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Questions and Answers
What percentage of total body mass does blood account for?
What percentage of total body mass does blood account for?
Blood is less viscous than water.
Blood is less viscous than water.
False
What is the main function of albumin in blood plasma?
What is the main function of albumin in blood plasma?
Maintains osmotic pressure
The plasma component of blood contains dissolved substances.
The plasma component of blood contains dissolved substances.
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Match the following formed elements with their primary functions:
Match the following formed elements with their primary functions:
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What is the adult average hematocrit percentage?
What is the adult average hematocrit percentage?
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Erythrocytes are capable of repairing damaged organelles after leaving the bone marrow.
Erythrocytes are capable of repairing damaged organelles after leaving the bone marrow.
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What hormone stimulates the formation of erythrocytes?
What hormone stimulates the formation of erythrocytes?
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Hematopoietic growth factors include erythropoietin, thrombopoietin, and _________.
Hematopoietic growth factors include erythropoietin, thrombopoietin, and _________.
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Match the following blood cell types with their primary functions:
Match the following blood cell types with their primary functions:
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What is the primary role of hemoglobin in erythrocytes?
What is the primary role of hemoglobin in erythrocytes?
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A high hematocrit level can lead to an increased risk of blood clots.
A high hematocrit level can lead to an increased risk of blood clots.
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What is the average number of erythrocytes per microlitre in adult females?
What is the average number of erythrocytes per microlitre in adult females?
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Which type of leukocyte is specifically known for fighting parasitic infections?
Which type of leukocyte is specifically known for fighting parasitic infections?
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Basophils are the fastest responders to bacterial infections.
Basophils are the fastest responders to bacterial infections.
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What is the primary function of monocytes in the immune response?
What is the primary function of monocytes in the immune response?
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Platelets are formed when myeloid stem cells are exposed to TPO and develop into __________.
Platelets are formed when myeloid stem cells are exposed to TPO and develop into __________.
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Match the following leukocytes with their primary functions:
Match the following leukocytes with their primary functions:
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What is the process that prevents excessive bleeding known as?
What is the process that prevents excessive bleeding known as?
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During hemostasis, the initial response involves __________ spasm.
During hemostasis, the initial response involves __________ spasm.
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Study Notes
Blood Composition and Function
- Blood is a type of extracellular fluid, making up 8% of total body mass.
- Average male blood volume: 5-6L; average female: 4-5L.
- Blood is more viscous than water with a temperature maintained around 38ºC and pH range of 7.35-7.45.
- Blood's three main functions: transportation (oxygen, nutrients, hormones, heat, waste), regulation (pH, temperature, osmotic pressure), and protection (against blood loss and disease).
Blood Composition
- Blood has two main components:
- Blood plasma (55%): 91.5% water; 8.5% solutes. The solutes include proteins (albumin, globulins, fibrinogen) and other substances like electrolytes, nutrients, hormones, and gases. Albumin maintains osmotic pressure; globulins include antibodies and transport proteins; and fibrinogen is involved in blood clotting.
- Formed elements (45%): erythrocytes (red blood cells), leukocytes (white blood cells), and platelets.
Erythrocytes (Red Blood Cells)
- Most abundant formed element.
- Transport oxygen and carbon dioxide.
- Mature erythrocytes lack organelles, allowing for maximum hemoglobin storage.
- Hemoglobin (Hb) transports oxygen; accounts for ~1/3 of RBC weight.
- Contain carbonic anhydrase to convert CO₂ to carbonic acid, a critical blood buffer system (pH regulation).
- Biconcave shape for large surface area.
- Flexible to pass through capillaries.
- Life span: ~120 days; constant regeneration is needed. Destruction occurs in the liver, spleen, or red bone marrow.
Leukocytes (White Blood Cells)
- Five types with diverse roles in fighting infection and combating disease.
- Granular leukocytes (neutrophils, eosinophils, basophils): contain granules that stain differentially.
- Neutrophils are phagocytic cells, with a multi-lobed nucleus, fighting bacterial infection.
- Eosinophils fight parasitic infections. Their granules stain acidic, with a bi-lobed nucleus.
- Basophils release histamine, a key player in inflammatory responses.
- Agranular leukocytes (lymphocytes, monocytes): lack visible granules in the cytoplasm.
- Lymphocytes: primarily in lymphatic system, crucial for cell-mediated and humoral immunity.
- B lymphocytes mature into plasma cells to secrete antibodies.
- T lymphocytes and natural killer cells directly attack invading pathogens and infected cells.
- Monocytes: develop into macrophages that phagocytose cellular debris and infection sites.
- Lymphocytes: primarily in lymphatic system, crucial for cell-mediated and humoral immunity.
Platelets
- Thrombocytes: cell fragments involved in blood clotting.
- Formed from megakaryocytes in red bone marrow.
- Contain granules essential for blood clotting.
Hemostasis
- The process preventing hemorrhage (excessive bleeding):
- Vascular spasm: smooth muscle contraction reduces blood loss.
- Platelet plug formation: platelets adhere, activate, and aggregate to form a temporary clot.
- Blood clotting (coagulation): formation of a stable fibrin clot.
- Two pathways (intrinsic and extrinsic) converge to form a common pathway involving factors such as calcium ions and enzymes leading to fibrin formation.
- Regulation of clotting is crucial: clots can cause strokes and pulmonary embolisms.
Blood Cell Formation (Hemopoiesis)
- Occurs in red bone marrow.
- Starts with pluripotent stem cells.
- Two main lineages: myeloid and lymphoid.
- Myeloid stem cells develop into erythrocytes, leukocytes (granular and agranular), and platelets.
- Lymphoid stem cells develop into lymphocytes.
- Growth factors (EPO, TPO, cytokines) regulate the process.
Blood Groups
- ABO blood groups based on glycolipid antigens.
- Agglutinins (antibodies) recognize and bind foreign antigens, causing erythrocyte clumping (agglutination).
- Individuals make antibodies against foreign antigens.
- Blood transfusions must consider blood type compatibility to prevent agglutination.
- Rh factor (another antigen) can cause hemolytic disease of the newborn (HDN) if a mother's immune system attacks the fetus's blood.
Diseases/Disorders of Blood
- Anemia (low RBC count) has various causes.
- Sickle cell disease: genetic mutation causes abnormal hemoglobin, leading to deformed red blood cells. This trait provides resistance to malaria.
- Hemophilia: inherited bleeding disorder due to insufficient clotting factors.
- Polycythemia (high RBC count): too many red blood cells that lead to thickened blood, increasing the risk of blood clots.
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Description
Explore the intricate details of blood's composition and its vital functions in the human body. This quiz covers blood volume, plasma components, and the key roles of erythrocytes, leukocytes, and platelets. Test your knowledge on how blood regulates various bodily functions and protects against diseases.
