BSI: Cardiovascular Anatomy

The heart is located in the mediastinum between the lungs, just superior to the diaphragm.

The heart is in the pericardial cavity.

• The heart is shaped like a cone.
• The top of the heart is the base (broad area)
• The apex is the bottom of the heart (the pointy part).

The Pericardium is a serous membrane that surrounds and protects the heart. It is sort of like a sac that surrounds the heart. It is made up of two layers:

• 1) Outer parietal layer
• Consists of dense irregular connective tissue

• 2) Inner visceral layer
• Adheres to heart
• Made up of epithelial cells

Pericardial fluid is secreted by the epithelial cells that line the inner visceral layer of the pericardium (the layer that adheres to the heart).

Pericardial fluid reduces the friction between the layers.

• Right and Left Atria
• 1) Superior chambers of heart
• 2) Auricle: pouch like structure that increases volume capacity of atria
• 3) Interatrial septum
• 4) Opening of coronary sinus (in right atrium)

• Right and Left Ventricles
• 1) Inferior chambers of heart
• 2) Chordae tendineae
• 3) Papillary muscle
• 4) Interventricular septum

• 1) Endocardium
• Inner most layer
• Thin layer of endothelium over thin layer of connective tissue
• -Continuous with endothelium of vessels that open into heart chambers
• -Lines entire cardiovascular system

• 2) Myocardium
• Middle layer of the heart
• Cardiac muscle tissue

• 3) Epicardium
• Visceral layer of pericardium

• Note:
• 

Endocardium

Epicardium

Cardiac Muscle Tissue

• Valves on right side of heart:
• 1) Tricuspid valve (atrioventricular valve)
• 2) Pulmonary valve (semilunar valve)

• Valves on left side of heart:
• 1) Bicuspid (mitral) valve (atrioventricular
• valve)
• 2) Aortic valve (semilunar valve)

Only the atrioventricular valves have chordae tendineae and papillary muscle associated with them. The function of chordae tendinae and papillary muscle is to prevent backflow.

• 1) Superior and inferior vena cava
• 2) Pulmonary arteries and veins
• 3) Coronary Sinus
• 4) Aorta
• - Ascending, arch of aorta
• - Descending (thoracic & abdominal aorta)

• Arteries branching off of ascending aorta:
• 1) Left coronary artery
• - Anterior interventricular branch
• - Circumflex branch
• 2) Right coronary artery
• - Posterior interventricular branch
• - Marginal branch

• Arteries branching off of arch of aorta:
• 1) Brachiocephalic trunk
• - Right common carotid artery
• - Right subclavian artery
• 2) Left common carotid artery
• 3) Left subclavian artery

• Descending aorta (abdominal aorta) divides into:
• 1) Left common iliac
• 2) Right common iliac

The aorta

• 1) The Brachiocephalic Trunk
• 2) Left common carotid artery
• 3) Left subclavian artery

The right subclavian

The coronary sinus is a collection of veins on the posterior surface of the heart joined together to form a large vessel that collects blood from the myocardium of the heart. It delivers deoxygenated blood to the Right atrium in conjunction with the superior and inferior vena cava.

• Brachiocephalic trunk
• right shoulder, right upper extremities, head on right side

• Left common carotid artery
• left side of neck and head

• Left subclavian artery
• left shoulder and left upper extremities

• Right common iliac
• right lower extremities

• Left common iliac
• left lower extremities

• 1) Arteries
• 2) Arterioles
• 3) Capillaries
• 4) Venules
• 5) Veins

• 1) Right Atrium (deoxygenated blood)
• 2) through Tricuspid Valve
• 3) Right Ventricle
• 4) through Pulmonary Valve
• 5) Pulmonary Arteries
• 6) Lungs (exchange of gases)
• 7) Pulmonary Veins
• 8) Left Atrium (oxygenated blood)
• 9) through Bicuspid/Mitral Valve
• 10) Left Ventricle
• 11) through Aortic Valve
• 12) Systemic Circulation
• 13) Inferior & Superior Vena Cava & Coronary Sinus
• 14) Returns to Right Atrium

• 

Systemic Circulation is the circulation that supplies blood to all of the body except the lungs.

• Deoxygenated blood enters the Right Atrium via:
• 1) Inferior Vena Cava
• 2) Superior Vena Cava
• 3) Coronary Sinus

Oxygenated blood enters the Left Atrium via the Pulmonary Veins.

Recall that normally, veins carry deoxygenated blood. The pulmonary veins are the exception to the rule.

However, if you think of the rule more of as veins carry blood toward the heart and arteries carry blood away from the heart, then you won't go wrong.

Blood leaving the Left Ventricle is oxygenated because this is the ventricle that pumps oxygenated blood to the systemic circulation.

Blood leaving the Right Ventricle is deoxygenated because this is the ventricle that pumps blood to the lungs for gas exchange (pick up oxygen, drop off carbon dioxide).

Blood entering the Right Atrium is deoxygenated because this is the first stop back to the heart from the systemic circulation.

• Sinoatrial (SA node)
• top of the right atrium

• Atrioventricular (AV node)
• bottom of right atrium

• Bundle of His (AV bundle)
• top of interventricular septum

• Right and left bundle branches
• right and left sides of interventricular septum (respectively)

• Perkinje fibers
• located in the inner ventricular walls of the heart, just beneath the endocardium

These fibers are specialized myocardial fibers that conduct an electrical stimulus or impulse that enables the heart to contract in a coordinated fashion.