Lab Ex. 30 Anatomy of the Heart

The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human. True or False

True. In both the sheep and human, the brachiocephalic artery is the first major vessel to exit the arch of the aorta. Further branching of the brachiocephalic artery and the arch of the aorta differs between a sheep and a human.

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

True. 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.

Name the inner lining of the heart.

Endocardium 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.

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

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.

What heart chamber pushes blood through the aortic semilunar valve?

Left ventricle 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.

Identify the most muscular chamber.

Left ventricle 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.

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

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.

What is the function of the coronary circulation?

Provide a blood supply to the heart 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.

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

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.

The heart is enclosed in a double-walled sac called the

pericardium

Which of the following is a branch of the right coronary artery?

posterior interventricular artery The posterior interventricular artery is a branch of the right coronary artery, although an anastomosis with the circumflex artery meets with it near its origin.

Which of these vessels returns blood to the left atrium of the heart?

pulmonary veins The pulmonary veins transport oxygen-enriched blood from the lungs to the left atrium.

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

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

What is the ligamentum arteriosum?

A remnant of the ductus arteriosus 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.

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

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

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

Chordae tendineae 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.

Oxygenated blood flows through the right side of the heart. True or False

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.

The heart serves as a double pump. The __________ side serves as the pulmonary circulation pump, shunting carbon dioxide-rich blood to the lungs.

Right

The right atrioventricular valve prevents backflow of blood from the right ventricle into the

Right Atrium Flow from the right ventricle to the right atrium is prevented by the right atrioventricular valve.

Which chamber of the heart exits into the pulmonary trunk?

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

Name the needle like ridges of muscle lining the ventricles.

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

Identify the right atrioventricular valve.

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.

The base of the heart is located at the bottom of the heart. True or False

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.