L20 Coronary Circulation, Pathology and Effects of Ischemic Heart Disease Flashcards
Which coronary vessels branch from the aorta?
Left and right coronary arteries
True or false: The left coronary artery passes posteriorly to the left atrium
False
The left coronary artery passes anterior to the left atrium
What are the main branches of the left coronary artery?
Circumflex
Anterior descending
Remember Left Coronary Artery = LCA:
L = left coronary artery C = circumflex A = anterior descending
Where does the circumflex branch go?
Circumflex runs along the coronary sulcus and supplies the left atrium and ventricle with blood
Where does the left anterior descending branch go?
LAD extends along anterior interventricular sulcus and supplies blood to the walls of both ventricles
True or false: The right coronary artery extends inferiorly to the right atrium
True
It has small branches that supply the right atrium
What are the main branches of the right coronary artery?
Posterior descending
Right marginal
Think! RPM:
R = right coronary artery
P = posterior descending
M = marginal (right)
Where does the posterior descending (posterior interventricular) branch go?
Follows posterior interventricular sulcus and supplies walls of both ventricles
Where does the right marginal branch go?
Follows the coronary sulcus and supplies the right ventricle
Which coronary vessel drains deoxygenated blood from the anterior region of the heart?
Great cardiac vein
Which coronary vessel drains deoxygenated blood from the posterior region of the heart?
Middle cardiac vein
The great and middle cardiac veins return deoxygenated blood to which common vessel?
Coronary sinus
Where does the coronary sinus empty into?
Right atrium
What happens in myocardial ischemia?
Partial or full obstruction of a coronary artery causes hypoxia. Lack of O2 means heart cells cannot produce ATP, and this inhibits actin/myosin contraction, Na/K pumps, ATP-gated K channels.
Can induce angina pectoralis
True or false: Pain in the neck, chin or left arm could be a symptom of angina pectoralis
True
What is a chylomicron?
The largest classification of lipoprotein (100nm-1um)
What is the function of apoproteins?
Ligands incorporated to the outer shell of a lipoprotein. They govern how and where the protein is transported.
The outer shell of a lipoprotein is made of apoproteins and amphipathic lipids (having hydrophobic and hydrophilic parts).
What amphipathic lipids make up the outer shell of the lipoprotein?
Phospholipid
Cholesterol
What molecules make up the core of the lipoproteins?
Triglycerides and cholesterol ester
Apoprotein-B100 is present in LDL-C particles. Where does it direct the LDL-C molecules to go?
To cells where cholesterol is used in membrane and steroid synthesis
Fill in the gaps: Lipoprotein lipase hydrolyses triglycerides into __1__ fatty acid chains and one __2__ molecule.
- two
2. monoacylglycerol
How does an atheroschlerotic plaque develop?
- ↑ in LDL lipoproteins. These are removed by macrophages.
- Macrofages form foam cells, which attach themselves to endothelial wall.
- Foam cells release cytokines, inducing replication of SMCs of tunica intima and attracting more monocytes
- Macrophages, SMCs and endothelial cells take up lipoproteins, resulting in atherosclerotic plaque
- Gaps form in endothelium and platelets attach to exposed collagen - forms clot
What are the treatments for hypercholesterolaemia?
- Statins: inhibit HMG-CoA and mevalonate pathway
- Fibrates: ↑ hepatic LDL-C uptake
- Bile acid-binding resins: reduce cholesterol absorption from intestines, stimulate upregulation of LDL receptors to ↑ clearance from the blood. Often cause diarrhoea
