Anatomy of the heart

Explain a little on the interventricular septum?

- Bulges (convex) to right - Lies vertically & in coronal plane - Attaches to AV rings - As thick as left ventricular wall

What are the functions of the pericardium?

- Protects and anchors the heart - Prevents overfilling of the heart with blood - Allows for the heart to work in a relatively friction-free environment

What are the layers of the pericardium?

1. A superficial fibrous pericardium 2. A deep two-layer serous pericardium

What are the features of the right ventricle?

1. Cordae tendinae 2. Papillary muscles 3. Moderator band / septomarginal trabecula 4. AV valve (tricuspid valve) 5. Pulmonary valves

What are the general features of the right ventricle?

1. Crescent-shaped on transverse section 2. Smooth part: infundibulum / conus arteriosus 3. Rough part: Projecting ridges called trabeculae carneae. 4. Supraventricular crest demarcation between the smooth & rough part/inflow & outflow tract

What are the three layers of the heart?

1. Epicardium (outer, visceral layer of serous pericardium) 2. Myocardium : cardiac muscle 3. Endocardium (inner) : Thin layer of endothelium lining chambers of heart and valves

What are the internal features of the right atrium?

1. Fossa ovalis 2. Limbus fossa ovalis 3. SA node 4. AV node

What are the features of the left atrium?

1. Large smooth-walled part 2. Rough part (left auricle has musculi pectinati / small pectinate muscle) 3. Interatrial septum: which slopes posteriorly and to the right 4. Left AV (mitral) valves

What are the features of the right atrium?

1. Larger and thinner wall than left trium 2. Auricle (ear); contains pectinate muscles 3. Rough anterior wall; contains pectinate muscles 4. Smooth posterior wall/sinus venarum 5. Sulcus terminalis (externally) and crita terminalis (internally) between the 2 parts

What are the 2 parts of the interventricular septum?

1. Membranous part (superior) 2. Muscular part (inferior)

what are the two pericardial sinuses?

1. Oblique sinus of the pericardium 2. Transverse sinus of the pericardium

Describe the three papillary muscles

1. Posterior - large and connected to anterior and posterior cusps 2. Posterior - small and connected to posterior and septal cusps 3. Septal - connected to anterior and septal cusps

What are the borders of the heart?

1. Right 2. Inferior 3. Left 4. Superior

What are the openings of the right atrium?

1. SVC 2. IVC 3. Coronary sinus 4. Tricuspid orifice 5. Anterior cardiac vein 6. Venae cordis minimae (Thebesian veins)

What are the surfaces of the heart?

1. Sternocostal/Anterior 2. Diaphragmatic/inferior 3. Base/Posterior

What are the two serous pericardium layers?

1. The Parietal layer 2. The Visceral layer

What is the nerve supply of the pericardium?

1. The somatic innervation (sharp pain) of fibrous pericardium & parietal serous layers is by phrenic and intercostal nerves 2. The insensitive/visceral (dull pain) innervation of the visceral serous layer is by (autonomic) superficial and deep cardiac plexuses

what are the features of the left ventricle?

1. Thicker wall than the right ventricle 2. The aortic vestibule / smooth walled part 3. Rough part / Trabeculae carneae 4. Inflow and outflow tracts are separated by the anterior mitral leaflet (anterior cusps) V shape 5. Two papillary muscles 6. AV valve (Bicuspid) 7. Aortic valve 8. Behind each cusps aortic wall bulges to form an aortic sinus

What forms the superior border of the heart?

2 Auricles, pulmonary trunk

How many surfaces does the heart have?

3 Surfaces

How many cusps does the aortic valve have?

3 cusps. Right cusp on anterior wall and left + posterior cusps are situated on the posterior wall

The pericardium is composed of how many layers?

3 layers

How many sets of valves does the heart have?

4 sets of valves

What is the pericardium?

A double-walled fibrous serous sac around the heart

What is the moderator band?

A muscular bundle extending from the inferior part of the IV septum to the base of the anterior papillary muscle.

What separates the two serous pericardium layers?

A pericardial cavity with a small amount (10-20ml) of pericardial fluid

Why is the transverse sinus of the pericardium important to cardiac surgeons?

A temporary ligature is passed through this sinus during some lung and cardiac operations

The fibrous pericardium firmly blends (attaches) with what?

Adventitia of aorta, pulmonary trunk, superior vena cava (not IVC), central tendon of diaphragm and sternum (sternopericardial ligaments)

What forms the base surface of the heart?

Almost all of the left atrium

what is found on the interatrial wall of the left atrium?

An oval thin area which is the fossa ovalis. Superior edge of septum primum is found.

What is the fossa ovalis?

An oval, thumbprint sized depression in the interatrial septum (remnant of foramen ovale, in fetus)

What are the two papillary muscles in the left ventricle?

Anterior and posterior

What are the cusps of the tricuspid valve?

Anterior, posterior and septal cusps. (admits 3 fingers)

Papillary muscles are divided into 3. What are they?

Anterior, posterior and septal.

How big is the heart?

Approximately the size of a fist

At which surface is the left atrium located?

At the base of the heart (posterior surface)

Where is the pulmonary valve located?

At the location between the infundibulum / conus arteriosus and the pulmonary trunk.

Where do the two serous pericardium layers become continuous?

At the roots of the great vessels.

Auricles are found at the ____ only

Atria

What are the valves between the atria and the ventricles called?

Atriocentricular valves

The coronary sulcus marks the border between what?

Between atria and ventricles

Where is the transverse sinus of pericardium located?

Between the atria and the great vessels. The pulmonary trunk and ascending aorta in front, superior vena cava behind, pulmonary veins and left atrium below.

What do the two interventricular sulci mark?

Border between the two ventricles

How is the oblique sinus of the pericardium formed?

By pericardial reflexions surrounding the inferior vena cava and four pulmonary veins

How are AV and Semilunar valves closed?

By pressure. They are NOT closed by muscular contraction applied to the cusps

What are pectinate muscles like?

Comb-like horizontal parallel ridges

Where is the oblique sinus of the pericardium located?

Dorsal to the left atrium at the base of the heart

Closing of Semilunanr valves produces ___ sound

Dub

What is the difference between trabeculae carnae in left ventricle with those in the right ventricle?

Finer, and more numerous

What happens during cardiac tamponade?

Fluid in the pericardial sac limits movement of the heart and thus, compromises cardiac output

What is the function of the mitral valve?

Guards the AV orifice.

What is the function of the aortic valve

Guards the aortic artifice

What is the function of the papillary muscles?

Helps prevent valve prolapse and regurgitation of blood (Note: The chordae tendinae and papillary muscles do not "pull" the valves open)

Where is the AV node located?

In the lower part of the interatrial septum, above attachment of septal cusp of tricuspid valve and tto the left of opening of coronary sinus

Where is the SA node located?

In the superior end of sulcus terminalis, at the junction between right atrium & SVC

What is the function of the moderator band?

It carries part of the right bundle of the AV bundle. It separates the ridged muscular wall of the inflow part of the chamber from the smooth wall of the conus arteriosus (outflow part)

Where is the cordae tendinae located?

It extends from the free edges of tricuspid valve to the apices of papillary muscle

How many openings does the right atrium have?

It has 6 openings

Where is the position of the heart within the body?

It is found in the mediastinum and 2/3 of it lies left of the midline with 1/3 on the right.

What forms the left border of the heart?

Left ventricle, top by left auricle

Closing of AV valves produces ____ sound

Lub

What forms the diaphragmatic surface of the heart?

Mainly 2/3rds of the left ventricle, 1/3rd of the right ventricle

What forms the sternocostal surface of the heart?

Mainly the right ventricle, right atrium and left ventricle.

What is the blood supply of the pericardium?

Pericardiocophrenic branch of internal artery/veins

What is the function of semilunar cusps?

Prevent regurgitation of blood from pulmonary trunk during diastole.

What is the function of the cordae tendinae?

Prevents evertion of tricuspid valves into the right atrium and regurgitation of ventricular blood into atrium during systole.

What forms the right border of the heart?

Right atrium

Compare right & left ventricle in terms of shape in cross section

Right ventricle - Crescentic, Left ventricle - Circular

What forms the inferior border of the heart?

Right ventricle, Apex by left ventricle

What vessels does the smooth posterior wall receive?

SVC, IVC, coronary sinus & anterior cardiac veins

What are the valves between the ventricles and arterial trunks called?

Semilunar valves

what is the function of the smooth-walled part of the left atrium?

Site of emptying of the four large valveless pulmonary veins on the posterior wall

What do the cordae tendinae look like?

Strands are like the cords of a parachute

What forms the base of the heart?

The base is the posterior aspect of the heart. It is formed largely by left atrium and a narrow portion of the right atrium.

Describe the course that the blood takes in the right ventricle

The blood takes a U-shaped course from the orifice of entrance to the orifice of exit

What does the parietal pericardium layer line?

The internal surface of the fibrous pericardium

Where does the heart apex point to?

The left hip

What forms the apex of the heart?

The left ventricle

What is the limbus fossa ovalis?

The ridge around the fossa ovalis

What does the visceral pericardium layer a.k.a epicardium line?

The surface of the heart

How many borders of the heart are there?

There are 4 borders of the heart.

What are pericardial sinuses?

These are blind pouches formed by the reflection of the parietal pericardium to the visceral pericardium around the great vessels

What are the characteristics of the fibrous pericardium?

Tough, collagenous and indistensible

The base of the heart is directed where?

Toward the right shoulder

Left atrium has a slightly thicker wall than right atrium. T/F?

True

What is the blood flow course in the left ventricle?

V-shape course

How much does the heart weigh?

Varies with body height and weight; it averages approximately 250 to 300g in females and 300-350g in males.

Mitral valve looks like ___

a miter, the headdress worn by bishops

what are the papillary muscles?

conical muscular projections from the ventricular wall and are attached to cordae tendinae.

The sulci are filled with ____

fat and vessels

In bicuspid valve, anterior cusp is ___ than the posterior cusp (size)

larger

The Mitral valve opens to ___

left ventricle

In left atrium, Windsock-like left auricle forms the ___ part of the left border

superior

Smooth walled part of LV is the _____

superior portion (outflow path)

Atrioventricular valves close during ____ whereas semilunar valves close during ____

systole, diastole