Anatomy Of The Heart

Front 1

Describe the circulatory system

Back 1

The circulatory system provides nutrients and oxygen to cells and carries away waste and CO2. The systemic circulation supplies muscle, bones, and organs. Pulmonary circulation supplies lungs so blood is oxygenated. Coronary circulation provides blood to the heart.

Front 2

Describe the location of the heart

Back 2

The heart is set in the mediastinum, an area between the right and left lung. The heart itself is located in the fibrous pericardium. Normally the apex of the heartbeat can be felt in the 5th left intercostal space. This can deviate in various individuals due to body build, gravity, age, and inspiration vs. expiration.

Front 3

Describe the sternocostal relationships of the heart.

Back 3

1) Brachiocephalic veins: behind each clavicle
2) Superior Vena Cava: Meets heart behind 3rd costal cartilage.
3) Inferior Vena Cava: meets heart behind 6th costal cartilage
4) Right Border of Heart: 3rd to 6th costal cartilage
5) Apex of Heart: 5th intercostal space
6) Left border of Heart: 2nd intercostal space curving along to the apex
7) Ascending aorta: curves at sternal angle

Front 4

Draw the surface projection and landmarks of the heart (base, apex, margins) in the living subject, and the portions of the outline formed by the various chambers and the aorta.

Back 4

To listen to the heart using surface anatomy, place the stethoscope in the following places:
a) pulmonic valve: left 2nd intercostal space
b) aortic valve: right 2nd intercostal space
c) tricuspid valve: left 5th intercostal space near sternal body
d) mitral valve: left 5th intercostal space near mid-clavicular line

Front 5

Explain the double-walled nature of the pericardial sac, and its structural makeup by serous and fibrous layers

Back 5

the heart is surrounded by 3 layers. From outside to inside, they are fibrous pericardium, the serous parietal pericardium, and the serous visceral pericardium. The fibrous pericardium provides a tough layer to protect the heart. Fused to the fibrous pericardium is the serous parietal pericardium. And fused to the heart is the visceral parietal pericardium, hence the double-walled nature of the sac. These serous layers create a fluid that reduces friction between the heart and the fibrous pericardium (think of oil between pistons and the engine block in your car)

Front 6

Describe the major features of each of the chambers of the heart

Back 6

Right Atrium: receives blood from the IVC, SVC, and coronary sinus. On external heart, defined by coronary sulcus. Internal right atrium contains the fossa ovalis. Border between right atrium and right ventricle is defined by the tricuspid valve. Anterior right atrium muscle is called pectinate muscle.

Left Atrium: Mostly formed by the pulmonary veins. Unremarkable internal structures.

Right Ventricle: crescent shape and lined with trabeculae carnae (elevated ridges). Three papillary muscles at the inferior portion of the ventricle attach to the tricuspid valve via chordae tendinae that help to keep the valve from inverting during contraction.

Left Ventricle: Very similar to the right ventricle except there are only two papillary muscles that connect to the mitral (bicuspid valve). The muscle of the left ventricle is also 3 times thicker due to the need to pump blood at a much higher pressure (3x the pressure experienced by pulmonary circuit)

Front 7

Describe the fibrous skeleton of the heart

Back 7

There are four fibrous rings that surround the four valves of the heart. They are connected to each other to form a skeleton. They protect the valves from stretching apart and prevent electrical conduction from the atrium to ventricles (except at bundle of His)

Front 8

List structural changes that occur at birth in changing from a fetal to an adult circulatory pattern.

Back 8

3 key points:

a) conversion of the foramen ovale to the fossa ovalis: during prenatal life, the foramen ovale shunts blood from the right atrium, which causes blood to bypass the pulmonary system. When born, the lungs expand, causing increased pulmonary pressure int eh left atrium. This forces shut the foramen ovale which fuses into the fossa ovalis.

b) conversion of the ductus arteriosus to the ligamentum arteriosum: the ductus arteriosum ducts blood from the pulmonary trunk to the aortic arch, bypassing the pulmonary system. As a baby takes its first breath, the pulmonary pressure decreases significantly, causing blood to flow to the pulmonary system (lungs). This causes the duct to constrict, which eventually turns into the ligamentum arteriosum.

c) conversion of the ductus venosus to the ligamentum venosum: the ductos venosus ducts blood from the umbilical cord to bypass the liver and go straight to the IVC. When the umbilical cord is cut, the ductus venosus closes, leaving the ligamentum venosum.

Front 9

Describe the components of the cardiac conduction system.

Back 9

SA node: area with fastest rate of pacemaker cells, causing it to pace the heart. Located at superior part of right atrium.

AV node: located at interatrial septum just above the coronary sinus. Relays conduction from SA node to the Bundle of His.

AV bundle of His: extends from AV node through the fibrous skeleton and branches into the right and left crus. Right crus extends down to the papillary muscles and muscles of each ventricle.

Purkinje fibers: extends form the end of each crus to each ventricular cardiac cell, causing all cells to beat simultaneously in the ventricle.

Front 10

Describe the coronary arterial circulation and its venous return.

Back 10

There are two main arteries of the heart that branch off into other arteries.

A) Right coronary artery: comes from the right anterior aortic valve, travels in coronary sulcus and branches into the right marginal branch on the right side of the heart and then wraps posteriorly to give off the posterior interventricular branch.

B) Left coronary artery: comes from left anterior aortic valve. Quickly divides into anterior interventricular branch and the circumflex. Both supply the left side of the heart.

There are 4 veins to know:
a) great cardiac vein: follows the anterior interventricular branch
b) middle cardiac vein: follows the posterior interventricular branch
c) small cardiac vein: follows the marginal branch
d) coronary sinus: all cardiac veins dump into the coronary sinus, which lies on the posterior surface of the heart and dumps into the right atrium.

Front 11

Describe the major structures in the mediastinum.

Back 11

The mediastinum is divided into the superior and inferior mediastinum. the border is a plane betweent he sternal angle to the 4th thoracic vertebrae. Furthermore, the inferior mediastinum is divided into the anterior, middle, and posterior mediastinum.

(more to this --> look in syllabus!)