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Questions and Answers
What is the main role of albumin in blood?
What percentage of blood is composed of plasma proteins?
How does the pH of blood contribute to homeostasis?
What is the total blood volume in an average male?
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Which component of blood is primarily responsible for protecting against pathogens?
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What is a characteristic feature of blood regarding its taste?
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What type of connective tissue is blood classified as?
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What is the average temperature of blood in the human body?
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What is the primary function of neutrophils in the body?
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Which white blood cells account for the majority of the body's leukocytes?
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What is the role of basophils in the immune response?
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Eosinophils primarily combat which of the following?
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What distinctive characteristic do lymphocytes possess compared to other white blood cells?
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Which of the following types of cells primarily differentiates into macrophages?
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What are platelets primarily responsible for?
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What feature distinguishes granulocytes from agranulocytes?
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Which white blood cell type is mainly involved in the activation of lymphocytes?
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What type of immunity do T cells primarily provide?
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What is the first phase of hemostasis that occurs in response to injury?
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What is the role of thrombin in blood clotting?
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Which component is essential for the formation of prothrombinase?
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What do platelets release to initiate vascular spasms?
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Which blood group classification is based on the presence of specific antigens and antibodies?
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What is the consequence of a Rh-negative mother having a Rh-positive fetus?
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What is fibrinolysis?
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What type of examination can predict conditions like anemia?
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What is the main function of agglutinogens found on RBC membranes?
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Which substances act as anticoagulants in the blood?
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What is the primary site of hematopoiesis after birth?
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What type of stem cells give rise to all formed elements of blood?
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Which hormone stimulates myeloid stem cells to develop into red blood cells?
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How long is the lifespan of a typical red blood cell?
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What is oxyhemoglobin?
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Which ion is essential for the oxygen-carrying capacity of hemoglobin?
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Carbon dioxide is primarily transported in the blood as which of the following?
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Which blood components are considered complete cells?
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What happens to old red blood cells that become rigid and fragile?
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Which component gives feces its brown color?
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Which type of cell is responsible for the protection against invading microorganisms?
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Which structure primarily facilitates the transport of oxygen in red blood cells?
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What triggers the release of erythropoietin from the kidneys?
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Study Notes
Cardiovascular System
- Consists of blood, the heart, and blood vessels
- Connects different tissues of the body
- Circulatory system is the network of blood vessels
- Blood delivers nutrients and picks up waste products
Functions of Blood
- Transport of gases, nutrients, and waste products
- Transport of processed molecules
- Transport of regulatory molecules
- Regulation of pH and osmosis
- Maintenance of body temperature
- Protection against foreign substances
- Clot formation
Composition of Blood
- Connective tissue consisting of a liquid matrix (plasma) and cells and cell fragments (formed elements)
- Total blood volume: 4-5L (female) and 5-6L (male)
- Sticky, opaque fluid with a metallic taste
- Color varies from scarlet to dark red
- Blood pH 7.35–7.45
- Blood temperature 38°C
- Blood accounts for 8% of body weight
Plasma
- Pale yellow fluid
- 91% water and 9% other substances
- Contains ions, nutrients, waste products, gases, and regulatory substances
- Plasma proteins account for 7% of plasma
Plasma Proteins
- Albumin regulates water movement between blood and tissues (colloid osmotic pressure) and transports molecules
- Globulin transports substances and includes antibodies
- Fibrinogen responsible for blood clot formation
- Serum is plasma without clotting factors
Production of Formed Elements
- HEMATOPOIESIS: process of blood cell production
- After birth, occurs primarily in red bone marrow
- Some WBCs mature in lymphatic tissue
- Adults: red bone marrow found in ribs, sternum, vertebrae, pelvis, femur, and humerus
- All formed elements originate from HEMOCYTOBLASTS.
Production of Formed Elements
- Most blood cells don't divide but are renewed from stem cells (hemocytoblasts)
- Hematopoiesis occurs in different locations before and after birth
- Fetus: liver, thymus, spleen, lymph nodes, and red bone marrow
- After birth: red bone marrow of axial skeleton, girdles, and epiphyses of the humerus and femur
- Some WBCs are produced in lymphatic tissues
- Hemocytoblasts give rise to all formed elements
- Growth factors determine the type of formed element from the stem cell
Production of Formed Elements
- Chemical signals regulate formed element development
- Colony-Stimulating Factors (CSFs) and hormones transported to the bone marrow
- EPO (Erythropoietin) stimulates myeloid stem cells to become RBCs
Red Blood Cells
- Biconcave discs, anucleate, with no organelles
- Dedicated to respiratory gas transport
- Filled with hemoglobin responsible for gas transport
- Biconcave shape provides a large surface area for gas exchange and allows flexibility
- Bending allows for shape change as needed
Hemoglobin (Hb)
- Accounts for 1/3 of a RBC's volume
- Consists of:
- Globin protein (2 alpha & 2 beta chains, each bound to a heme group)
- Heme group contains an iron atom that binds to one oxygen molecule
- Oxygen content determines blood color (oxygenated: bright red, deoxygenated: darker red)
- Globin molecules transport carbon dioxide
- One RBC contains 250 million Hb groups carrying 1 billion O2 molecules
RBC Transport
- Oxygen attaches to the heme group of hemoglobin (OXYHEMOGLOBIN)
- Hemoglobin not bound to O2 is DEOXYHEMOGLOBIN
- CO2 does not bind to the iron atom but to the globin molecule (CARBAMINOHEMOGLOBIN vs CARBOXYHEMOGLOBIN)
- NO (Nitric Oxide) transported by hemoglobin
RBC Transport
- Oxygen transport: ~98.5% bound to hemoglobin, ~ 1.5% dissolved in plasma
- Carbon dioxide transport: ~7% dissolved in plasma, ~70% transported as bicarbonate (HCO3-), ~23% bound to hemoglobin
Formation of the RBC
- Erythropoiesis is the process of RBC production
- Stem cells called hemocytoblasts are the precursors to Red blood cells
RBC Production
- Circulating erythrocyte count reflects a balance between production and destruction
- Too few RBCs leads to tissue hypoxia
- Too many RBCs causes blood viscosity
- Erythropoiesis is hormonally controlled and needs iron, amino acids, and B vitamins
- EPO (Erythropoietin) released by the kidneys is triggered by hypoxia
- EPO enhances erythropoiesis, increasing RBC count and oxygen-carrying ability
Negative Feedback Mechanism for Erythropoiesis
- When oxygen levels in the blood are low, the kidneys release EPO.
- EPO stimulates the red bone marrow to produce more red blood cells.
- As the number of red blood cells increases, oxygen levels in the blood rise.
- This increase in oxygen levels inhibits the release of EPO, slowing down red blood cell production.
RBC Life Cycle
- RBC lifespan: 100-120 days
- Old RBCs become stiff and fragile, with degraded Hb
- Macrophages in the spleen and liver engulf dying RBCs
- Heme and globin are separated, and iron is recycled
- Globin chains break down into amino acids for protein synthesis.
- Iron released from heme goes to red bone marrow to make new hemoglobin
- Heme becomes bilirubin, secreted in bile
Hemoglobin Breakdown
- Globin is broken down into amino acids
- Heme is broken down into iron and bilirubin
- Iron is recycled, and bilirubin is excreted in bile
White Blood Cells (WBCs)
- Only blood components that are complete cells
- Less numerous than RBCs
- Make up 1% of total blood volume
- Two functions:
- Protect the body against invading microorganisms
- Remove dead cells and debris by phagocytosis
- Classified by appearance in stained preparations
White Blood Cell Movement
- AMEBOID MOVEMENT: movement like amoeba by cytoplasmic projections
- DIAPEDESIS: WBCs become thin and elongated to slip between blood vessel walls
- CHEMOTAXIS: attraction to foreign materials or dead cells in tissues
Buffy Coat
- Thin, whitish layer of WBCs and platelets found between red blood cells and plasma during centrifugation
White Blood Cells / Leukocytes
- Two main categories:
- Granulocytes: contain large cytoplasmic granules (neutrophils, eosinophils, basophils)
- Agranulocytes: very small granules, not visible with light microscope (lymphocytes, monocytes)
White Blood Cells (Granulocytes)
- Neutrophils (most common): granules stain with both acidic and basic dyes, have a lilac appearance, contain enzymes, and are bacteria slayers
- Basophils (0.5%): possess purplish-black granules with histamine (vasodilator) and heparin (anti-coagulant)
- Eosinophils (1-4%): have red-staining bilobed nuclei, red to crimson granules, lessen allergy severity, and fight parasitic worms.
White Blood Cells (Agranulocytes)
-
Lymphocytes (25%+): large, dark-purple circular nuclei, thin rim of blue cytoplasm, found in lymphoid tissue
- B cells: produce antibodies
- T cells: protect against viruses and intracellular microorganisms, destroy infected cells
- Monocytes (4-8%): largest leukocytes, abundant pale-blue cytoplasm, purple U-shaped nuclei, differentiate into macrophages, highly mobile, phagocytic, and activate lymphocytes
Platelets
- Cell fragments of megakaryocytes, blue outer region, purple granular center
- Function in clotting:
- Formation of platelet plugs to seal small vessel breaks
- Formation of clots for larger wounds
- Granules contain ADP and thromboxanes
Hemostasis
- Series of reactions for stopping bleeding
- Three phases:
- Vascular spasms: immediate vasoconstriction (thromboxanes and endothelin)
- Platelet plug formation: accumulation of platelets seals small breaks
- Coagulation (blood clotting): fibrin network traps blood cells, platelets, and fluid
Vascular Spasm
- Immediate temporary constriction of a blood vessel
- Smooth muscle contraction in the vessel wall
- Activation of the nervous system and release of chemicals
- ENDOTHELIN produced by endothelial cells
- THROMBOXANES released by platelets
Platelet Plug Formation
- Accumulation of platelets seals small tears in blood vessels
Coagulation (Blood Clotting)
- Occurs when a blood vessel is severely damaged
- BLOOD CLOT: fibrin network traps blood cells, platelets, and fluid
- Clotting factors in plasma play a crucial role
Clot Formation
- Process of blood clotting involving the formation of a fibrin network to trap blood cells, platelets, and fluid.
Blood Clotting
- Begins with the extrinsic or intrinsic pathway
- Both pathways result in activated factor X
- Extrinsic pathway: starts with release of thromboplastin from damaged tissue
- Intrinsic pathway: begins with activation of factor XII
Blood Clotting
- Activated factor X, factor V, phospholipids, and Ca2+ form prothrombinase
- Prothrombin converted to thrombin by prothrombinase
- Fibrinogen converted to fibrin by thrombin
- Insoluble fibrin strands form the clot structure
- Fibrin traps plasma, forming a gel-like structure
- Factor XIII cross-links fibrin, strengthening and stabilizing the clot
- Anticoagulants like antithrombin and heparin prevent clot formation.
Clot Retraction and Fibrinolysis
-
Clot retraction: stabilization of the clot by squeezing serum from fibrin strands
- Platelet contraction pulls damaged tissue edges closer
- Serum (plasma minus fibrinogen and some clotting factors) is squeezed out
- Thrombin and tissue plasminogen activator activate plasmin, which dissolves fibrin (fibrinolysis)
Blood Grouping
- RBC membranes have glycoprotein antigens on their surface
- Antigens are unique to the individual, recognized as foreign during transfusions, and promote agglutination (agglutinogens)
- Antigen presence or absence classifies blood groups
ABO Blood Group
- ABO blood groups:
- Two antigens (A and B) on RBC surface
- Two antibodies (anti-A & anti-B) in plasma
Rh Blood Group
- Rh-positive blood has Rh antigens (D antigen), while Rh-negative blood does not
- Rh antibodies are produced when an Rh-negative person is exposed to Rh-positive blood
- Hemolytic disease of the newborn can occur when the fetus is Rh-positive, and the mother is Rh-negative
Diagnostic Blood Tests
- Assessing an individual's health
- Microscopic examination:
- Abnormal RBC size and shape: potential anemia
- WBC type and number indicate various diseases
- Chemical analysis: comprehensive picture of overall health
Normal Values
- Reference ranges for blood tests to assess health status
Diagnostic Blood Tests
- Type and Crossmatch: determines ABO and Rh blood groups, necessary for blood transfusions, and ensures donor-recipient compatibility
Clotting
- The process of blood clotting involving a series of steps to stop bleeding.
Blood Chemistry
- Composition of dissolved or suspended materials in plasma (e.g., glucose, urea nitrogen, bilirubin, cholesterol) is assessed to gauge body system function and status.
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Description
Explore the vital components and functions of the cardiovascular system. This quiz covers the composition of blood, its various functions, and the role of the heart and blood vessels. Test your knowledge on how this complex network supports body homeostasis.
