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Questions and Answers
What is one of the primary functions of fibrinogens in blood?
Which vitamin is essential for the development of red blood cells?
What is the lifespan of platelets in circulation?
What type of white blood cell is primarily responsible for the first response in early inflammation?
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Which organ serves as a reserve pool for platelets?
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What is the primary responsibility of erythrocytes?
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Which of the following leukocytes is primarily involved in allergic reactions?
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What function does albumin primarily serve in the plasma?
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What effect can decreased albumin production have on the body?
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Which component of blood is responsible for initiating the immune response?
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What role do platelets play in the circulatory system?
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What is primarily found in the buffy coat of blood?
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What type of globulins are primarily involved in immune defense?
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What is one of the primary functions of red blood cells in the hematological system?
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Which component of blood is responsible for maintaining oncotic pressure?
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Which of the following is NOT a component of plasma?
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What is a key role of white blood cells in the hematological system?
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Which diagnostic approach is used to identify red blood cell disorders?
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Which factor is NOT considered in the pathophysiology of hematological disorders?
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Which component of blood is involved in the clotting process?
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What is the approximate blood volume in adults?
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What is the main site of T cell maturation in the human body?
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What process describes the production of blood cells?
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Which factor increases the production of leukocytes?
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Which vitamin is commonly prescribed to pregnant women to prevent anemia?
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What component is responsible for the oxygen-carrying function of erythrocytes?
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Which organ produces thrombopoietin (TPO), a regulator of platelet levels?
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Which of the following is NOT directly associated with the production of erythrocytes?
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Which part of the body acts as a 'check stop' for immune responses?
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What is the primary function of the clotting factors in hemostasis?
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Which of the following statements about the aging hematological system is true?
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What triggers the activation of the extrinsic pathway of the clotting cascade?
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During hemostasis, what is the first physiological response following vascular injury?
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What is a primary outcome of fibrinolysis in the clotting process?
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What role does tissue plasminogen activator (tPA) play in hemostasis?
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What percentage of iron is typically lost daily through urine, sweat, and other means?
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What is the primary diagnostic use of D-dimer in clinical practice?
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What is primarily responsible for the oxygen-carrying function of erythrocytes?
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Which vitamin is essential for erythropoiesis?
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What role do platelets primarily play in hemostasis?
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Which of the following factors is NOT required for the development of red blood cells?
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What type of leukocyte is primarily involved in the immune defense against parasites?
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What is the primary site for the maturation of T cells?
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Which hormone stimulates the production and maturation of red blood cells?
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What is the primary role of the spleen in hematological function?
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What is the main component of hemoglobin that binds to oxygen?
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Which factor is likely to increase the production of leukocytes?
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What stimulates the release of erythropoietin from the kidneys?
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Which of the following is a nutritional requirement for red blood cell and hemoglobin synthesis?
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Which organ is responsible for the destruction of aging platelets?
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What is the main role of globulins in the blood?
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How do albumin levels affect overall blood volume?
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What is the primary function of the buffy coat in blood?
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Which type of leukocyte is involved in mediating the adaptive immune response?
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What is the consequence of cirrhosis on albumin levels in the body?
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Which type of leukocyte is primarily responsible for combating parasitic infections?
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What is the primary physiological role of platelets?
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Which of the following is NOT a typical component of the blood?
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What initiates the intrinsic pathway of the coagulation cascade?
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Which component is primarily responsible for the formation of a blood clot?
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What is the primary function of the fibrinolytic system after a clot is formed?
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What change occurs in the hematological system as one ages?
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What is a key characteristic of the hemostatic plug during hemostasis?
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What triggers the activation of the coagulation cascade?
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Which group of individuals is characterized by having more atypical lymphocytes due to frequent viral infections?
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What happens to the size of a clot during the process of fibrinolysis?
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What is one of the primary responsibilities of white blood cells in the hematological system?
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Which component of blood is primarily responsible for the transport of carbon dioxide?
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What percentage of blood volume is made up of plasma?
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Which protein in plasma is primarily responsible for maintaining oncotic pressure?
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What is a common clinical manifestation of anemia?
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What role does water play in the composition of blood?
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Which diagnostic test is commonly used to identify disorders related to white blood cells?
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What is a significant consequence of decreased platelet levels?
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What is the life cycle duration of erythrocytes in the blood?
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Which essential component is required for the production of erythrocytes?
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Which type of white blood cell is responsible for engulfing and digesting particles?
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What primary function do platelets serve in the circulatory system?
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Which organ serves as a site for the proliferation and differentiation of lymphocytes?
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What is the primary function of albumin in plasma?
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Which type of leukocyte is primarily responsible for mediating the adaptive immune response?
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What function do white blood cells primarily serve in the hematological system?
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How do eosinophils participate in immune response?
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What is a potential consequence of decreased albumin production in the body?
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Which component of blood primarily helps in maintaining oncotic pressure?
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What percentage of blood volume is typically made up by the buffy coat?
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Which of the following is a component of plasma involved in clotting?
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What is a key factor in the pathophysiology of hematological disorders?
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What is the role of basophils in the immune system?
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Which of the following is a function of globulins in plasma?
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Which diagnostic test is typically used to identify white blood cell disorders?
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What is the impact of excessive loss of albumin due to kidney disease?
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What complication can arise from disorders affecting platelets?
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Which type of anemia is characterized by a deficiency of vitamin B12?
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How does the hematological system help maintain acid-base balance?
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What is the primary role of the thymus in the immune system?
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Which component of the blood is chiefly responsible for the production of thrombopoietin?
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What occurs when there is a deficiency of essential vitamins for red blood cell production?
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Which of the following statements about the spleen is false?
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What is erythropoiesis primarily regulated by?
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Which of the following minerals is crucial for hemoglobin synthesis?
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What is the role of macrophages in lymph nodes?
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How long do platelets typically circulate before losing their functionality?
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What triggers the activation of the intrinsic pathway in the clotting cascade?
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Which component plays a primary role in the formation of the hemostatic plug during hemostasis?
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What is the main function of the fibrinolytic system?
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What is a common diagnostic use for D-dimer in clinical practice?
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Which of the following statements is true regarding the retraction and lysis of blood clots?
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How does aging affect erythrocyte replacement in the body?
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Which factor contributes to the increase of platelet adhesiveness with age?
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What is the significance of petechiae, purpura, and ecchymosis in nursing assessment?
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Study Notes
Functions of the Hematological System
- Blood ensures delivery of substances crucial for cellular metabolism, including oxygen via red blood cells.
- It removes waste products of metabolism, such as carbon dioxide.
- Blood also plays a vital role in defense against microorganisms and injuries through white blood cells.
- It helps maintain acid-base balance and facilitates blood clotting through clotting factors and platelets.
Components of Blood
- Blood volume in adults is approximately 5.5 liters.
- Plasma comprises 55% of blood and contains proteins, water, and solutes.
- Cellular components, making up 45% of blood, include erythrocytes (red blood cells), platelets, and leukocytes.
Plasma Proteins
- Albumin, the major component of plasma osmotic pressure, functions as a carrier molecule and plays a crucial role in maintaining oncotic pressure.
- Globulins include antibodies and transport proteins, carrying proteins and immunoglobulins.
- Fibrinogens are essential for blood clotting.
- Other plasma proteins have various roles, including α-1-antitrypsin, coagulation factors, and more.
Cellular Components
Erythrocytes (Red Blood Cells)
- Erythrocytes are the most abundant blood cells, produced in the bone marrow (erythropoiesis) and have a lifespan of 80-120 days.
- Responsible for tissue oxygenation, their biconcave shape allows for reversible deformation, facilitating passage through microcirculation.
- Hemoglobin, responsible for carrying oxygen, is essential for this function.
- Red blood cell development requires vitamin B12, folic acid, copper, cobalt, and, most importantly, iron.
Leukocytes (White Blood Cells)
- Leukocytes are essential for immune defense, categorized into granulocytes and agranulocytes.
- Granulocytes include neutrophils (first responders in inflammation), eosinophils (ingesting antibodies), and basophils (containing histamine).
- Agranulocytes include phagocytes (cells engulfing and digesting particles) and immunocytes (immunocytes create immunity, primarily lymphocytes).
Platelets (Thrombocytes)
- Platelets are essential for blood coagulation and control of bleeding, inducing vasoconstriction.
- They change shape to conform to the injured site, forming a platelet plug.
- Platelets activate the coagulation cascade to stabilize the plug and initiate repair processes including clot retraction and clot dissolution, known as fibrinolysis.
- The spleen serves as a reserve pool for platelets, and platelets typically live for 8-11 days before being removed by macrophages, primarily in the spleen.
- Normal platelet concentration ranges from 150 to 400 x 10^9/L.
Lymphoid Organs
- Lymphoid organs, connected to the circulatory system, are crucial for residence, proliferation, and differentiation of lymphocytes and phagocytes.
Primary Lymphoid Organs
- The thymus is responsible for the maturation of T-cells.
- Bone marrow is where both T-cells and B-cells are produced.
Secondary Lymphoid Organs
- The spleen serves as a blood reserve and is involved in the phagocytosis of old blood cells.
- Lymph nodes act as "check stops" for immunity, housing macrophages.
Development of Blood Cells
- Hematopoiesis, the process of blood cell production, primarily occurs in the bone marrow.
- Bone marrow is found in the cavities of bones, but not all bones have active marrow.
- Stem cells differentiate to generate erythrocytes, leukocytes, and platelets.
Development of Platelets & WBCs
Platelets
- Platelets are fragments of megakaryocytes, produced in the bone marrow.
- Platelet levels are regulated by thrombopoietin (TPO), produced by the liver.
- Platelets circulate for 10 days before losing functionality.
- The spleen sequesters and destroys aging platelets through phagocytosis.
WBCs
- Leukocytes originate from stem cells within the bone marrow and are stored in the thymus and lymph nodes.
- Leukocyte production increases during infections, steroid presence, or reduced bone marrow reserves.
Development of RBCs
- Erythropoiesis, the production of red blood cells, occurs in the bone marrow.
- Erythrocytes develop from erythroblasts within the bone marrow, with maturation stimulated by erythropoietin (EPO).
- Erythropoietin production is regulated by a feedback loop; in cases of tissue hypoxia, the kidney increases erythropoietin production, leading to enhanced red blood cell production and release from the bone marrow.
Hemoglobin Synthesis
- Hemoglobin, the oxygen-carrying protein of the erythrocyte, comprises two pairs (alpha and beta) of polypeptide chains (globins) and four iron-protoporphyrin complexes (heme).
- Each heme molecule carries one molecule of oxygen.
Nutritional Requirements for RBCs & Hgb
- Proteins: Amino acids are crucial for hemoglobin synthesis.
- Vitamins: Vitamins B12, B6, B2, E, and C, folate, pantothenic acid, and niacin are all vital for red blood cell formation. Folate deficiencies are common and can be remedied through supplementation, particularly for pregnant women, as folate demands increase during pregnancy.
- Minerals: Iron is required for hemoglobin synthesis, and copper plays a supporting role in iron metabolism.
Iron Cycle
- Total body iron is bound to heme or muscle cells or stored bound to ferritin.
- Daily iron loss is minimal, around 1 mg (3%), lost through urine, sweat, bile, and epithelial cells or via the gut.
- Iron is recycled from aged, abnormal, or damaged red blood cells.
Mechanisms of Hemostasis
- Hemostasis refers to the arrest of bleeding.
- Platelets, clotting factors, and the vasculature are components of hemostasis.
Sequence of Hemostasis
- Vascular injury triggers vasoconstriction, reducing blood flow.
- Platelet-to-platelet interactions form a hemostatic plug.
- The coagulation cascade, also known as clotting, is activated, forming fibrin clots.
- Fibrinolysis is activated to limit clot size and initiate healing.
Function of Clotting Factors
- Blood clots are meshwork of protein strands that stabilize the platelet plug and trap other cells, such as erythrocytes and phagocytes, which remove any microorganisms that may have entered.
- The protein strands are made of fibrin, produced by the clotting (coagulation) system.
- Initiation triggers the clotting cascade, known as secondary hemostasis.
- Two pathways exist - the intrinsic pathway, activated by factor XII contact with subendothelial substances exposed by vascular injury, and the extrinsic pathway, activated by tissue factor (TF) release from damaged endothelial cells.
Retraction and Lysis of Blood Clots
- After clot formation, clot retraction, or solidification, occurs.
- Lysis (breakdown) of blood clots is achieved by the fibrinolytic system.
- Tissue plasminogen activator (tPA) triggers fibrin clot degradation.
- Fibrin degradation products, such as D-dimer, are used to diagnose conditions like deep vein thrombosis (DVT).
Age and the Hematological System
Pediatrics
- Blood cell counts are higher at birth than in adults due to the trauma of birth and umbilical cord cutting.
- Children often have more atypical lymphocytes due to frequent viral infections.
Geriatrics
- Erythrocyte life span remains normal, but replacement is slower. Iron depletion, decreased total serum iron, iron-binding capacity, and intestinal iron absorption are common.
- Lymphocyte function diminishes with age.
- Platelet adhesiveness may potentially increase with age.
Functions of the Hematological System
- Ensures delivery of substances needed for cell metabolism, removes waste products, protects against microorganisms and injury, maintains acid-base balance and participates in blood clotting.
- Oxygen is delivered by red blood cells.
- Carbon dioxide is removed as a waste product.
- White blood cells are responsible for immune defense.
- Clotting factors and platelets are involved in hemostasis.
Components of Blood
- Blood volume in adults is about 5.5 liters.
-
Plasma (55%): Composed of proteins, water, and other solutes.
- Proteins: Albumin (maintains oncotic pressure), globulins (contain antibodies), fibrinogen and prothrombin (involved in clotting).
- Water: Acts as a solvent for various components.
- Other Solutes: Electrolytes for osmotic pressure, waste products for excretion.
-
Cellular Components (45%): Includes erythrocytes (RBC), platelets, and leukocytes.
- Erythrocytes (RBC): Transport oxygen throughout the body.
-
Buffy Coat (<2%): Contains platelets and leukocytes.
- Platelets: Essential for coagulation and bleeding control.
-
Leukocytes: Fight against microorganisms.
- Neutrophils: First responders in inflammation.
- Eosinophils: Respond to allergies and parasitic infections.
- Basophils: Release histamine during wound healing.
- Lymphocytes: Mediate adaptive immune response.
- Monocytes: Involved in phagocytosis.
Plasma Proteins
- Albumin: Maintains plasma oncotic pressure, carries molecules, and draws fluid back into the intravascular space. Low levels can lead to edema and ascites.
- Globulins: Transport proteins and antibodies.
- Fibrinogens: Involved in blood clotting.
- Other: Perform various roles, including α-1-antitrypsin and coagulation factors.
Cellular Components
Erythrocytes (Red Blood Cells)
- Most abundant cells in blood.
- Produced in bone marrow (erythropoiesis).
- Life cycle is 80-120 days.
- Responsible for tissue oxygenation.
- Hemoglobin carries the gases.
- Biconcave shape allows for reversible deformation (torpedo-like) for microcirculation.
Leukocytes (White Blood Cells)
- Immune defense!
-
Granulocytes:
- Neutrophils: First responders for early inflammation.
- Eosinophils: Ingest antibodies.
- Basophils: Contain histamine.
- Mast Cells: Released during wound healing.
-
Agranulocytes:
- Phagocytes: Engulf and digest particles in the immune response.
- Immunocytes: Create immunity (Lymphocytes).
Platelets (Thrombocytes)
- Essential for blood coagulation and control of bleeding.
- Induce vasoconstriction.
- Change shape to conform to the injured site (platelet plug).
- Activate the coagulation cascade to stabilize the plug.
- Initiate repair processes including clot retraction and dissolution (fibrinolysis).
- The spleen acts as a reserve pool for platelets.
- Platelets have a lifespan of 8-11 days before being removed by macrophages, usually in the spleen.
- Normal concentration: 150-400 x 10°/L.
Lymphoid Organs
- Lymphoid system is connected with circulatory system via lymphoid organs.
- Sites for residence, proliferation, and differentiation of lymphocytes and phagocytes.
Primary Lymphoid Organs
- Thymus: T cell maturation.
- Bone Marrow: Production of T and B cells.
Secondary Lymphoid Organs
- Spleen: Blood reserve, phagocytosis of old blood cells.
- Lymph Nodes: Immune checkpoints, harbor macrophages.
Development of Blood Cells
- Hematopoiesis: Blood cell production occurring in bone marrow.
- Bone marrow is found in bone cavities, not all bones have active marrow.
- Cellular differentiation creates erythrocytes, leukocytes, and platelets from stem cells.
Development of Platelets and WBCs
Platelets
- Fragments of megakaryocytes produced in bone marrow.
- Platelet levels are regulated by thrombopoietin (TPO) produced in the liver.
- Platelets circulate for 10 days before becoming functionally inactive.
- The spleen sequesters and destroys aging platelets through phagocytosis.
WBCs
- Arise from stem cells in bone marrow.
- Stored in thymus and lymph nodes.
- Production increases in infection, with steroid presence, or reduced bone marrow reserves.
Development of RBCs
- Erythropoiesis: Development of RBCs.
- Erythrocytes originate from erythroblasts in bone marrow and mature stimulated by erythropoietin (EPO).
- Controlled by a feedback loop.
- In tissue hypoxia, erythropoietin is stimulated by the kidney.
- Erythropoietin increases red blood cell production and release from bone marrow.
Hemoglobin Synthesis
- Hemoglobin: Oxygen-carrying protein of the erythrocyte.
- Two pairs of polypeptide chains (Globins): α and β.
- Four iron-protoporphyrin complexes (Heme): Each heme carries one oxygen molecule.
Nutritional Requirements for RBCs and Hemoglobin
- Proteins: Amino acids.
-
Vitamins: B12, B6, B2, E, and C, folic acid, pantothenic acid, and niacin.
- Folate deficiency is common and develops rapidly. Supplements are prescribed to pregnant women to avoid anemia and neural tube defects in the baby.
- Minerals: Iron (for hemoglobin) and copper.
Iron Cycle
- Total body iron is bound to heme, muscle cells, or stored with ferritin.
- Less than 1 mg of iron is lost daily through urine, sweat, bile, and epithelial cells or from the gut.
- Iron is recycled from old, abnormal, or damaged RBCs.
Mechanisms of Hemostasis
- Hemostasis: Arrest of bleeding.
- Components: platelets, clotting factors, and vasculature.
Sequence of Hemostasis
- Vascular injury: Vasoconstriction limits blood flow.
- Platelet-to-platelet interactions: Formation of a hemostatic plug (platelet plug).
- Coagulation: Activation of the coagulation cascade to form fibrin clots.
- Fibrinolysis: Activation to limit clot size and begin healing process (dissolution).
Function of Clotting Factors
- Blood Clot: A meshwork of protein strands that stabilizes the platelet plug and traps other cells like erythrocytes and phagocytes.
- Fibrin: Protein strands produced by the clotting (coagulation) system.
-
Coagulation Cascade: Initiates the clotting process.
- Intrinsic Pathway: Activated when factor XII (Hageman factor) contacts subendothelial substances exposed by vascular injury.
- Extrinsic Pathway: Activated when tissue factor (TF) (tissue thromboplastin) is released from damaged endothelial cells.
Retraction and Lysis of Blood Clots
- Clot Retraction: Clot solidifies after formation.
-
Fibrinolysis: Breakdown of blood clots by the fibrinolytic system.
- Tissue Plasminogen Activator (tPA): Triggers fibrin clot degradation.
- Fibrin Degradation Products: Include D-dimer.
- D-dimer: Diagnostic marker for blood clots.
Age and the Hematological System
Pediatrics
- Blood cell counts are higher than in adults at birth due to trauma of birth and umbilical cord cutting.
- Children have more atypical lymphocytes due to frequent viral infections.
Geriatrics
- Erythrocyte life span is normal, but replacement is slower.
- Iron depletion: Decreased total serum iron, iron-binding capacity, and intestinal iron absorption.
- Lymphocyte function decreases with age.
- Platelet adhesiveness may increase with age.
Functions of the Hematological System
- Blood circulation delivers nutrients and removes waste products.
- Red blood cells carry oxygen.
- White blood cells fight against microorganisms and injury.
- Blood clotting factors and platelets help with hemostasis (stopping bleeding).
- Acid-base balance is maintained by the hematological system.
Components of Blood
- Blood volume: 5.5 liters in adults.
- Plasma (55%): Contains proteins like albumin, globulins, fibrinogen, and prothrombin, water, and other solutes like ions and waste products.
-
Cellular Components (45%): Contains erythrocytes (RBCs), platelets, and leukocytes.
- Erythrocytes (RBCs): Transport oxygen throughout the body.
-
Buffy Coat (<2%): Composed of platelets and leukocytes.
- Platelets: Essential for blood coagulation and control of bleeding.
-
Leukocytes: Fight against microorganisms.
- Neutrophils: First responders for early inflammation.
- Eosinophils: Involved in allergic reactions and parasitic infections.
- Basophils: Contain histamine and are released during wound healing.
- Lymphocytes: Mediate the adaptive immune response.
- Monocytes: Involved in phagocytosis.
Plasma Proteins
- Albumin: Maintains oncotic pressure, acts as a carrier molecule, and draws fluid back into the intravascular space.
- Globulins: Include antibodies (immunoglobulins) and transport proteins.
- Fibrinogens: Functions in blood clotting.
- Other: Includes α-1-antitrypsin, coagulation factors, etc., and have various roles in the body.
- Plasma protein functions include clotting, defense, transport, and regulation.
Cellular Components
Erythrocytes (Red Blood Cells)
- Most abundant cells in the blood, produced in bone marrow (erythropoiesis).
- Life cycle of 80-120 days.
- Transport oxygen through hemoglobin (Hb).
- Biconcave shape allows for deformability for passage through microcirculation.
- Development requires vitamin B12, folic acid, copper, cobalt, and iron.
Leukocytes (White Blood Cells)
- Immune defense.
-
Granulocytes:
- Neutrophils: First responders in early inflammation
- Eosinophils: Ingest antibodies
- Basophils: Contain histamine
- Mast Cells: Released during wound healing.
-
Agranulocytes:
- Phagocytes: Engulf and digest particles as part of the immune response.
- Immunocytes: Create immunity (Lymphocytes).
Platelets (Thrombocytes)
- Essential for blood coagulation and control of bleeding.
- Initiate vasoconstriction.
- Change shape to form a platelet plug at injury sites.
- Activate the coagulation cascade to stabilize the plug.
- Initiate repair processes including clot retraction and dissolution (fibrinolysis).
- Spleen acts as a reserve pool for platelets.
- Life cycle of 8-11 days, removed by macrophages.
- Normal concentration of 150-400 x 10^9/L.
Lymphoid Organs
- Lymphoid organs are sites for lymphocyte and phagocyte residence, proliferation, and differentiation.
Primary Lymphoid Organs
- Thymus: Maturation of T cells.
- Bone Marrow: Production of T and B cells.
Secondary Lymphoid Organs
- Spleen: Blood reserve; phagocytosis of old blood cells.
- Lymph Nodes: Checkpoints for immunity, residence of macrophages.
Development of Blood Cells
- Hematopoiesis: Production of blood cells in the bone marrow.
- Bone marrow found in cavities of bones.
- Differentiation of cells from stem cells to create erythrocytes, leukocytes, and platelets.
Development of Platelets and White Blood Cells
Platelets
- Fragments of megakaryocytes, produced in bone marrow.
- Levels regulated by thrombopoietin (TPO) produced by the liver.
- Circulate for 10 days before losing functionality.
- Spleen sequesters and destroys aging platelets.
White Blood Cells
- Arise from stem cells in the bone marrow.
- Stored in the thymus and lymph nodes.
- Production increases in infection, presence of steroids, and reduced bone marrow reserves.
Development of Red Blood Cells
- Erythropoiesis: Development of RBCs.
- Erythrocytes derived from erythroblasts in bone marrow, stimulated by erythropoietin (EPO).
- Erythropoietin production is controlled by a feedback loop. Hypoxia stimulates EPO production by the kidney.
- EPO increases RBC production and release from bone marrow.
Hemoglobin Synthesis
- Hemoglobin: Oxygen-carrying protein of the erythrocyte.
- Contains two pairs (alpha & beta) of polypeptide chains (globins) and four iron-protoporphyrin complexes (heme).
- Each heme molecule carries one molecule of oxygen.
Iron Cycle
- Total body iron is bound to heme, muscle cells, or stored bound to ferritin.
- Less than 1 mg per day is lost through urine, sweat, bile, epithelial cells, or the gut.
- Iron is recycled from aged, abnormal, or damaged RBCs.
Mechanisms of Hemostasis
- Hemostasis: Arrest of bleeding.
- Components: Platelets, clotting factors, and vasculature.
Sequence of Hemostasis
- Vascular injury: Vasoconstriction limits blood flow.
- Platelet-to-platelet interactions: Form a hemostatic plug.
- Coagulation cascade: Activated to form fibrin clots.
- Fibrinolysis: Activated to limit clot size (retraction) and begin healing (dissolution).
Function of Clotting Factors
- Blood clot: Meshwork of protein strands that stabilizes the platelet plug and traps cells.
- Fibrin: Protein strands produced by the clotting system (coagulation).
- Coagulation cascade: Initiated by vascular injury.
- Intrinsic pathway: Activated when factor XII (Hageman factor) contacts exposed subendothelial substances.
- Extrinsic pathway: Activated when tissue factor (TF) (tissue thromboplastin) is released by damaged cells.
Retraction and Lysis of Blood Clots
- Clot retraction: Solidifies the clot.
- Fibrinolytic system: Breaks down blood clots through fibrinolysis.
- Tissue plasminogen activator (tPA): Triggers fibrin clot degradation.
- Fibrin degradation products include D-dimer.
- D-dimer can be used to diagnose conditions related to blood clots.
Age and the Hematological System
Pediatrics
- Blood cell counts are higher at birth (due to birth trauma and umbilical cord cutting).
- Children have more atypical lymphocytes due to frequent viral infections.
Geriatrics
- Erythrocyte lifespan is normal but replacement is slower.
- Iron depletion
- Decreased total serum iron, iron-binding capacity, and intestinal iron absorption.
- Lymphocyte function decreases with age.
- Platelet adhesiveness increases with age.
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Description
This quiz covers the critical functions of the hematological system, including the delivery of oxygen and removal of waste. It also explores the components of blood, such as plasma proteins and cellular elements, and their significance in the body.
