Cardiovascular System - Heart

What is the primary function of the circulatory system?

Transport of materials, including gases, nutrients, waste, communication, defense against pathogens, and temperature homeostasis.

What are the main components of the heart?

Atria, ventricles, septum, heart valves, myocardium.

What do the right and left sides of the heart pump?

Right side pumps de-oxygenated blood; left side pumps oxygenated blood.

What are the two sets of heart valves called?

Atrioventricular valves and semi-lunar valves.

What is the role of the SA Node in the heart?

It sets the pace of the heartbeat, typically at 70 bpm.

How do electrical signals travel through the heart?

From the SA node to the AV node via internodal pathways, then through bundle branches to Purkinje fibers.

What signifies the depolarization of the atria in an ECG?

The P wave.

What does the QRS complex represent in an ECG?

Ventricular depolarization.

What happens during diastole in the cardiac cycle?

Cardiac muscle relaxes.

What is stroke volume?

The amount of blood pumped by one ventricle during a contraction.

What happens during isovolumic ventricular contraction?

The first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open SL valves.

What are the two types of heart failure?

Hypertrophic (diastolic) and Dilated (systolic) heart failure.

What characterizes Type 1 myocardial infarction?

Plaque rupture/erosion with occlusive or non-occlusive thrombus.

What influences stroke volume?

Length of muscle fiber (preload), contractility, and inotropic agents.

What is cardiac output?

The volume of blood pumped by one ventricle in a given period of time, calculated as heart rate times stroke volume.

What causes the second heart sound?

Closing of the semi-lunar valves.