cells joined by desmosomes and are dead keratinocytes, protein envelope, called called cornified cells.

• Cell remnants have a soft protein envelop of keratin, a mixture of keratin fibers

and keratohyalin

cells shed to surface due to desmosomes breaking, which results in dandruff

also shed from clothes,

Thick and Thin Skin

Callus

corn

Thick skin (designation refers only to the epidermis)

• Has all 5 epithelial strata.

• Found in areas subject to pressure or friction.

• Palms of hands, fingertips, soles of feet.

• Fingerprints and footprints. Papillae of underlying dermis in

parallel rows.

Thin skin.

• Composed of _4___ strata (no stratum lucidum).

• More flexible than thick skin.

• Covers rest of body.

• Hair grows here.

both think and thin: down below

Callus: Increase in number of layers in stratum

corneum. friction, added protection

When this occurs over a bony

prominence, a corn forms, painfil

Skin Color

Determined by 3 factors: pigments in the skin, blood

circulating through the skin, thickness of stratum corneum

Pigments….

Melanin

Melanocytes

where is carotene found??????

Melanin: provides for protection against U V light. Group of

chemicals derived from amino acid tyrosine. Colored

brown to black, may be yellowish or reddish. freckles, nipples, moles, genitalia, axillae lips,

• . processes extend between keratinocytes; deposit

melanosomes. irregular shapes, between basale and spinosum

• Albinism: deficiency or absence of pigment; production determined

by genetics, hormones, exposure to light.

• Carotene: yellow pigment from vegetables; accumulates

in stratum corneum, in adipose cells of dermis, and in

subcutaneous tissue,

during preg

estrogen and melano hormones causes motehr body to have dark nips, areolae, genitalia, cheeks, forehead, chest,

addisons disease

increase melanin

Melanin Transfer to Keratinocytes

Melanin Transfer to Keratinocytes

1. Melanocytes produce

and package melanin

into vesicles called

____melanomsomes ________.

2. These melanosomes

move into cell processes

of the melanocytes.

3. Keratinocytes

phagocytize the tops of

the melanocyte cell

processes, thereby

acquiring melanosomes.

Racial variations in skin color due to:

Types of melanin produced

• ___amount______ of melanin produced

• Size of melanosomes

• Number of melanosomes

• Distribution of melanosomes

Certain hormones, such as estrogen and MSH, can increase

melanin production during pregnancy

Blood circulating through the skin imparts

reddish hue and

increases during blushing, anger, inflammation

Cyanosis

Erythema

Cyanosis: blue color caused by decrease in blood oxygen

content. pale

• Erythema: red color caused by increased blood flow, infection , sunburn, allergic, bites,

impacts color.

Thickness of stratum corneum

Thicker areas can be what color?

yellowish

dermis or

subcutaneous tissue color

bluish color to the skin;

the deeper, the bluer.

The most common type of cancer.

Most result from damage from U V radiation that damages the

D N A in epidermal cells.

The amount of melanin affects the likelihood of developing

skin cancer; fair-skinned people are at a greater risk than

dark-skinned people

Three major types:

Basal cell carcinoma

• Squamous cell carcinoma

• Melanoma

basal Types of Skin Cancer 1

_____basal__ cell carcinoma

Most common

• Cells of stratum basal

• Varied appearance

• Cured by removal or

destruction

open sores: bleed, crust, shiny bumps, taut,

Squamous cell carcinoma

Cells of stratum spinosum

• Varied appearance; may bleed

• Most cases cured by removal

or destruction

2nd most type, wartlike, depressed,

Melanoma

Most deadly

• A B C D E Rule for signs of

melanoma:

• A – asymmetry

• B – border irregularity

• C – Color not uniform

• D – diameter_______ greater than 6mm

• E – evolving or changing

most deadly, black, not treated after melanoma in dermis and spreads, limit sun exposure,

light reflected off dark pigments in dermis or subcu are…..

scattered by collagen fibers of dermis to produce blue color.

Dermis

Gives structural strength. C.T. with many fibers (collagen, elastic, and

reticular), fibroblasts, macrophages, and adipocytes.

• Contains nerves, blood vessels, hair follicles, smooth muscles, glands,

and lymphatic vessels.

• Sensory functions: pain, itch, tickle, temperature, touch, pressure, two-

point discrimination

nutrient exchange, free nerve ending, bulbous corpuscles and ruffini end organs

Two layers of dermis, variable in

thickness.

Papillary. Superficial. Areolar with

lots of elastic fibers, dermal

papillae, capillary beds. Friction

ridges form fingerprints. Whorls of

ridges. Touch receptors (Meissner,

Pacinian, and Ruffini), free nerve

endings sensing pain.

dermal papillae: extend epidermis, loose CT, o2, remove waste, body temp,

//

• ___Reticular______: Deep. Dense irregular

C.T. of collagen and elastic fibers.

Also contains some adipose tissue,

hair follicles, nerves, oil glands,

ducts of sweat glands, heat sensors

friction ridges

dermal papillae, impressions, finger prints,

Cleavage (tension) lines

elastic and collagen fibers

oriented in some directions

more than in others

reticular layer, tension lines,

stretch mark location

abdomen, breast, preg,

Important in surgery

If incision parallel to

lines, there is less

gapping, faster healing,

less scar tissue.

If skin is overstretched,

stretch marks occur

Subcutaneous tissue

Deep to skin.

Also called hypodermis.

Consists of loose connective tissue

with collagen and elastic fibers.

Types of cells.

• Fibroblasts.

• Adipose cells.

• Macrophages.

Contains about one-half of body’s

___adipose____ tissue.

Functions as.

• Energy source.

• Insulation.

• Padding.

Three types of injections:

Intradermal – into the dermis; skin taut; needle at shallow

angle

• Subcutaneous – into subcutaneous layer; pinch skin; short

needle, tent, pinching,

• Intramuscular – long needle perpendicular to skin, 90 deg, vacc, antibiotics,

Accessory Skin Structures: Hair

Found everywhere on human

body except palms, soles, lips,

nipples, parts of external

genitalia, and distal segments of

fingers and toes.

Hair structure and coloration

changes as a person ages

Lanugo – delicate,

unpigmented hair of the fetus

__terminal______ hair – long, course,

pigmented hair of the scalp,

eyelids, eyebrows, and with

puberty, axilla, pubic, and

face.

• Vellus hair – fine, short hair on

the rest of the body.

Hair Structure

Shaft protrudes above skin

surface.

Root located below surface; base

of root is the hair bulb,

Has 3 concentric layers.

Medulla: central axis.

• Cortex: forms bulk of hair. hard keratin

• Cuticle: forms hair surface, single layer of cells, hard keratin

Hair bulb expanded base of root

Internal matrix is source of hair.

• Dermis projects into bulb as

hair papilla, serves as blood

supply.

Hair Follicle……..

Dermal root sheath

Epithelial root sheath

part of dermis that surrounds the epithelial

root sheath.

follicle that envelops and anchors

///

with internal and external parts.

• Internal part contains stratum basale that may remain after

injury and supply a source of new epidermis.

• When hairs are pulled out, internal part comes out and is visible

as white bulb.

Hair Growth

Growth and resting stages are cyclic.

Growth stage: cells added at base and hair elongates.

• Resting stage: follicle shortens and holds hair in place.

Rest, then hair falls out of follicle. New hair begins.

• The amount of time spent in each stage depends on the

type or location of the hair

Regular hair loss means hair is

being replaced

Permanent hair loss

pattern baldness most common

cause.

Alopecia areata

is spot baldness most likely due to an

autoimmune response, destroy itself,

Hair Color.

Caused by varying amounts and types of melanin. Melanin

can be black-brown and red. Color is controlled by several

genes

\

blond hair little melanin,

Arrector pili

Type of __smooth____ muscle

Extends from the dermal root sheath of the follicle to the

papillary layer of the dermis.

• Muscle contraction causes hair to “stand on end”

.

• Skin pushed up by movement of hair follicle to produce

“goose bumps”.

perpendicular, stand on end,

Sebaceous Glands

where not found in

Holocrine (death of

secretory cells).

• Oily secretion called

_sebum_____.

• Prevents drying and

inhibits some bacteria.

• Most empty into hair

follicle.

• Exceptions: lips, meibomian

glands of eyelids, genitalia

Sweat (Sudoriferous) Glands

Two types traditionally called apocrine and merocrine, but apocrine may secrete

in a merocrine or holocrine fashion

both are what???

Eccrine (__mero__crine) glands.

Most common; numerous in palms and soles.

• Simple coiled tubular glands.

• Open directly onto surface of skin. Have own pores.

• Coiled part in dermis, duct exiting through epidermis.

• Produce _____ fluid (sweat) containing mostly water and some wastes.

• Important role in body temperature regulation

deep coiled (isotonic) in dermis, and duct skin surface

ammonia, urea, uric acid, lactic acid

///

__apo__crine glands.

• Active at puberty.

• Simple coiled tubular, usually open into hair follicles superficial to opening of

sebaceous gland.

• Secretion: organic compounds that are odorless but, when acted upon by

bacteria, may become odiferous.

• Found in axillae, genitalia (external labia, scrotum), around anus.

• Do not help regulate temperature.

active at puberty and sex hormones,

Most common; numerous in palms and soles.

Eccrine (merocrine) glands

Simple coiled tubular glands.

Eccrine (merocrine) glands

Open directly onto surface of skin. Have own pores.

Eccrine (merocrine) glands

Coiled part in dermis, duct exiting through epidermis.

Eccrine (merocrine) glands

Produce watery_ fluid (sweat) containing mostly water and some wastes.

Eccrine (merocrine) glands

Important role in body temperature regulation.

Eccrine (merocrine) glands

Active at puberty.

apocrine glands

Simple coiled tubular, usually open into hair follicles superficial to opening of

sebaceous gland.

apocrine glands

Secretion: organic compounds that are odorless but, when acted upon by

bacteria, may become odiferous

apocrine glands

Found in axillae, genitalia (external labia, scrotum), around anus.

apocrine glands

Ceruminous glands

modified eccrine sweat glands in the

external auditory canal

They secrete a thick, lipid-rich substance that mixes with oil from sebaceous glands and dead skin cells to form cerumen (earwax

Earwax (cerumen)

Composed of a combination of sebum

and secretion from ceruminous

ceruminous and sebaceous glands

Function

In combination with hairs, prevent dirt and

insects from entry

Mammary glands

modified _apocrine___ sweat glands that

produce milk.

Nails

Structure – thin plate of layers of

dead stratum corneum cells with

hard keratin

Nail body

Eponychium or cuticle

hyponychium

Matrix and nail bed

Nail root

Nail body

Eponychium cuticle

Matrix

Nail root

stratum corneum;

visible portion

is

corneum superficial to nail body,

hyponychium is corneum

beneath the free edge

cells that

give rise to the nail

covered by skin;

extends from nail matrix

Nail Growth

The nail matrix and bed are composed of epithelial tissue

with a stratum basale that gives rise to the cells that form

the nail.

• Grow continuously unlike hair.

• Fingernails grow 0.5 to 1.2 mm/day; faster than toenails

Lunula

– small part of nail matrix seen through the nail

body as a whitish, crescent-shaped area at the base of the

nail.

Physiology of the Integumentary System

Protection

Against abrasion, sloughing off of bacteria as

desquamation occurs.

• Against microorganisms and other foreign substances.

Glandular secretions bacteriostatic and skin contains cells

of the immune system.

• Melanin against UV radiation

which tissue protects skin and prevents tear

irregular dense CT of reticular layer

Protection of Hair on head is

insulator and protection against light, and

from abrasion.

Eyebrows how they protect

keep sweat out of the eyes;

eyelashes protect eyes from foreign objects. Hair in nose

and ear against dust, bugs, etc

Nails protect

ends of digits, self defense

barrier protection

Acts as barrier to diffusion of water