The Heart

Question 1

In which specific region of the thorax is the heart and its pericardial sac located?

Answer 1

The middle mediaastinum

Question 2

The apex of the heart projects in which direction?

Answer 2

Inferiorly and to the left.

Question 3

Be able to label the components of the surface anatomy of the heart and vessels that leave it.

Answer 3

Information on the diagrams on pages 171, 172 coupled with the coronary circulation in the diagrams on page 181/182, WILL BE on the exam - primarily in diagramatic form but also matching questions may be used.

Question 4

What is the ligamentum arteriosum and what was its fetal function?

Answer 4

The obliterated ductus arteriosum. Fetally, it was used as a bypass for fetal blood that passed into the right ventricle by not passing through the foramen ovale and is shunted out into the aorta rather than continuing out into the lungs as oxygenation is neither needed or possible.

Question 5

Be able to label the various chambers of the heart, their major structural internal features, major vessels that exit or enter each, and the various valves that guard these orifices.

Answer 5

These diagrams are on pages 173, 176, 177. This material WILL BE tested on the exam - in a matching question primarily. You must know what components are found in which chambers.

Question 6

What is the moderator band? Where is it found? What is its function?

Answer 6

A band of cardiac muscle that stretches from the septal wall of the right ventricle to the base of the anterior papillary muscle. It contains Purkinje fibers so is thought to represent a shortcut for the conducting system of the heart.

Question 7

Name the parts of the septum found between the right and left heart.

Answer 7

From the base up: the muscular interventricular septum, the membranous interventricular septum, the membranous atrioventricular septum and the membranous interatrial septum.

Question 8

What was the fossa ovalis in the fetus? What was its function?

Answer 8

The foramen ovale. A fetal bypass for oxygenated blood, bypassing the right ventricle and lungs.

Question 9

Know the arrangement of the various components of the AV and semilunar valves.

Answer 9

An AV valve consists of the cusp, the fibrous chordae tendineae and a papillary muscle. A semilunar valve consists of a fibrous cusp, a thin flexible edge on the cusp - the lunule and a geometric central portion of the lunule - the nodule.

Question 10

Be able to name each cusp of the semilunar and AV valves.

Answer 10

Pulmonary semilunar: anterior, left and right; aortic semilunar: left, right and posterior; mitral valve: anterior and posterior; tricuspid valve; anterior, posterior and septal.

Question 11

What is the function of the papillary mm.?

Answer 11

They contract to pull down on the chordae tendineae which in turn prevent the cusps of the AV valves from everting into the atria during contraction of the ventricle.

Question 12

Be able to identify the correct location for listening to the specific valve sounds for each valve of the heart.

Answer 12

Check diagram on page 180. This has been used on the exam in the past.

Question 13

What is the fibrous skeleton of the heart?

Answer 13

A fibrous thickening (network) within the cardiac muscle surrounding the various valvular openings of the heart.

Question 14

What is the function of the fibrous skeleton?

Answer 14

Provides for the sturdy attachment of the cusps of both the AV and semilunar valves of the heart.

Question 15

How does the morphology of the fibrous skeleton differ around AV as opposed to semilunar valves?

Answer 15

Around the AV openings the skeleton is ring-like. Around the semilunar openings the skeleton is cuff-like to allow attachment of the pocket-like cusps.

Question 16

Which spinal cord levels contain sympathetic neurons associated with innervating the cardiopulmonary plexus?

Answer 16

T1 to T5.

Question 17

How does these fibers access the plexus?

Answer 17

Via the cardiac cervical rami.

Question 18

Where do the parasympathetic fibers that penetrate this plexus come from?

Answer 18

The vagus nerve (CN X).

Question 19

What is the function of each ANS fiber type in the heart?

Answer 19

Parasympathetic fibers slow heart rate, sympathetic fibers speed heart rate.

Question 20

What is the function of each ANS fiber type in the lungs?

Answer 20

Parasympathetic fibers constrict smooth muscle, sympathetic fibers relax smooth muscle.

Question 21

Sate the location of the SA and AV nodes of the conduction system of the heart.

Answer 21

The SA nodes is found subepicardially between the base of the superior vena cava and the top of the sulcus terminalis on the right atrium. The AV node is found subendocardially between the opening of the coronary sinus and the tricuspid valve on the inside of the right atrium.

Question 22

Be able to trace the pathway of impulse conduction in the heart.

Answer 22

From the cardiac plexus - SA node - internodal fibers traverse the atrial wall - AV node - AV bundle to the top of the muscular interventricular septum - bundles of HIS spread impulse throughout entire left and right ventricular walls.

Question 23

What cells comprise the bundles of His?

Answer 23

Purkinje fibers

Question 24

They are modified ___________ cells.

Answer 24

Cardiac muscle fibers (cells).

Question 25

Between which two anatomical components of the right ventricle does the moderator (septomarginal) band extend?

Answer 25

The muscular interventricular septum to the base of the anterior papillary muscle of the right ventricle.

Question 26

Be able to label the components of the coronary circulation on a diagram of the heart- anterior and posterior surfaces (in conjunction with the surface anatomy features).

Answer 26

This is critical. Will be on the exam as well as the lab exam. See the diagrams on page 176. Be able to superimpose the surface anatomy of the heart onto these diagrams well as label the vessels of the aortic arch from the anterior view as well as the posterior view.

Question 27

What is meant by the indirect nature of the venous drainage of the heart?

Answer 27

Venous blood from the heart does not drain directly back to the right atrium but first drains to the coronary sinus which in turn drains to the right atrium - indirect venous drainage.

Question 28

Name an exception to this indirect venous drainage- and the locations drained.

Answer 28

The anterior cardiac veins. They drain blood from the right ventricle directly back into the right atrium. In addition tiny veins (venae cordis minimae) drain tiny amounts of venous blood directly back into all 4 chambers.

Question 29

List the 3 arterial coronary anastomoses?

Answer 29

1. Betweeen the continuation of the RCA and circumflex aa.; 2. Between the anterior interventricular and posterior interventricular aa.; and 3. Between anterior and posterior interventricluar aa. within the muscular interventricular septum of the heart.

Question 30

Where are these major arterial anastomoses of the heart located?

Answer 30

On the posterior surface (except for the interventricular septal ones).

Question 31

What is the function of these anastomoses?

Answer 31

They allow small amounts of blood to pass between the RCA and LCA. However, they are generally referred to as insufficient anastomoses as insufficent amounts of blood pass between these vessels to prevent significant heart (myocardium) damage.

Question 32

Which vessels primarily supply the muscular interventricular septum?

Answer 32

Anterior and posterior interventricular arteries - the larger branches come from the anterior interventricular artery.

Question 33

Typically, which coronary artery is most dominant?

Answer 33

The left coronary artery is typically dominant.