Heart

The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk to be distributed to the lungs.

Which chamber of the heart exits into the pulmonary trunk?

Pulmonary semilunar valve The pulmonary valve is the semilunar valve found between the right ventricle and the pulmonary trunk. Deoxygenated blood travels through the pulmonary valve as it exits the right side of the heart on its way to the lungs.

Identfiy the valve located at the exit of the right ventricle.

The auricles are flap like extensions of the atria that are observed on the external surface of the heart.

Identify the ear like flaps that are attached to the top chambers of the heart.

The left ventricle is responsible for pumping blood out to the body. This requires a lot of force. The left ventricle is the most muscular in order to pump the blood with adequate force.

Identify the most muscular chamber.

Tricuspid valve The tricuspid valve is the atrioventricular valve located on the right side of the heart. It separates the right atrium from the right ventricle.

Identify the right atrioventricular valve.

The atrioventricular valve on the left is the bicuspid valve. The mitral valve is also called the mitral valve.

Identify the valve found between the left atrium and left ventricle.

Pectinate muscles The pectinate muscles are ridge like elevations of muscle. They are parallel to each other and resemble teeth of a comb. They are easily observed inside the right atrium.

Name the ridged bundles of muscle found projecting inside the right atrium.

False Oxygenated blood returning from the lungs is received by the left atrium, then to the left ventricle before being pumped out to the body. This pathway of blood flow is known as the systemic circulation.

Oxygenated blood flows through the right side of the heart.

Once fetal modifications (i.e. foramen ovale, ductus arteriosus) close following delivery of the infant, blood on the right side of the heart should not mix with blood on the left side of the heart.

Blood on the right never mixes with blood on the left, once the heart is fully developed.

The endocardium is the smooth, slick lining of the chambers of the heart. Endocardium is a continuation of endothelium that lines blood vessels. Both endocardium and endothelium are composed of simple squamous epithelial tissue, which minimizes friction between the wall of the chamber/vessel and the blood.

Name the inner lining of the heart.

Trabeculae carneae are the small elevated ridges of muscle arranged in a web type fashion found in both the right and left ventricles.

Name the irregular ridges of muscle lining the ventricles.

False The base is located at the top of the heart. It is unusual to see the largest portion of an organ at the top. Typically, the base is at the bottom of an organ, as in the lungs.

The base of the heart is located at the bottom of the heart.

False The moderator band is a cord like structure found in the right ventricle. It contains portions of the cardiac conduction system that help convey the electrical message for the ventricles to contract. It works as a shortcut within the cardiac conduction system.

The moderator band is found on both the right and left side of the heart.

Chordae tendineae are the fibrous cords that attach the atrioventricular valves to papillary muscles. They help anchor the atrioventricular valves in a closed position during ventricular contraction.

What fibrous structure functions to anchor the atrioventricular valves in a closed position?

The aortic valve is located between the left ventricle and the aorta. The left ventricle pumps oxygenated blood out of the heart through the aortic valve to the body.

What heart chamber pushes blood through the aortic semilunar valve?

The coronary circulation provides oxygenated blood to the heart through coronary arteries. Coronary veins return the deoxygenated from the heart to the coronary sinus on the posterior surface of the heart. The coronary sinus empties the deoxygenated blood directly into the right atrium where it joins deoxygenated from the body.

What is the function of the coronary circulation?

The ligamentum arteriosum is a remnant of the ductus arteriosus. The ductus arteriosus is a fetal shunt that connects the pulmonary trunk to the aorta.

What is the ligamentum arteriosum?