Blood Overview and Functions
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Questions and Answers

What is the lifespan of red blood cells?

  • Lifespan of 120 days (correct)
  • Lifespan of 10 days
  • Lifespan of 180 days
  • Lifespan of 60 days

    • White blood cells contain hemoglobin.

    False

    One of the formed elements in blood, also known as __________, plays a defense mechanism role.

    white blood cells

    Match the following components of hemostasis with their corresponding descriptions:

    <p>Vascular spasm = Occurs within seconds to reduce blood loss Platelet plug formation = Takes about 30 seconds to occur Coagulation = Final process that leads to blood clot formation</p> Signup and view all the answers

    What is the primary function of thromboxane A2 and serotonin released by platelets?

    <p>To act as vasoconstrictors, reducing blood flow</p> Signup and view all the answers

    Platelets have a nucleus.

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

    What is required by the liver to synthesize clotting factors?

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

    The contraction of smooth muscle during vascular spasm ________ blood flow.

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

    Match the following components with their functions:

    <p>Platelets = Form platelet plug and release chemicals Fibrinogen = Converted to fibrin during coagulation Calcium = Essential for blood clotting Oxyhaemoglobin = Binds oxygen, making blood bright red</p> Signup and view all the answers

    What is the percentage of carbon dioxide transported in plasma dissolved directly?

    <p>7%</p> Signup and view all the answers

    Deoxyhaemoglobin is responsible for giving blood a bright red color.

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

    What is the main purpose of the complex cascade of reactions during blood coagulation?

    <p>Permanent repair of blood vessels</p> Signup and view all the answers

    What percentage of carbon dioxide in plasma is found as bicarbonate ion?

    <p>70%</p> Signup and view all the answers

    Oxygen dissolved in blood plasma makes up 98.5% of oxygen transport.

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

    What does the oxygen dissociation curve illustrate?

    <p>The levels of saturation of hemoglobin and oxygen partial pressures.</p> Signup and view all the answers

    As acidity increases, the affinity of O2 for Hb __________.

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

    Match the following factors with their effects on hemoglobin-oxygen affinity:

    <p>Increased acidity = Decreases O2 affinity Exercise = Increases acidity High altitudes = Impairs O2 saturation Bohr effect = Enhances unloading of O2</p> Signup and view all the answers

    What happens to the oxygen saturation at a partial pressure of 60 mmHg?

    <p>Oxygen saturation is almost fully saturated</p> Signup and view all the answers

    The binding of O2 and hemoglobin is an irreversible reaction.

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

    What is one function of blood?

    <p>Transportation of nutrients</p> Signup and view all the answers

    What is the effect of exercise on blood acidity and hemoglobin-oxygen binding?

    <p>Exercise increases blood acidity, which decreases hemoglobin's affinity for oxygen.</p> Signup and view all the answers

    Blood has a pH range of 7.35 to 7.45.

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

    What is the average blood volume in an adult male?

    <p>5-6 L</p> Signup and view all the answers

    Blood is more viscous than water and flows more _______.

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

    Match the following blood components with their functions:

    <p>Albumin = Maintains blood osmotic pressure Globulins = Transport and immune functions Fibrinogen = Clotting Red blood cells = Oxygen transport</p> Signup and view all the answers

    What component makes up approximately 92% of blood plasma?

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

    White blood cells play a role in transporting oxygen.

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

    What term describes the formation of blood cells?

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

    Formed elements include red blood cells, white blood cells, and _________.

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

    Which component of blood is primarily responsible for transporting carbon dioxide?

    <p>Red blood cells</p> Signup and view all the answers

    Study Notes

    Blood Overview

    • Blood is a fluid component of the cardiovascular system
    • It flows through a closed network of blood vessels
    • Arteries carry blood away from the heart to tissues
    • Capillaries allow nutrient, gas, and waste exchange
    • Veins return blood to the heart

    Blood Functions

    • Transportation: Oxygen, carbon dioxide, metabolic waste, nutrients, heat, and hormones
    • Regulation: pH, water, ion content of interstitial fluids, body temperature
    • Protection: Blood/fluid loss, disease (white blood cells and antibodies)

    Blood Characteristics

    • More viscous than water; flows slower (specific gravity 1.050-1.060)
    • Beneficial due to its role in transportation
    • Temperature: 38°C
    • pH: 7.4 (7.35-7.45)
    • 8% of total body mass
    • Volume: 5-6L (males), 4-5L (females)
    • Hormonal negative feedback systems maintain constant blood volume and osmotic pressure
    • Hematopoiesis: Formation of blood cells

    Blood Composition

    • Blood Plasma (55%): Primarily water (91.5%), proteins (7%), and other solutes (1.5%)
      • Proteins: Albumins (54%), Globulins (38%), Fibrinogen (7%), others (1%)
      • Other solutes: Electrolytes, nutrients, gases, regulatory substances, waste
    • Formed Elements (45%):
      • Red blood cells (erythrocytes): 4.8-5.4 million per μL *
      • White blood cells (leukocytes): 5,000-10,000 per μL (neutrophils, lymphocytes, monocytes, eosinophils, basophils)
      • Platelets (thrombocytes): 150,000-400,000 per μL

    Blood Plasma Details

    • 92% water
    • Extracellular fluid (combination of interstitial fluid plus blood plasma)
    • Plasma proteins synthesized in the liver and confined to the bloodstream
      • Albumin: maintains blood osmotic pressure
      • Globulins: transport and immunoglobulins (IgG, IgM, IgA)
      • Fibrinogen: clotting
    • Other substances: electrolytes, nutrients, hormones, gases, waste products

    Formed Elements - Red Blood Cells

    • Also called erythrocytes
    • Formed in red bone marrow (erythropoiesis)
    • Biconcave disk, 8 μm diameter
    • Shape allows a large surface area to volume ratio
    • Stacking for smooth blood flow
    • Smooth/flexible shape to enter capillaries
    • Lifespan: approximately 120 days
    • No nucleus or other organelles; no division or mitochondrial ATP formation.
    • Primed for gas transport
    • Short life span (120 days)
    • Hematocrit levels: Females (38-46%), Males (40-54%)
    • 1/3 of weight is haemoglobin
    • Flexible internal protein scaffold

    Formed Elements - White Blood Cells

    • Also called leukocytes
    • Defence mechanism
    • Contain nuclei and other organelles
    • Do not contain haemoglobin
    • Many types: monocytes, lymphocytes, eosinophils, neutrophils, basophils
    • Lymphocytes (T, B, natural killer (NK))
    • Increase in number during infections
    • Phagocytosis: engulf and destroy microbes and damaged tissue

    Haemostasis

    • Blood's ability to seal leaks, cuts, and breaks in blood vessels to limit blood loss
    • Three basic mechanisms:
      • Vascular spasm (within seconds)
      • Platelet plug formation (after 30 seconds)
      • Blood clotting (coagulation)

    Vascular Spasm

    • Smooth muscle contracts
    • Constricts blood vessels, decreasing blood flow
    • Important initial step to decrease blood loss

    Platelet Plug Formation

    • Platelets carry chemicals (Ca²⁺, ADP, ATP, clotting factors, serotonin) producing thromboxane A2
    • Thromboxane A2 and serotonin act as vasoconstrictors, restricting blood flow through the injured vessel
    • Tiny cell fragments
    • No nucleus
    • 5-9 days survival
    • Help in stopping blood loss: form platelet plug, release chemicals to promote blood clotting, release chemicals to promote vascular spasms.

    Clotting (Coagulation)

    • Permanent repair
    • Complex cascade of reactions
    • Coagulation factors activate each other
    • Conversion of fibrinogen into fibrin
    • Vitamin K: required by the liver to synthesize clotting factors
    • Calcium: essential for blood clotting; low blood calcium impairs clotting

    Transport Function

    • Blood transports various substances throughout the body

    Haemoglobin (Hb)

    • Composed of 4 protein chains (2 alpha and 2 beta)
    • Iron (Fe²⁺) at the center of each heme group binds oxygen reversibly
    • Oxyhaemoglobin: makes blood bright red
    • Deoxyhaemoglobin: no oxygen bound to iron; blood is dark red/burgundy

    Carbon Dioxide Transport

    • Occurs in three ways:
      • Dissolved in plasma (7%)
      • Combined with globin part of Hb molecule, forming carbaminohaemoglobin (23%)
      • As part of bicarbonate ion in plasma (70%)

    Oxygen Transport

    • 98.5% of oxygen combines chemically with haemoglobin inside red blood cells (oxyhaemoglobin)
    • 1.5% dissolves in blood plasma
    • Oxygen dissociation curve shows levels of saturation and oxygen partial pressures

    Oxygen-Dissociation Curve

    • Relates haemoglobin saturation to oxygen partial pressure at normal blood pH (7.4) and temperature (38°C)
    • Cooperative binding method: Binding of oxygen to haemoglobin is a reversible reaction.
    • Blood almost fully saturated at pO₂ of 60 mmHg
    • Implications at high altitudes and diseases. Between 20 and 40 mm Hg oxygen released in areas of need (e.g., contracting muscles).

    Factors Affecting Haemoglobin-Oxygen Affinity

    • pH/Acidity:
      • High blood pH favors oxygen binding.
      • Low blood pH favors oxygen release (Bohr effect). Increased CO₂ levels (meaning lower pH) means decreased oxygen capacity. Decreased CO₂ levels (meaning higher pH) means higher oxygen capacity.
    • Exercise and metabolism acidity of blood; as acidity increases, O₂ affinity of Hb decreases
    • Exercise and metabolism, blood, acidity, as acidity increases, O₂ affinity of Hb decreases

    External Respiration

    • Calculate % oxygen saturation of blood passing through pulmonary capillaries on its way to the left heart (98%)
    • Calculate % oxygen saturation of blood in pulmonary artery before entering the lungs (75%)

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    Description

    Explore the essential overview of blood, its functions, and characteristics within the cardiovascular system. This quiz covers aspects such as transportation, regulation, and protection, along with the composition and physiological properties of blood. Delve into the vital role blood plays in maintaining homeostasis.

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