Blood Overview and Physiology
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Questions and Answers

What percentage of total body weight does blood represent?

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

    • Arterial blood is dark red and found in the veins.

    False

    What is the primary function of erythrocytes?

    Oxygen transport

    The liquid portion of blood is called __________.

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

    Match the following blood components with their functions:

    <p>Erythrocytes = Oxygen transport Leukocytes = Immune defense Platelets = Blood clotting Plasma = Suspends blood components</p> Signup and view all the answers

    What is the average volume of blood in men?

    <p>5.5 liters</p> Signup and view all the answers

    The buffy coat layer in blood is composed mainly of erythrocytes.

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

    What role does blood play in regulating body temperature?

    <p>Blood vessels contract to maintain temperature.</p> Signup and view all the answers

    What is a primary function of plasma proteins?

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

    Albumins are the least abundant type of plasma protein.

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

    What role does fibrinogen play in blood clotting?

    <p>Fibrinogen is an inactive precursor that converts to fibrin to form a meshwork for blood clots.</p> Signup and view all the answers

    The most abundant type of plasma protein that contributes to osmotic pressure is called __________.

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

    Match the following components with their functions:

    <p>Albumin = Most abundant protein in blood Globulins = Transport water-insoluble substances Fibrinogen = Inactive precursor of fibrin Water = Acts as a transport medium</p> Signup and view all the answers

    Which electrolyte is most abundant in plasma and crucial for membrane excitability?

    <p>Sodium (NA+)</p> Signup and view all the answers

    Gamma globulins are primarily produced in the liver.

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

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

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

    What is the primary function of erythrocytes?

    <p>Transporting gases like O2 and CO2</p> Signup and view all the answers

    Hemoglobin binds irreversibly to carbon monoxide (CO).

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

    What shape do erythrocytes have and why?

    <p>Biconcave shape to increase surface area for gas exchange.</p> Signup and view all the answers

    A single hemoglobin molecule can transport _ O2 molecules.

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

    Match the following components with their respective functions:

    <p>Hemoglobin = Carries oxygen in the blood Carbonic anhydrase = Catalyzes conversion of CO2 to bicarbonate Glycolysis enzymes = Generate ATP for active transport Nucleus = Not present in mature erythrocytes</p> Signup and view all the answers

    What percentage of oxygen is carried in the blood bound to hemoglobin?

    <p>98.5%</p> Signup and view all the answers

    Erythrocytes have a long lifespan due to the presence of organelles.

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

    What role does the spleen play in erythrocyte management?

    <p>Removes old or damaged erythrocytes from circulation.</p> Signup and view all the answers

    Erythrocytes are produced through a process called _.

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

    What is the key reason for erythrocytes to lack organelles?

    <p>To carry more oxygen</p> Signup and view all the answers

    Erythrocytes can divide because they have a nucleus.

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

    How many red blood cells are estimated to be circulating in the vessels at any given time?

    <p>23-30 trillion</p> Signup and view all the answers

    The binding of iron and oxygen in hemoglobin is described as _.

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

    What happens to erythrocytes as they age?

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

    Study Notes

    Blood: An Overview

    • Blood constitutes approximately 8% of total body weight.
    • Average blood volume:
      • 5 liters in women with a hematocrit of 42%.
      • 5.5 liters in men with a hematocrit of 45%.
    • Hematocrit refers to the percentage of formed elements in the total blood volume.
    • Blood is composed of three cellular components suspended in plasma:
      • Erythrocytes: Red blood cells, essential for oxygen transport.
      • Leukocytes: White blood cells, forming the mobile defense units of the immune system.
      • Platelets (thrombocytes): Cell fragments involved in hemostasis (blood clotting).
    • The buffy coat is a thin layer separating plasma and formed elements, containing leukocytes and platelets.

    Blood Physiological Roles

    • Transport: Carries oxygen, nutrients, hormones, metabolic wastes, and heat.
    • Regulation: Regulates body temperature and pH.
      • Blood vessels constrict to maintain temperature in cold environments and relax in hot environments.
    • Protection: Involved in clotting and contains immunoglobulins.
      • Defends against injury and seals wounds.

    Plasma

    • Plasma is the liquid portion of blood, primarily composed of water.
    • It contains various components:
      • Electrolytes: Essential for membrane excitability, fluid distribution, and pH buffering. Sodium (Na+) and chloride (Cl-) are the most abundant electrolytes.
      • Nutrients and Waste: Transported in blood. Blood CO2 plays a role in acid-base balance.
      • Gases and Hormones: Also transported through the blood.

    Plasma Proteins

    • Plasma proteins contribute to osmotic pressure, regulate pH, and transport various substances.
    • All plasma proteins are synthesized in the liver except for gamma globulins.
    • Types of Plasma Proteins:
      • Albumins:
        • Most abundant protein in blood.
        • Transport various substances and contribute significantly to colloid osmotic pressure.
        • Non-specific in their binding.
      • Globulins:
        • Alpha and Beta Globulins: Transport specific substances, such as cholesterol, iron, and complement.
        • Gamma Globulins: Antibodies (immunoglobulins) produced by immune cells in tissues, not blood.
      • Fibrinogen: An inactive precursor for the fibrin meshwork involved in blood clotting.
        • Activates during blood clotting.
        • Serum is plasma minus fibrinogen.

    Erythrocytes

    • Erythrocytes, also called red blood cells, are responsible for oxygen transport.
    • An average of 5 billion erythrocytes are present per milliliter of blood. (5 x 10^6 / mm3)
    • Erythrocytes are biconcave discs, a shape that increases the surface area of the membrane and allows quick oxygen diffusion.
    • Erythrocytes are highly flexible and can squeeze through capillaries smaller than their diameter (8 µm diameter can pass through 3 µm capillaries).

    Hemoglobin

    • Hemoglobin (Hb), found only in red blood cells, is an iron-containing pigment.
    • Oxygen-carrying capacity of hemoglobin is crucial for oxygen transport.
      • Hb appears reddish when oxygenated and bluish when deoxygenated.
    • Each hemoglobin molecule can bind and transport four oxygen molecules.
    • Hemoglobin also binds with:
      • Carbon dioxide (CO2): Although not the primary way CO2 is transported.
      • Acidic hydrogen ions (H+): From ionized carbonic acid, generated at the tissue level from CO2.
      • Carbon monoxide (CO): Binds irreversibly, leading to CO poisoning.
      • Nitric oxide (NO2): A vasodilator, relaxing and dilating arterioles in the lungs, facilitating oxygen-rich blood flow and blood pressure regulation.

    Erythrocyte Structure and Function

    • Mature erythrocytes lack a nucleus, organelles, and ribosomes, maximizing space for hemoglobin and oxygen transport.
    • Erythrocytes rely entirely on glycolysis for energy production due to the lack of mitochondria.
    • Enzymes present in Erythrocytes:
      • Glycolysis enzymes: Involved in energy generation for active transport.
      • Carbonic anhydrase: Plays a critical role in CO2 transport. Catalyzes the conversion of CO2 into bicarbonate ions (HCO3-), the primary form of CO2 transport in blood.
    • Absence of organelles results in a short lifespan of approximately 120 days.
    • Spleen removes old erythrocytes from circulation.

    Erythropoiesis

    • Erythropoiesis is the process of red blood cell production.
    • Pluripotent stem cells in the bone marrow differentiate into erythrocytes.
    • The erythroblast, the last stage with a nucleus, is still in the bone marrow.
    • Reticulocytes are immature erythrocytes that lose their organelles and migrate from the bone marrow.
    • Mature erythrocytes leave the bone marrow.
    • Erythrocytes cannot divide due to the lack of a nucleus, requiring constant replenishment through erythropoiesis.
    • Average erythrocyte turnover rate: 2-3 million cells per second.
    • The loss of red blood cells triggers erythropoiesis.
    • Erythropoiesis is a robust system crucial for maintaining sufficient oxygen transport.

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    Related Documents

    The Blood - Lecture 1 PDF

    Description

    Explore the essential functions and components of blood in this quiz. Understand how blood is composed, its volume in different genders, and its physiological roles in the body. Test your knowledge about erythrocytes, leukocytes, platelets, and more.

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