The Heart VHS211

What part of the thoracic cavity is the heart located?

The mediastinum

What binds the heart cranially, ventrally, and dorsally?

Thoracic cavity, spinal chord, and sternum

What is the cranial end of the heart called? What shape is it?

The base of the heart; it is rounded

What is the caudal end of the heart called? What shape is it?

The Apex; it is pointed

How is the heart situated in vivo?

The base is shifted towards the right, facing more dorsal. The apex is shifted towards the left and sits more ventral.

What is the main sac around the heart called?

Pericardium

What are the two parts of the pericardium?

The pericardial sac and the serous pericardium.

How is the serous pericardium divided?

Parietal (lines pericardial sac) serous pericardium and visceral (on heart) serous pericardium.

What is the space between the two serous membranes of the pericardium? It is filled with?

The pericardial space; filled with pericardial fluid.

What is the thickest layer of the heart called? Where is it located?

It is the myocardium; it is the middle layer.

What is the myocardium made of?

Cardiac muscle; muscle fibers jointed side to side via branches and jointed end to end via intercalated discs.

What are two advantageous traits of cardiac muscle?

It is autorythmic (beats without outside stimuli) and it does not fatigue.

What is the outermost layer/external membrane of the heart wall called? What is another name for this layer?

Epicardium; AKA visceral layer of serous pericardium.

What is the membrane that lies on the internal surface of the myocardium? What is it continuous with?

Endocardium; it is continuous with the endothelium lining of blood vessels

What else does the endocardium cover? Is it smooth or textured?

The endocardium also covers the valves that separate the 4 chambers; the endocardium is not smooth bc it has ridges and projections called papillary muscles, which vessels attach to.

What are the four chambers of the heart?

Left and right atria, left and right ventricles

Do

Do the ventricles send or receive blood?

The ventricles pump blood OUT of the heart

Which ventricle wall forms the apex?

The left ventricle

What separates the left and right atrium? What is it continuous with?

The interatrial septum; it is continuous with the myocardium

What separates the ventricles? It is a continuation of what?

Interventricular septum; it is a continuation of the interatrial septum

What do the 2 septa of the heart form altogether?

The atrioventricular septum

Which septum is visible from the outside of the heart? How is it identified?

The interventricular septum; it is identified via the interventricular groove.

Where does blood from the right ventricle go?

To the pulmonary artery, making pulmonary circulation to the lungs

Where does blood from the left ventricle go?

To the aorta, creating systemic or whole body circulation

Which ventricular wall is thicker? Why?

The left ventricle is thicker; it is thicker to create greater contracting force, as it has to pump blood to the aorta and the rest of the body

What are the 4 valves of the heart?

Tricuspid valve (right atria to right ventricle), bicuspid/mitral valve (left atria to left ventricle), pulmonary/pulmonic valve (to lungs) and aortic valve (to rest of body).