Middle Mediastinum Structure

Pericardial Sac (pericardium)

Double walled sac in which heart resides, made of three layers

What are the three layers of the pericardial sac

Fibrous pericardium, parietal layer of the serous pericardium, visceral layer of the serous pericardium

What is the outer layer of the pericardial sac

Fibrous pericaridum

What is the middle layer of the pericardial sac

Parietal layer of the serous pericardium

What is the middle layer lining the fibrous pericardium of the pericardial sac

Parietal layer of the serous pericardium

What is the third, deepest layer of the pericardial sac

Visceral layer of the serous pericardium

What lines the actual surface of the heart and is separated from the parietal layer of the serous pericardium

Visceral layer of the serous pericardium

What separates the visceral layer of the serous pericardium from the parietal layer of the serous pericardium

Pericardial cavity

Right/Left Atrium

Chambers of the heart that reside posteriorly adn slightly medially to auricles

What are the atria separated from eachother by

Interatrial septum

What separates the atria from the ventricles

Rings of annulus and tricuspid and bicuspid valves

What are examples of atrio-ventricular valves

Triscupid and biscupid valves

What is an example of cartilage skeleton of heart

Rings of annalus

Auricles (L/R)

Ear-like flaps that reside anteriorly and slightly laterally to atria

What are the inner walls of the auricles lined with on their anterior aspect

Pectinate muscles

What are the pectinate muscles of the auricles continuous with

Anterior aspect of the atria

Tricuspid valve (3 cups)

Separates right atrium from right ventricle, hinged at the annulus

What are the three flaps that make up the tricuspid valve made up of

Connective tissue

Right/Left Ventricle

Large, muscular chambers with thick walls (left thickest)

What represents the majority of the hearts mass

Right/ventricle

What is the wall of the ventricles made up of

Myocardium

Interventricular septum

Thick wall separating right and left ventricles, electrically insulated in many areas

Trabeculae carneae

Associated with the inner walls of the ventricle, appear as columns of muscle running in random direction

What are the papillary muscles comprised of

Myocardium

Where do the papillary muscles project into

Ventricular chambers

How many papillary muscles are in the right

3

How many papillary muscles are in the left

2

Chordae tendineae

Fibrous strands spanning between papillary muscles and inferior aspects of AV valves

Where does the aortic semilunar valve extend from

Left ventricle

Aortic semilunar valve

Located at the superior aspect of the aortic outflow tract

What is the structure of the flaps/cupss of the aortic semilunar valve

Semi-lunar

How many flaps is the aortic semilunar valve comprised of

3

Bicuspid valve

Separates left atrium from left ventricle hinged at annalus

How many cupss/valves comprises the bicuspid alve

2

What are the cusps/flaps of the bicuspid valve comprised of

Connective tissue

Pulmonary veins

Large vessels that drain blood from lungs to left atrium

Pulmonary arteries (L/R)

Large vessels that emerge from bifurcation of pulmonary trunk

Pulmonary trunk

Emerges directly from right ventricular outflow tract, bifurcates into right and left pulmonary arteries

How long is the pulmonary trunk

2 inches

Ligamentum arteriosum

Remnant of ductus arteriosus, fibrous cord between pulmonary trunk to aortic arch

Pulmonary semilunar valve

Located at superior aspect of right ventricular outflow tract extending from right ventricule

How many flaps/cusps make up the pulmonary semilunar valve

3

What is the structure of the flaps of the pulmonary semilunar valve

Semi-lunar