Lecture 1

Flashcards for review of Hemodynamics and Cardiovascular System lecture notes.

Hemodynamics

The study of blood flow, relating Ohm’s law to fluid flow, and the relationship between blood flow, blood pressure, and resistance to blood flow.

Ohm's Law Applied to Fluid Flow

Flow equals the pressure difference between two fixed points divided by resistance (F = ∆P/R).

Resistance

Friction that impedes flow, or how difficult it is for blood to move between 2 points at any given pressure.

Hydrostatic Pressure

The pressure that the volume of blood within our circulatory system exerts on the walls of the blood vessels.

Viscosity

Friction between molecules of a flowing fluid; affected by hematocrit (number of red blood cells).

Poiseuille’s Equation

Resistance (R) is equal to 8 times eta times L divided by pi times r raised to the fourth power R = 8 L η/ π r4,. Factors include vessel length (L), blood viscosity (η), and vessel radius (r).

Arterioles

Small branching vessels with high resistance.

Capillaries

Transport of blood between small arteries and veins; exchange of materials between blood and cells in the body.

Atria

Thin-walled, low pressure chambers that receive blood returning back to the heart.

Ventricles

Thick-walled chambers responsible for the forward propulsion of blood when they contract.

Interatrial Septum

Separates left and right atria of the heart.

Interventricular Septum

Separates left and right ventricles of the heart.

Pulmonary Circuit

Carries blood to and from the gas exchange surfaces of the lungs.

Systemic Circuit

Transports blood to and from the rest of the body.

Pericardium

A fibrous sac surrounding the heart and the roots of the great blood vessels providing stabilization, protection, friction reduction, and overfilling prevention.

Fibrous Pericardium

Outer layer of the pericardial sac; provides protection and stabilization.

Parietal Pericardium

Part of the serous pericardium; lies underneath the fibrous pericardium and is attached to it.

Visceral Pericardium

Part of the serous pericardium; innermost layer of the pericardial sac, also called the epicardium.

Pericardial Cavity

Separates the parietal pericardium from the visceral pericardium; contains fluid to decrease friction.

Pericarditis

Inflammation of the pericardium caused by viruses, bacteria, fungi, trauma or malignancy; leads to fluid accumulation in the pericardial cavity

Cardiac Tamponade

Compression of heart chambers due to excessive accumulation of pericardial fluid.

Epicardium

Layer immediately outside the heart muscle, covering the outer surface; functions as a protective layer.

Myocardium

The muscular wall of the heart, lying underneath the epicardium; contains muscle cells, nerves, and blood vessels.

Endocardium

Innermost layer of the heart wall; lines heart cavities and heart valves; a thin layer of endothelium.

Myocytes

Cardiac muscle cells; branched or Y shaped cells, striated, single nucleus, rich in mitochondria, and connected by intercalated disks.

Desmosomes

Adhering junctions that hold cells together in tissues subject to mechanical stress.

Gap Junctions

Communicating junctions that electrically couple heart cells, allowing ion movement.