Week 1

• What is the primary function of the cardiovascular system?

  To transport oxygen and nutrients to body tissues and remove carbon dioxide and waste products
• How is the heart structured in terms of its pumping systems?

  The heart is divided into two separate pumping systems: the right side and the left side
• What are the three layers of the heart wall from inside out?

  • Endocardium
  • Myocardium
  • Epicardium
• What is the innermost layer of the heart called?

  Endocardium
• What is the function of the subendocardial layer?

  It unites the endocardium and myocardium and surrounds modified cardiac muscle fibers for impulse conduction
• What type of tissue primarily makes up the myocardium?

  Cardiac muscle tissue
• How does the thickness of the myocardium relate to its function?

  The thickness of the myocardium is directly proportional to the work the chamber has to perform to pump blood
• What is the outermost layer of the heart called?

  Epicardium
• What type of epithelium is the epicardium composed of?

  Simple squamous mesothelium
• What is the role of the cardiac conduction system?

  To ensure that cardiac myocytes contract in sync
• What is Starling's law of the heart?

  Stroke volume (SV) is dependent on end diastolic volume (EDV)
• How does myocardial stretch affect stroke volume?

  Myocardial stretch causes a more forceful systolic contraction, increasing stroke volume
• What does the autonomic nervous system control in the heart?

  The heart rate and cardiac output
• What neurotransmitter is released by the sympathetic nervous system to increase heart rate?

  Noradrenaline
• What effect does the parasympathetic nervous system have on heart rate?

  It decreases heart rate
• What are the phases of the cardiac cycle?

  1. Atrial depolarization/contraction
  2. Isovolumetric contraction
  3. Rapid ejection
  4. Reduced ejection
  5. Isovolumetric relaxation
  6. Ventricular filling
• What is the primary function of blood vessels in the cardiovascular system?

  To act as conduits for blood flow
• What is the average pressure in systemic arteries?

  Approximately 100 mmHg
• What happens during right side heart failure?

  Blood pools in the right atrium and can lead to increased pressure in the jugular vein
• What is a common symptom of left side heart failure?

  Coughing up blood-stained mucus
• What is the normal left ventricular ejection fraction?

  About 50-60%
• What is the role of valves in the heart?

  To ensure blood flows in one direction around the circulation
• What happens when valves in the heart fail?

  They can become narrowed or fail to close properly, causing heart failure
• What is the basic friction equation in relation to blood flow?

  Q = DP / R
• What factors affect resistance to blood flow?

  The radius of the tube, length of the tube, and viscosity of the fluid
• How does the radius of a blood vessel affect resistance to flow?

  Resistance to flow is inversely proportional to the radius of the vessel
• What is the primary job of the heart in relation to arterial pressure?

  To ensure that the pressure within the arteries remains higher than that of the veins
• What is the average pressure in systemic veins?

  Approaches 0 mmHg
• What is the sinoatrial node's role in the heart?

  It initiates the heartbeat and determines the heart rhythm
• What is the average heart rate in normal hearts?

  About 72 beats/min in males and 80 beats/min in females
• What are the three types of muscle cells in the body?

  Skeletal, smooth, and cardiac muscle cells
• What role does calcium play in cardiac muscle contractions?

  Calcium binds to troponin C, allowing myosin heads to access the actin binding sites
• What are the phases of cardiac action potentials?

  1. Phase 0 - Upstroke
  2. Phase 1 - Initial repolarization
  3. Phase 2 - Plateau
  4. Phase 3 - Rapid repolarization
  5. Phase 4 - Resting potential
• What occurs during phase 0 of cardiac action potentials?

  The resting membrane potential reaches the threshold, causing Na channels to open and resulting in rapid depolarization
• What is the role of intercalated discs in cardiac myocytes?

  They facilitate communication and synchronization between cardiac muscle cells
• How does the structure of cardiac myocytes contribute to their function?

  The synctial architecture ensures simultaneous contraction of all cardiac myocytes for effective pumping
• What is the significance of the pacemaker region in the heart?

  It initiates the heartbeat and regulates the heart rhythm
• What happens to the troponin complex when calcium binds to troponin C?

  Troponin I moves away from the myosin binding site on actin, making it accessible to myosin heads
• What occurs when calcium is removed from the troponin C complex?

  The troponin complex resumes its inactivated position
• What is the relationship between cardiac myocytes and action potentials?

  Cardiac myocytes generate action potentials that lead to heart contractions