Circulatory Pathways

Question 1

pathway of blood

Answer 1

flows through all 4 chambers of the heart and into associated circuits on repeating journey

Question 2

left side of heart

Answer 2

systemic circuit pump

Question 3

right side of heart

Answer 3

pulmonary circuit pump

Question 4

amount of blood pumped into each circuit at any given time is ________, but the ventricular workloads are ________

Answer 4

equal
unequal

Question 5

pulmonary circuit work load

Answer 5

short and low pressure

Question 6

systemic circuit work load

Answer 6

longer and higher resistance

Question 7

arteries

Answer 7

carry blood away from the heart
- blood is typically oxygen-rich

Question 8

veins

Answer 8

return blood to the heart
- typically blood is oxygen-poor

Question 9

exceptions of pulmonary circuit

Answer 9

• pulmonary trunk carries oxygen-poor blood from right ventricle to lungs
• pulmonary veins carry oxygen-rich blood from the lungs to left atrium

Question 10

from the aorta

Answer 10

• Ascending Aorta -> R and L Coronary Arteries
• Aortic Arch -> Brachiocephalic Trunk, L Common Carotid Artery, L Subclavian Artery
• Descending Aorta -> all other systemic arteries

Question 11

left coronary arteries

Answer 11

serves the left side of the heart

Question 12

anterior interventricular artery

Answer 12

follows the anterior interventricular culcus, supplies blood to the anterior walls of both ventricles + the interventricular septum (“widow maker”)

Question 13

circumflex artery

Answer 13

supplies the left atrium and the posterior wall of the left ventricle

Question 14

right coronary artery

Answer 14

serves the right side of the heart

Question 15

right marginal artery

Answer 15

supplies the myocardium of the lateral side of the heart

Question 16

posterior interventricular artery

Answer 16

supples the apex of the heart and the posterior ventricular walls

Question 17

where do the anterior and posterior interventricular arteries merge?

Answer 17

near the heart’s apex

Question 18

variation in coronary circulation

Answer 18

• 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

Question 19

anastomosis

Answer 19

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

Question 20

myocardial infarction

Answer 20

tissue death caused by complete blockage of a coronary artery

Question 21

blood flow through coronary arteries

Answer 21

• 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

Question 22

angina pectoris

Answer 22

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

Question 23

Myocardial infarction (in depth)

Answer 23

• 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

Question 24

coronary veins

Answer 24

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

Question 25

coronary sinus drains into

Answer 25

the right atrium

Question 26

the tributaries of the coronary sinus

Answer 26

• great cardiac vein from the anterior interventricular sulcus
• middle cardiac vein from the posterior interventricular sulcus
• small cardiac vein from the right inferior margin

Question 27

some _______ empty directly into the ___________

Answer 27

anterior cardiac veins
right atrium