All formed elements

• Erythrocytes(Red Blood Cells): transport oxygen and carbon dioxide

  • biconcave, anucleate disc, salmon-colored
  • 45% of whole blood
  • take 15 days to make and live for 100-120
• Plasma Proteins: most abundant in plasma

  • remain in blood, aren't taken by cells
  • proteins are produced by liver(most)
• formed elements: red and white blood cells, platelets

  • white bloods are complete
  • red blood cells don't have a nuclei or organelles
  • platelets are fragments
  • formed elements only survive a few days
  • originate in bone marrow
• SEM of blood

  A) leukocytes

  B) Erythrocytes

  C) Platelets

  
• Erythrocytes are small diameter cells that contribute to gas transport

  • biconcave discs, anucleate, really no organelles
  • filled with hemoglobin for gas transports
  • RBCs diameters are larger than some capillaries
• Why Erythrocytes Are Good At Transporting Oxygen: A Trilogy

  • biconcave discs offer so much space
  • hemoglobin makes up 97% of cell volume
  • no mitochondria so anaerobic ATP production, meaning they don't take in the oxygen they transport
• RBCs are dedicated to respiratory gas transport and each one contains 250 million hemoglobin molecules
• Hematopoietic Stem Cells (hemocytoblasts): stem produces formed elements
• Too many red blood cells increase blood viscosity and too few lead to tissue hypoxia
• Low levels of O2, oxygen sensitive enzymes can't degrade hypoxia inducible factor

  • HIF can accumulate which triggers synthesis of EPO, leading to too many RBCs leading to increase blood viscosity
• Hypoxia can cause:

  • decreased RBC numbers due to hemorrhage( increased destruction)
  • Insufficient hemoglobin per RBCs
  • not enough O2 around
  • too many erythrocytes or high oxygen levels
• Erythropoietins causes erythrocytes to mature faster

  • testosterone increase EPO production resulting in more red blood cells in males
• Dietary Requirements for Erythropoiesis

  • amino acids, lipids, and carbs
  • iron: 65% found in hemoglobin
• Vitamin B12 and folic acid are necessities for DNA synthesis of developing RBCs
• Erythrocytes only live for 100 to 120 days.
• Red Blood cells don't have a nucleus so they can't synthesize and divide
• Leukocytes or white blood cells: defense against disease

  • can leave capillaries via diapedesis
  • more through tissue spaces by amoeboid motion and positive chemotaxis
• Leukocytosis: WBC count is over 11000 per uL

  • reaction to infection
• The two groups of leukocytes are:

  Granulocytes: have visible cytoplasmic granules

  Agranulocytes: without visible cytoplasmic granules
• The decreasing abundance in the blood:

  never: neutrophils (50-70%)

  let: lymphocytes(25- 45%)

  monkeys: monocytes(3-8%)

  eat: eosinophils(2-4%)

  bananas: basophils(0.5-1%)
• granulocytes include neutrophils, eosinophils, and basophils

  • live shorter and are bigger than red blood cells
  • contain lobed nuclei
  • stained with Wright's stain
  • all are phagocytic to some degree
• neutrophils: from spears that pierce holes in membrane of ingest microbes

  • multilobular
  • most numerous
  • phagocytize bacteria(synthesize bleach or hydrogen peroxide(respiratory burst)
  • cytoplasmic granules
  • hydrolytic enzymes or defensias(antimicrobial proteins), drawn to sites of inflammation
• eosinophils

  • bilobed( has little headband that connects lobes)
  • red cytoplasmic granules contain digestive enzymes, that digest parasitic worms
  • play a role in asthma and allergies as well as immune response modulators
• basophils

  • bilobed nucleus; large-purplish-black cytoplasmic granules
  • contains histamine and heparin
  • histamine is an inflammatory chemical that acts as a vasodilator( makes blood vessels dilate) and attracts WBCs to inflamed areas
  • similar to a mast cell
• Agranulocytes have two types: lymphocytes and monocytes

  • both have spherical or kidney-shaped nuclei
• lymphocytes: spherical or indented nucleus; pale blue cytoplasm

  • mount immune response by direct cell attack or via antibodies
  • found in lymphoid tissue: lymph nodes, spleen, and sometimes blood)
  • crucial to immunity
• Two lymphocytes:

  T lymphocytes(T cells): act against virus-infected and tumor cells

  B lymphocytes (B cells): make plasma cells, that produce antibodies
• monocytes: abundant, pale, blue cytoplasm, largest white blood cell

  • U-or kidney shaped nuclei
  • leave circulation enter tissues and turn into macrophages
  • actively phagocytic cells; crucial against viruses, intracellular bacterial parasites and chronic infections
  • activate lymphocytes to mount an immune response
• There are more granulocytes in the bone marrow than in the blood. There is also more WBCs produced because they die faster fighting microbes.
• Production of Agranulocytes:

  lymphocytes: derived from lymphoid line

  • T lymphocyte precursors give rise to immature T lymphocytes that will then mature in thymus
  • B lymphocytes precursors turn into immature B lymphocytes that mature in bone marrow
• • Lymphocytes live from hours to decades
• platelets: form temporary plug that seals breaks in blood vessels(clots)

  cytoplasmic fragments of megakaryocytes