Blood and Cardiovascular System

• Blood


  Connective tissue that transports vital substances, maintains stability of interstitial fluid, and distributes heat
• Blood components


  • Red blood cells (RBCs)
  • White blood cells (WBCs)
  • Platelets (cell fragments)
• Size of Heart


  • 14 cm long
  • 9 cm wide
• Blood


  • The amount varies with body size, changes in fluid concentration, changes in electrolyte concentration, and amount of adipose tissue
  • Blood is about 8% of body weight
  • Adult blood volume is about 5 liters
• Location of Heart


  • posterior to sternum
  • medial to lungs
  • anterior to vertebral column
  • base lies beneath 2nd rib
  • apex at 5th intercostal space
  • lies upon diaphragm
• Centrifuged blood sample


  • Plasma
  • Buffy coat (white blood cells and platelets)
  • Red blood cells
• Heart Chambers


  • Right Atrium receives blood from inferior vena cava, superior vena cava, coronary sinus
  • Left Atrium receives blood from pulmonary veins
  • Right Ventricle receives blood from right atrium
  • Left Ventricle receives blood from left atrium
• Plasma


  55% of blood volume
• Heart Valves


  • Tricuspid Valve
  • Pulmonary and Aortic Valve
• Plasma components


  • Hormones
  • Proteins (Globulins, Albumins, Fibrinogen)
  • Nutrients
  • Gases (O2, CO2)
  • Wastes
  • Water
  • Electrolytes
  • Vitamins
• Skeleton of Heart


  • fibrous rings to which the heart valves are attached
• Hematopoietic stem cells


  Give rise to more stem cells or specialize/differentiate
• Origin of blood cells

  1. Hematopoietic stem cell

  2. Myeloid stem cell

  3. Lymphoid stem cell

  4. Differentiation into various blood cell types
• Heart Actions


  1. Atrial Systole/Ventricular Diastole

  2. Atrial Diastole/Ventricular Systole
• Red blood cells (erythrocytes)

  • Biconcave discs
  • One-third hemoglobin (oxyhemoglobin, deoxyhemoglobin)
  • Able to readily squeeze through capillaries
  • Lack nuclei and mitochondria
• Cardiac Cycle

  1. Atrial Systole/Ventricular Diastole

  2. Ventricular Systole/Atrial diastole
• Red blood cell count

  Number of RBCs in a cubic millimeter or microliter of blood
• Heart Sounds

  • Lubb
  • Dupp
  • Murmur
• Low blood oxygen

  Kidneys and liver release erythropoietin (EPO) which stimulates RBC production
• Dietary factors affecting RBC production

  • Vitamin B12 and folic acid are necessary for DNA synthesis and cell growth/division
  • Iron is required for hemoglobin synthesis
• Cardiac Muscle Fibers

  • Cardiac muscle fibers form a functional syncytium
  • atrial syncytium
  • ventricular syncytium
• Destruction of red blood cells

  1. Hemoglobin breakdown into bilirubin, iron, and biliverdin

  2. Bilirubin transported to liver

  3. Bilirubin excreted in bile
• Electrocardiogram

  • recording of electrical changes that occur in the myocardium
  • used to assess heart's ability to conduct impulses
  • P wave - atrial depolarization
  • QRS wave - ventricular depolarization
  • T wave - ventricular repolarization
• Types of white blood cells

  • Granulocytes (Neutrophils, Eosinophils, Basophils)
  • Agranulocytes (Lymphocytes, Monocytes)
• A prolonged QRS complex may result from damage to the A-V bundle fibers
• Neutrophils


  • Light purple granules
  • Lobed nucleus
  • First to arrive at infections
  • Phagocytic
  • 54-62% of leukocytes
• Arrhythmias

  • Ventricular fibrillation
  • Tachycardia
  • Atrial flutter
• Eosinophils

  • Deep red granules
  • Bi-lobed nucleus
  • Defend against parasitic worm infestations
  • 1-3% of leukocytes
• Regulation of Cardiac Cycle

  Autonomic nerve impulses alter the activities of the S-A and A-V nodes
• Basophils

  • Deep blue granules
  • Release histamine and heparin
  • Less than 1% of leukocytes
• Additional Factors that Influence HR

  • physical exercise
  • body temperature
  • concentration of various ions
  • potassium
  • calcium
  • parasympathetic impulses decrease heart action
  • sympathetic impulses increase heart action
  • cardiac center regulates autonomic impulses to the heart
• Blood Vessels

  • arteries
  • arterioles
  • capillaries
  • venules
  • veins
• Monocytes

  • Largest of all blood cells
  • May leave bloodstream to become macrophages
  • 3-9% of leukocytes
  • Phagocytize bacteria, dead cells, and other debris
• Lymphocytes

  • Slightly larger than RBCs
  • T cells and B cells
  • B cells produce antibodies
  • 25-33% of leukocytes
• Artery

  • thick strong wall
  • endothelial lining
  • middle layer of smooth muscle and elastic tissue
  • outer layer of connective tissue
  • carries blood under relatively high pressure
• Functions of white blood cells

  1. Squeeze between capillary cells and enter tissue space (diapedesis)

  2. Protect against infection
• Arterioles

  • thinner wall than artery
  • endothelial lining
  • some smooth muscle tissue
  • small amount of connective tissue
  • helps control blood flow into a capillary
• • Smallest arterioles only have a few smooth muscle fibers
  • Capillaries lack muscle fibers
• White blood cell count

  • Number of WBCs per cubic millimeter of blood
  • Leukopenia: low WBC count (below 5,000)
  • Leukocytosis: high WBC count (above 10,000)
• Metarteriole

  connects arteriole directly to venule