Cardiovascular Anatomy and Physiology Quiz

Cardiac Anatomy

• Heart consists of multi-chambers and functions as a dual cycle electrical pump.
• Key coronary vessels:
  • Right coronary artery includes conus, right marginal branch, and posterior descending branch.
  • Left coronary artery comprises the left anterior descending and circumflex arteries.
  • Coronary capillaries facilitate nutrient exchange.
  • Coronary veins include the coronary sinus, great cardiac vein, and posterior vein of the left ventricle.

Cardiac Cycle

• Represents the sequence of events in one heartbeat, including:
  • Diastole: heart relaxation phase.
  • Systole: heart contraction phase.
• Phases of cardiac cycle:
  • Atrial systole,
  • Isovolumic contraction,
  • Ejection,
  • Isovolumic relaxation,
  • Ventricular filling.

Electrical Circuit and Ion Concentrations

• Sodium and potassium ion concentrations are crucial:
  • Sodium [Na+] = 140 mEq/L, [Na+] inside cell = 10 mEq/L.
  • Potassium [K+] = 4.0 mEq/L, [K+] inside cell = 120 mEq/L.
• Electrochemical gradients contribute to action potential generation.

Excitation-Contraction Coupling

• Excitation-contraction coupling involves steps leading to muscle contraction in cardiomyocytes, the heart's muscle cells.

Cardiac Output and Regulation

• Cardiac output (CO) calculated as CO = Stroke Volume (SV) x Heart Rate (HR), measured in liters/minute.
• Factors influencing blood pressure include cardiac output (BP = CO x Peripheral Vascular Resistance).
• Resistance in the cardiovascular system is determined by the formula:
  • Resistance = 8ηL / πr^4, with r being the radius, L as the length, and η denoting viscosity.

Blood Pressure Regulation

• Normal blood pressure is regulated by monitoring cardiac output and peripheral vascular resistance.
• Sympathetic activity boosts heart rate and contractility while promoting vasoconstriction.
• Hormonal influences from substances like epinephrine and natriuretic peptides also modulate blood pressure.

Heart Failure

• Types of heart failure include:
  • Systolic dysfunction characterized by low cardiac output and decreased ejection fraction.
  • Diastolic dysfunction with preserved ejection fraction but increased left ventricular end-diastolic pressure (LVEDP).
• Common etiologies encompass hypertension, ischemic injury, valvular disease, genetic factors, and myocarditis (viral or autoimmune).

Atherosclerosis and Coronary Artery Disease (CAD)

• Atherosclerosis is a specific form of arteriosclerosis, defined by:
  • Thickening and hardening of arterial walls due to lipid-laden macrophages.
  • Involves plaque development through inflammation, cellular proliferation, and oxidized LDL formation.
• Coronary artery disease refers to vascular disorders narrowing or occluding coronary arteries, typically stemming from atherosclerosis.
• Risk factors for CAD include dyslipidemia, hypertension, smoking, diabetes, obesity/sedentary lifestyle, and chronic kidney disease.

Myocardial Remodeling and Baroreceptor Activity

• Myocardial remodeling can manifest as hypertrophy, atrophy, or apoptosis due to nutrient/oxygen delivery fluctuations.
• Baroreceptors respond to changes in blood flow and pressure, leading to adjustments in renal sympathetic activity and sodium retention.

Integrated Function

• The relationship between flow (I), pressure (P), and resistance (R) encapsulates cardiovascular dynamics, emphasizing the importance of these elements in maintaining physiological homeostasis.