creation date: 2026-08-01 14:38
tags: Anatomy & Physiology

Heart

Background

Opening through the interatrial septum that connects the atria before birth. This closes off at birth to form the fossa ovalis.

If it fails to close, this is known as atrial septal defect (ASD).

Coronary arteries

Right coronary artery (RCA)
- Supplies the right atrium and right ventricle
- Sinoatrial nodal artery supplies SA node
- Supplies AV node via septal perforating branch (90% of people)
- Descends into smaller branches:
  - Right posterior descending artery (PDA)
    - Posterior 1/3 of interventricular septum
  - Acute marginal artery
Left main coronary artery (LMCA)
- Left anterior descending (LAD) artery
  - Anterior portion of left ventricle
- Left circumflex (LCx)
  - Left atrium and posterior-lateral aspect of left ventricle
- Smaller branches
  - Obtuse marginal artery
  - Diagnoals
  - Septal perforator
Coronary anastomoses
- Between the circumflex and RCA
- Between the anterior and posterior interventricular arteries
- Stabilizes blood supply

Coronary veins

Anterior cardiac vein
- Empties to right atrium
Great cardiac vein
- Empties to coronary sinus
- Drains posterior , middle, and small cardiac veins
Coronary sinus empties into right atrium

Pressure that drives blood flow through the coronary arteries to the heart’s muscle
Calculated with left ventricular end-diastolic pressure (LVEDP) and aortic diastolic pressure (ADP)
- CPP = ADP - LVEDP
During contraction (systole), arterial branches are compressed and thus perfusion occurs during diastole
Coronary blood flow moves from epicardial (where pressure is approx. ADP) to endocardial (which would be LVEDP at the left ventricle)
Pressures needed are lower in the right ventricle and thus perfusion occurs in systole as well as systolic aortic pressure > systolic RV pressure.
Normal range: 60-80 mmHg