Anatomy and Physiology - Problem Drill 16: The Cardiovascular System No. 1 of 10 Instruction: (1) Read the problem statement and answer choices carefully (2) Work the problems on paper as needed (3) Pick the answer (4) Go 1. What is the flow of deoxygenated blood through the heart as it returns from the body? A. Vena cava - right ventricle - right atrium- left ventricle B. Vena cava - right atrium - right ventricle - pulmonary vein C. Vena cava - right atrium - right ventricle - pulmonary artery D. Vena cava - pulmonary artery - right atrium - right ventricle The left ventricle receives oxygenated blood from the lungs via the left atrium. The pulmonary vein returns oxygenated blood from the lungs. C. Correct! Deoxygenated blood travels this path through the heart: Vena cava right atrium right ventricle pulmonary artery. The pulmonary artery does carry deoxygenated blood from the body, but this occurs after the blood has passed through the right atrium and ventricle. As the deoxygenated blood returns to the heart from the body it passes through the superior and inferior vena cava. The blood then enters the right atrium and is pumped into the right ventricle. The right ventricle then pumps the blood through the pulmonary artery to the lungs. The pulmonary artery is the only artery in the body to carry deoxygenated blood.
No. 2 of 10 2. Which of the following statements about arteries and veins is correct? A. Blood flow through arteries is driven by pressure and a series of one-way valves. B. Blood flow through arteries is driven by pressure and elastic recoil. C. Blood flow in the veins occurs under high pressure. D. Blood flow in the veins occurs under high pressure and is influenced by muscular contraction. Blood flow through arteries is driven by pressure and elastic recoil. B. Correct! Blood flow through arteries is driven by pressure and elastic recoil. Blood flow in the veins occurs under low pressure. Blood flow in the veins occurs under low pressure; it is influenced by muscular contraction and is facilitated by a series of one-way valves. As the heart beats, pressure is generated within the arterial system and is transmitted to the venous system. Pressure and the elastic recoil of the arteries drive Blood flow through arteries. Blood flow through the venous system occurs under low pressure; it is influenced by muscular contraction and is facilitated by a series of one-way valves. Systolic blood pressure: the peak pressure in the arteries during the cardiac cycle. Specifically, it is the maximum arterial pressure during contraction of the left ventricle. Diastolic blood pressure: the lowest pressure at the resting phase of the cardiac cycle.
No. 3 of 10 3. An action potential, depolarization? A. Corresponds to the rising phase of the action potential, brought on by an influx of sodium ions into the cell. B. Corresponds to the rising phase of the action potential, brought on by an influx of potassium ions into the cell. C. Involves a change in membrane potential from the negative resting membrane potential towards a more negative peak. D. Is caused by the efflux of positively charged potassium ions, leaving the cell. A. Correct! Corresponds to the rising phase of the action potential, brought on by an influx of sodium ions into the cell. Corresponds to the rising phase of the action potential, brought on by an influx of sodium ions into the cell. Involves a change in membrane potential from the negative resting membrane potential towards a positive peak. The efflux of positively charged potassium ions out of the cell causes repolarozation. Depolarization: the rising phase of the action potential, brought on by an influx of sodium ions into the cell, from the negative resting membrane potential towards a positive peak. Repolarization: the return of the membrane potential to its normal negative value, from a peak of the action potential. Repolarization is caused by the efflux of positively charged potassium ions leaving the cell. As more positively charge leaves the cell, inside the cell becomes more negative relative to outside the cell.
No. 4 of 10 4. The Sinoatrial node? A. Contains pacemaker cells, which create action potentials at a frequency that results in a normal heart rate of 70-80 beats/minute. B. The central nervous system controls and initiates the rate of contraction of the heart. C. After the SA node receives the signal to contract from the AV node, the action potential spreads out over the right atrium. D. After the SA node receives the signal to contract from the AV node, the action potential spreads out over the left atrium. A. Correct! Sinoatrial node contains pacemaker cells, which create action potentials at a frequency that results in a normal heart rate of 70-80 beats/minute. Sinoatrial node contains pacemaker cells, which create action potentials at a frequency that results in a normal heart rate of 70-80 beats/minute. After the SA node initiates the signal to contract, the action potential spreads out over the right atrium. Eventually, the contraction impulse reaches the A-V node. After the SA node initiates the signal to contract, the action potential spreads out over the right atrium. Eventually, the contraction impulse reaches the A-V node. The heart has a unique, automatic electrical conducting system. The central nervous system (CNS) modulates the rate of contraction of the heart, but the heart can generate and maintain its own rhythm independent of the CNS. Sinoatrial node contains pacemaker cells, which create action potentials at a frequency that results in a normal heart rate of 70-80 beats/minute. After the SA node initiates the signal to contract, the action potential spreads out over the right atrium. Eventually, the contraction impulse reaches the A-V node.
No. 5 of 10 5. Which of the following statements about the atrioventricular node is correct? A. The atrioventricular (A-V) node receives the action potential from the right ventricle, and continues the contraction impulse. B. After the A-V node generates its signal for the ventricles to contract, the action potentials spreads to the left and right atria. C. The A-V node also contains pacemaker cells, and normally generates action potentials at a similar rate as the SA node. D. The A-V node also contains pacemaker cells, and normally generates action potentials at a faster rate as the SA node. The atrioventricular (A-V) node receives the action potential from the right atrium, and continues the contraction impulse. After the A-V node generates its signal for the ventricles to contract, the action action potentials spreads to the Bundle of His, down the left and right bundle branches and ultimately to the rest of the ventricles. C. Correct! The A-V node also contains pacemaker cells, and normally generates action potentials at a similar rate as the SA node. The A-V node also contains pacemaker cells, and normally generates action potentials at a similar rate as the SA node. The atrioventricular (A-V) node receives the action potential from the right atrium, and continues the contraction impulse. The A-V node also contains pacemaker cells, and normally generates action potentials at a similar rate as the SA node. After the A-V node generates its signal for the ventricles to contract, the action action potentials spreads to the Bundle of His, down the left and right bundle branches and ultimately to the rest of the ventricles.
No. 6 of 10 6. Which of the following statements about the electrocardiogram is correct? A. The P wave represents the depolarization as it spreads over the atria. B. The P wave represents the repolarization as it spreads over the atria. C. During the P wave time interval, the left and right ventricles contract. D. The QRS complex corresponds to the current that spreads over the atria; the atria contract during this time period. A. Correct! The P wave represents the depolarization as it spreads over the atria. The P wave represents the depolarization as it spreads over the atria. During the P wave time interval, the left and right atria contract. The QRS complex corresponds to the current that spreads over the ventricles; the ventricles contract during this time period. The electrocardiogram, detects the electrical activity of each heartbeat as it develops over time. The P wave represents the depolarization as it spreads over the atria. The left and right atrium contract during this time period. The QRS complex corresponds to the current that spreads over the ventricles; the ventricles contract during this time period.
No. 7 of 10 7. Peripheral resistance? A. Is due to smooth muscle around the post-capillary arterioles and it modulates blood pressure by changing peripheral resistance. B. Is due to smooth muscle around the pre-capillary arterioles and it modulates blood pressure by changing peripheral resistance. C. Can be increased by the relaxation of the smooth muscle and this leads to an increase in systemic blood pressure. D. Can be increased by the relaxation of the smooth muscle and this leads to a decrease in systemic blood pressure. Smooth muscle around arterioles modulates blood pressure by changing peripheral resistance. B. Correct! Smooth muscle around arterioles modulates blood pressure by changing peripheral resistance. Smooth muscle around arterioles modulates blood pressure by changing peripheral resistance. Smooth muscle around arterioles modulates blood pressure by changing peripheral resistance. Smooth muscle around arterioles modulates blood pressure by changing peripheral resistance. If systemic blood pressure is decreased, neuromodulation of the arterioles causes vasoconstriction, which, in turn, causes an increase in blood pressure. Normally, the pre-capillary smooth muscle permits blood flow through the capillary bed, to facilitate the exchange of oxygen, carbon dioxide and nutrients. If the systemic blood pressure decreases, the pre-capillary smooth muscle can constrict to increase the peripheral vascular resistance. Pre-capillary vasoconstriction will cause an increase in the systemic blood pressure.
No. 8 of 10 8. Platelets. A. Are cell fragments produced by stimulation of the spleen by thrombopoietin. B. Are cell fragments produced by stimulation of the bone marrow by thrombopoietin. C. Release anti-coagulation factors when activated and form a plug to stop bleeding, in conjunction with fibrin. D. Have a lifespan of approximately 1-2 years; they are destroyed in the liver. Platelets are cell fragments produced by stimulation of the bone marrow by thrombopoietin. B. Correct! Platelets are cell fragments produced by stimulation of the bone marrow by thrombopoietin. They release coagulation factors when activated and form a plug to stop bleeding, in conjunction with fibrin. Platelets have a lifespan of approximately 5-9 days; they are destroyed in the spleen. Platelets: cell fragments produced by stimulation of the bone marrow by thrombopoietin. Platelets have a lifespan of approximately 5-9 days; they are destroyed in the spleen. They release coagulation factors when activated and form a plug to stop bleeding, in conjunction with fibrin.
No. 9 of 10 9. Which of the following statement about blood clotting is correct? A. Platelets adhere to exposed endothelium and prevent the clotting cascade. B. Platelets adhere to intact endothelium and prevent the clotting cascade. C. Coagulation is an important process in which insoluble proteins form a soluble clot. D. Coagulation is an important process in which soluble proteins form an insoluble clot. Platelets adhere to exposed endothelium and contribute to the clotting cascade. Platelets adhere to exposed endothelium and contribute to the clotting cascade. Coagulation is an important process in which soluble proteins form an insoluble clot. D. Correct! Coagulation is an important process in which soluble proteins form an insoluble clot. The human body responds to changes in acid-base balance in the following ways: Acidosis ph < 7.35 - Compensated by stimulating the respiratory center and causing an increase in respiratory frequency. This causes decrease In Pco2 and a resultant increase in ph. Metabolic Acidosis (Low Bicarb. and ph) - Compensated by stimulating the respiratory center and causing an increase in respiratory frequency. This causes a decrease in Pco2 and a resultant increase in ph. Respiratory Acidosis (High Pco2 and low ph) - Compensated by stimulating the kidneys to increase the excretion of ammonium, which removes protons H+ along with the ammonium. This causes an increase in ph.
No. 10 of 10 10. Where does molecular oxygen disassociate with hemoglobin? A. In the lungs where hemoglobin s affinity for oxygen is lowest. B. In the tissue where hemoglobin s affinity for oxygen is the highest. C. In the lungs where hemoglobin s affinity for oxygen is highest. D. In the tissue where hemoglobin s affinity for oxygen is the lowest. Hemoglobin has a high affinity for molecular oxygen in the lungs and therefore, molecular oxygen stays bound to hemoglobin. In the tissue hemoglobin s affinity for oxygen is lower not higher, than the lungs and therefore disassociates there. It is true that in the lungs hemoglobin s affinity is highest, but this would cause molecular oxygen to stay bound to hemoglobin, not be released. D. Correct! In the tissue hemoglobin s affinity for oxygen is lower than the lungs and therefore disassociates there. When hemoglobin is in the lungs, its affinity is highest and this leads to a rapid binding and high oxygen saturation. As hemoglobin travels through the circulation and reaches the tissue, its affinity for molecular oxygen decreases and it disassociates there. The presence of higher carbon dioxide in the tissues and the resultant lowering of ph, in part contribute to the disassociation of molecular oxygen with hemoglobin.