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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. 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






2. 1. depolarization caused by fast Na channels - where action potential through intercalated discs reaches threshold potential - opening Na channels 2. initial depolarization with Na channels closing and k channels opening - but Ca channels also open 3






3. Key proteins for the function of the immune system that are produced and released by B- cells






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






5. Pass through the capillaries in order to patrol the tissue for invading organisms; only macrophages and neutrophils can squeeze through cleft






6. 2 chambers of the heart






7. Stretching to greater degree of heart muscle causes more forceful contraction; stretching increase occur by increasing fluid volume






8. Essentially 0 mmHg - which results b/c of branching of vessels dissipating pressure to overcome resistance






9. CO2 is soluble in H2O - and thus some is dissolved and carried to lungs and tissues in plasma - O2 is not soluble in plasma at all






10. What causes tendency of water flow out of blood?






11. Valves between the large arteries and the ventricles






12. 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






13. Protein in RBC that transport O2 though the blood since O2 is too hydrophobic in plasma; protein has 4 subunits that change confirmation cooperatively depending on the concentration of O2






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






15. Purpose of erythrocytes?






16. Inadequate blood flow - resulting in tissue damage due to shortage of O2 and nutrients - and increase of metabolic waste






17. Blood clot or scab circulating in bloodstream






18. At position 6 - missense mutation substitutes valine for glutamate. valine is hydrophobic - where glutamate was charged. It is an autosomal recessive disease where RBCs accumulated in small vessels - heterozygote for (blank) shows resistance to malar






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






20. Connected to SA node via internodal tract - and passes signal to Common bundle of His to contract ventricles






21. Reservoirs where blood collects from veins






22. AV valve between right atrium and right ventricle






23. Transportation of blood though the body and exchange of material btw blood and tissues






24. Highest blood pressure that occurs during ventricular contraction






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






26. Receives deoxygenated blood from systemic circulation (superior and inferior vena cava)






27. Universal donor






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






29. Which is longer - diastole or systole?






30. Voltage - gated channels that open quickly; open at threshold potential






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






32. Response by CNS when blood pressure is too high






33. First branches from the aorta that provide the heart's blood supply






34. Number of systole contractions per unit time






35. Monocyte that phagocytoses debris and microorganisms - has amoeboid motility - and displays chemotaxis






36. Absorbed in the intestine and packaged in chylomicrons - which enter the lymphatic system - and dumped into the subclavian vein via the thoracic duct; the liver takes fats once in blood - converts them to another lipoprotein and sends them to adipocy






37. Excessive bleeding that results from defective proteins






38. Body's mechanism of preventing bleeding






39. Valves between the ventricle and the atria to prevent back flow






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






41. When do semilunar valves close?






42. Mother has Rh - blood with Rh+ antibodies that attack the babies Rh+ blood






43. When do Rh antibodies develop?






44. 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






45. Buffer in blood. Keeps pH around 7.4






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






47. Osmotic pressure in capillaries due to plasma proteins






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






49. Store and release histamine and are involved in allergic rxns






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