560A: Pathophysiology Flashcards
Pathophysiology
Etiology:
cause of disease
Diagnosis:
determination of the nature and cause of a patient’s illness
Cardinal signs of inflammation:
a. dilation (expansion) of blood vessels
b. increased vascular permeability
c. attraction of leukocytes (white blood cells) to site of injury
d. heat, redness, tenderness, swelling, pain
e. systemic response (fever, leukocytosis)
Causes of inflammation:
a. chemical agents (mediators) of inflammation that are formed & released when tissue is damaged; some are from cells; others from proteins in blood plasma
b. when antibodies and antigens (toxin or foreign bodies) interact; causes inflammatory response followed by tissue necrosis
Acute inflammation:
a. 1st line of defense in response to injury
b. nonspecific
c. may occur in response to any injury in short of one that is lethal
d. short duration
e. exudation of fluid & emigration of leukocytes
f. occurs before immune response
g. goal to remove injurious agents
Chronic inflammation:
a. non-degradable pathogens
b. lasts for several months to years
c. failure to rid whatever was causing an acute inflammation
Lymphocytes:
a. respond to foreign antigens, macrophages and related cells that process antigen and “present” it to lymphocytes;
b. important cells of immune system that communicate with one another;
c. secrete lymphokines that are chemical messengers
Complement system - 2 pathways of activation
- classical pathway - triggered by antigen-antibody interactions
- alternative pathway - activated by bacterial cell wall material or products generated during inflammation
Antibodies:
globulins produced by plasma cells and are usually called immunoglobulins
5 Classes of Antibodies
- IgM
- IgG
- IgA
- IgD
- IgE
Components of Healing Process: Type 1 - Immediate Hypersensitivity
a. allergy
b. IgE antibodies
c. antigen-antibody interaction
d. antihistamines
e. desensitization w/IgA & IgG (i.e. - food allergy)
f. anaphylaxis (i.e. bee sting)
g. mediator from mast cells & basophils
Components of Healing Process: Type 2 - Cytotoxic Hypersensitivity
a. antibody attaches to antigen
b. complement activated followed by cell tissue damage
Components of Healing Process: Type 3 - Immune Complex Disease
antigen-antibody complexes form; activate complement and cause inflammatory reaction
i.e. rheumatoid arthritis
Components of Healing Process: Type 4 - Delayed (Cell-Mediated) Hypersensitivity
T-lymphocytes secrete cytokines that attract lymphocytes, macrophages, and other inflammatory cells
i.e. tuberculosis, contact dermatitis
Control and Complications of Healing: Suppression of the Immune Response
a. unwanted effects of immune response
(autoimmune disease, rejected transplanted organs, Rh hemolytic disease in newborn infants)
b. methods for suppressing - radiation, cytotoxic drugs, adrenal corticosteroids, antibodies
c. tissue grafts and immunity (foreign antigens; lymphocytes reject foreign antigens; immune suppression to prevent rejection)
Control and Complications of Healing: Autoimmune Diseases
a. pathogenesis - antibodies formed, cross-reaction, T-lymphocytes fail to control immune response
b. treatment - corticosteroids, cytotoxic drugs
c. connective tissue diseases (autoimmune diseases)
i. e lupus erythematosus, scleroderma
Tissue growth disorders (neoplastic diseases)
a. viruses - some animal tumors are caused by viruses; human tumors may be virus induced
b. gene and chromosomal abnormalities
c. failure of immunologic defenses
d. heredity and tumors
Tumor:
disturbed cell growth
Benign tumors:
mass of cells (tumor) that lacks the ability to invade neighboring tissue or metastasize; non-cancerous
Malignant tumors:
a. cancer
b. carcinoma - arising from surface, glandular or parenchymal epithelium
c. sarcoma - solid tumor from other tissue
d. leukemia - neoplasm of blood-forming tissue
Benign vs. Malignant
Benign - grow slowly, expands, stays local, cells well differentiated
Malignant - grow rapidly, grow by infiltration, metastasize, cells not well differentiated
Hemopoiesis:
production of blood cells & platelets, which occurs in bone marrow
Hemostasis:
complex system for causing blood to clot when and where necessary
Factors concerned with hemostasis:
a. blood vessels and platelets
b. reflex contraction of blood vessels after injury
c. platelets adhere to injury
d. small breaks in capillaries are sealed by platelets
e. plasma coagulation factors
Phases of Hemostasis
Phase I - generation of prothrombin activation (intrinsic & extrinsic system)
Phase II - formation of thrombin
Phase III formation of fibrin
4 Major Categories of Bleeding Disorders:
- Abnormalities of small blood vessels
- Abnormalities of platelet function
- Deficiency of 1 or more of plasma coagulation factors
- Liberation of thromboplastin material into the circulation
Erythrocyte Disorders:
anemia - abnormally low oxygen carrying capacity
examples: hemorrhagic anemia, hemolytic anemia, aplastic anemia
Leukocyte Disorders:
leukemia - cancerous conditions involving white blood cells
Intravascular blood clot (thrombus):
Pathogenesis:
- slowing or stasis of blood flow
- damage to blood vessel wall
- increased coagulability of blood
Thrombosis:
blood clot formed withing the vascular system
Embolus:
detached clot carried in circulation
Infarct:
tissue necrosis caused by interruption of blood supply
Formation of blood clots within leg veins - Predisposing factors:
a. stasis of blood
b. varicose veins
c. increased blood coagulability
Formation of blood clots within leg veins - Major complication:
a. detachment of clot
b. embolus lodges in pulmonary artery or branches
c. clinical manifestations depend on size and location
Large pulmonary emboli:
- obstruct main pulmonary artery or major brances
- obstruct blood flow to lungs, causing severe dyspnea, cyanosis, shock, sudden death
- lung usually not infarcted because adequate collateral blood flow is provided by the bronchial arteries
What causes a small pulmonary emboli?
- impacted in peripheral branches of pulmonary artery
2. lung infarct may develop due to inadequate collateral circulation causing chest pain, cough, bloody sputum
What causes a septic pulmonary emboli?
- thrombi form in pelvic vein following uterine infection
- bacteria invade thrombi
- emboli from infected thrombus travel to lungs, causing pulmonary infarct
- bacteria in clot invade pulmonary infarct, causing lung abscess
Arterial Thrombosis:
- roughening of arterial wall secondary to arteriosclerosis
2. thrombi from on roughened area
What can occur as a result of Arterial Thrombosis?
- blockage of coronary artery: myocardial infarction
- major artery in leg occluded: gangrene
- occlusion of artery to brain: stroke
What causes intracardiac thrombosis?
a. clot forms (heart failure, valve injury or myocardial infarction)
b. may dislodge into circulation and cause infarction in spleen, kidneys or brain
