Blood

Question 1

name the blood stainings

Answer 1

• eosin/methylene blue (Romanovsky)
• red (acidic) blue (basic) for staining specific granules (azurophilic – lysosomes)

Question 2

describe components of blood

Answer 2

• blood = 55% plasma and 45% formed elements
• plasma
  
  • 91.5% water
  • 8.5% solutes
    
    • principal solutes = albumins, globulins, fibrinogen

Question 3

describe functions of albumin, globulin and fibrinogen

Answer 3

• albumin
  
  • maintain blood osmotic pressure
• globulins (immunoglobulins)
  
  • antibodies bind to foreign substances called antigens
• fibrinogen
  
  • for clotting

Question 4

name the formed elements of blood

Answer 4

• erthyrocytes (red blood cells)
• leukocyes (white blood cells)
  
  • granular
    
    • neutrophils, eosinophils, basophils
  • agranular
    
    • lymphocytes = T cells, B cells and natural killer cells
    • monocytes
• thrombocytes (platelets) – special cell fragments

Question 5

name percentages of the formed elements

Answer 5

• neutrophils 60-70%
• lymphocytes 20-25%
• monocytes 3-8%
• eosinophils 2-4%
• basophils .5-1.0%

Question 6

describe erythrocytes

Answer 6

• proerythoblasts give rise to immature RBC called reticulocytes
  
  • once in circulation they become erythrocytes
• stains uniformly with eosin
• 4 proteins: band 4, band 3, ankyrin and spectrin important in maintaining shape

Question 7

describe hemoglobin

Answer 7

• composed of globin (made up of 4 highly folded polypeptide chains) + 4 heme groups (with iron)
• each molecule can carry 4 molecules of O2

Question 8

describe leukocytes

Answer 8

white blood cells or WBCs, which are nucleated cells

• granular leukocytes include eosinophils, basophils and neutrophils based on the staining of the specific granules
• agranular leukocytes do not have specific cytoplasmic granules and include lymphocytes and monocytes

Question 9

describe function of leukocytes

Answer 9

• WBCs leave the blood stream by emigration
• rolling, adhesion and transmigration – brought about by arteriolar dilatation and post capillary venule leakage
• the chemical attraction of WBCs to a disease or injury site is termed chemotaxis

Question 10

describe the emigration and phagocytosis of leukocytes

Answer 10

• WBCs roll along endothelium, stick to it and squeeze between cells
  
  • adhesion molecules (selectins) helps WBCs stick to endothelium
  • molecules (integrins) found on neutrophils assist in movement through wall
• neutrophils and macrophages phagocytize bacteria + debris
  
  • chemotaxis of both
    
    • kinins from injury site and toxins

Question 11

describe levels of hematocrit in males vs females

Answer 11

• female normal range = 42%
• male normal range = 46%
• anemia = not enough RBCs or not enough hemoglobin
• polycythemia = too many RBCs (over 65%), caused by dehydration, hypoxia, blood doping in athletes

Question 12

describe neutrophils (granulocyte)

Answer 12

• polymorphonuclear leukocyte (PMN)
  
  • young cells called band cells because of horseshoe shaped nucleus (band)
  • older cells have more lobes
• 60-70% of circulating leukocytes
• Barr body found in neutrophils

Question 13

name the function of neutrophils

Answer 13

• fastest response of all leukocytes to bacteria
• recognize bacteria and other infectious agents
• direct action against bacteria:
  
  • release lysozymes which destroy/digest bacteria
  • release defensin proteins that act like antibiotics and poke holes in bacterial cell walls destroying them
  • release strong oxidants (hypochlorous acid) that destroy bacteria

Question 14

describe eosinophils (granulocytes)

Answer 14

• nucleus is bi-lobed
• 4 major proteins:
  
  • Major Basic Protein (MBP), imparts acidophilia to the cells
  • other proteins - ECP - eosinophil cationic protein
  • EPO - eosinophil peroxidase
  • EDN - eosinophil derived neurotoxin
• 2-4% of circulating leukocytes

Question 15

name functions of eosinophils

Answer 15

• leave capillaries to enter tissue fluid
• MBP, ECP and EPO - impart cytotoxic effect on protozoans and helminthic parasites
• Release histaminase which neutralizes histamine
• Arylsulphatase neutralizes leukotrienes produced by basophils and mast cells
• hydrolysis of antibody-antigen complexes internalized by eosinophils

Question 16

describe basophils (granulocyte)

Answer 16

• smallest of leukocytes
• large, dark purple, variable-sized granules stain with basic dyes
• contain specific and azurophilic granules
  
  • specific granules = heparin sulfate, histamine and leukotrienes
• less than 1% of circulating leukocytes

Question 17

describe function of basophil

Answer 17

• involved in inflammatory and allergy reactions
• release:
  
  • heparin: anticoagulant
  • histamine: vasoactive substance causing vasodilation
  • leukotrienes: prolonged constriction of smooth muscles in pulmonary airways
  • interleukin 4 and 13 promote synthesis of IgE antibodies

Question 18

describe lymphocytes and their function

Answer 18

• 20-25% of circulating leukocytes
• high amounts found in patients with chronic infections
• T-cells (differentiate in thymus)
  
  • cell mediated immunity
• B-cells (first recognized in bone marrow)
  
  • production of antibodies
• Natural killer cells (NK)

Question 19

describe monocytes (agranulocyte) and its functions

Answer 19

• largest WBC in cirulating blood
• kidney shaped or indented nucleus
• 3-8% of circulating leukocytes
• phagocytosis and antigen presentation
• increased amounts in fungal/viral infections