Aorta & Coronary Circulation Quiz

Aorta & Coronary Circulation

• Oxygenated blood is pumped from the left ventricle (LV) through the aortic valve (AoV) into the aorta (Ao).
• The aorta delivers oxygenated blood to the heart, head, and body.
• Normal aortic pressure is less than 120/80 mmHg.
• Normal aortic oxygen saturation is 98%.

Aorta Segments

• Aortic Root (AoR): The area from the AoV up to the sinotubular junction (STJ). The STJ is where the aortic arch (Ao Arch) meets the ascending aorta (AAo). It encompasses the Sinuses of Valsalva (SofV).
• Ascending Aorta (AAo): Begins superior to the AoR and continues to the beginning of the Aortic Arch.
• Transverse or Aortic Arch (Ao Arch): This section of the aorta branches into three major arteries.
• Thoracic Descending Aorta (DAO): Begins after the aortic arch, descends inferiorly within the chest cavity, and is superior to the diaphragm.
• Abdominal Descending Aorta: Begins after the DAO, passing inferior to the diaphragm, and extends within the abdominal cavity. Numerous branches supply different organs.

Aortic Arch

• The aortic arch is also known as the Transverse Aorta.
• It's the origin of three important arteries: Brachiocephalic (innominate), Left Common Carotid, and Left Subclavian Arteries. These vessels supply the head and arms.

1st Aortic Arch Branch: Brachiocephalic Artery

• Also known as the innominate artery.
• It's the largest of the three aortic arch branches.
• It divides into the Right Common Carotid Artery and Right Subclavian Artery.
  • The Right Common Carotid Artery runs along the right side of the neck, supplying the right side of the face and brain.
  • The Right Subclavian Artery runs under the right clavicle, supplying the right arm.

2nd Aortic Arch Branch: Left Common Carotid Artery

• Runs up the left side of the neck, supplying blood to the left side of the face and brain.

3rd Aortic Arch Branch: Left Subclavian Artery

• Runs under the left clavicle, supplying the left arm.

Aortic Isthmus

• Prone to dissection or tear, especially caused by deceleration injuries.
• Located between the Left Subclavian Artery and Ligamentum Arteriosum.
• Ligamentum Arteriosum: An embryonic remnant of the ductus arteriosus.
• Ductus Arteriosus: A fetal shunt from the pulmonary artery to the aorta, which usually closes after birth.

Thoracic Descending Aorta (DAO)

• Begins after the Aortic Arch, travels inferiorly within the chest cavity and superior to the diaphragm.
  • Within the chest cavity,the aorta gives off various branches that supply vital organs.

Abdominal Descending Aorta

• Begins once the aorta passes inferior to the diaphragm.
• Numerous branches supply the various organs in the abdominal cavity.

Aortic Branches & Circulation

• Arteries split into arterioles, which deliver oxygen. Arterioles then split into capillaries.
• Capillaries exchange nutrients and oxygen within tissues.
• Capillaries join venules, which excrete carbon dioxide and waste.
• Venules merge into veins.

Coronary Arteries

• Coronary arteries supply the myocardium (heart muscle) with oxygenated blood via a dense capillary network.
• An inadequate blood supply results in:
  • Ischemia: Lack of oxygen (partial blockage).
  • Infarct: Necrosis, or tissue death (total blockage) which is also known as a heart attack.

Coronary Arteries (Origin)

• Coronary arteries begin at the Sinuses of Valsalva.
• They travel down the heart muscle's exterior.

Two Primary Coronary Arteries

• Left Coronary Artery (LCA): originates at the Left Coronary Cusp of the Sinus of Valsalva, splits into the Left Anterior Descending Artery (LAD) and Left Circumflex Artery (LCX).
• Right Coronary Artery (RCA): originates at the Right Coronary Cusp of the Sinus of Valsalva, branches into the Acute Marginal Artery (AMA) and Posterior Descending Artery (PDA).

Heart's Grooves

• Atrioventricular Groove (aka Coronary Sulcus):
  • Horizontal groove between atria and ventricles.
• Interventricular Groove:
  • Vertical groove between ventricles, aligned with interventricular septum.

Left Coronary Artery Branches

• Left Anterior Descending Artery (LAD): Follows the anterior interventricular groove to the apex, supplying the septal, anterior, and apical walls of the left ventricle.
• Left Circumflex Artery (LCX): Follows the atrioventricular groove, supplying the atria and posterior wall of the left ventricle.

Right Coronary Artery Branches

• Acute Marginal Artery (AMA): Small branch on the side of the right ventricle (RV).
• Posterior Descending Artery (PDA): Branch of the RCA; follows the coronary groove to the inferior surface of the heart and down the interventricular groove. This supplies the inferior portion of the heart.

Coronary Dominance

• 85% of cases, the Right Coronary Artery (RCA) gives rise to the Posterior Descending Artery (PDA)
• In ~7% of cases of the population, the RCA & LCX gives rise to the PDA (Co-Dominant).
• In ~8% of cases, the LCA/LCX artery gives rise to the PDA. (Left Dominant).

Cardiac Venous System

• Collects deoxygenated blood from coronary arteries and returns the blood to the right atrium (RA).
• Major veins included: Great cardiac vein, Middle cardiac vein, Left cardiac veins, Right coronary vein, Anterior cardiac veins, and Thebesian veins.

Coronary Sinus

• Located behind the LA, along the posterior atrioventricular groove.
• Receives deoxygenated blood from coronary veins and drains into the RA.
• Approximately 2.5 cm long.
• Lowest O2 sat in the body.

Great Cardiac Vein

• Travels along the left anterior descending artery
• Collects blood from the anterior myocardium
• Drains into the coronary sinus

Middle Cardiac Vein

• Also known as the posterior cardiac vein
• Collects blood from posterior myocardium
• Drains into the coronary sinus
• Runs along the posterior descending artery

Left Cardiac Veins (3-4 small vessels)

• Collects blood from the posterior surface of the left ventricle (LV)
• Drains into the coronary sinus.

Right Coronary Vein (aka Small Coronary Vein)

• Collects blood from posterior portion of the right atrium (RA) and right ventricle (RV)
• Drains into the coronary sinus.

Anterior Cardiac Veins

• Collects blood from the anterior surface of the right ventricle (RV)
• Drains directly into the right atrium (RA).
• Similar course to Right Coronary Artery.

Thebesian Veins

• Numerous minute veins return blood from myocardium directly into cardiac chambers, without flowing through the coronary sinus

Parasternal Wall Segments

• A technique for visualizing the heart using ultrasound.
• Allows visualization of the cardiac wall segments in the long and short axis views. Different parts are identified by their position: anterior, posterior, lateral, and septal.
• Specific segment locations are referenced as basal or apical or mid.

Note: Page numbers are from the provided text.

Test your knowledge on the aorta and coronary circulation with this quiz. Explore the segments of the aorta, normal pressure readings, and how oxygenated blood travels through the body. Perfect for students learning about cardiovascular anatomy and physiology.