lec finals

• Blood


  Specialized type of LOOSE connective tissue

  
• Location of blood


  Within blood vessels

  
• Contents of blood


  • PLASMA (extracellular material; fluid matrix)
  • FORMED ELEMENTS

  
• Formed elements of blood

  • Erythrocytes – red blood cells (RBC)
  • Leukocytes – white blood cells (WBC)
  • Platelets (cell fragments)

  
• Leukocytes


  • Granulocytes
  • Agranulocytes
• Granulocytes


  • Neutrophil
  • Eosinophil
  • Basophil
• Agranulocytes


  • Lymphocytes
  • Monocytes
• Blood characteristics


  • About 8% of total body weight
  • ~5L in a 60kg person
  • pH 7.4
  • Light red – oxygenated
  • Dark red – unoxygenated

  
• Blood functions


  • Respiration
  • Nutrition
  • Excretory
  • Protection
  • Regulatory

  
• Plasma


  • Transparent, yellowish fluid
  • 92% WATER
  • 8% DISSOLVED SUBSTANCES
• Plasma proteins


  • ALBUMIN – most abundant, smallest plasma protein; maintain osmotic pressure
  • GLOBULINS (Alpha & Beta – transport proteins, Gamma – immunoglobulins (antibodies))
  • FIBRINOGEN – largest plasma protein; polymerizes during the formation of clots into fibrin fibers

  
• Plasma vs Serum


  Plasma – water and dissolved substances

  Serum – plasma minus fibrinogen and clotting factors; + growth factors (proteins released by the platelets)

  
• Hemopoiesis


  Production of the formed elements of blood

  
• Hemopoietic tissues


  Embryonic (Yolk sac, Liver & Spleen, Bone marrow)

  Adult (Myeloid Tissue - Bone marrow, Lymphoid Tissue - Bone marrow, Thymus, Lymph nodes, Spleen, MALT)

  
• Erythrocytes (RBC)


  Biconcave discs

  Mature RBCs are anucleate; no organelles

  Hemoglobin – protein with oxygen-carrying capacity fills the cytoplasm

  Most numerous cells in the blood
• Erythrocytes


  • Biconcave shape increases surface area to carry respiratory gases

  Normal lifespan 120 days

  Shape is maintained by peripheral proteins (Spectrin, Ankyrin, Band 3 protein, Glycophorin A)
• Rouleaux formation


  At level of smaller vessels, RBCs stack up in loose aggregates
• Erythropoiesis


  Low oxygen levels detected by the kidneys erythropoietin release

  Erythropoietin hormone produced by the kidneys that stimulates the bone marrow to produce RBCs

  
• Spherocytosis


  RBCs become sphere-shaped rather than biconcave due to defective spectrin, ankyrin, band 3 proteins
• Hematocrit


  Erythrocyte volume

  Low levels leading to low hemoglobin = ANEMIA

  High levels = POLYCYTHEMIA
• Leukocytes (WBC)


  Grouped into Granulocytes and Agranulocytes

  All WBCs become active after leaving the blood to enter tissues

  Death by apoptosis after performing cell-specific function

  
• Types of granules in leukocytes

  • Azurophilic granules (specialized lysosomes)

  Specific granules (smaller granules containing proteins and enzymes)
• Granulocytes


  • Neutrophils

  Eosinophils

  Basophils
• Agranulocytes


  • Lymphocytes

  Monocytes
• Platelets (Thrombocytes)


  Membrane-bound cell fragments

  Produced by fragmentation of Megakaryocytes

  Anucleate; but with organelles (mitochondria, ribosomes, Golgi complex, smooth and rough ER)
• Platelet function


  Hemostasis = arrest of bleeding after injury to blood vessel (platelet plug and clot formation)

  
• Circulatory system


  Hollow channels where blood, and other components suspended in it, are transported throughout the body

  
• Components of circulatory system

  • Cardiovascular system (Heart, Blood vessels)

  Lymph vascular system (Lymph vessels)

  
• Two systems of circulation

  • Pulmonary circulation

  Systemic circulation
• Heart anatomy


  4 Chambers (2 Atrium, 2 Ventricles)

  3 Great Vessels (Inferior Vena Cava, Superior Vena Cava, Aorta)

  Coronary Vessels (supplies the heart)

  Pulmonary arteries and veins

  
• Pericardium


  Connective tissue covering the heart

  Fibrous pericardium (dense irregular CT)

  Serous pericardium (Parietal pericardium - loose CT covered by mesothelium, Visceral pericardium - synonymous with epicardium)

  Pericardial cavity - containing pericardial fluid

  
• Impulse conducting system of the heart

  Components made of Purkinje fibers (modified cardiac muscle fibers)

  Sinoatrial node - 'pacemaker'

  Internodal tracts

  Atrioventricular node

  AV bundle of His

  Bundle branches

  
• Cardiac skeleton


  Dense irregular connective tissue

  Attachment site of cardiac muscles and valves
• Cardiac valves


  • Bicuspid valve - Left Atrioventricular valve

  Tricuspid valve - Right Atrioventricular valve

  Semilunar valves - Pulmonic and Aortic valves

  
• Histologic layers of the heart

  • Endocardium

  Myocardium

  Epicardium

  
• Endocardium


  Thinnest histologic layer of the heart

  Lining all internal surfaces of the heart and great vessels

  4 layers: Endothelium, Subendothelium, Dense irregular CT layer, Subendocardium

  
• Myocardium


  Thickest histologic layer of the heart

  Thickest in the left ventricle, thinnest in the atria

  Component: cardiac muscle fibers

  
• Epicardium


  Synonymous with the visceral pericardium

  Outermost histologic layer of the heart

  Components: loose connective tissue covered lined externally by mesothelium

  
• Endothelium


  Specialized epithelium: squamous cells

  Semi-permeable barrier between blood and interstitial fluid

  Provides non-thrombogenic surface, involved in inflammatory response, maintenance and repair of blood vessels, limited phagocytotic activity

  
• Classification of arteries


  • Small (Arterioles)

  Medium (Muscular arteries; Distributing arteries)

  Large (Elastic arteries; Conducting arteries)