Cardiovascular System: Heart Structure, Function, and Blood Flow

What is the primary function of the heart?

To pump blood through the blood vessels of the body.

What are the two main functions of the right side of the heart?

Pumps blood to the lungs and receives blood returning from the body.

What are the two main functions of the left side of the heart?

Pumps blood to the remaining tissues of the body and receives blood from the lungs.

What is the size of an adult heart?

About the size of a closed fist.

What is the apex of the heart?

The blunt rounded point of the cone-shaped heart.

Where is the heart located?

In the thoracic cavity, specifically in the mediastinum.

What is the pericardium?

The pericardial sac that consists of two layers surrounding the heart.

What are the two layers of the pericardium?

The fibrous pericardium (outer layer) and the serous pericardium (inner layer).

What is the function of the fibrous pericardium?

Prevents overdistention and acts as an anchor for the heart.

What are the three layers of the heart wall?

Epicardium (visceral pericardium), myocardium, and endocardium.

What is the myocardium responsible for?

The contraction of the heart.

What are pectinate muscles?

Muscular ridges in the auricles and right atrial wall.

What are trabeculae carneae?

Muscular ridges and columns on the inside walls of the ventricles.

What are the two types of heart valves?

Atrioventricular (AV) valves and semilunar valves.

What are the names of the AV valves?

Tricuspid valve (right) and mitral valve (left).

What are the names of the semilunar valves?

Pulmonary semilunar valve (right) and aortic semilunar valve (left).

What is the route of blood flow through the heart starting from the right atrium?

Right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk → lungs.

What happens to blood in the lungs?

It becomes oxygenated.

What is the function of the heart skeleton?

Provides support for valves, serves as electrical insulation, and provides a site for muscle attachment.

How does cardiac muscle differ from skeletal muscle?

Cardiac muscle is striated, branched, interconnected, and mononucleate.

What are intercalated discs?

Specialized cell-cell contacts in cardiac muscle that allow action potentials to move between cells.

What is the significance of the fossa ovalis?

It is a remnant of the fetal opening between the atria (foramen ovale).

What is the interventricular septum?

The wall between the right and left ventricles.

What is the role of chordae tendineae?

They attach the leaf-like cusps of the heart valves to the papillary muscles.

What is the cardiac cycle?

The sequence of events in one heartbeat, including contraction and relaxation of the heart chambers.

What is an electrocardiogram (ECG)?

A recording of the electrical activity of the heart.

What is the pulmonary circuit?

The path of blood from the right side of the heart to the lungs and back to the left side.

What is the systemic circuit?

The path of oxygen-rich blood from the left side of the heart to the rest of the body.

What is the primary function of the aorta?

To carry oxygenated blood from the heart to the body.

What is the role of the right atrium?

To receive deoxygenated blood from the body via the superior and inferior vena cavae.

What do the pulmonary arteries do?

They carry deoxygenated blood from the right ventricle to the lungs.

What is the function of the pulmonary veins?

To carry oxygenated blood from the lungs to the left atrium.

What is the pulmonary trunk?

A large vessel that carries deoxygenated blood from the right ventricle to the pulmonary arteries.

Define 'heartbeat'.

The coordinated contraction of the entire heart, ensuring blood flows in the correct direction.

What are contractile cells?

Cells that produce contraction and form the bulk of the myocardium.

What is the function of the conducting system in the heart?

To control and coordinate the activity of contractile cells by relaying electrical impulses.

What is the sinoatrial (SA) node?

The pacemaker of the heart that generates spontaneous action potentials.

What is the role of the atrioventricular (AV) node?

To conduct action potentials more slowly, ensuring ventricles contract after atria have contracted.

What is the pathway of an action potential in the heart?

SA node → AV node → AV bundle → bundle branches → Purkinje fibers.

What is the significance of the plateau phase in cardiac muscle?

It prolongs the action potential and prevents tetany in the heart muscle.

What does the P wave represent in an electrocardiogram (ECG)?

Depolarization of the atrial myocardium and the onset of atrial contraction.

What does the QRS complex indicate?

Ventricular depolarization and the onset of ventricular contraction.

What does the T wave represent?

Repolarization of the ventricles, preceding ventricular relaxation.

Define 'systole'.

Contraction of a chamber of the heart.

Define 'diastole'.

Relaxation of a chamber of the heart.

What are heart sounds?

Sounds produced by the vibrations of blood flow as valves close during the cardiac cycle.

What role do baroreceptors play in heart function?

They monitor blood pressure and send sensory information to the cardioregulatory center to adjust heart rate.

How do chemoreceptors affect heart rate?

They monitor pH and carbon dioxide levels, adjusting heart rate to maintain homeostasis.

What are some age-related changes in the heart?

Hypertrophy of the left ventricle, increased aortic pressure, and decreased maximum heart rate.

What happens if the SA node is damaged?

The AV node may take over as the pacemaker, leading to a slower heart rate.

What is the function of the Purkinje fibers?

To distribute the electrical impulse to the ventricular muscle cells for contraction.

What is the significance of gap junctions in cardiac muscle?

They allow for the conduction of action potentials from cell to cell, facilitating coordinated contractions.

What is the impact of exercise on atrial contraction?

During exercise, atrial contraction becomes necessary for effective heart function.

What does the term 'arrhythmia' refer to?

An irregular heartbeat or abnormal heart rhythm.