Blood Physiology Overview
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Questions and Answers

What is the approximate hemoglobin content for a 5-year-old child?

  • 10 gm/dl
  • 12 gm/dl (correct)
  • 16 gm/dl
  • 14 gm/dl
  • Which factor does NOT directly affect erythropoiesis?

  • Dietary protein content
  • Tissue oxygenation
  • Age of the individual (correct)
  • State of bone marrow
  • What is the primary source of erythropoietin in normal adults?

  • Bone marrow
  • Liver
  • Spleen
  • Kidney (correct)
  • During which condition would you expect hypoxia to stimulate increased erythropoiesis?

    <p>All of the above</p> Signup and view all the answers

    Which vitamin is directly mentioned as being crucial for erythropoiesis?

    <p>Vitamin B12</p> Signup and view all the answers

    What percentage of blood volume is made up of plasma?

    <p>55%</p> Signup and view all the answers

    Which plasma protein is primarily responsible for maintaining blood volume?

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

    Where are the majority of plasma proteins synthesized?

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

    Which component is NOT a function of plasma proteins?

    <p>Stoppage of bleeding</p> Signup and view all the answers

    What is the normal concentration range of albumin in plasma?

    <p>3.5 – 5.0 gm/dl</p> Signup and view all the answers

    What role do red blood cells primarily serve in the blood?

    <p>Transport of oxygen</p> Signup and view all the answers

    What is a primary function of fibrinogen in the blood?

    <p>Blood clot formation</p> Signup and view all the answers

    Which of the following substances is primarily transported in the blood?

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

    What is the primary hormonal factor synthesized by the kidneys that plays a crucial role in erythropoiesis?

    <p>Erythropoietin (EPO)</p> Signup and view all the answers

    Chronic liver disease can lead to which type of anemia due to impaired erythropoiesis?

    <p>Normocytic normochromic anemia</p> Signup and view all the answers

    What condition is characterized by the destruction or hypofunction of bone marrow leading to pancytopenia?

    <p>Aplastic anemia</p> Signup and view all the answers

    Which of the following is NOT a cause of megaloblastic anemia?

    <p>Chronic blood loss</p> Signup and view all the answers

    What is the consequence of a deficiency in vitamin B12 or folic acid during erythropoiesis?

    <p>Production of large, immature red blood cells</p> Signup and view all the answers

    What primarily contributes to the increased viscosity of blood compared to water?

    <p>Presence of red blood cells and plasma proteins</p> Signup and view all the answers

    Which plasma protein is responsible for transporting thyroid hormones and fatty acids?

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

    Which of the following is the main intracellular cation found in red blood cells?

    <p>Potassium (K+)</p> Signup and view all the answers

    What is the normal range of red blood cells for an adult female?

    <p>4.5 - 5 million/mm3</p> Signup and view all the answers

    What is the function of carbonic anhydrase enzyme in red blood cells?

    <p>Assist in carbon dioxide transport in the blood</p> Signup and view all the answers

    How does the biconcave shape of red blood cells enhance their functionality?

    <p>Increases surface area for gas exchange</p> Signup and view all the answers

    What is the primary reason for red blood cells lacking mitochondria?

    <p>To enhance their oxygen-carrying capacity</p> Signup and view all the answers

    What is the average lifespan of a red blood cell?

    <p>120 days</p> Signup and view all the answers

    What is the primary role of erythropoietin in the body?

    <p>Stimulates red bone marrow to increase RBC production</p> Signup and view all the answers

    Which mineral is crucial for the formation of the heme part of hemoglobin?

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

    What is the function of copper in erythropoiesis?

    <p>Acts as a co-factor in hemoglobin synthesis</p> Signup and view all the answers

    Which vitamin is essential for DNA synthesis and maturation of bone marrow cells?

    <p>Folic acid</p> Signup and view all the answers

    What physiological trigger leads to the increased release of erythropoietin?

    <p>Hypoxia due to decreased RBC count</p> Signup and view all the answers

    Which component is NOT a requirement for proper erythropoiesis?

    <p>Excessive iron supplementation</p> Signup and view all the answers

    Where is the majority of erythropoietin produced in the body?

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

    What is cobalt's specific role related to erythropoietin?

    <p>Stimulates erythropoietin secretion from the kidney</p> Signup and view all the answers

    Study Notes

    Blood Physiology

    • Blood is the circulating part of extracellular fluid (ECF) within the cardiovascular system (CVS).
    • Total blood volume is approximately 8% of body weight.
    • Typical blood volume for a 70 kg individual is around 5600 ml.
    • Infant blood volume (5 kg) is roughly 400 ml.

    General Functions of Blood

    • Transport Medium: Blood carries various substances between organs, such as glucose, oxygen (O2), carbon dioxide (CO2), and hormones.
    • Homeostasis: Blood maintains a stable internal environment by continuously exchanging substances with interstitial fluid (surrounding tissues) and organs.
    • Defense (Immunity): Blood protects the body against foreign microorganisms through both cellular and humoral immune responses.
    • Hemostasis: Blood stops bleeding through platelet plug formation and blood clot development.

    Blood Composition

    • Blood is composed of cells (45% of volume) and plasma (55% of volume).
    • Cells:
      • Red blood cells (RBCs): 4.5-5 million/mm³ (males), 4.5-5 million/mm³ (females), ranging higher for newborns and those at high altitudes
      • White blood cells (WBCs): 4-11 thousand/mm³
      • Platelets: 150-400 thousand/mm³
    • Plasma: About 90% water and consists of other elements like inorganic substances and organic molecules.

    Plasma Proteins

    • Normal plasma protein (PP) concentration ranges from 6-8 grams/deciliter (g/dL).
    • Major protein components include albumin (3.5-5 g/dL), globulins (2.4-2.7 g/dL), and fibrinogen (0.2-0.4 g/dL).
    • Liver: Synthesizes most plasma proteins (albumin, fibrinogen, prothrombin, most globulins), excluding gamma globulin.
    • Lymphoid Tissue: Synthesizes gamma globulins (immunoglobulins).

    Functions of Plasma Proteins

    • Blood Viscosity: Primarily due to fibrinogen.
    • Fluid Balance: Primarily through albumin's role in colloid osmotic pressure.
    • pH Buffering: Plasma proteins buffer blood pH; ~15% of blood's buffering capacity.
    • CO2 Transport: CO2 combines with amino groups of plasma proteins forming carbamino compounds.
    • Carrier Functions: Plasma proteins transport various substances (e.g., hormones, lipids, vitamins, drugs).

    Red Blood Cells (RBCs)

    • Structure: Biconcave discs, lack nuclei and mitochondria in mature form.
    • Size and Shape: Diameter ~7.8 microns, thickness ~2.5 microns, volume ~90 cubic microns. Enhanced surface area facilitates gas exchange.
    • Normal RBC Count: Males ~5-5.5 million/ mm³, Females ~4.5-5 million/ mm³, Newborns ~6-8 million/ mm³.
    • Lifespan: ~120 days.
    • Content: Primarily hemoglobin (Hb) (~34% of RBC volume), potassium (K+), and other substances for gas transport.
    • Functions: Carry oxygen from the lungs to the tissues, carry carbon dioxide from tissues to the lungs, provide some viscosity to blood which helps regulate blood pressure (BP).

    Erythropoiesis

    • Definition: The process of RBC production.
    • Sites:
      • Infancy and childhood: Active red bone marrow (BM) in most bones.
      • Adults: Active red BM mainly in ends of long bones, vertebrae, ribs, sternum, skull, and pelvic bones.
    • Stages:
      • Stem cell (hemocytoblast) → committed cell (proerythroblast) → early erythroblast → late erythroblast → normoblast → reticulocyte → erythrocyte
    • Factors Affecting Erythropoiesis:
      • Oxygen supply to tissues (hypoxia stimuli for erythropoietin (EPO) release)
      • Nutritional factors (iron, vitamins, proteins)
      • Hormonal factors (e.g., thyroid hormone)
      • State of bone marrow/liver/kidney

    Erythropoietin (EPO)

    • Source: Primarily kidney (90%) and liver (10%) in normal adults; liver is the sole source in the fetus.
    • Molecular Weight: ~34,000 daltons (Da).
    • Function: Stimulates differentiation of stem cells in bone marrow into RBC lineage; speeds up RBC maturation.

    Anemia

    • Definition: Reduced RBC count or hemoglobin content.
    • Types:
      • Blood loss anemia: acute (hemorrhage) or chronic (iron deficiency from blood loss)
      • Megaloblastic (macrocytic) anemia: caused by vitamin B12 or folic acid deficiencies (related to intrinsic factor).
      • Hemolytic anemia: caused by premature destruction of RBCs (membrane defects, disorders of hemoglobin, enzyme deficiencies).
      • Aplastic anemia: caused by destruction of bone marrow cells.

    Polycythemia

    • Definition: Increased RBC count.
    • Types:
      • Primary Polycythemia (rubra vera): Unknown cause; increase in RBCs.
      • Secondary Polycythemia: Increased RBCs possibly due to tissue hypoxia (e.g., high altitude, chronic lung disease, cyanotic heart disease).

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    Description

    This quiz explores the essential aspects of blood physiology, including its composition, functions, and significance within the cardiovascular system. Test your knowledge on blood volume, transport functions, and immunological roles. Ideal for students studying human biology or physiology.

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