LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins- answer key.pdf

4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Due: 11:59pm on Saturday, April 6, 2024 To understand how points are awarded, read the Grading Policy for this assignment. IP: Action Poten...

4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Due: 11:59pm on Saturday, April 6, 2024 To understand how points are awarded, read the Grading Policy for this assignment. IP: Action Potentials in Autorhythmic Cells Click on the link or the image below to view an animation on cardiac action potentials from Interactive Physiology (IP), then answer the questions to the right. IP: Action Potentials in Autorhythmic Cells Part A Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the membrane? Hint 1. Which of these structures would enable ions to move easily from one cell to another? ANSWER: tight junctions intercalated discs desmosomes gap junctions Correct Yes, action potentials generated by the autorhythmic cells spread waves of depolarization to contractile cells through gap junctions. If the depolarization causes the contractile cells to reach threshold, they will in turn generate an action potential. Part B One of the changes that occurs in the pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is a decreased efflux of what ion? Hint 1. Decreased efflux of this ion must cause depolarization (the inside of the cell becoming less negative) so that threshold is reached. ANSWER: sodium calcium potassium https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 1/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Correct Yes, if there is a decreased efflux of potassium while there is a normal influx of sodium, the inside of the cell would become less negative. Thus, threshold would be reached. The ability of these autorhythmic cells to spontaneously depolarize is what results in the pacemaker potential. Part C When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane? Hint 1. Depolarization is due to the inside of the cell becoming less negative (or more positive). ANSWER: potassium fast sodium slow calcium fast calcium Correct Yes, unlike nerve cells or cardiac muscle cells, fast calcium channels are responsible for the depolarization phase of the autorhythmic cell action potential. When the fast calcium channels open, calcium rushes into the cell making it less negative (or more positive). Part D Repolarization of an autorhythmic cell is due to the opening of which channels? Hint 1. For repolarization, the inside must become more negative. ANSWER: Chemically gated potassium channels voltage-gated sodium channels chemically gated calcium channels voltage-gated potassium channels Correct Yes, opening of voltage-gated potassium channels causes positive potassium ions to move out of the cell. This efflux of potassium causes the cell to become more negative inside thus, repolarizing the cell. Part E In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells? Hint 1. Movement of what ions from the autorhythmic cells (or adjacent cells) would cause the contractile cells to depolarize (become less negative/more positive)? ANSWER: https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 2/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins the flow of positive ions from adjacent cells an unstable resting membrane potential in the contractile cells the flow of negative ions from adjacent cells Correct Yes, the flow of positive ions from the autorhythmic cells (or adjacent cells) brings the membrane to threshold initiating depolarization of the contractile cell. IP: Intrinsic Conduction System of the Heart Click on the link or the image below to view an animation on the Intrinsic Conduction System of the Heart from Interactive Physiology (IP), then answer the questions to the right. IP: Intrinsic Conduction System of the Heart Part A Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart? Hint 1. This area is known as the pacemaker of the heart. ANSWER: Purkinje fibers AV bundle (bundle of His) AV node SA node Correct Yes, the SA Node spontaneously depolarizes, causing the wave of depolarization that spreads through the rest of the conduction system and heart. Part B What does the ECG wave tracing represent? Hint 1. Remember that this wave is recorded from electrodes placed on the skin on various parts of the body. ANSWER: https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 3/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins electrical activity in the heart contraction of the heart Correct Yes, the ECG waves show the depolarization and repolarization in various areas of the heart. Part C What does the QRS complex represent in the ECG wave tracing? Hint 1. This is a large wave. Which are larger in the heart, the ventricles or atria? ANSWER: atrial repolarization atrial depolarization ventricular repolarization ventricular depolarization Correct Yes, the QRS complex represents depolarization in the ventricles, which have greater mass than the atria. Part D Contraction of the atria results from which wave of depolarization on the ECG tracing? Hint 1. Which happens first, atrial or ventricular depolarization? ANSWER: P wave T wave QRS complex Correct Yes, the P wave represents atrial depolarization, which leads to atrial contraction. Part E Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles? Hint 1. If this part delays the impulse before it moves into the ventricles, where must it be located? ANSWER: https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 4/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Purkinje fibers SA node AV bundle (bundle of His) bundle branches AV node Correct Yes, the AV node slows down the impulse giving the atria time to contract before the ventricles contract. SmartArt Video: Conducting System Watch the SmartArt Video for chapter 18, and then complete the question at right. Part A The portion of the tracing of an electrocardiogram, ECG, that represents ventricular depolarization is the __________. ANSWER: P-R segment T wave QRS complex Q wave P wave Correct The QRS complex represents the entire events of ventricular depolarization. PAL: Cadaver > Cardiovascular System: Heart > Lab Practical > Question 1 https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 5/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Part A Identify the highlighted vessel. ANSWER: anterior interventricular artery Correct PAL: Cadaver > Cardiovascular System: Heart > Lab Practical > Question 5 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 6/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Identify the highlighted structures. ANSWER: chordae tendineae Correct PAL: Cadaver > Cardiovascular System: Heart > Lab Practical > Question 8 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 7/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Identify the highlighted structure. ANSWER: interventricular septum Correct PAL: Cadaver > Cardiovascular System: Heart > Lab Practical > Question 13 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 8/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Identify the highlighted structures. ANSWER: papillary muscles Correct PAL: Cadaver > Cardiovascular System: Heart > Lab Practical > Question 15 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 9/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Identify the highlighted vessel. ANSWER: posterior interventricular artery Correct PAL: Cadaver > Cardiovascular System: Heart > Lab Practical > Question 16 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 10/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Identify the highlighted structure. ANSWER: pulmonary semilunar valve Correct PAL: Cadaver > Cardiovascular System: Heart > Lab Practical > Question 17 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 11/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Which chamber of the heart ejects blood into the highlighted vessel? ANSWER: right ventricle Correct PAL: Cadaver > Cardiovascular System: Heart > Lab Practical > Question 18 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 12/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Identify the highlighted vessel. ANSWER: pulmonary trunk Correct PAL: Cadaver > Cardiovascular System: Heart > Quiz > Question 2 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 13/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Which artery is highlighted? ANSWER: left common carotid left subclavian aortic arch brachiocephalic trunk Correct PAL: Cadaver > Cardiovascular System: Heart > Quiz > Question 3 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 14/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Which vessel is highlighted? ANSWER: superior vena cava ascending aorta inferior vena cava pulmonary trunk Correct PAL: Cadaver > Cardiovascular System: Heart > Quiz > Question 4 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 15/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Which valve is highlighted? ANSWER: bicuspid aortic semilunar pulmonary semilunar tricuspid Correct PAL: Cadaver > Cardiovascular System: Heart > Quiz > Question 9 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 16/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Which structure is highlighted? ANSWER: pulmonary trunk fibrous pericardium covering heart ascending aorta visceral pericardium covering heart Correct PAL: Cadaver > Cardiovascular System: Heart > Quiz > Question 11 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 17/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Which vessel is highlighted? ANSWER: coronary sinus superior vena cava inferior vena cava right coronary artery Correct PAL: Cadaver > Cardiovascular System: Heart > Quiz > Question 12 Part A https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 18/19 4/1/24, 10:06 PM LW - Chapter 20 - the Heart Functionality and Cadaver Heart ID ~15 mins Which structure is highlighted? ANSWER: left auricle right auricle right ventricle left ventricle Correct Score Summary: Your score on this assignment is 100%. You received 4.5 out of a possible total of 4.5 points. https://session.masteringaandp.com/myct/assignmentPrintView?assignmentID=10505312 19/19