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

Which vitamin is directly mentioned as being crucial for erythropoiesis?

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

What percentage of blood volume is made up of plasma?

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

Which plasma protein is primarily responsible for maintaining blood volume?

<p>Albumin (D)</p> Signup and view all the answers

Where are the majority of plasma proteins synthesized?

<p>Liver (A)</p> Signup and view all the answers

Which component is NOT a function of plasma proteins?

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

What is the normal concentration range of albumin in plasma?

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

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

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

What is a primary function of fibrinogen in the blood?

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

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

<p>Hormones (C)</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) (C)</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 (C)</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 (D)</p> Signup and view all the answers

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

<p>Chronic blood loss (B)</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 (D)</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 (B)</p> Signup and view all the answers

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

<p>Albumin (B)</p> Signup and view all the answers

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

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

What is the average lifespan of a red blood cell?

<p>120 days (A)</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 (C)</p> Signup and view all the answers

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

<p>Iron (C)</p> Signup and view all the answers

What is the function of copper in erythropoiesis?

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

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

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

What physiological trigger leads to the increased release of erythropoietin?

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

Which component is NOT a requirement for proper erythropoiesis?

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

Where is the majority of erythropoietin produced in the body?

<p>Kidney (A)</p> Signup and view all the answers

What is cobalt's specific role related to erythropoietin?

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

Flashcards

What is blood and what is its percentage in body weight?

Blood is the circulating component of the extracellular fluid (ECF) within the circulatory system (CVS). It makes up about 8% of the body's weight.

What is the approximate blood volume in an adult and an infant?

In a 70 kg individual, the blood volume is approximately 5600 ml. In a 5 kg infant, it's about 400 ml.

What is the main function of blood?

Blood's primary function is to act as a transport medium for various substances throughout the body, including glucose, oxygen, carbon dioxide, and hormones.

How does blood contribute to homeostasis?

Blood plays a crucial role in maintaining a stable internal environment (homeostasis) through continuous exchanges of substances between interstitial fluid and organs.

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Explain the defensive function of blood.

Blood protects the body from invaders like microorganisms through cellular and humoral immunity.

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What is haemostasis?

Blood clotting is the process of stopping bleeding through the formation of a platelet plug and a blood clot.

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What is plasma and what is its composition?

Plasma is the liquid component, comprising about 55% of blood volume. It primarily consists of water (90%), dissolved organic substances (9.1%), and inorganic substances (0.9%).

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What are plasma proteins and their functions?

Plasma proteins make up 6-8 gm/dl of plasma and play several vital roles in blood function, including regulating blood volume, buffering blood pH, and aiding CO2 transport.

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Blood Viscosity

The thickness of blood compared to water. It's affected by red blood cells (RBCs) and plasma proteins, especially fibrinogen.

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Plasma Proteins (PP)

Plasma proteins that transport substances throughout the body. They help with blood clotting and immunity.

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Albumin's role in transport

Albumin is a PP that binds to and carries various substances in the blood, including hormones, fatty acids, and bilirubin.

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Globulin's role in transport

Globulins are a group of PPs that carry specific substances, like iron, copper, and vitamin B12.

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Why RBCs are not 'true' cells

The red blood cells are actually not true cells because they lack a nucleus and other organelles such as the endoplasmic reticulum (ER) and mitochondria.

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RBC Count

The number of red blood cells in a cubic millimeter of blood. This is higher in newborns and people living at high altitude.

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RBC Shape and Significance

RBCs are shaped like flattened discs with a depressed center. This shape increases their surface area for oxygen absorption.

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Hemoglobin (Hb)

The main component of RBCs, responsible for carrying oxygen throughout the body.

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What is erythropoiesis?

The formation of new red blood cells.

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What is erythropoietin?

A glycoprotein hormone produced primarily by the kidneys responsible for stimulating the production of red blood cells.

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What is hematocrit?

The ratio of red blood cell volume to total blood volume.

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What causes hypoxia?

A decrease in the oxygen supply to the tissues which triggers the production of more red blood cells.

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Where is red bone marrow located in adults?

The primary sites of red blood cell production in adults are the ends of long bones, vertebrae, ribs, sternum, skull, and pelvic bones.

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What triggers erythropoietin release?

Erythropoietin production is triggered by a decrease in blood oxygen levels, which can occur due to reduced red blood cell count, insufficient oxygen availability, or increased tissue demand for oxygen.

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How does erythropoietin increase blood oxygen levels?

Erythropoietin stimulates the bone marrow to increase the production of red blood cells, leading to an increase in the oxygen-carrying capacity of the blood.

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Why are proteins important for red blood cell production?

Proteins of high biological value are essential for the synthesis of hemoglobin, a key component of red blood cells that carries oxygen in the blood. Lack of sufficient protein can lead to anemia.

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What is the role of iron in red blood cell production?

Iron plays a vital role in the formation of heme, a part of hemoglobin that binds to oxygen. Iron deficiency can lead to anemia.

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What is the role of copper in red blood cell production?

Copper is necessary for the synthesis of hemoglobin and is involved in the transport of iron in the blood. Copper deficiency can also contribute to anemia.

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How does cobalt influence red blood cell production?

Cobalt is essential for the production of vitamin B12, which is required for the maturation of red blood cells. Cobalt deficiency can impair red blood cell development.

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What is the role of vitamin B12 and folic acid in red blood cell production?

Vitamin B12 and folic acid are essential for DNA synthesis and the maturation of red blood cells in the bone marrow. Deficiencies in these vitamins can lead to anemia.

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Megaloblastic Anemia

A type of anemia caused by a deficiency of vitamin B12 or folic acid, leading to the formation of large, fragile red blood cells with a shorter lifespan.

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Erythropoietin (EPO)

A hormone mainly produced by the kidneys that stimulates the production of red blood cells in the bone marrow.

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Aplastic Anemia

The destruction or malfunction of bone marrow, often due to radiation, drugs, or toxins, leading to a decrease in all blood cell types (red, white, and platelets).

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Anemia

A decrease in the number of red blood cells or hemoglobin content, leading to a reduced oxygen-carrying capacity of the blood.

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Blood Loss Anemia

Anemia caused by excessive blood loss, either acute (haemorrhage) or chronic (slow bleeding).

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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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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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