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MCAT Biology Circulatory System

Subjects : mcat, health-sciences
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Valves between the ventricle and the atria to prevent back flow






2. Vessels that carry blood back to the heart at low pressure






3. Why is the SA node the primary pacemaker?






4. Occurs when increased cardiac output is needed; the postganglionic nerve directly innervates the heart - releasing norepinephrine - increasing heart rate and force of contraction






5. Fat storage cells of the body






6. 2 chambers of the heart






7. At the end of the capillary - is the osmotic pressure high or low?






8. Ensure the one - way flow through the circulatory system






9. Because the veins have essentially 0 pressure - these valves ensure one - way flow - skeletal muscle contraction encourages flow through veins






10. Blood clot or scab circulating in bloodstream






11. Adequate circulation - but O2 supply is reduced (no build up waste products or loss of nutrients)






12. Pool of deoxygenated blood at low pressure - which collects blood from coronary veins - Only deoxygenated blood to not enter the right atrium via the vena cava






13. Connects the two capillary beds of the intestine and the liver






14. Vessels where deoxygenated blood from coronary sinus continue to flow into heart






15. 3 substances that can diffuse through intercellular cleft






16. 2 lymphocytes






17. As low as pressure gets btw heart beats in arteries






18. ABO blood group and Rh blood group






19. Opposing friction force to flow - which increases with decreased radius; determined by degree of contraction of arterial smooth muscle






20. Where blood passes through 2 sets of capillaries before returning to the heart; Evolved as direct transport routes






21. Precursor to fibrin - which is necessary for blood clotting






22. When the valve of a vein fails and back flow occurs; blood not being moved toward the heart






23. Which is longer - diastole or systole?






24. Site of exchange btw blood and tissues; smallest vessels that allow one RBC through at a time






25. Contraction of the ventricles - where pressure increases rapidly - causing AV valves to close - Marks the beginning of the 'lub' sound






26. Region that initiates start of cardiac cycle - which acts as a pacemaker of the heart; has unstable resting potential due to Na leak channels






27. Produced during cell metabolism and diffuses through the endothelial cells into the blood stream - where it is picked up by the liver and converted to forms that can be excreted (all other wastes are picked up by the kidneys)






28. 73% of CO2 converted to carbonic acid by carbonic anhydrase - and carbonic acid is converted to bicarbonate - which acts a buffer






29. Crosses septum and connects to Purkinje fibers to allow coordinated contraction of ventricles. Key is that is slows transmission across septum to allow ventricles to fully fill before contraction






30. Pump blood out of the heart at high pressures into arteries






31. The difference in pressure divided blood flow; controlled by the sympathetic nervous system generating adrenergic tone






32. Gap junctions in the cardiac muscle - where depolarization is communicated directly btw cytoplasm of neighboring cardiac cells






33. Confirmation of hemoglobin with O2 bound - where affinity is high 1. pH 2. pCO2 3.






34. Peptide hormone secreted from the kidneys to increase RBC production in bone marrow






35. Vessels that carry blood away from the heart at high pressure






36. Lipoproteins that enter lacteal vessels of lymphatic system in the intestinal wall






37. Metabolic waste product in breakdown of amino acids






38. Resting membrane potential of -90mV and have long duration action potentials






39. Capillaries dilate - increasing the cleft size - which allows more H2O to move through to tissues






40. Absorbed by the GI tract and brought to the liver via the hepatic portal vein - where they are stored in the liver and enter the blood stream when needed






41. Purpose of erythrocytes?






42. Have single layer endothelial cells w/ spaces in between cells called intercellular cleft






43. Return of blood to the heart by the vena cava - where increased venous return causes increased stretching of the muscle (increases stroke volume)






44. Glycoproteins that are coded for by 3 alleles (A - B - i)






45. 3 factors that dictate the affinity of hemoglobin for O2






46. Response by CNS when blood pressure is too low






47. What is the only process RBC use to generate ATP?






48. Where are RBCs broken down?






49. Hematocrit or RBC those compose 35-45% of the blood; cells are non - nucleated and have no organelles. Acquire ATP through glycolysis have biconcave shape to maximize surface area for binding O2






50. Reservoirs where blood collects from veins