Medical Physiology - Blood: Erythrocytes Overview
48 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary reason for the red color of red blood cells (RBCs)?

  • The biconcave shape of the cells
  • The presence of hemoglobin (correct)
  • The structure of the cell membrane
  • The amount of oxygen present

    • What is the average RBC count in adult females?

  • 6 millions/cu mm
  • 4 millions/cu mm
  • 5 millions/cu mm
  • 4.5 millions/cu mm (correct)

    • Which of the following is NOT an advantage of the biconcave shape of RBCs?

  • Ease of squeezing through capillaries
  • Rapid diffusion of oxygen into the cell
  • Increased surface area for gas exchange
  • Lower risk of cytoplasmic contents spilling (correct)

    • What is the typical diameter of a red blood cell?

    <p>7.2 μm</p> Signup and view all the answers

    What cellular structures are absent in red blood cells?

    <p>Nucleus and all organelles</p> Signup and view all the answers

    What phenomenon occurs when RBCs pile up like coins after blood is drawn?

    <p>Rouleaux formation</p> Signup and view all the answers

    Which of the following is a function of red blood cells?

    <p>Carrying oxygen</p> Signup and view all the answers

    What is the thickness of a red blood cell at its periphery?

    <p>2.2 μm</p> Signup and view all the answers

    What is the average lifespan of red blood cells (RBCs)?

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

    What is packed cell volume (PCV) also known as?

    <p>Hematocrit value</p> Signup and view all the answers

    Where does the destruction of old red blood cells primarily occur?

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

    What percentage of the blood is made up of packed cell volume (PCV)?

    <p>45%</p> Signup and view all the answers

    Which protein combines with iron to form ferritin for storage?

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

    What is the specific gravity range of red blood cells (RBC)?

    <p>1.092 to 1.101</p> Signup and view all the answers

    What happens to hemoglobin after red blood cells are destroyed?

    <p>It is degraded into iron, globin, and porphyrin.</p> Signup and view all the answers

    What is the primary difference between fetal hemoglobin and adult hemoglobin?

    <p>Fetal hemoglobin has a higher oxygen affinity.</p> Signup and view all the answers

    What are pluripotential hematopoietic stem cells responsible for?

    <p>Producing all types of blood cells</p> Signup and view all the answers

    What causes the formation of methemoglobin in the blood?

    <p>Certain drugs and oxidizing agents.</p> Signup and view all the answers

    What is carboxyhemoglobin and why is it a concern?

    <p>It reduces the blood's oxygen transport capacity.</p> Signup and view all the answers

    What percentage of the body's total iron is typically found in hemoglobin?

    <p>65 percent.</p> Signup and view all the answers

    How does iron enter the bloodstream after absorption in the small intestine?

    <p>By combining with transferrin.</p> Signup and view all the answers

    Where is excess iron primarily deposited in the body?

    <p>In liver hepatocytes.</p> Signup and view all the answers

    What forms when iron combines with apoferritin in the cell cytoplasm?

    <p>Ferritin.</p> Signup and view all the answers

    What is referred to as 'storage iron' in the body?

    <p>Iron stored as ferritin.</p> Signup and view all the answers

    What is the primary function of transferrin in the body?

    <p>Binding and transporting iron to erythroblasts</p> Signup and view all the answers

    What causes hypochromic anemia?

    <p>Insufficient hemoglobin production</p> Signup and view all the answers

    Which pigment is derived from the conversion of porphyrin during hemoglobin destruction?

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

    What is a common outcome of chronic blood loss with inadequate iron absorption?

    <p>Microcytic, hypochromic anemia</p> Signup and view all the answers

    Where is hemoglobin primarily phagocytized after red blood cells burst?

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

    What happens to iron released from hemoglobin degradation?

    <p>It is transported by transferrin to the bone marrow and liver</p> Signup and view all the answers

    What is the initial response of the body to rapid blood loss?

    <p>Replace the fluid portion of plasma within 1 to 3 days</p> Signup and view all the answers

    Aplastic anemia is characterized by which of the following?

    <p>Insufficient production of blood components</p> Signup and view all the answers

    What physiological response leads to secondary polycythemia?

    <p>Decreased oxygen delivery to tissues</p> Signup and view all the answers

    Which condition is characterized by a red blood cell count of 7 to 8 million/mm3 and heightened blood viscosity?

    <p>Polycythemia vera</p> Signup and view all the answers

    At what bilirubin level does jaundice typically become evident?

    <p>2 to 3 mg/dL</p> Signup and view all the answers

    What is a characteristic of prehepatic or hemolytic jaundice?

    <p>Increased destruction of red blood cells</p> Signup and view all the answers

    Which type of polycythemia occurs as a normal adaptation at high altitudes?

    <p>Physiologic polycythemia</p> Signup and view all the answers

    Which of the following best describes the hematocrit in a person with polycythemia vera?

    <p>Approximately 60 to 70 percent</p> Signup and view all the answers

    What condition results from the destruction of bone marrow, often leading to lethal anemia?

    <p>Bone marrow aplasia</p> Signup and view all the answers

    What causes the yellow coloration in jaundice?

    <p>Increased bilirubin levels in blood</p> Signup and view all the answers

    Which type of anemia is characterized by abnormally large and oddly shaped red blood cells known as megaloblasts?

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

    What factors can contribute to secondary polycythemia?

    <p>Hypoxia due to low oxygen environments</p> Signup and view all the answers

    Exposure to which of the following can lead to bone marrow aplasia?

    <p>Gamma ray radiation</p> Signup and view all the answers

    In sickle cell anemia, what causes the red blood cells to assume a sickle shape?

    <p>Faulty beta chains in hemoglobin</p> Signup and view all the answers

    Megaloblastic anemia can result from a deficiency of which of the following?

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

    Which of the following conditions may result in poor absorption of vitamin B12 and folic acid, leading to megaloblastic anemia?

    <p>Intestinal sprue</p> Signup and view all the answers

    What is the primary issue in hemolytic anemia that leads to a decrease in red blood cells despite normal production?

    <p>Fragility of the red blood cells</p> Signup and view all the answers

    Erythroblastosis fetalis is a condition that involves the destruction of Rh-positive red blood cells by which of the following?

    <p>Maternal antibodies from an Rh-negative mother</p> Signup and view all the answers

    Study Notes

    Medical Physiology - Blood

    • Erythrocytes (Red Blood Cells): Non-nucleated formed elements in the blood, responsible for oxygen transport. Their red colour is due to haemoglobin.
    • RBC Count: Varies between 4 and 5.5 million/cu mm in blood. 5 million/cu mm in adult males, and 4.5 million/cu mm in adult females.
    • Normal Shape: Disk-shaped, biconcave (dumbbell-shaped). The central portion is thinner, and the periphery is thicker. This shape provides mechanical and functional advantages.
    • Advantages of Biconcave Shape: Facilitates rapid and even diffusion of oxygen and other substances into the cell. Provides a large surface area for absorption/removal of substances. Minimises membrane tension during cell volume changes. RBCs can squeeze through capillaries easily.
    • Normal Size: Diameter: 7.2 µ (6.9 to 7.4 µ). Thickness: Thicker at the periphery (2.2 µ) and thinner at the centre (1 µ). Surface area: 120 sq µ. Volume: 85 to 90 cu µ.
    • Normal Structure: Non-nucleated cells. Lack of nucleus means DNA is absent. Lack of mitochondria means energy production is via glycolysis. Lack of other organelles like Golgi apparatus.
    • Rouleaux Formation: Blood taken from a blood vessel with RBCs piled up one above another like a stack of coins due to blood plasma proteins.
    • Specific Gravity of RBCs: Ranges from 1.092 to 1.101.
    • Packed Cell Volume (PCV) / Hematocrit: The percentage of blood volume occupied by RBCs. Value is 45% and plasma volume is 55%.
    • Suspension Stability: Ability of RBCs to remain uniformly suspended in the blood during circulation.
    • Lifespan of RBCs: Approximately 120 days.
    • Fate of RBCs: Old RBCs are destroyed in the reticuloendothelial system.
      • Hemoglobin is broken down into iron, globin, and porphyrin.
      • Iron is stored as ferritin and reused.
      • Globin is used in protein synthesis.
      • Porphyrin is converted to bilirubin, which is excreted by the liver.
    • Daily Hemoglobin Release: About 0.6 g/dL of hemoglobin released into the plasma.
    • Bilirubin Formation: 0.9 to 1.5 mg/dL of bilirubin is formed daily.

    Blood Cell Production

    • Pluripotential Hematopoietic Stem Cells: Single cell type in bone marrow responsible for all blood cells.
    • Growth and Differentiation: Stem cells proliferate, some remain as stem cells maintaining supply, and others differentiate into specialized blood cells. Intermediate cells, committed stem cells.
    • Colony-Forming Units: Specific types of blood cells are named such as CFU-E (erythropoiesis) or CFU-GM(granulocytes, monocytes).

    Erythropoietin

    • Principal Stimulus for RBC Production: A circulating glycoprotein hormone, crucial for RBC production in low oxygen states.
    • Production Location: Mainly in the kidneys, and to a lesser degree in the liver.
    • Effect on Erythropoiesis: Stimulates proerythroblast production from hematopoietic stem cells, causing rapid progression through erythroblast stages, resulting in increased RBC production.
    • Role of vitamins: Vitamin B12 and folic acids are vital for final maturation.

    Role of Kidneys and Other Factors in Erythropoiesis

    • Factors that decrease oxygenation: Low blood volume, anemia, low hemoglobin, poor blood flow, and pulmonary disease.

    Types of Hemoglobin

    • Fetal Hemoglobin (HbF): Found in fetal blood, has a higher affinity for oxygen than adult hemoglobin.
    • Methemoglobin: Oxidized iron in hemoglobin, altered to ferric form; causes discoloration and reduced oxygen transport.
    • Carbon Monoxide Hemoglobin (Carboxyhemoglobin): Binds carbon monoxide with higher affinity than oxygen, reducing oxygen carrying capacity.

    Iron Metabolism

    • Iron Importance: Essential for hemoglobin synthesis and other compounds.
    • Body Iron Quantity: Typically 4-5 grams. 65% exists in hemoglobin, 4% is in myoglobin).
    • Iron Transport: Absorbed iron binds to apotransferrin to form transferrin, which then transports iron to tissues.
    • Iron Storage: Stored as ferritin, primarily in reticuloendothelial and liver cells.
    • Iron Metabolism Processes: Absorption, transport, storage, and utilization in the body.

    Anemia (General overview)

    • Definition: Insufficient hemoglobin in the blood. Can be caused by too few red blood cells or low hemoglobin levels per cell.
    • Types: Blood loss anemia, aplastic anemia, megaloblastic anemia, and hemolytic anemia.

    Specific Anemia Types

    • Blood Loss Anemia: Rapid hemorrhage reduces blood volume and/or haemoglobin, causing red blood cell count to decrease. The body takes up to 3-6 weeks to recover if hemorrhage is controlled.
    • Aplastic Anemia: Lack of functioning bone marrow. This may follow incidents like gamma ray radiation (nuclear bombs, treatment) or exposure to industrial chemicals.
    • Megaloblastic Anemia: Red blood cells grow abnormally, are too large with inappropriate shapes due to vitamin deficiencies. (e.g. vitamin B12 deficiency) .
    • Hemolytic Anemia: Premature destruction of red blood cells due to hereditary or acquired factors. Fragile red cells rupture easily when passing through small capillaries (especially the spleen), and they have shortened lifespans. This can lead to severe anemia.

    Polycythemia

    • Secondary polycythemia: Tissue hypoxia (low oxygen) stimulates bone marrow to produce more red blood cells as seen in high altitudes.
    • Polycythemia Vera: (Erythremia) Genetic abnormality in hemocytoblastic cells causing overproduction of red blood cells, leading to an increased blood volume and viscosity.

    Jaundice

    • Definition: Yellowing of skin and mucous membranes due to bilirubin accumulation in the blood.
    • Types: Prehepatic (hemolytic), Hepatic (hepatocellular), Posthepatic (obstructive)

    Destruction of Hemoglobin

    • Macrophages and Destruction: In spleen and liver, macrophages break down old/damaged red blood cells, releasing hemoglobin, iron, and porphyrins.
    • Recycling: Iron is recycled for new hemoglobin, and porphyrins are converted to bilirubin for excretion via the liver.

    Normal Values

    • Bilirubin: 0.5-1.5 mg/dL

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Medical Physiology 2nd Class: Blood (2024-2025) PDF

    Description

    This quiz covers the essential aspects of erythrocytes, or red blood cells, including their structure, function, and significance in oxygen transport. Understand the normal characteristics, shape advantages, and counts of RBCs for a comprehensive grasp of their role in human physiology.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser