BIPN 100 - N1 Cardiac Physiology III

Wigger's Diagram

Learning Outcomes

  • Understand and be able to DIAG Wigger’s Diagram.
  • Understand and be able to calculate (CC, CALC) measures of cardiac performance such as Stroke Volume (SV) and Cardiac Output (CO).
  • Understand and be able to explain (CC, SEQ) the relationship between preload, contractility, afterload, SV, and CO.
  • Understand blood and DIAG, SEQ Control of Blood Pressure

Lecture Outline

  • Wigger's Diagram
  • Cardiac Output
  • Regulation of Stroke Volume
  • Blood Pressure

Cardiac Mechanics

  • Anatomy:
    • Right Side: Superior Vena Cava, Inferior Vena Cava, Right Atrium, Tricuspid Valve, Right Ventricle, Pulmonic Valve, Pulmonary Artery, Lungs
    • Left Side: Lungs, Pulmonary Vein, Left Atrium, Mitral (Bicuspid) Valve, Left Ventricle, Aortic Valve, Aorta, Body
    • Valves:
      • Atrioventricular Valves: Tricuspid and Mitral Valves
      • Semilunar Valves: Pulmonic and Aortic Valves

Cardiac Cycle

  • A. Diastole (“true diastole”)
    1. Atria/ventricles relaxed
    2. AV valves (tricuspid/mitral) open
    3. Blood fills ventricles
    4. Semilunar valves (pulmonic/aortic) closed
    • Passive filling occurs as blood flows from the vena cava to the right atrium (RA) to the right ventricle (RV), and from the pulmonary veins to the left atrium (LA) to the left ventricle (LV).
  • B. Atrial systole
    1. Atria contract, leading to active filling, which accounts for ~20% of ventricular filling at rest.
  • C. Ventricular systole (“Systole”)
    1. Ventricles contract.
    2. P{RV} > P{RA} and P{LV} > P{LA}, causing AV valves to close.
    3. P{RV} > P{pulmonary artery} and P{LV} > P{aorta}, causing semilunar valves to open.
    4. Blood is ejected, known as the