Blood Composition and Volume Quiz
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Blood Composition and Volume Quiz

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Questions and Answers

Arterial blood is darker in color than venous blood.

False

What percentage of total body weight does blood represent?

  • 8% (correct)
  • 12%
  • 10%
  • 5%

    • What is the main function of erythrocytes?

    Oxygen transport

    The __________ is the layer that contains white blood cells in blood.

    <p>buffy coat</p> Signup and view all the answers

    Match the following blood components with their descriptions:

    <p>Erythrocytes = Red blood cells responsible for oxygen transport Leukocytes = White blood cells that are immune defense units Platelets = Cell fragments important for blood clotting Plasma = Liquid portion of blood containing nutrients and waste</p> Signup and view all the answers

    What is the average hematocrit level in women?

    <p>42%</p> Signup and view all the answers

    Plasma appears clear and yellow unless a person has a lot of lipids in their system.

    <p>True</p> Signup and view all the answers

    The formed elements in blood mainly consist of red blood cells, white blood cells, and __________.

    <p>platelets</p> Signup and view all the answers

    What is the role of blood in regulating body temperature?

    <p>Maintaining body temperature through vessel contraction.</p> Signup and view all the answers

    Match the following blood functions with their descriptions:

    <p>Carrying = Transport of oxygen, nutrients, hormones Regulation = Controlling body temperature and pH Protection = Defense against infections through leukocytes Clotting = Stopping bleeding through platelets</p> Signup and view all the answers

    What is the primary function of plasma proteins?

    <p>Exerting an osmotic effect</p> Signup and view all the answers

    Gamma globulins are synthesized in the liver.

    <p>False</p> Signup and view all the answers

    What are the two most abundant electrolytes in plasma?

    <p>Sodium (Na+) and chloride (Cl-)</p> Signup and view all the answers

    Plasma minus fibrinogen is known as ______.

    <p>serum</p> Signup and view all the answers

    Match the plasma proteins with their functions:

    <p>Albumins = Contribute to colloid osmotic pressure Fibrinogen = Inactive precursor for clot formation Gamma globulins = Act as antibodies Globulins = Transport water-insoluble substances</p> Signup and view all the answers

    Which component of plasma is responsible for transporting heat?

    <p>Water</p> Signup and view all the answers

    Erythrocytes are also known as white blood cells.

    <p>False</p> Signup and view all the answers

    How many red blood cells are typically found in 1 ml of blood?

    <p>5 billion</p> Signup and view all the answers

    The primary force that prevents excessive loss of plasma from the capillaries is due to ______.

    <p>plasma proteins</p> Signup and view all the answers

    Which plasma protein is specifically involved in the blood-clotting process?

    <p>Fibrinogen</p> Signup and view all the answers

    What is the main function of erythrocytes?

    <p>Transporting oxygen and carbon dioxide</p> Signup and view all the answers

    Erythrocytes contain a nucleus to aid in their function.

    <p>False</p> Signup and view all the answers

    What happens to red blood cells after an average lifespan of 120 days?

    <p>They are removed by the spleen and recycled.</p> Signup and view all the answers

    Hemoglobin can transport up to _____ O2 molecules.

    <p>4</p> Signup and view all the answers

    Match the following components of hemoglobin to their roles:

    <p>Iron = Binds to oxygen Heme = Part of hemoglobin structure Alpha and Beta subunits = Protein components of hemoglobin Carbonic anhydrase = Catalyzes conversion of CO2</p> Signup and view all the answers

    What is the primary form in which CO2 is transported in the blood?

    <p>As bicarbonate ion</p> Signup and view all the answers

    What are the two key benefits of erythrocytes having no organelles?

    <p>More hemoglobin molecules and a shorter lifespan.</p> Signup and view all the answers

    Red blood cells produce ATP using mitochondria.

    <p>False</p> Signup and view all the answers

    The diameter of a typical erythrocyte is approximately _____ micrometers.

    <p>8</p> Signup and view all the answers

    What is the consequence of carbon monoxide binding to hemoglobin?

    <p>It causes carbon monoxide poisoning.</p> Signup and view all the answers

    What role do eosinophils primarily serve in the immune system?

    <p>Fight parasitic infections</p> Signup and view all the answers

    Individuals with Rh-positive blood can develop anti-Rh antibodies after exposure to Rh-positive blood.

    <p>False</p> Signup and view all the answers

    The primary function of ____ is phagocytosis and antigen presentation.

    <p>monocytes</p> Signup and view all the answers

    Match the following leukocytes with their primary characteristics:

    <p>Neutrophils = First responders to bacterial infection Eosinophils = Fight parasitic infections Basophils = Least numerous, involved in allergic reactions Monocytes = Differentiate into macrophages</p> Signup and view all the answers

    What is the primary function of basophils?

    <p>Production of histamine and heparin</p> Signup and view all the answers

    What happens if an Rh-negative person is exposed to Rh-positive blood?

    <p>They become sensitized and produce anti-Rh antibodies</p> Signup and view all the answers

    The degranulation of eosinophils can lead to allergic conditions such as asthma.

    <p>True</p> Signup and view all the answers

    What is the primary function of lymphocytes?

    <p>Recognize foreign antigens and produce antibodies</p> Signup and view all the answers

    What is the lifespan range of macrophages in tissues?

    <p>Months to years</p> Signup and view all the answers

    Neutrophils primarily produce antibodies.

    <p>False</p> Signup and view all the answers

    What role do granulocytes play in the immune system?

    <p>They help in fighting off infections by engulfing and destroying pathogens.</p> Signup and view all the answers

    When blood from one type is transfused into another incompatible type, the body can react with ________.

    <p>hemolysis</p> Signup and view all the answers

    Match the immune cell type with its function:

    <p>Lymphocytes = Produce antibodies Neutrophils = Engulf pathogens Eosinophils = Combat parasites Basophils = Release histamine</p> Signup and view all the answers

    Blood type incompatibility can lead to an immune response that destroys the transfused red blood cells.

    <p>True</p> Signup and view all the answers

    Which of the following processes do neutrophils primarily use to eliminate pathogens?

    <p>Phagocytosis</p> Signup and view all the answers

    What is phagocytosis?

    <p>The process by which immune cells engulf and destroy pathogens.</p> Signup and view all the answers

    Granulocytes have granules in their cytoplasm that contain __________ to help fight infections.

    <p>enzymes</p> Signup and view all the answers

    Match the following immune cells with their primary characteristics:

    <p>Lymphocytes = Involved in adaptive immunity Neutrophils = Most abundant white blood cells Eosinophils = Fight off parasitic infections Basophils = Involved in allergic reactions</p> Signup and view all the answers

    What is the primary function of neutrophils in the immune system?

    <p>Engulfing and destroying bacteria</p> Signup and view all the answers

    Eosinophils are the most abundant immune cells in the human body.

    <p>False</p> Signup and view all the answers

    What happens to red blood cells during a transfusion reaction resulting from blood type incompatibility?

    <p>They rupture and are destroyed.</p> Signup and view all the answers

    ____ are important immune cells that specialize in the detection and response to pathogens.

    <p>Lymphocytes</p> Signup and view all the answers

    Match the white blood cells with their characteristics:

    <p>Neutrophils = Phagocytic specialists that respond first to infections Eosinophils = Responsible for combating parasitic infections Basophils = Release histamine during inflammatory reactions Monocytes = Develop into macrophages and dendritic cells in tissues</p> Signup and view all the answers

    Which of the following statements is true about granulocytes?

    <p>All granulocytes contain a nucleus with multiple shapes.</p> Signup and view all the answers

    Phagocytosis is the process by which immune cells engulf and destroy pathogens.

    <p>True</p> Signup and view all the answers

    What type of blood group antigens are involved in Rh compatibility?

    <p>D antigen</p> Signup and view all the answers

    When antibodies from type A blood interact with type B antigens, the result is a _____ reaction.

    <p>transfusion</p> Signup and view all the answers

    Which type of blood cell is primarily involved in the initial response to infection?

    <p>Neutrophils</p> Signup and view all the answers

    Blood type incompatibility can lead to the immune system destroying a transplanted organ.

    <p>True</p> Signup and view all the answers

    What is the primary role of neutrophils in the immune system?

    <p>Phagocytosis of pathogens</p> Signup and view all the answers

    What process do immune cells, such as phagocytes, use to consume pathogens?

    <p>Phagocytosis</p> Signup and view all the answers

    Granulocytes are characterized by the presence of ______ in their cytoplasm, which play a role in inflammation and defense against infections.

    <p>granules</p> Signup and view all the answers

    Match the following immune cell types with their primary functions:

    <p>Lymphocytes = Produce antibodies Neutrophils = Engulf pathogens Monocytes = Differentiate into macrophages Basophils = Release histamine during allergic reactions</p> Signup and view all the answers

    What is the primary role of natural killer (NK) cells?

    <p>Effective against virally infected cells</p> Signup and view all the answers

    Natural killer (NK) cells release lytic granules to kill infected cells.

    <p>True</p> Signup and view all the answers

    What do NK cells produce to limit viral replication?

    <p>Cytokines</p> Signup and view all the answers

    NK cells will attack infected cells even when viruses evolve to hide their __________.

    <p>ID</p> Signup and view all the answers

    Which of the following characteristics applies to large granular lymphocytes?

    <p>Contain granules</p> Signup and view all the answers

    Natural killer (NK) cells can only recognize viruses that have not evolved.

    <p>False</p> Signup and view all the answers

    What response are NK cells a part of?

    <p>Innate immune response</p> Signup and view all the answers

    Match the following immune cell types with their primary functions:

    <p>Natural Killer Cells = Kill virally infected cells Neutrophils = Phagocytosis of pathogens T-lymphocytes = Adaptive immune response B-lymphocytes = Produce antibodies</p> Signup and view all the answers

    How do NK cells recognize infected cells?

    <p>By detecting abnormal markers or absence of 'ID'</p> Signup and view all the answers

    Natural killer cells are a type of large granular __________.

    <p>lymphocytes</p> Signup and view all the answers

    What is meant by the term 'pathogen capacity'?

    <p>The inherent ability of a pathogen to cause disease</p> Signup and view all the answers

    All pathogens have the same capacity to cause disease.

    <p>False</p> Signup and view all the answers

    What are the three types of external defenses in immunity?

    <p>Mechanical, Chemical, Microbiological</p> Signup and view all the answers

    What is the primary role of the immune system?

    <p>To protect against harmful foreign invaders</p> Signup and view all the answers

    Nasal cilia play an important role in __________ pathogens.

    <p>trapping</p> Signup and view all the answers

    Bacteria have a nucleus and are multicellular organisms.

    <p>False</p> Signup and view all the answers

    The body mounts inappropriate immune responses that can lead to __________ diseases.

    <p>autoimmune</p> Signup and view all the answers

    Which of the following is NOT a method through which pathogens commonly enter the body?

    <p>Through exercise</p> Signup and view all the answers

    Name one type of virus mentioned in the content.

    <p>SARS-CoV-2</p> Signup and view all the answers

    Microbiota can help prevent pathogens from multiplying by competing for resources.

    <p>True</p> Signup and view all the answers

    Match the following external defense mechanisms with their descriptions:

    <p>Mechanical = Prevents pathogen entry through physical barriers Chemical = Involves antimicrobial peptides produced by epithelial cells Microbiological = Involves competition from beneficial bacteria Plan B = Strategically positioned internal defenses</p> Signup and view all the answers

    What are antimicrobial peptides and who produces them?

    <p>Antimicrobial peptides are protective substances made by epithelial cells.</p> Signup and view all the answers

    Match the following types of pathogens with their characteristics:

    <p>Bacteria = Non-nucleated, single-celled microorganisms Viruses = Consist of DNA or RNA enclosed by a protein coat Fungi = Multicellular organisms that can decompose organic matter Parasites = Organisms that live on or in a host and cause harm</p> Signup and view all the answers

    The best types of microbiota are found on __________.

    <p>fiber</p> Signup and view all the answers

    The thymus is responsible for the production of B-cells.

    <p>False</p> Signup and view all the answers

    Autoimmune reactions occur when the immune system targets foreign invaders.

    <p>False</p> Signup and view all the answers

    Which of the following statements best describes the 'Plan B' defense?

    <p>It involves internal defenses aimed at combatting infections.</p> Signup and view all the answers

    What is the term for cells that have generated from the body's own tissues but are deemed abnormal?

    <p>mutant cells</p> Signup and view all the answers

    Protozoan parasites, such as __________, can cause malaria.

    <p>plasmodium</p> Signup and view all the answers

    The appendix has no role in the immune function.

    <p>False</p> Signup and view all the answers

    Which immune response is characterized as non-specific and rapid?

    <p>Innate responses</p> Signup and view all the answers

    Which of the following is a common effect of viral infections?

    <p>Invade host cells to reproduce</p> Signup and view all the answers

    Cytokines released during inflammation increase blood vessel permeability.

    <p>True</p> Signup and view all the answers

    The __________ is a lymphoid tissue where immune cells are produced and divide.

    <p>bone marrow</p> Signup and view all the answers

    Match the lymphoid tissues with their primary functions:

    <p>Lymph nodes = Checkpoints that drain lymph and check for antigens Spleen = Contains white pulp with immune cells Tonsils = Higher chance of entry for pathogens through the mouth Appendix = Has immune function related to gut flora</p> Signup and view all the answers

    Which of the following immune cells drink large amounts of fluid and activate T-cells?

    <p>Dendritic cells</p> Signup and view all the answers

    Which type of immune response is responsible for allergies?

    <p>Inappropriate immune response</p> Signup and view all the answers

    What is the primary role of natural killer (NK) cells in the immune response?

    <p>To destroy infected or cancerous cells</p> Signup and view all the answers

    The __________ are patches of lymphoid tissue found in the gut and lungs.

    <p>Peyer's patches</p> Signup and view all the answers

    What type of immunity involves the production of antibodies by plasma cells?

    <p>Antibody-mediated immunity</p> Signup and view all the answers

    What is the primary goal of inflammation?

    <p>To eliminate pathogens and repair tissue damage</p> Signup and view all the answers

    Twisting the ankle is an external cause of inflammation.

    <p>False</p> Signup and view all the answers

    What type of immune cells are first responders in the inflammatory process?

    <p>Macrophages</p> Signup and view all the answers

    The release of __________ by mast cells dilates blood vessels during inflammation.

    <p>histamine</p> Signup and view all the answers

    Match the immune cell type with its function:

    <p>Macrophages = Engulf pathogens and debris Mast cells = Release histamine Dendritic cells = Activate T-cells Cytokines = Signal other immune cells</p> Signup and view all the answers

    Which of the following describes the role of phagocytes during inflammation?

    <p>To ingest and destroy pathogens</p> Signup and view all the answers

    Which immune response is mediated by T-cells and involves the production of activated lymphocytes?

    <p>Cell-mediated immunity</p> Signup and view all the answers

    What are the three main functions of phagocytes during inflammation?

    <p>Isolate and destroy invaders, remove debris, prepare for healing</p> Signup and view all the answers

    What physical changes are typically associated with inflammation?

    <p>Redness, swelling, heat, and pain</p> Signup and view all the answers

    During an inflammatory response, __________ are recruited to the injured area to assist in clearing pathogens.

    <p>phagocytes</p> Signup and view all the answers

    What is the primary role of dendritic cells (DC) in the immune system?

    <p>Acting as a bridge between innate and adaptive immunity</p> Signup and view all the answers

    Mannose is a type of glucose that is only found on pathogen surfaces.

    <p>False</p> Signup and view all the answers

    What happens when a dendritic cell encounters a pathogen?

    <p>It matures and presents pathogen peptides on MHC proteins to T-cells.</p> Signup and view all the answers

    The formation of _________ allows for the punching of holes in pathogens.

    <p>membrane attack complexes (MAC)</p> Signup and view all the answers

    Which of the following mechanisms enhances the uptake of pathogens?

    <p>Opsonization</p> Signup and view all the answers

    Mature dendritic cells can directly kill pathogens.

    <p>False</p> Signup and view all the answers

    What unique structural characteristic is associated with dendritic cells?

    <p>Star-shaped morphology</p> Signup and view all the answers

    Dendritic cells cut up pathogens into smaller peptides and combine them with ________ to present on their surface.

    <p>MHC proteins</p> Signup and view all the answers

    Match the immune cell function with its respective type:

    <p>Dendritic Cells = Antigen presentation Phagocytes = Uptake and destruction of pathogens Complement Proteins = Pathogen destruction and opsonization T-cells = Adaptive immunity activation</p> Signup and view all the answers

    Antibodies bind to carbohydrates on human cells.

    <p>False</p> Signup and view all the answers

    What is the primary role of interleukin (IL) 1 and IL 6 in the body?

    <p>To regulate metabolism and temperature</p> Signup and view all the answers

    Cytokines only have one specific function in the immune system.

    <p>False</p> Signup and view all the answers

    What does TNF stand for in the context of inflammatory cytokines?

    <p>Tumor Necrosis Factor</p> Signup and view all the answers

    The body generates fever through the action of ______, which is an endogenous pyrogen.

    <p>interleukin 1</p> Signup and view all the answers

    Match the following cytokines to their effects:

    <p>Interferons = Limit viral spread IL-6 = Stimulate acute phase proteins TNF-alpha = Induce fever IL-1 = Increase metabolism and heat</p> Signup and view all the answers

    What is the ultimate goal of the inflammatory response?

    <p>Tissue repair</p> Signup and view all the answers

    Chronic inflammation has no association with diseases such as diabetes and cancer.

    <p>False</p> Signup and view all the answers

    Name one type of drug commonly used to manage inflammation.

    <p>NSAIDs or glucocorticoids</p> Signup and view all the answers

    The complement system is considered a ______ response to pathogens.

    <p>nonspecific</p> Signup and view all the answers

    What happens to the plasma concentration of iron in response to TNF-alpha?

    <p>It decreases to limit iron availability to pathogens</p> Signup and view all the answers

    What role do cytokines play in the inflammatory response?

    <p>They cause neutrophils and monocytes to stick to blood vessel walls.</p> Signup and view all the answers

    Chemotaxins repel neutrophils and monocytes away from the infection site.

    <p>False</p> Signup and view all the answers

    What is the process by which monocytes differentiate into macrophages called?

    <p>Differentiation</p> Signup and view all the answers

    _____ are responsible for the localized swelling and pain during the inflammatory response.

    <p>Histamines</p> Signup and view all the answers

    Match the following components of the inflammatory response with their descriptions:

    <p>Cytokines = Molecules that recruit phagocytes Histamines = Cause localized vasodilation Monocytes = Precursor cells that become macrophages Neutrophils = First responders to infection</p> Signup and view all the answers

    What is the term for the process where phagocytes squeeze through blood vessel walls?

    <p>Diapedesis</p> Signup and view all the answers

    The inflammatory response is dependent on the type of triggering event.

    <p>False</p> Signup and view all the answers

    What do opsonins do in the immune response?

    <p>Mark bacteria for destruction</p> Signup and view all the answers

    The process in which complement proteins attach to pathogens is known as _____ .

    <p>opsonization</p> Signup and view all the answers

    Which cells are primarily responsible for killing microbes directly?

    <p>Cytokines</p> Signup and view all the answers

    What is the primary function of B lymphocytes in the immune system?

    <p>Produce antibodies</p> Signup and view all the answers

    Activated T lymphocytes do not directly engage with pathogens.

    <p>False</p> Signup and view all the answers

    What are memory B and T cells responsible for?

    <p>Faster immune response upon re-exposure to a specific antigen.</p> Signup and view all the answers

    An antigen is a large, foreign, unique complex molecule that can elicit an ________ response.

    <p>immune</p> Signup and view all the answers

    Match the type of cell to its function in adaptive immunity:

    <p>B lymphocytes = Produce antibodies T helper cells = Provide instructions to B cells T killer cells = Directly attack infected cells Memory B cells = Remembers past infections</p> Signup and view all the answers

    Which of the following statements about clonal selection is true?

    <p>Only those lymphocytes that recognize a specific antigen will proliferate.</p> Signup and view all the answers

    All antigens are proteins.

    <p>False</p> Signup and view all the answers

    How do T cells recognize pathogens?

    <p>Through peptide fragments presented on Major Histocompatibility Complex (MHC) molecules.</p> Signup and view all the answers

    What happens to B cells after they become activated?

    <p>They proliferate and differentiate into plasma cells.</p> Signup and view all the answers

    What is the primary role of CD4 T cells in the immune system?

    <p>Amplify the activity of other immune cells</p> Signup and view all the answers

    Inactive T cells can respond to pathogens immediately upon recognition.

    <p>False</p> Signup and view all the answers

    What happens to a T cell if it does not recognize the antigen presented by an APC?

    <p>It leaves the lymph node.</p> Signup and view all the answers

    CD8 T cells are also known as __________ T cells.

    <p>cytotoxic</p> Signup and view all the answers

    The more complex a molecule is, the greater its ________.

    <p>antigenicity</p> Signup and view all the answers

    Identify the two types of T cells mentioned in the content.

    <p>CD4 T cells and CD8 T cells.</p> Signup and view all the answers

    What is the role of dendritic cells in T cell activation?

    <p>To activate T cells by presenting antigens</p> Signup and view all the answers

    Match the following types of T cells with their roles:

    <p>CD4 = Helper T cells that modulate immune responses CD8 = Cytotoxic T cells that kill infected cells Naïve T cells = Inactive until activated by APCs Active T cells = Leave lymph nodes to attack infections</p> Signup and view all the answers

    Which of the following describes the 'check and balance' system in T cell activation?

    <p>It prevents T cells from destroying healthy cells.</p> Signup and view all the answers

    Memory T cells are formed after the initial immune response and provide long-term immunity.

    <p>True</p> Signup and view all the answers

    After activation, helper T cells secrete __________ that amplify the activity of other immune cells.

    <p>chemicals</p> Signup and view all the answers

    Study Notes

    Blood Composition and Volume

    • Blood makes up approximately 8% of total body weight.
    • Average blood volume is 5 liters in women and 5.5 liters in men.
    • Hematocrit is the percentage of red blood cells in the blood. Average hematocrit is 42% for women and 45% for men.
    • Venous blood is darker red than arterial blood.
    • Blood is composed of three main components:
      • Erythrocytes (red blood cells): responsible for oxygen transport.
      • Leukocytes (white blood cells): defend the body against infections.
      • Platelets (thrombocytes): fragments important for blood clotting (hemostasis).
    • The buffy coat is a thin layer between plasma and formed elements containing white blood cells and platelets.

    Physiological Role of Blood

    • Transports oxygen, nutrients, hormones, metabolic wastes and heat.
    • Regulates body temperature and pH.
    • Protects the body through clotting and immune responses (immunoglobulins).

    Plasma

    • Plasma is the liquid portion of blood.
    • Mostly composed of water.
    • Contains electrolytes, nutrients, wastes, gases and hormones.

    Plasma Proteins

    • Exert osmotic pressure which helps distribute fluid between the vascular and interstitial compartments.
    • Prevent excessive loss of plasma from capillaries into interstitial fluid.
    • Buffer pH changes.
    • Synthesized in the liver except for gamma globulins.

    Albumins

    • Most abundant plasma protein.
    • Transport various substances.
    • Contribute significantly to colloid osmotic pressure.
    • Non-specific in terms of transport.

    Globulins

    • Alpha and beta globulins transport specific water-insoluble substances like cholesterol, iron, and complement.
    • Involved in the blood-clotting process.
    • Gamma globulins are antibodies (immunoglobulins) produced by immune cells.

    Fibrinogen

    • Inactive precursor of fibrin meshwork involved in blood clotting.
    • Activated during blood clotting.
    • Serum is plasma minus fibrinogen.

    Erythrocytes (Red Blood Cells)

    • Contain hemoglobin, a pigment responsible for oxygen transport.
    • Red blood cells are shaped like biconcave discs to increase surface area and maximize gas exchange.
    • Packed with over 250 billion hemoglobin molecules each carrying >100 million oxygen molecules.
    • In the absence of a nucleus, organelles, and ribosomes, erythrocytes focus on carrying oxygen, hydrogen and carbon dioxide.
    • Erythrocytes have a lifespan of 120 days.
    • Spleen removes old erythrocytes from circulation.
    • Dead red blood cells are recycled in the spleen.

    Erythropoiesis (Red Blood Cell Production)

    • The process of producing new red blood cells to replenish dying ones.
    • Occurs in bone marrow.
    • Pluripotent stem cells differentiate into erythrocytes through various stages:
      • Erythroblast: last stage with a nucleus.
      • Reticulocyte: organelle degradation is ongoing.
      • Erythrocyte: mature red blood cell released into circulation.

    Hemoglobin

    • Located in red blood cells.
    • Iron-containing pigment.
    • Appears reddish when oxygenated, bluish when deoxygenated.
    • Each hemoglobin molecule can bind four oxygen molecules.
    • Hemoglobin also binds to carbon dioxide, acidic hydrogen ions, and carbon monoxide.

    Significance of No Nucleus in Erythrocytes

    • No nucleus allows for increased space for hemoglobin molecules.
    • The absence of organelles allows for a more efficient oxygen carrying capacity.
    • However, it also results in a limited lifespan.
    • Fragile cell structure.

    Blood Groups

    • Blood types are determined by surface antigens on red blood cells (RBCs).
    • Antigens are large, complex molecules triggering specific immune responses.
    • Antigens are found on the surface of RBCs, protruding outwards for identification.
    • Over 100 types of antigens exist on RBCs.
    • Most antigens are proteins.
    • Immune cells initially did not evolve to combat transplants.
    • The immune system destroys organs that do not match the recipient's blood type.
    • Transfusion reactions occur when mismatched blood types are mixed.
    • Antibodies in the recipient's blood bind to the donor's RBC antigens, causing the cells to rupture.
    • This can lead to blood clots, blocking blood vessels.

    Rhesus (Rh) Blood Group

    • The Rh blood group is characterized by the CDE system, with 50 blood group antigens and 5 primary antigen groups (D, C, E, c, e).
    • The D antigen determines whether someone is Rh-positive (D present) or Rh-negative (D absent).
    • The 'd' notation is a placeholder for the absence of the D antigen, not a separate antigen.
    • The D antigen is the most prevalent and antigenic, making it crucial for blood compatibility.
    • Rh-positive individuals possess the D antigen.
    • Rh-negative individuals lack the D antigen.
    • People with the Rh factor have Rh-positive blood (D present).
    • Individuals without the Rh factor are Rh-negative (d absent).
    • Naturally occurring antibodies against the Rh factor do not typically develop.
    • Rh-negative individuals only produce anti-Rh antibodies after exposure to Rh-positive blood, either through transfusion or pregnancy.
    • Rh-positive individuals never produce antibodies against the Rh-negative factor they possess.
    • Therefore, Rh-negative individuals should only receive Rh-negative blood transfusions.

    Leukocytes

    • Leukocytes are white blood cells (WBCs) found in the blood.
    • They are the mobile units of the body's immune system, responsible for defending against pathogens.
    • Leukocytes are comprised of various cell types, their derivatives, and plasma proteins.
    • They are involved in immune responses, including producing defending substances and communicating with other cells.
    • Leukocytes have diverse shapes and functions.
    • Plasma proteins, such as complement proteins and globulins, contribute to the immune system.
    • Complement proteins are produced by the liver but have immune functions.
    • Globulins are produced by immune cells.

    Polymorphonuclear Granulocytes (PMNs)

    • PMNs are characterized by their multi-shaped nucleus, despite having only one nucleus.
    • They are granulocytes, meaning they contain granules.
    • One type of PMN is the neutrophil, known for its acidic granules, which bind to acidic molecules .
    • Neutrophils are phagocytic specialists, engulfing and destroying bacteria intracellularly.
    • They are typically the first responders to pathogen detection in tissues, with many dying during their initial defense.
    • Neutrophils release neutrophil extracellular traps (NETs), a sticky web of extracellular fibers containing bacteria-killing chemicals, to trap pathogens.

    Polymorphonuclear Granulocytes: Eosinophils

    • Eosinophils are a type of granulocyte with acidic granules (staining red).
    • They are primarily involved in fighting and killing parasites and capturing and releasing granules to eliminate them.
    • Eosinophils kill antibody-coated parasites by releasing the contents of their granules.
    • An increase in circulating eosinophils (eosinophilia) is associated with:
      • Allergic conditions like asthma and hay fever, often due to eosinophils degranulating on harmless substances.
      • Internal parasitic infestations, like worms.
      • Eosinophils attach to worms and secrete substances to kill them.
    • Eosinophils lack the specificity to distinguish between parasites and harmless substances, potentially attacking the latter.

    Polymorphonuclear Granulocytes: Basophils

    • Basophils are the least abundant and least understood leukocytes.
    • They bind to basic dyes, staining blue, and are involved in immune responses to parasites.
    • Basophils produce and store:
      • Histamine, crucial for allergic reactions.
      • Heparin, which accelerates the removal of fat particles from the blood after a fatty meal and prevents blood clotting.

    Mononuclear Agranulocytes: Monocytes

    • Monocytes are characterized by a single (simple-shaped) nucleus and lack granules.
    • They are larger than other leukocytes and can engulf more material.
    • Their main functions include:
      • Phagocytosis, ingesting foreign material.
      • Antigen presentation, displaying antigens to other immune cells.
      • Cytokine production, releasing signaling proteins.
      • Cytotoxicity, directly killing cells.
    • Monocytes are released from the bone marrow in an immature state, circulating for 1-2 days before settling in various tissues.
    • They mature and enlarge in resident tissues, becoming macrophages.
    • Macrophages have a lifespan ranging from months to years, but they die sooner during phagocytosis.
    • They communicate with other cells by producing cytokines and chemokines, a subgroup of cytokines that attract other cells.
    • Tissue-resident macrophages are the first to detect invading microorganisms, secreting cytokines/chemokines to recruit neutrophils and other leukocytes.
    • They engulf dead neutrophils, contributing to tissue repair.

    Mononuclear Agranulocytes: Lymphocytes

    • Lymphocytes recognize antigens and produce antibodies against them.
    • Antibodies bind to specific antigens, leading to the antigen's destruction by various mechanisms.
    • The immune system learns to tolerate self-antigens, but may react to foreign antigens.
    • This can lead to allergic reactions to food antigens.
    • There are varying responses to pathogens.
    • Lymphocytes produce antibodies, essential for immunity.
    • COVID-19 vaccines contain antigens, prompting the body to recognize and generate antibodies.
    • Upon subsequent exposure to the virus, the body can mount a faster and more effective response.
    • Antibodies bind to specific antigens, leading to their destruction.
    • Pathogens can evolve, changing their antigens, which can render existing antibodies ineffective.
    • The immune system has learned to tolerate our own antigens, but can react to foreign antigens.
    • Foods contain antigens, and some individuals develop allergic reactions.
    • Different pathogens trigger varying immune responses.

    How Leukocytes Work (Generally)

    • The immune system recognizes and destroys or neutralizes foreign materials in the body.
    • It utilizes receptors to identify threats.
    • The immune system defends against invading microbes (e.g., eosinophils, basophils).
    • Other important immune cells not primarily circulating in the blood are involved in immune responses.
    • Various immune cell types, including neutrophils, basophils, monocytes, and lymphocytes, are involved in the immune response.
    • When different blood types mix, antibodies in the recipient's blood bind to the donor's RBC antigens causing the cells to rupture.

    Large Granular Lymphocytes (NK Cells)

    • Large granular lymphocytes, also known as natural killer (NK) cells, are effector cells of the innate immune response.
    • They are highly effective against virally infected cells.
    • NK cells release lytic granules to kill infected cells.
    • They produce cytokines to limit viral replication.
    • Cells display markers indicating their health or infection status.
    • NK cells attack infected cells, even if the virus evolves to hide infection markers.
    • This suggests NK cells have learned to detect subtle abnormalities even when conventional markers are masked.

    Immune System: Overview

    • Immunity is the body's ability to defend itself against foreign invaders like bacteria, viruses, and abnormal cells.
    • Most immune cells reside in tissues, not the bloodstream.

    Immune System: Pathogenic Microbes

    • Bacteria: Non-nucleated, single-celled organisms that damage tissues by releasing enzymes or toxins. Examples include chlamydia, Streptococcus, E.coli, and Salmonella.
    • Viruses: Consists of DNA or RNA enclosed in a protein coat. They cannot reproduce without invading a host cell. Examples include SARS-CoV-2, HIV, HCV, Influenza, Ebola, and Polio.
    • Fungi: Examples include aspergillus and Candida.
    • Parasites: Include protozoan parasites like plasmodium malaria and helminth parasites (worms).
    • Virulence: The inherent ability of a pathogen to cause disease. Pathogens vary in their virulence, with some being more potent than others.

    Immunity: External Defenses

    • Mechanical defenses: Prevent pathogens from entering the body. Examples include cilia in the nasal passages trapping bacteria and skin acting as a barrier.
    • Chemical defenses: Antimicrobial peptides produced by epithelial cells directly fight pathogens.
    • Microbiological defenses: Microbiota (bacteria) found in the gut and skin compete with harmful pathogens for resources.

    Immunity: Internal Defenses

    • Lymphoid tissue: Sites where immune cells are produced, stored, or processed.
      • Bone marrow: Produces and divides immune cells. Mature cells then circulate in the blood or lymphatic vessels.
      • Thymus: Where T cells mature.
    • Lymph nodes: Checkpoints where lymph and its cells are examined for foreign antigens. B and T cells circulate through lymph nodes.
    • Spleen: Has patches of white pulp containing immune cells.
    • Tonsils and adenoids: Smaller lymph nodes that act as entry points in the mouth and pharynx.
    • Appendix: Contributes to immune function.
    • Peyer's patches (GALT): Lymphoid tissue found in the gut and lungs.

    Immunity: Functions of Lymphoid Tissue

    • Bone Marrow: Produces and divides immune cells.
    • Thymus: Where T cells mature.
    • Lymph Nodes: Checkpoints that filter lymph and its cells ensuring they are not infected.
    • Spleen: Houses immune cells and filters blood.
    • Tonsils and Adenoids: Smaller lymph nodes in the mouth and throat, acting as entry points.
    • Appendix: Contributes to immune function.
    • Peyer's Patches (GALT): Located in the gut and lungs to combat pathogens.

    Immunity: Immune Responses

    • Innate Immune Response: Non-specific and rapid, providing the first line of defense against foreign material. Includes:
      • Inflammation: A localized response to injury or infection.
      • Interferons: Anti-viral proteins.
      • Natural Killer cells (NK): Kill virus-infected and cancer cells.
      • Complement system: A cascade of proteins that work together to kill pathogens.
      • Dendritic cells: Resident in tissues like lungs, liver, and skin. They engulf pathogens and activate T cells.
    • Adaptive Immune Response: Selective targeting of specific invaders. Includes:
      • Antibody-mediated immunity (humoral): Production of antibodies by plasma cells (B lymphocyte derivatives).
      • Cell-mediated immunity: Production of activated T lymphocytes that directly attack unwanted cells.

    Inflammation

    • Innate, nonspecific response to tissue injury, characterized by redness, swelling, pain, and heat.
    • Begins locally, but can become systemic if not stopped.
    • Goal: repair tissue damage and remove pathogens.
    • Triggered by tissue damage, like a twisted ankle, or by pathogens.
    • Resident tissue macrophages activate the inflammatory response by releasing cytokines and histamine.

    Macrophages

    • First line of defense against pathogens.
    • Engulf pathogens.
    • Release cytokines and chemokines to activate other cells and recruit more immune cells.

    Mast cells

    • Release histamine, which dilates blood vessels and increases capillary permeability.

    Neutrophils and monocytes

    • Recruited to the site of inflammation.
    • Perform phagocytosis (engulf and destroy pathogens).
    • Monocytes differentiate into macrophages.

    Cytokines

    • Potent signaling molecules that regulate and coordinate the immune response.
    • Produced by leukocytes.
    • Include interleukin-1, interleukin-6, and Tumor Necrosis Factor Alpha (TNF-α).
    • Induce fever (endogenous pyrogens).
    • Decrease plasma iron levels.
    • Stimulate release of acute phase proteins.
    • Trigger clotting and anticlotting systems.

    Complement System

    • Nonspecific response.
    • Composed of plasma proteins produced by the liver.
    • Three mechanisms of activation:
      • Spontaneous activation on microbial surfaces.
      • Binding to carbohydrates on microbial surfaces.
      • Activation by antibody binding to antigens on pathogens.
    • Destroys pathogens by:
      • Forming Membrane Attack Complexes (MACs), which punch holes in the pathogen.
      • Enhancing phagocytosis (opsonization).

    Dendritic Cells (DCs)

    • Bridge between innate and adaptive immunity.
    • Resident tissue cells with star-shaped morphology.
    • Immature DCs actively internalize antigens via micropinocytosis.
    • Encounter with pathogen causes them to mature.
    • Professional antigen-presenting cells.
    • Migrate to lymphoid organs to present antigens to T cells.

    Adaptive Immunity

    • Two branches of adaptive immunity: antibody-mediated (humoral) and cell-mediated
    • Antibody-mediated immunity involves B lymphocytes, which differentiate into plasma cells to produce antibodies
    • Antibodies are released into the blood and circulate to infection sites, but also remain in lymph tissue
    • Cell-mediated immunity involves T lymphocytes, which directly attack unwanted cells
    • Two types of T cell attacks: direct killing of infected cells and instructing other immune cells

    Antigens

    • Large, foreign, unique complex molecules
    • Elicit an immune response
    • More complex molecules generally have higher antigenicity (ability to elicit an immune response)
    • Most proteins in nature are highly antigenic

    Functions of Adaptive Immunity

    • Specificity: billions of lymphocytes recognize different antigens, forming memory T and B cells
    • Clonal expansion: lymphocytes with receptors that recognize a specific antigen proliferate, with the ability to fight infection
    • Clonal selection: only lymphocytes that can recognize the antigen are selected for expansion
    • Immunological memory: some lymphocytes are preserved as memory cells to provide a faster immune response during subsequent infections

    B Lymphocytes

    • Secrete antibodies
    • Have membrane-bound antibodies on their surface that function as antigen receptors
    • B cell activation leads to proliferation, differentiation into plasma cells, and secretion of soluble antibodies with the same specificity

    Basic Functions of Antibodies

    • Binding to antigens
    • Fc (fragment, crystallizable) region of antibody allows for:
      • Activation of the complement system
      • Neutralization: blocking pathogens from entering cells, binding and neutralizing bacteria, and preventing toxins from reaching cells
      • Enhancing phagocytosis (opsonization): coating pathogens facilitates their engulfment by phagocytes

    T Lymphocytes

    • Recognize peptides of pathogens
    • Carry out cell-mediated immunity
    • Do not secrete antibodies but directly bind to targets
    • Killer T cells release chemicals (granules) that destroy targeted cells within seconds, triggering apoptosis
    • Clonal and antigen-specific
    • Mature in the thymus and are activated only when they encounter a foreign antigen presented on the surface of a cell

    T Cells and Their Targets

    • T cell receptors (TCRs) recognize peptide fragments bound to MHC (Major Histocompatibility Complex) proteins on the surface of antigen presenting cells (APCs, like dendritic cells)
    • Two T cell states: inactive/naïve and active
    • Inactive T cells are activated by APCs in lymph tissues, leading to proliferation and differentiation
    • Active T cells leave the lymph nodes to attack infected cells at the site of infection

    Two Types of T Cells

    • CD4 cells (helper T cells):
      • Act as generals, modulating the activity of other immune cells and secreting chemicals to amplify their functions
    • CD8 cells (cytotoxic/killer T cells):
      • Directly kill infected cells by releasing granules, targeting viral-infected and cancerous cells
      • Bind to viral antigens and self-antigens on the surface of infected cells
      • Can kill cells directly or through enzymes that induce self-destruction

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    Related Documents

    The Blood - Lecture 1 PDF
    Antigens - Leukocytes - Immune Cells - Lecture 2 PDF
    The Immune System - Body Defenses Lecture 3 PDF
    Innate Immunity PDF
    Adaptive Immunity PDF

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    Test your knowledge on the components and physiological roles of blood. This quiz covers topics such as blood volume, hematocrit levels, and the functions of different blood cells. Perfect for anyone studying human biology or anatomy.

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