Circulatory Pathways Flashcards
pathway of blood
flows through all 4 chambers of the heart and into associated circuits on repeating journey
left side of heart
systemic circuit pump
right side of heart
pulmonary circuit pump
amount of blood pumped into each circuit at any given time is ________, but the ventricular workloads are ________
equal
unequal
pulmonary circuit work load
short and low pressure
systemic circuit work load
longer and higher resistance
arteries
carry blood away from the heart
- blood is typically oxygen-rich
veins
return blood to the heart
- typically blood is oxygen-poor
exceptions of pulmonary circuit
- pulmonary trunk carries oxygen-poor blood from right ventricle to lungs
- pulmonary veins carry oxygen-rich blood from the lungs to left atrium
from the aorta
- Ascending Aorta -> R and L Coronary Arteries
- Aortic Arch -> Brachiocephalic Trunk, L Common Carotid Artery, L Subclavian Artery
- Descending Aorta -> all other systemic arteries
left coronary arteries
serves the left side of the heart
anterior interventricular artery
follows the anterior interventricular culcus, supplies blood to the anterior walls of both ventricles + the interventricular septum (“widow maker”)
circumflex artery
supplies the left atrium and the posterior wall of the left ventricle
right coronary artery
serves the right side of the heart
right marginal artery
supplies the myocardium of the lateral side of the heart
posterior interventricular artery
supples the apex of the heart and the posterior ventricular walls
where do the anterior and posterior interventricular arteries merge?
near the heart’s apex
variation in coronary circulation
- arterial supply of heart varies
- in 15% of people the left coronary artery supplies both interventricular arteries
- in 4% of people a single artery supples the whole heart
- some have both R and L marginal arteries
anastomosis
cross connection between adjacent channels
- there are many of these between coronary arterial branches - these provide collateral routs and important redundancy, but they don’t compensate for a coronary artery occlusion
- how 2 vessels fuse together, ex circle of willis
myocardial infarction
tissue death caused by complete blockage of a coronary artery
blood flow through coronary arteries
- flow of blood through coronary arteries is intermittent and pulsating (not constant)
- when ventricles are relaxed, blood flows into myocardium
- when ventricles contract, coronary arteries are compressed and flow is temporarily ceased
angina pectoris
thoracic pain caused by a fleeting deficiency in blood supply to the myocardium
- caused by increased physical demands on the heart (like exercise), stress induced spasms of the coronary arteries
- myocardial cells will be weakened, but they will not die
Myocardial infarction (in depth)
- prolonged coronary blockage, heart attack
- myocardial cells are cut off from blood supply and die
- dead cells are replaced by noncontractile scar tissue
- prolonged coronary blockage of the vessels supplying the left ventricle is the most likely to be fatal
coronary veins
after passing through the myocardium’s capillary beds, venous blood is collected by cardiac veins
- the path of cardiac veins roughly follows the coronary arteries
- cardiac veins merge to form the coronary sinus
coronary sinus drains into
the right atrium
the tributaries of the coronary sinus
- great cardiac vein from the anterior interventricular sulcus
- middle cardiac vein from the posterior interventricular sulcus
- small cardiac vein from the right inferior margin
some _______ empty directly into the ___________
anterior cardiac veins
right atrium
