Immunology and Hematology Quiz

Acquired Immunity and Immunological Memory

• Artificially Acquired Active Immunity is achieved through vaccination, providing lifelong or temporary immunity.
• Artificially Acquired Passive Immunity involves injecting preformed antibodies, offering short-lived immunity.
• Humoral Immunity involves B cells producing antibodies against foreign antigens, found in extracellular fluids.
• Cell-Mediated Immunity involves T cells recognizing foreign antigens and regulating immune system cells.
• Immunological Memory refers to the immune system's ability to respond more rapidly to subsequent exposures to an antigen.
• Antibody Titer measures the amount of antibodies in the serum, displaying patterns during infection.
• Hypersensitivity Disorders include Type I (Anaphylactic), Type II (Cytotoxic), Type III (Immune Complex), and Type IV (Cell-Mediated) reactions.
• Type I Anaphylactic Reactions involve IgE antibodies, mast cell degranulation, and can lead to anaphylactic shock.
• Type II Cytotoxic Reactions activate complement to lyse antigenic cells, causing transfusion reactions.
• Type III Immune Complex Reactions involve immune complex deposition in organs, leading to diseases like glomerulonephritis.
• Type IV Cell-Mediated Reactions result in delayed hypersensitivity reactions, frequently displayed on the skin.
• Autoimmunity involves the breakdown of self-recognition mechanisms, leading to tissue damage and diseases like scleroderma and lupus.

Hemostasis and Immune System Overview

• Hemostasis involves three phases: vascular spasms, platelet plug formation, and coagulation
• Mechanisms preventing clot growth include swift removal of clotting factors and inhibition of activated clotting factors
• Substances used to prevent undesirable clots include aspirin, heparin, and warfarin
• Disseminated Intravascular Coagulation (DIC) leads to widespread clotting in intact blood vessels, causing blockage of blood flow and severe bleeding
• Thrombocytopenia is a condition where the number of circulating platelets is deficient, leading to spontaneous hemorrhage
• Bleeding disorders may result from the inability to synthesize procoagulants by the liver, caused by conditions such as vitamin K deficiency, hepatitis, or cirrhosis
• Hemophilias are hereditary bleeding disorders caused by a lack of specific clotting factors
• The immune system is localized in primary organs like bone marrow and thymus, and immune responses occur in secondary organs
• Innate immunity consists of physical and chemical barriers, cellular responses, and soluble factors
• The inflammatory response involves increased circulation to the site, WBCs leaking into tissues, and release of histamine and prostaglandin
• Innate immunity is present from birth and operates against any substance, while acquired immunity is tailored to individual pathogens and is enhanced by prior exposure
• Types of acquired immunity include naturally acquired active and passive immunity, as well as artificially acquired immunity through vaccines or immune serum

Cardiac Physiology and Function

• The cardiovascular system consists of the myocardium and a network of vascular vessels (arteries, capillaries, veins) that supply cells and tissues with nutrients and remove waste products.
• The primary contractile unit in cardiac muscle tissue is the cardiac muscle cell (myocyte), which is joined by tight gap junctions facilitating action potential propagation.
• The heart comprises various cellular phenotypes, including myocytes, cardiac fibroblasts, vascular cells, Purkinje cells, and connective tissue cells, with limited proliferative capacity of myocytes and promotion of cardiac fibroblast proliferation.
• The ventricular action potential (AP) overview involves different phases, including resting, initiation, plateau, and re-polarization, with specific ion channels opening and closing during each phase.
• Electrical conduction in the heart involves pacemaker cells such as the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, and Purkinje fibers, with the SA node commonly setting the pace of the heart.
• The electrical impulse migration from the SA node through the atrial muscle, AV node, and bundle of His allows atria to fully contract before ventricles depolarize.
• An electrocardiogram (ECG) records electrical currents of the heart, with different intervals corresponding to conduction through the AV node, ventricular depolarization and repolarization.
• Cardiac activity is regulated by the autonomic nervous system (ANS), with sympathomimetics stimulating cardiac rate and contractility, and parasympathomimetics decreasing the rate of depolarization.
• Excitation-contraction coupling in cardiac myocytes involves the availability of ATP and Ca2+ for contraction and relaxation, with the ATPase sarcoplasmic reticulum pump (SERCA) playing a crucial role.
• Cardiac function is characterized by the recording of electrical currents through an ECG and the measurement of cardiac output (CO) which is dependent on heart rate and stroke volume, typically around 5L/min.
• Toxicants can affect cardiac function through their effects on the heart, vasculature, and/or the nervous system, potentially leading to disturbances in heart rhythm, such as arrhythmias.
• Disturbances in cardiac function may include abnormal heart rhythm, ischemic heart disease, cardiac hypertrophy, and heart failure, with potential implications for myocardial infarction, scar tissue formation, and reduced cardiac output.