BCIT NSCC 7150 MIDTERM UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS
Question:
1. what are the 2 characteristics of mechanical cells?
Answer:
1. contractility (allow to shorten and return to original length)
2. extensibility (ability of muscle fibres to stretch)
Question:
2. what are the 5 characteristics of electrical cells
Answer:
1. automaticity:
ability to generate an electrical impulse spontaneously, without external
stimulation
2. excitability:
the ability of cardiac cells to depolarize in response to an electrical stimulus
3. refractoriness:
the period of time which cardiac electrical cells are unresponsive to any stimulus,
regardless of strength
4. rhythmicity:
the ability of cardiac pacemaker cells to fire at regular intervals
5. conductivity:
the spread of electrical activity from one specialized cardiac cell to another
Question:
3. sinoatrial node (SA node)
Answer:
-where electrical impulses begin, 60-100 bpm
-can conduct faster; max 180 per min, sinus tachycardia
Question:
4. internodal tracts
Answer:
-3 pathways in the right atrium that connect the SA to the AV node
-anterior middle and posterior tracts
-abnormal pathways exist
,Question:
5. atrioventricular node (AV node)
Answer:
-floor of the right atrium just above the tricuspid valve
-delays conduction of impulses from the SA node to give time for the atria to
contract
-CANT generate impulses, but some junctional tissue cells can if the SA nodes fail.
40 to 60 times/min
Question:
6. bundle of His (and bundle branches)
Answer:
-arises from the AV junction and passess into the interventricular septum, where it
divides into the right and left bundle branches.
-right goes down interventricular septum and terminates in purkinje fibres
-left goes down interventricular septum and divides into 2 branches or fasciles,
the superior and the inferior branches of the left bundle. terminate in the purkinje
fibres
Question:
7. purkinje cells
Answer:
-form a network across both the left and right ventricles
-pacemaker cells throughout that can form impulses IF SA and junctional tissue
sites fail
-less than 40 per min
Question:
8. describe the 6 steps of electrical flow throughout the
heart
Answer:
1. impulse arises in SA node
2. pass through the intermodal tracts
3. to the AV node
4. the impulses flow to the bundle of His
5. through the bundle branches
6. terminating at the purkinje fibres
, Question:
9. vector
Answer:
-physical quantity that has direction and magnitude.
-detected by ACG electrodes
-vary in size depending on the amount of current that is flowing. ie less electrical
flow, smaller vector.
Question:
10. if electricity flows toward the negative electrode, the
patterns produced on the graph paper will be ____
Answer:
inverted
Question:
11. if electricity flows toward the positive elctrode, the
patterns produced on the graph paper will be ____
Answer:
upright
Question:
12. action potential
Answer:
-the difference in the concentration of positive and negative ions across the cell
membrane at any given time
-polarization, depolarization, and repolarization
Question:
13. polarization
Answer:
-the resting state during which no electrical activity occurs in the cardiac cells
-inside of the cell is more negative than outside. due to Na+, K+, and Ca+.
QUESTIONS AND CORRECT ANSWERS
Question:
1. what are the 2 characteristics of mechanical cells?
Answer:
1. contractility (allow to shorten and return to original length)
2. extensibility (ability of muscle fibres to stretch)
Question:
2. what are the 5 characteristics of electrical cells
Answer:
1. automaticity:
ability to generate an electrical impulse spontaneously, without external
stimulation
2. excitability:
the ability of cardiac cells to depolarize in response to an electrical stimulus
3. refractoriness:
the period of time which cardiac electrical cells are unresponsive to any stimulus,
regardless of strength
4. rhythmicity:
the ability of cardiac pacemaker cells to fire at regular intervals
5. conductivity:
the spread of electrical activity from one specialized cardiac cell to another
Question:
3. sinoatrial node (SA node)
Answer:
-where electrical impulses begin, 60-100 bpm
-can conduct faster; max 180 per min, sinus tachycardia
Question:
4. internodal tracts
Answer:
-3 pathways in the right atrium that connect the SA to the AV node
-anterior middle and posterior tracts
-abnormal pathways exist
,Question:
5. atrioventricular node (AV node)
Answer:
-floor of the right atrium just above the tricuspid valve
-delays conduction of impulses from the SA node to give time for the atria to
contract
-CANT generate impulses, but some junctional tissue cells can if the SA nodes fail.
40 to 60 times/min
Question:
6. bundle of His (and bundle branches)
Answer:
-arises from the AV junction and passess into the interventricular septum, where it
divides into the right and left bundle branches.
-right goes down interventricular septum and terminates in purkinje fibres
-left goes down interventricular septum and divides into 2 branches or fasciles,
the superior and the inferior branches of the left bundle. terminate in the purkinje
fibres
Question:
7. purkinje cells
Answer:
-form a network across both the left and right ventricles
-pacemaker cells throughout that can form impulses IF SA and junctional tissue
sites fail
-less than 40 per min
Question:
8. describe the 6 steps of electrical flow throughout the
heart
Answer:
1. impulse arises in SA node
2. pass through the intermodal tracts
3. to the AV node
4. the impulses flow to the bundle of His
5. through the bundle branches
6. terminating at the purkinje fibres
, Question:
9. vector
Answer:
-physical quantity that has direction and magnitude.
-detected by ACG electrodes
-vary in size depending on the amount of current that is flowing. ie less electrical
flow, smaller vector.
Question:
10. if electricity flows toward the negative electrode, the
patterns produced on the graph paper will be ____
Answer:
inverted
Question:
11. if electricity flows toward the positive elctrode, the
patterns produced on the graph paper will be ____
Answer:
upright
Question:
12. action potential
Answer:
-the difference in the concentration of positive and negative ions across the cell
membrane at any given time
-polarization, depolarization, and repolarization
Question:
13. polarization
Answer:
-the resting state during which no electrical activity occurs in the cardiac cells
-inside of the cell is more negative than outside. due to Na+, K+, and Ca+.
