Cardiovascular/Heart (ch.18) Pt1

What is the main function of the heart's right side?

To receive oxygen-poor blood from tissues and pump it to the lungs via the pulmonary circuit.

What does the left side of the heart do?

Receives oxygenated blood from the lungs and pumps it to the body tissues via the systemic circuit.

What separates the right atrium from systemic blood?

The superior vena cava and inferior vena cava return blood to the right atrium.

How is the heart positioned in the body?

In the mediastinum, between the second rib and fifth intercostal space, with two-thirds to the left of the midsternal line.

What is the pericardium?

A double-walled sac that surrounds the heart, consisting of a superficial fibrous layer and a deep serous layer.

What purpose does the fluid in the pericardial cavity serve?

It decreases friction as the heart beats.

What are the four chambers of the heart?

Two atria (upper chambers) and two ventricles (lower chambers).

What are the roles of atrioventricular (AV) valves?

They prevent backflow of blood into the atria when the ventricles contract.

What are chordae tendineae?

Fibrous cords that anchor the cusps of the AV valves to the papillary muscles.

What is the function of semilunar valves?

Prevent backflow from major arteries back into the ventricles.

What two major arteries supply the heart muscle?

Left coronary artery and right coronary artery.

How does blood flow through the right side of the heart?

From the superior and inferior vena cavae into the right atrium, through the tricuspid valve into the right ventricle, then through the pulmonary semilunar valve into the pulmonary trunk.

What is the structure of cardiac muscle cells?

They are striated, short, branched, interconnected cells with a central nucleus.

What is the significance of intercalated discs in cardiac muscle?

They connect cardiac cells and allow ions to pass between cells, enabling coordinated contractions.

What distinguishes cardiac muscle contractions from skeletal muscle contractions?

Cardiac muscle contracts as a unit (functional syncytium), while skeletal muscle can contract independently.

What is unique about the refractory period in cardiac muscle fibers?

It is longer than in skeletal muscle fibers, preventing tetanic contractions.

What are the two types of myocytes in cardiac muscle?

Contractile cells (responsible for contraction) and pacemaker cells (initiate depolarization).

What is the role of calcium in cardiac muscle contraction?

Calcium influx from extracellular fluid triggers calcium release from the sarcoplasmic reticulum.

How do coronary arteries function?

They supply oxygenated blood to the heart muscle and are crucial for coronary circulation.

What is myocardial infarction?

A heart attack caused by prolonged coronary blockage leading to cell death.

What are the differences between the pulmonary and systemic circuits?

The pulmonary circuit is short and low-pressure, while the systemic circuit is long and high-friction.

What is angina pectoris?

Thoracic pain caused by fleeting deficiency in blood delivery to the myocardium.

What are trabeculae carneae?

Irregular ridges of muscle on the ventricular walls.

How does the left ventricle differ from the right ventricle?

The left ventricle has thicker walls and pumps with greater pressure.

What causes pericarditis?

Inflammation of the pericardium leading to roughened membrane surfaces.

What are the three components of the cardiac skeleton?

Fibrous connective tissue that anchors valve cusps, supports cardiac muscle, and provides electrical insulation.

What is the significance of the apical impulse?

It can be palpated to assess the heart's position and size.

What major structures return deoxygenated blood to the right atrium?

Superior vena cava, inferior vena cava, and coronary sinus.

What is the main source of energy for cardiac muscle?

Aerobic respiration, which requires oxygen.

What do gap junctions allow in cardiac muscle?

They allow ions to pass from cell to cell for electrical coupling.

Which valve prevents backflow into the left ventricle?

aortic semilunar valve

Which receives blood during ventricular systole?

both aorta & pulmonary trunk

A plateau occurs during cardiac muscle AP because of a large influx of …?

Calcium

Electrical impulse pass through the conduction system of the heart in the following sequence.

SA node, AV node, bundle of HIS (av bundle), bundle branches, purkinje fibers

What is most responsible for the synchronized contraction of cardiac muscle tissue?

Gap Junctions

Which is the volume of blood pumped out by one ventricle with each beat?

stroke volume

Normal heart sounds are caused by which events?

closure of heart valves