Blood Discrete Questions- July 09, 2024

• What are hematocrits?

  percentage of red blood cells
• Four primary components of blood

  1. erythrocytes red blood cells
  2. leukocytes white blood cells
  3. thrombocytes platelets
  4. plasma
• Normal hematocrit levels ranges around 40-50%


  hematocrit is the calculated volume percentage of red blood cells (aka erythrocytes)
• Hemoglobin is a protein complex found within red blood cells that is responsible for carrying oxygen from the lungs to other tissues and organs.
• Leukocytes also known as white blood cells are part of the body's immune system.
• Plasma is the main non-cellular factor of blood.
• What does plasma contain in its water-like solution?

  1. albumin
  2. clotting factors
  3. ions
• Blood is a circulatory fluid responsible for transporting nutrients throughout the body
• Plasma makes up a majority of blood volume: about 55%
• How does human blood clotting work?

  1. injury to vessels triggers the release of clotting factors
  2. meanwhile, vasoconstriction of blood vessel limits blood flow
  3. platelets crowd the injury site to form a sticky plug
  4. clotting factors convert prothrombin into thrombin
  5. thrombin converts soluble fibrinogen into insoluble fibrin
  6. fibrin strands adhere to the platelet plug to form an insoluble clot
• True or false: Plasma contains erythrocytes

  False

  
  

  both are components of blood

  plasma is non-cellular component of blood, does not contain cells
• How long do erythrocytes live in blood before being recycled?

  120 days
• After circulating the body for about 120 days, a erythrocyte gets recycled by macrophages found in the liver, spleen, and lymph nodes.

  • main site of red blood cell recycling occurs in spleen
• • Hemoglobin (the protein responsible for carrying oxygen from lungs to the rest of the body) is removed from red blood cells, and gets excreted from the body through bile
  • Macrophages engulf red blood cells for recycling via phagocytosis, where hemoglobin is isolated and lysed into heme groups and globin proteins
  • Heme groups are metabolized into Bilirubin and Biliverdin, which are excreted through bile along with cholesterol, drugs and vitamins and alkaline salts. On the other hand, globin proteins are metabolized into amino acids, used for other functions in the body
• Erythropoiesis refers to the process in which erythrocytes are formed and matured. During this process, precursor erythrocytes (called proerythroblasts) will shed their organelles and DNA in order to carry more hemoglobin, and consequently transfer more oxygen, rather than consuming it itself for metabolic processes.
• Types of bone marrow and what they produce:

  • Red bone marrow: responsible for creating erythrocytes, leukocytes, and platelets
  • Yellow bone marrow: responsible for creating fat, cartilage, and bone cells (also known as osteocytes)
• Megakaryocytes are large cells found in the red bone marrow that can fragment to create platelets, a cellular component of blood that helps with blood clotting and wound repair.
• The main function of megakaryocytes is to produce platelets. The main function of platelets is to form clots.
• A megakaryocyte is so large, that fragmentation of just one megakaryocyte can lead to the creation of over 1000 platelets
• Platelets lack a nucleus, but do contain some organelles, such as mitochondria and endoplasmic reticulum fragments.
• Do red blood cells have a nucleus? No.


  Red blood cells do not have ANY organelles. RBCs do not have nuclei, DNA, or mitochondria.
• Do leukocytes (WBCs) have organelles like the nucleus, mitochondria, lysosome, ribosomes, endoplasmic reticulum? Yes.
• Why do platelets not have a nucleus?

  Platelets do not need to be able to replicate, therefore do not have nuclei or DNA.
• Erythropoietin is a hormone secreted by the kidneys that promotes the creation of erythrocytes from haemopoietic stem cells found in the red bone marrow. Leukopoietin induces leukopoiesis, production of white blood cells. Thrombopoietin induces thrombopoiesis, production of platelets.
• What is Hematopoiesis?

  Hematopoiesis refers to the process of producing blood cells. Hemocytoblasts are pluripotent hematopoietic stem cells in the bone marrow.
• Hemocytoblasts are pluripotent hematopoietic stem cells, found in the red bone marrow, that can differentiate into a common myeloid progenitor or common lymphoid progenitor.
• Common myeloid progenitors (CMGs) are oligopotent progenitor cells that develop from hematopoietic stem cells. They can differentiate into different types of myeloid cells, including megakaryocytes, erythrocytes, mast cells, myeloblasts.

  • Megakaryocytes fragments to make thrombocytes.
  • Erythrocytes are red blood cells
  • Mast cells are connective tissues found in nearly all organs of the body, that play a role in inducing the inflammatory cascade.
  • Myeloblasts can form granulocytes (type of white blood cells including neutrophils, eosinophils, basophiles) and monocytes (which create macrophages)
• Common lymphoid progenitors (CLGs) are oligopotent progenitor cells that develop from hematopoietic stem cells. They can differentiated into all types of lymphocytes, including including B cells, T cells, plasma cells, and natural killer cells.
• CLGs... natural killer cells: destroys infected and diseased cells, like viruses and cancer cells

  B cells: make antibodies (molecules that can destroy invading pathogens, viruses, or bacteria), also can become activated to produce plasma B cells (NOT THE SAME AS BLOOD plasma)

  T cells help kill tumor cells, helps produce cytokine (molecules that regulate inflammatory response)
• Precursors of erythrocytes: proerythroblasts, erythroblasts, reticulocytes

  • hematopoietic stem cells make proerythroblasts
  • proerythroblasts become erythroblasts and reticulocytes
  • reticulocytes are another precursor cells to erythrocytes. they no longer have a nucleus but still contain a small number of organelles
• How many oxygens can a hemoglobin carry? 4 oxygen (O2) molecules in total. Hemoglobin structure:

  • total of four globin polypeptide protein chains and four heme groups
  • each globin connected together
  • each globin tightly binds and surrounds a heme group
  • each globin and its associated heme creates a subunit. one hemoglobin molecule has a total of four subunits
  • each heme group can carry one molecule of oxygen (1 O2). so in total four heme groups = four molecules of oxygen (4 O2)
• Human Blood Clotting Pathway:

  1. release clotting factors
  2. prothrombin to thrombin
  3. fibrinogen to fibrin
• Percentage of blood components:

  1. plasma: about 55 %
  2. RBCs (erythrocytes): about 45 %
  3. 
WBCs (leukocytes): about 1 %
  4. Platelets (thrombocytes): less than 1 %
• Bile has two main functions:

  1. digestion: break down fats to fatty acids to be absorbed by digestive system. bile contains bile salts that can emulsify fats (break large globules into smaller pieces) that are easier for digestive enzymes to break down
  2. waste removal: bile carries waste products, like bilirubin (main metabolite from RBC recycling) to be excreted in feces
• Bile is produced by the liver and stored in the gallbladder, a small organ near the underside of the liver. During meals, bile is released from the gallbladder through the common bile duct, which passes through the pancreas to connects the gallbladder and liver to the duodenum, the first part of the small intestine.
• oligopotent stem cells can differentiate into only a few different types of cells. pluripotent or multipotent stem calls can differentiate into ANY type of cell in the body.