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Exam(Elaborations)SHARP ECG TEST Rated 100% Correct!!
Question 1: What are the layers of the heart?
CORRECT ANSWER : pericardium, myocardium, endocardium
Question 2: What is the pericardium?
CORRECT ANSWER : outermost layer: fibrous and serous
Question 3: What is the fibrous layer of the pericardium?
CORRECT ANSWER : outer sack that anchors the heart
Question 4: What is the serous layer of the pericardium?
CORRECT ANSWER : inner, fluid secreting membrane with
two layers - parietal (lines inner surface of fibrous sac), visceral (AKA epicardium) lines myocardium - between the two is the pericardial space, with 10-30ml of fluid to give the heart space to relax and contract
Question 5: What is the myocardium?
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CORRECT ANSWER : i. Thick, middle muscular layer that
makes up the bulk of the heart wall ii. Composed of cardiac muscle cells and is responsible for the heart's ability to contract
Question 6: What is the endocardium?
CORRECT ANSWER : i. Thin layer of tissue that lines the inner
surface of heart muscle and heart chambers ii. Extensions and folds of this tissue forms the valves of the heart.
Question 7: What are the 4 primary characteristics of the heart?
CORRECT ANSWER : automaticity, excitability, conductivity,
contractility
Question 8: What is automaticity?
CORRECT ANSWER : i. Specific to the pacemaker cells; ability
to generate their own electrical impulse spontaneously
Question 9: What is excitability?
CORRECT ANSWER : Ability of ALL cardiac cells to respond
to an electrical impulse
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Question 10: What is conductivity?
CORRECT ANSWER : i. Ability of ALL cardiac cells to
conduct an electrical impulse
Question 11: What is contractility?
CORRECT ANSWER : i. Specific to muscle cells; ability to
cause cardiac muscle contraction
Question 12: Which electrons/ions are responsible for
depolarization/repolarization of the heart muscle?
CORRECT ANSWER : Potassium, Sodium
Question 13: What is the role of Potassium in the heart muscle?
CORRECT ANSWER : i. Primary ion inside the cell ii. Plays a
role in depolarization and repolarization
Question 14: What is the role of Sodium in the heart muscle?
CORRECT ANSWER : i. Primary ion outside the cell ii. Major
role in depolarization
Question 15: What is the sodium-potassium pump?
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CORRECT ANSWER : i. Actively transports ions across the
membrane against the electrochemical gradient ii. In a resting cardiac cell, there are more negative ions on the inside than the outside. This is a resting, or polarized cell. No electrical activity is occurring and there is an isoelectric (straight) line on ECG
Question 16: What is depolarization?
CORRECT ANSWER : i. When a cell is stimulated, potassium
begins to leave the cell, increasing permeability to sodium ii.Sodium rushes in, causing the inside of the cell to be more positive than negative iii. Contraction is a mechanical process that FOLLOWS the electrical event of depolarization
Question 17: What is repolarization?
CORRECT ANSWER : i. Sodium-potassium pump activated to
transport sodium out of the cell and move potassium back into the cell ii. Inside becomes more negative again
Question 18: What are positive, negative, and biphasic
deflections?CORRECT ANSWER : i. Positive deflection: electric current