Lec.9 without answers.pdf

 Blood platelets (Thrombocytes) 1. What is the primary function of blood platelets?  a) Oxygen transport  b) Immunity  c) Blood clotting and vessel repair  d) Hormone production 2. What is the shape of blood platelets?  a) Spherical  b) Cuboidal  c...

 Blood platelets (Thrombocytes) 1. What is the primary function of blood platelets?  a) Oxygen transport  b) Immunity  c) Blood clotting and vessel repair  d) Hormone production 2. What is the shape of blood platelets?  a) Spherical  b) Cuboidal  c) oval discs  d) Flat sheets 3. What is the normal range of blood platelet count per microliter (µL)?  a) 5,000 - 10,000  b) 20,000 - 50,000  c) 150,000 - 400,000  d) 500,000 - 1,000,000 4. What is the approximate size of a blood platelet?  a) 0.5 - 1 µm  b) 1 - 2 µm  c) 2 - 4 µm  d) 5 - 6 µm 5. Which of the following best describes the appearance of blood platelets under a light microscope?  a) Individual cells  b) Clumped together  c) In rows  d) As rods 6. Which of the following parts forms the outer pale part of the blood platelet?  a) Granulomere  b) Hyalomere  c) Alpha granules  d) Delta granules ① 7. What is the function of the cell coat (glycocalyx) in blood platelets?  a) Energy production  b) Adhesion and activation during coagulation  c) Oxygen exchange  d) Structural support 8. Which structures are found in the peripheral marginal bundle of platelets?  a) Lysosomes  b) Glycogen granules  c) Microtubules and microfilaments  d) Ribosomes 9. What is the function of the open canalicular system in blood platelets?  a) Protein synthesis  b) Transport of factors with blood plasma  c) Cell division  d) Waste removal 10. Which part of the platelet contains fibrinogen and platelet-derived growth factor (PDGF)?  a) Delta granules  b) Alpha granules  c) Hyalomere  d) Lysosomes 11. Delta (δ) granules in platelets contain which of the following substances?  a) Fibrinogen  b) Serotonin  c) Glycogen  d) Histamine 12. What organelles are present in the granulomere of platelets?  a) Ribosomes and Golgi bodies  b) Lysosomes and mitochondria  c) Centrioles and nuclei  d) Endoplasmic reticulum 13. Blood platelets are derived from which type of stem cells?  a) Myeloid stem cells  b) Lymphoid stem cells  c) Epithelial stem cells  d) Neural stem cells ② 14. Which cell is the first precursor of blood platelets in the bone marrow?  a) Megakaryocyte  b) Megakaryoblast  c) Progenitor cell  d) HSC 15. Which hormone influences megakaryoblasts to undergo endomitosis?  a) Erythropoietin  b) Thrombopoietin  c) Insulin  d) Prolactin 16. What process occurs in megakaryoblasts due to endomitosis?  a) Cell division  b) Nuclear replication with cell division  c) Nuclear replication without cell division  d) Differentiation into red blood cells 17. What is the characteristic of a mature megakaryocyte nucleus?  a) Mononucleated  b) Binucleated  c) Polyploid  d) Non-lobulated 18. Where are megakaryocytes predominantly found in the bone marrow?  a) Near the sinusoids  b) Near the endosteum  c) In the periosteum  d) In the medullary cavity 19. What size are mature megakaryocytes?  a) 10-20 µm  b) 20-50 µm  c) 30-100 µm  d) 100-200 µm 20. What is the function of demarcation membranes in mature megakaryocytes?  a) Energy storage  b) DNA replication  c) Basis for platelet fragmentation  d) Cell adhesion ③ 21. How are platelets released from the megakaryocyte into the blood?  a) Via endocytosis  b) By cytoplasmic budding  c) Through fragmentation of proplatelets  d) Through exocytosis 22. What structure do megakaryocytes use to extrude platelets into blood sinusoids?  a) Flagella  b) Cilia  c) Pseudopodia  d) Microvilli 23. Which of the following is NOT a component of delta granules in platelets?  a) Serotonin  b) ADP  c) ATP  d) Fibrinogen 24. Which of the following cells do megakaryocytes arise from?  a) Myeloblasts  b) Lymphoblasts  c) Megakaryoblasts  d) Erythroblasts 25. Which of the following contains calcium and magnesium ions in platelets?  a) Glycocalyx  b) Delta granules  c) Alpha granules  d) Peripheral bundle 26. Which of the following components is involved in maintaining the platelet's shape?  a) Delta granules  b) Microtubules and microfilaments in the peripheral marginal bundle  c) Fibrinogen in alpha granules  d) Mitochondria in the granulomere 27. Which of the following statements about the outer pale part (hyalomere) of a platelet is TRUE?  a) It contains dense granules like serotonin and calcium  b) It is responsible for platelet shape through its marginal bundle of microtubules  c) It is the site where lysosomes and mitochondria are found  d) It contains large amounts of glycogen for energy storage ④ ⑤