CHAPTER 3

INFLAMMATION, THE INFLAMMATORY RESPONSE, AND FEVER

PRE LECTURE QUIZ TRUE/FALSE

Acute inflammation is the immediate and early response to an injurious agent and occurs in two phases; the vascular phase and the cellular phase.

Chronic inflammation is self-perpetuating and may last for weeks, months, or even years.

Erythrocytes play a central role in the physiology of inflammation.

Vasoconstriction occurs during the vascular stage of inflammation.

Fever is a pathologic response to bacterial and viral infection with and has no positive outcome on illness.

T

T

F

F

F

PRE LECTURE QUIZ The ______________ signs of inflammation are

known as redness, swelling, heat, pain, and loss of function.

Histamine, serotonin, cytokines, bradykinin, arachidonic acid, and platelet-activating factor are _____________ of inflammation.

Body temperature is regulated by the thermoregulatory center in the ________________.

____________, or pyrexia, represents an increase in body temperature due to resetting of the hypothalamic thermoregulatory set point as the result of endogenous pyrogens released from host macrophages or endothelial cells.

_____________ refers to heat transfer through the circulation of air currents.

cardinal

Convection

Fever

hypothalamus

mediators

INFLAMMATION Inflammation is an automatic response to cell

injury that: Neutralizes harmful agents Removes dead tissue

INFLAMMATION Damaged cells release

inflammatory mediators.

These compounds stimulate inflammation.

Damaged cells release

inflammatory mediators

local responses

vascular stage

cellular stage

systemic (whole-body) responses

white blood cell response

acute-phase response

ACUTE INFLAMMATION Vascular stage

Prostaglandins and leukotrienes affect blood vessels.

Arterioles and venules dilate.º Increasing blood flow to injured areaº Redness and warmth result

Capillaries become more permeable.º Allowing exudate to escape into the tissuesº Swelling and pain result

QUESTION

What mechanism causes the redness (erythema) associated with the inflammatory process?

a. Prostaglandinsb. Leukotrienesc. Arachidonic acidd. All of the abovee. a and b

ANSWER

e. a and bProstaglandins and leukotrienes cause

vasodilation, which brings more blood to the injured/affected area. The symptoms caused by this vasodilation are redness/erythema and warmth.

KINDS OF EXUDATE Serous Hemorrhagic Fibrinous Membranous Purulent

SCENARIO:A woman has peritonitis … She has a distended abdomen, low blood pressure, and fluid in her abdominal cavity. After surgery, she is told to report any GI distress as it may indicate fibrous

adhesions.Question: What kinds of exudate are involved? What useful purposes do

they serve? What complications may they cause?

CELLULAR STAGE White blood cells enter

the injured tissue: Destroying infective

organisms Removing damaged

cells Releasing more

inflammatory mediators to control further inflammation and healing

WHITE BLOOD CELLS INVOLVED IN INFLAMMATION

Granulocytes Neutrophils Eosinophils Basophils Mast cells

Monocytes Monocytes Macrophages

LEUKOCYTES Leukocytes enter the

injured area Leukocytes express

adhesive proteins Attach to the blood vessel

lining Squeeze between the

cells Follow the inflammatory

mediators to the injured area

LEUKOCYTES (CONT.)

LEUKOCYTES (CONT.)Leukocytes release many inflammatory

mediators at the injured area: Histamine and serotonin Platelet-activating factor Cytokines

Colony-stimulating factors Interleukins Interferons Tumor necrosis factor

Nitric oxide

QUESTION Which leukocytes participate in the acute

inflammatory response?a. Eosinophils b. Monocytesc. Neutrophils d. All of the abovee. a and c

ANSWER d. All of the aboveGranulocytes and monocytes play a role

in the acute phase of the immune response. Eosinophils and neutrophils are granulocytes, so all of the leukocytes listed participate.

OTHER INFLAMMATORY MEDIATORS

Other inflammatory mediators travel in the plasma:

Kinins Coagulation and fibrinolysis proteins Complement system C-reactive protein

damaged cells release

inflammatory mediators

local responses

vascular stage

cellular stage

systemic (whole-body) responses

white blood cell response

acute-phase response

ACUTE-PHASE RESPONSE Leukocytes release interleukins and

tumor necrosis factor Affect thermoregulatory center fever Affect central nervous system lethargy Skeletal muscle breakdown

Liver makes fibrinogen and C-reactive protein Facilitate clotting Bind to pathogens Moderate inflammatory responses

FEVER

QUESTION

Tell whether the following statement is true or false:

Body temperature is controlled through negative feedback loops.

ANSWER TrueWhen the body senses a change out of the

norm (as illustrated in the previous slides), it activates mechanisms that oppose that change (vasodilation and sweating with increased temperatures; vasoconstriction and shivering with decreased temperatures). This is known as negative feedback. Positive feedback, on the other hand, senses a change but activates a mechanism that exaggerates the change.

SCENARIO:Mr. X says he has “chills and fever”… His daughter wants you to explain how he could

have both at the same time and from the same disease

Question: Should she be keeping him warmer or

helping him cool off?

WHITE BLOOD CELL RESPONSE

Inflammatory mediators cause WBC production WBC count rises Immature neutrophils (bands) released into blood

CHRONIC INFLAMMATION Macrophages accumulate in the damaged

area and keep releasing inflammatory mediators.

Nonspecific chronic inflammation Fibroblasts proliferate Scar tissue forms

Granulomatous inflammation Macrophages mass together around foreign bodies Connective tissue surrounds and isolates the mass

SCENARIO: A man had tuberculosis (TB) long ago, and when he

first had the disease, he had a fever, productive cough, and bloody sputum.

Later, he had trouble breathing and the doctor said his lungs were “consolidated” with fibrous proteins.

He recovered and his fever went down; he thought he was cured.

Three years later, an x-ray showed nodules in his lungs and he was told they contained the TB bacteria.

Question: Identify inflammatory events in his case.

TISSUE REPAIR Growth factors stimulate local cells to

divide. Tissue organization is controlled by the

extracellular matrix. New cells are laid down on the

extracellular matrix. Tissue regeneration: injured tissue is replaced

by the same kind of cells Fibrous tissue repair: injured tissue is replaced

by connective tissueº Granulation tissue scar tissue

QUESTION

Tell whether the following statement is true or false:

If you get a paper cut, epithelial tissue will be replaced with connective tissue.

ANSWER

FalseThe surface epithelial cells of the skin are

most likely to be damaged in this instance. Surface epithelial tissue has the ability to regenerate, replacing the damaged tissue with the same type (epithelial).

WOUND HEALING

Inflammatory phase Proliferative phase Remodeling phase