6.3 - Coronary Circulation Flashcards
Left Coronary Artery
- located behind the left aortic valve cusp
2 Branches
1) Left anterior descending (IV septum and apex)
Area of heart supplied: R and L ventricle, IV septum
- travels down front (anterior) intraventricular septum towards the apex
2) Circumflex Artery
Area of heart supplied: L atrium and Lateral (side) wall of L ventricle
- runs in coronary sulcus: which separates L atrium and L ventricle
Right Coronary Artery
- located behind RIGHT cusp of aortic valve
3 Branches
1) Cornus
- supplied R ventricle (upper)
- 1st branch near sinus of valsava
2) Right Marginal Branch
- supplies side (lateral) of R ventrical
- rungs along side of R ventricle toward apex
3) Posterior Descending Artery
- supplies (posterior) back 1/3 of IV septum
- rungs along back
Collateral Circulation
- collateral arteries provide blood to ischemic areas when the primary coronary arteries are narrowed
- collateral arteries are located in epicardium (outermost layer of heart wall)
- collateral arteries are connections bw branches of the same artery
- they provide alternative route to blood flow when there is a blockage
2 Processes that support the Formation of Collateral Vessels
1) Arteriogenesis
- growth of new arteries from existing vessels
2) Angiogenesis
- formation of new capillaries within tissues
Blood Flow From Epicardium to Myocardium
1) Arterial Supply
- coronary arteries run along epicardium
- blood moves from the epicardium into myocardium via arterioles and arterial-luminal vessels
2) Capillary Exchange
- inside the myocardium, the network of capillaries allows nutrient and oxygen to deliver to heart muscles, and removes waste products
3) Venous Drainage
- deoxygenated blood (that also carries waste) is collected by veno-luminal vessels
- this blood drains into larger veins (where they join coronary veins)
Coronary Veins
1) Great Cardiac Vein (collects)
- runs along left anterior descending artery
- collects deoxygenated blood from R atrium, L atrium ands L ventricle and empties it into coronary sinus
2) Coronary Sinus (delivera)
- drains directly into R atrium
- located bw L atrium and L ventricle (atrioventricular groove)
Cardiac Lymphatic System
- myocardium contains lymhatic capillaries and vessels
Lymphatic vessels
1) drain excess fluid into lymph nodes
2) protect heart from infection and inflammation
Astherosclerosis
- damaged inner lining of arteries
Cause
- high cholesterol (high lipids = plaque buildup)
- hypertension
- smoking (oxidative stress)
Patho
- endothelial injury
- lipids infiltrate the damaged endothelium
- macrophages engulf lipids and form foam cells = fatty streaks
- smooth muscles migrate to site and form fibrous cap
- plaque causes narrowed arteries
Changes
- plaque formation
- arterial narrowing
- stiffening
Significance
- angina (narrowed arteries = ↓ blood supply
- thrombus = myocardial infraction
- coronary artery disease (plaques cause impaired blood flow)
Angina Pectoris
Cause
- astherosclerosis = narrowing = ↓ blood flow
- imbalance between demand of heart and oxygen supply
Patho
- oxygen demand exceeds the blood supply due to narrowed arteries
Types
1) Unstable - unpredictable, can occur at rest
2) Stable - predictable; triggered by exertion/stress
3) Variable - caused by coronary artery spasms
Changes
- artery narrowing (plaque buildup)
- ischemia w/out infraction (↓ oxygen causes ischemia but no permanent damage)
Symptoms
Stable: predictable chest pain during exertion
Unstable: unpredictable chest pain occurring at rest
Myocardial Infraction
Cause
- plaque ruptures = clot/thrombus = blocked coronary artery
- risk factors: astherosclerosis, hypertension, diabetes, smoking
Patho
- prolonged ischemia: plaque rupture = clot = blocks artery = no blood supply to heart muscle = myocardial necrosis
Changes
- myocardial necrosis
- necrosis causes loss of ability to contract = LVH
S&S
- chest pain that radiates to jaw, arm, shoulder, back
- heart failure
- sudden cardiac death
