Lab assignment 02- Heart anatomy

How many chambers make up the human heart?

4

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 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.

The major pumping chambers of the heart are ________.

Both ventricles

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.

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

Correct. 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.

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

Correct. 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.

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

Correct.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.

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.

Oxygenated blood flows through the right side of the heart.

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

False Correct. 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 pericardial sac that encloses the heart is a two-layered structure. The outer layer is the ________.

Fibrous pericardium

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.

The heart is located in a subdivision of the thorax called the ________.

Mediastinum

What is the function of the corona 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

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.)

Identify the highlighted vessel

Superior vena cava

How do the highlighted valve cusps function during a ventricular contraction?

They are held closed by the chordae tendineae to prevent blood from flowing back into the right atrium.

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

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

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.

The portion of the pericardium that covers the heart wall is called the ________.

Visceral layer (epicardium)

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

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

Cardiac muscle tissue ________.

is striated , like skeletal muscle tissue

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