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 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 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. Increasing blood flow to injured area Redness and warmth result Capillaries become more permeable. Allowing exudate to escape into the tissues Swelling and pain result

Question What mechanism causes the redness (erythema) associated with the inflammatory process? Prostaglandins Leukotrienes Arachidonic acid All of the above a and b

Answer a and b Prostaglandins 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

A woman has peritonitis … 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 release many inflammatory mediators at the injured area: 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? Eosinophils Monocytes Neutrophils All of the above a and c

Answer All of the above Granulocytes 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 systemic (whole- body) responses white blood cell response acute-phase response

Leukocytes release interleukins and tumor necrosis factor 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

Author: Title needed here?

Question Tell whether the following statement is true or false: Body temperature is controlled through negative feedback loops.

Answer True When 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.

Mr. X says he has “chills and fever”… 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

Nonspecific 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.

Growth factors stimulate local cells to divide. 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 tissue 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 False The 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