Chapter 3 Inflammation, the Inflammatory Response, and Fever

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Chapter 3Inflammation, the Inflammatory
Response, and Fever
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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
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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
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Inflammation

• Inflammation is an automatic response to cell
  injury that
• Neutralizes harmful agents
• Removes dead tissue

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Inflammation

• Damaged cells release inflammatory mediators.
• These compounds stimulate inflammation.

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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

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Question

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

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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.

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Kinds of Exudate

• Serous
• Hemorrhagic
• Fibrinous
• Membranous
• Purulent

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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?

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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

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White Blood Cells Involved in Inflammation

• Granulocytes
• Neutrophils
• Eosinophils
• Basophils
• Mast cells
• Monocytes
• Monocytes ? Macrophages

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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

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Leukocytes (cont.)
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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

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Question

• Which leukocytes participate in the acute
  inflammatory response?
• Eosinophils
• Monocytes
• Neutrophils
• All of the above
• a and c

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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.

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Other Inflammatory Mediators

• Other inflammatory mediators travel in the
  plasma
• Kinins
• Coagulation and fibrinolysis proteins
• Complement system
• C-reactive protein

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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

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Fever
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Question

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

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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.

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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?

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White Blood Cell Response

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

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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

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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.

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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

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Question

• Tell whether the following statement is true or
  false
• If you get a paper cut, epithelial tissue will be
  replaced with connective tissue.

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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).

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Wound Healing

• Inflammatory phase
• Proliferative phase
• Remodeling phase