Heart function: pumps blood, operates as a pressurizing pump system
Cardiac Output (Q)
Homeostatic variable for the cardiovascular system
Goal: keep cardiac output constant
Influenced by heart rate, stroke volume, blood pressure
Transport Functions of the Cardiovascular System
Delivers nutrients and oxygen to tissues
Removes waste products: lungs (exhalation), liver (excretion through feces), kidneys (excretion through urine)
Intra-cellular transport and exchange of materials via capillaries
Circulation Pathways
Pulmonary Circulation: right side of the heart (right atrium and right ventricle) pumping blood to lungs; carries deoxygenated blood
Systemic Circulation: left side of the heart (left atrium and left ventricle) pumping blood to the entire body; carries oxygenated blood
Heart Failure: inability of the heart to pump effectively; varies depending on which side fails (left side: breathing issues, right side: swelling in legs)
Hemodynamics
Pressure (measured in mmHg): difference between two points; blood flows from high to low pressure
Flow and Resistance: influenced by the pressure gradient and resistance (Ohm's law: Flow ∝ Pressure Gradient / Resistance)
Compliance: ability of the heart to hold volume of blood with minimal pressure changes; high compliance is desired for efficient heart functionality
Heart Anatomy and Function
Diastole: heart filling with blood
Systole: heart pumping blood out
Cardiac Muscle: striated muscle with T-tubules and sarcoplasmic reticulum; involved in intracellular calcium handling
Excitation-Contraction Coupling: involves calcium-induced calcium release; influenced by drugs like digitalis
Key Definitions and Concepts
Compliance: distensibility of a structure; heart's ability to fill with blood with low-pressure buildup
Autonomic Nervous System: regulates vessel constriction and dilation
Cardiac Output and Resistance: altering vessel radius can significantly impact cardiac output and resistance
Calcium Handling: crucial for myocardial contractility; influenced by calcium channel blockers and drugs like digitalis
Drug Effects
Digitalis: increases myocardial contraction by blocking the sodium-potassium ATPase pump, leading to more intracellular calcium and stronger heart contractions
Summary
Understanding definitions and basic principles of the cardiovascular system
Prepare for more in-depth topics on action potentials, EKGs, and more complex heart functions in subsequent lectures