Anatomy

Question 0

Where does the phrenic nerve originate and end?

Answer 0

Originates in the neck (C3-C5) and passes down between the lung and heart to the diaphragm.

Question 1

What is the phrenic nerve?

Answer 1

The nerve which innervates the diaphragm.

Question 2

How does the phrenic nerve interact with the pericardium.

Answer 2

Runs anterior to the root of the lung and into the pericardium between the fibrous and parietal layers.

Question 3

What is the arterial supply of the heart?

Answer 3

Right and left coronary arteries, which arise from the base of ascending aorta (from the anterior and posterior aortic sinuses) and encircle the heart in the atrioventricular groove like a crown.

Question 4

What are the differences between the left and right coronary arteries?

Answer 4

Left coronary artery is larger in diameter than the right coronary artery and arises from the posterior aortic sinus of ascending aorta.

Question 5

What two branches does the left coronary artery split into?

Answer 5

The anterior interventricular / left anterior descending artery and the circumflex artery.

Question 6

Which part of the heart does the left anterior descending supply?

Answer 6

It descends into the anterior interventricular groove towards the apex of the heart. It supplies the interventricular septum as well as the anterior walls of both ventricles.

Question 7

Which part of the heart does the circumflex artery supply?

Answer 7

The circumflex artery follows the coronary (atrioventricular) sulcus posteriorly and supplies the left atrium and the posterior part of the left ventricle.

Question 8

What does the right coronary artery branch into?

Answer 8

The right coronary artery emerges from the anterior aortic sinus and descends in the coronary sulcus on the anterior surface of the heart, between the right atrium and right ventricle. At the inferior border of the heart, the artery branches to give off the right marginal artery. Continuing into the posterior part of the coronary sulcus, the right coronary artery branches to give off the posterior interventricular artery that runs in the posterior interventricular groove.

Question 9

To which part of the heart does the right coronary artery provide blood?

Answer 9

Overall, the branches of the right coronary artery supply the right atrium and almost all of the right ventricle.

Question 10

What is the coronary sinus?

Answer 10

The venous blood collected by the cardiac veins that roughly follows the path of coronary arteries. All the cardiac veins ultimately join to form an enlarged vessel (coronary sinus) which occupies the posterior part of the coronary sulcus.

Question 11

What is the function of the coronary sinus?

Answer 11

The coronary sinus returns almost all the venous blood from the heart into the right atrium.

Question 12

What are the tributaries of the coronary sinus?

Answer 12

Great cardiac vein
Middle cardiac vein
Small cardiac vein
Oblique vein

Question 13

Describe the great cardiac vein

Answer 13

Begins at the cardiac apex and runs in the anterior interventricular sulcus along with anterior interventricular artery, drains the areas of the heart supplied by the left coronary artery, i.e. left and right ventricles and left atrium.

Question 14

Describe the oblique vein

Answer 14

The Oblique vein of the left atrium descends obliquely on the back of the left atrium to join the coronary sinus near its end.

Question 15

Describe the small cardiac vein

Answer 15

Runs in the posterior atrioventricular (AV) groove and opens into the coronary sinus near its atrial end, drains blood from the posterior part of the right atrium and ventricle.

Question 16

Describe the middle cardiac vein

Answer 16

Accompanies the posterior interventricular artery in the posterior interventricular sulcus, drains the areas supplied by the posterior interventricular branch of right coronary artery.

Question 17

What are the layers of heart muscle?

Answer 17

Endocardium (endothelial and subendothelial lining)
Myocardium
Epicardium (serous layer of visceral pericardium)
Pericardial layer
Parietal layer of serous pericardium
Fibrous pericardium

Question 18

What is the pericardium?

Answer 18

A fibroserous, fluid filled sack that surrounds the muscular body of the heart and the roots of the great vessels (the aorta, pulmonary artery, pulmonary vein and the superior and inferior vena cava).

Question 19

What are the functions of the pericardium?

Answer 19

Fixes the heart in the mediastinum and limits its motion.
Prevents overfilling of the heart – The relatively inextensible fibrous layer prevents a rapid increase in size
Lubrication – A thin film of fluid between the two layers of the serous pericardium reduces the friction generated by the heart.
Protection from infection – The fibrous pericardium serves as a physical barrier between the muscular body of the heart and adjacent organs prone to infection, such as the lungs.

Question 20

Describe the fibrous layer of the pericardium

Answer 20

It is continuous with the central tendon of the diaphragm, the fibrous pericardium is made of tough connective tissue and is relatively nondistensible. This rigidity prevents rapid overfilling of the heart.

Question 21

Describe the serous layer of the pericardium

Answer 21

Divided into two layers – the outer parietal layer which lines the internal surface of the fibrous pericardium and the internal visceral layer which forms the outer layer of the heart (also known as the epicardium). Each layer is made up of a single sheet of epithelial cells, known as mesothelium.

Question 22

Where is the pericardial cavity?

What is its function?

Answer 22

Found between the outer and inner serous layers, it contains a small amount of lubricating serous fluid. This fluid serves to minimize the friction generated by the heart as it contracts and moves about within the thoracic cavity.

Question 23

What is the acronym to remember the layers of the pericardium?

Answer 23

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F – Fibrous layer of the pericardium
P – Parietal layer of the serous pericardium
S – Serous fluid
V – Visceral layer of the serous pericardium

Question 24

Where is the transverse pericardial sinus located?

Answer 24

Posteriorly to the ascending aorta and pulmonary trunk.
Anteriorly to the superior vena cava.
Superior to the left atrium.

Question 25

What are vasa vasorum?

Answer 25

Vessels which supply blood to the bigger arteries