Questions and Answers
What is the primary mechanism of action of direct-acting anticoagulants, such as Apixaban and Rivaroxaban?
Which of the following is a characteristic of Heparin?
What is the mechanism of action of Aspirin as a platelet inhibitor?
What is the primary mechanism of action of indirect-acting anticoagulants, such as Warfarin sodium?
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What is the most toxic side-effect of anticoagulant therapy?
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Which of the following is a characteristic of Heparin-antithrombin III complex?
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What is the purpose of administering 81.25 mg/day of aspirin?
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What is the antidote for Heparin overdose?
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Which of the following is a characteristic of indirect-acting anticoagulants?
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What is the primary characteristic of T cells and B cells that respond to a specific antigen?
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What is the purpose of memory cells in the immune response?
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What is the origin of the term 'vaccine'?
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What is the purpose of using a weakened pathogen in a live attenuated vaccine?
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What is the characteristic of a killed/inactivated vaccine?
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What is the purpose of using genetic engineering in subunit/conjugate/engineered vaccines?
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What is the advantage of using memory cells in the immune response?
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What is the characteristic of the immune response upon first exposure to an antigen?
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What is the purpose of using a portion of a pathogen in a subunit/conjugate/engineered vaccine?
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What is the advantage of using vaccines in immunization?
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What is the function of MHC II protein in antigen presentation?
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What is the outcome of a humoral immune response?
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What is the primary function of interleukin-1 (IL-1) in a humoral immune response?
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What is the role of antigen-presenting cells (APCs) in a humoral immune response?
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Study Notes
The Cardiovascular System Overview
- The cardiovascular system has two main functions: distributing nutrients, oxygen, and hormones to all cells in the body, and carrying away metabolic waste products.
- The system consists of five main components: blood, heart, arteries, veins, and capillaries.
Blood Overview
- Blood is made up of two fractions: plasma and formed elements.
- Plasma makes up 55% of total blood volume and is composed of 92% water, electrolytes, proteins, and nutrients.
- Formed elements include blood cells, platelets, and white blood cells.
- Red blood cells (erythrocytes) have no nucleus, are bi-concaval, and make up 99.9% of all blood cells.
- Hemoglobin (Hb) in red blood cells can reversibly bind to 4O2 and 4CO2.
- White blood cells make up 0.1% of all blood cells and have five types.
Hematocrit and Blood Components
- Hematocrit is the proportion of red blood cells in the blood.
- Normal hematocrit values for males and females are shown.
Bohr and Haldane Effects
- The Bohr effect is the increase in oxygen binding to hemoglobin in response to a decrease in pH.
- The Haldane effect is the increase in carbon dioxide binding to hemoglobin in response to an increase in pH.
CO2 Transport and Buffering
- CO2 is an acid that reacts with water to form carbonic acid.
- Hemoglobin plays a crucial role in CO2 transport and buffering by binding to CO2 in the blood.
- The CO2 is temporarily bound to hemoglobin in red blood cells, transported to the lungs, and then released.
Blood Clotting and Hemostasis
- Hemostasis is the process of forming a blood clot to prevent bleeding.
- A blood clot consists of a plug of platelets enmeshed in a network of insoluble fibrin molecules.
- The clotting cascade requires the proteolytic enzyme thrombin (Factor II) and calcium ions (Ca2+).
- The clotting cascade also requires about a dozen other protein clotting factors, which are activated by proteolytic cleavage.
Fibrinolysis
- Fibrinolysis is the process of breaking down a blood clot.
- Plasmin is the enzyme that breaks down fibrin and degrades factors V and VIII, inhibiting further clotting.
- Plasminogen activators, such as tissue-type plasminogen activator (t-PA) and urokinase, convert plasminogen to plasmin.
Anticoagulants and Thrombocytopathics
- Direct-acting anticoagulants, such as apixaban and rivaroxaban, are highly selective and reversible direct inhibitors of factor X.
- Heparin is an anticoagulant that accelerates antithrombin III activity, which in turn inactivates factors IX, X, and XI.
- Indirect-acting anticoagulants, such as warfarin, inhibit vitamin K, which is necessary for the production of clotting factors II, VII, IX, and X.
- Platelet inhibitors, such as aspirin, inhibit thromboxane synthesis, resulting in decreased platelet aggregation.
Immunity and Body Defenses
- Immunity is the body's ability to resist or eliminate potentially harmful foreign materials or abnormal cells.
Anatomy and Physiology of Immunity
- The immune system is a functional system, not an organ system.
- It consists of multiple activities, including defense against invading pathogens, removal of worn-out cells and tissue debris, identification and destruction of abnormal or mutant cells, rejection of foreign cells, and inappropriate responses.
Types of Immunity
- Innate immunity is the first line of defense, providing rapid, non-specific responses to a broad range of microbes.
- Adaptive or acquired immunity is the second line of defense, providing slower, specific responses to specific microbes.
Innate Immunity
- External defenses include anatomical barriers (skin, mucous membranes, secretions), mechanical factors (flushing action of saliva, tears, urine), and chemical factors (antimicrobial peptides in sweat, lysozyme in tears/saliva).
- Internal defenses include cellular components (neutrophils, monocytes/macrophages, cytotoxic or killer cells) and extracellular components (cytokines, complement).
Cellular Components of Innate Immunity
- White blood cells (WBCs) fight infection, including lymphocytes (T and B cells), monocytes (which become macrophages), and granulocytes (neutrophils, eosinophils, basophils).
- Natural killer (NK) cells are activated by the release of IL-2 from T helper cells and recognize antigens on the surface of infected cells.
- Phagocytosis is the process by which cells engulf and digest foreign particles or microbes.
Toll-Like Receptors (TLRs)
- TLRs are innate immune sensors that trigger a cascade of events to kill or protect against pathogens.
- They are present on macrophages and few other cells, recognize microbial components, and bind to microbes or their components.
Cytokines
- Cytokines are small proteins secreted by cells of the immune system, including interferons, interleukins, and tumour necrosis factor (TNF).
- They affect the behavior of other cells, are signaling molecules, and are key players in both innate and acquired immunity.
Interferon (IFN)
- Interferon is a signaling protein produced by virus-infected monocytes and lymphocytes.
- It inhibits protein synthesis, "interferes" with virus replication, and warns neighboring cells that a virus is present.
Adaptive (Acquired) Immunity
- Adaptive immunity is the body's response to a specific invader after exposure, relying on the production of antibodies.
- It involves specificity and memory, with T cells and B cells reacting to specific antigens and producing memory cells for future responses.
Vaccines
- Vaccines are used to stimulate adaptive immunity, with different types including live attenuated, killed/inactivated, and subunit/conjugate/engineered vaccines.
Immunity and Body Defenses
- Immunity is the body's ability to resist or eliminate potentially harmful foreign materials or abnormal cells.
- It consists of defense against invading pathogens, removal of 'worn-out' cells and tissue debris, identification and destruction of abnormal or mutant cells, and rejection of 'foreign' cells.
Innate Immunity vs Adaptive (Acquired) Immunity
- Innate immunity is the first line of defense, providing immediate, non-specific defense against infection.
- Adaptive immunity is the second line of defense, providing specific defense against infection, with a lag period and development of memory.
External Defenses
- Anatomical barriers: skin, mucous membranes, and physiological barriers such as temperature, pH, and oxygen levels.
- Mechanical factors: flushing action of saliva, tears, and urine, and the mucociliary escalator.
- Chemical factors: antimicrobial peptides in sweat, HCl in the stomach, and lysozyme in tears and saliva.
Internal Defenses
- Cellular defenses: neutrophils, monocytes/macrophages, cytotoxic or killer cells, and natural killer cells.
- Extracellular defenses: cytokines, complement, and coagulation.
Toll-Like Receptors (TLRs)
- TLRs are innate immune sensors that exist as transmembrane proteins on macrophages and other cells.
- They are conserved across vertebrates and are sensitized to microbes or their components.
- They trigger a cascade of events to kill or protect against pathogens.
Cytokines
- Cytokines are small proteins secreted by cells of the immune system that affect the behavior of other cells.
- Examples include interferons, interleukins, and tumor necrosis factor (TNF).
- Cytokines are key players in both innate and acquired immunity.
Interferon (IFN)
- IFN is an anti-viral protein produced by virus-infected monocytes and lymphocytes.
- It inhibits protein synthesis and "interferes" with virus replication.
- IFN warns neighboring cells that a virus is present, inducing an anti-viral state.
Interleukins
- Interleukins are numbered, 1-37, and are secreted by T-lymphocytes and macrophages.
- They are key modulators of behavior of immune cells, promoting proliferation, activation, and antibody production.
- They are also involved in inflammation.
Tumor Necrosis Factor (TNF)
- TNF is an endogenous pyrogen that regulates immune cells, induces apoptotic cell death, and inhibits tumorigenesis and viral replication.
- It has multiple functions, including inducing fever, inflammation, and antibody production.
Antigens
- Antigens are substances that confer identity, recognized by the immune system.
- They are also known as immunogens.
- Immunogenicity is the ability to induce a humoral and/or cell-mediated immune response.
- Factors that determine immunogenicity include foreignness, size, chemical composition, structure, and physical form.
Antibodies
- Antibodies are protein molecules produced by activated B cells (plasma cells).
- They are Y-shaped molecules with hinges, and their ends include variable regions where antigen binding occurs.
- Antibodies occur in two forms: soluble and membrane-bound.
- There are five classes of antibodies: IgG, IgM, IgA, IgE, and IgD.
Humoral Immune Response
- A humoral immune response is an elaborate interplay between antigen, non-specific defenses, and B and T lymphocytes.
- The process involves direct contact and cytokines that bind to receptors on cell surfaces.
- Antigen-presenting cells (APCs) display antigen on the surface, attached to MHC, for other cells to interact with.
Humoral Activation
- Macrophages encounter and process antigen, displaying it on the surface with MHC II protein.
- T helper cells bind to the antigen-presenting cell, secreting IL-1, which activates the T helper cell.
- The T helper cell binds to the B cell and releases IL-4, which activates the B cell.
- The B cell becomes a plasma cell, releasing antibodies.
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Description
This quiz covers the basic functions and components of the cardiovascular system, including blood, heart, capillaries, and arteries.
