Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Heart and ECG.
441 Exam 1
| Question | Answer |
|---|---|
| Cardiac excitation normally begins with ... | the SA node |
| what does the SA node do? | repeatedly depolarize to threshold spontaneously- pacemaker potential |
| By conducting along the atrial muscle fibers, the action potential reaches the | AV node |
| after the AV node the action potential reaches the... | AV bundle |
| the bundle is the only site where action potentials can.. | conduct from the atria to ventricles |
| after the AV bundle, the AP enters the... | R and L bundle branches |
| the bundle branches extend through the... | interventricular septum towards the apex |
| purkine fibers rapidly | conduct the AP beginning at the apex of the heart upward to remainder of ventricular myocardium |
| an electrocardiogram (ECG or EKG) EKG-from German word is | a recording of the electrical signals of the heart; a composite record of action potentials produced by all of the heart muscle fibers during each heart beat |
| electrocardiograph is | the instrument used to record the changes |
| what can an ECG determine? | if the conducting pathways is abnormal, if the heart is enlarged, if certain regions of the heart are damaged, and the cause of chest pain |
| The P wave represnets | atrial depolarization |
| Atrial depolarization spreads from the ________ through the _________ | SA node; contractile fibers in the atria |
| The QRS complex represents the onset of ___________ | rapid ventricular depolarization |
| The T wave indicates _________ | ventricular repolarization; occurs just as ventricles are starting the relax |
| The T wave is __________ and ___________ than the QRS complex. Why? | smaller and wider because repolarization occurs more slowly than depolarization |
| Reading an ECG, the _________ of the waves can provide clues to abnormalities | size |
| Larger P waves indicate… | enlargement of the atria |
| An enlarged Q wave may indicate a … | myocardial infarction |
| An enlarged R wave generally indicates… | enlarged ventricles |
| The T wave is flatter than normal when.. | the heart is receiving insufficient oxygen; ex) CAD |
| The T wave may be elevated in… | hyperkalemia (high blood K+ level) |
| Analysis of an ECG involves measuring… | the time spans between waves |
| Time span between waves | intervals or segments |
| The P-Q interval is from the.. | beginning of the P wave to the beginning of the QRS complex |
| What does the P-Q interval represent? | conduction time from the beginning of atrial excitation to the beginning of ventricular excitation |
| Another way to look at it.. the P-Q interval is the time.. | required for the action potential to travel through the atria, AV node, and remaining fibers of the conduction system. |
| What happens to the P-Q interval in disorders such as CAD and rheumatic fever? | it lengthens |
| The S-T segment | begins at the end of the S wave and ends at the beginning of the T wave |
| S-T segment represents | time when the ventricular contractile fibers are depolarized during the plateau phase of the action potential |
| The S-T segment is elevated above the baseline in.. | acute myocardial infarction |
| The S-T segment is depressed below the baseline in.. | the heart receives insufficient oxygen |
| The Q-T interval goes from …. | the start of the QRS complex to the end of the T wave |
| Q-T interval is the time … | from the beginning of the ventricular depolarization to the end of ventricular repolarization |
| The Q-T interval may be lengthened by…. | myocardial damage, myocardial ischemia, or conduction abnormalities |
| Myocardial ischemia | decreased blood flow |
| Systole | contraction |
| Diastole | relaxation |
| The ECG waves predict… | the timing of atrial and ventricular systole and diastole |
| ECG graph paper is divided into… | 1 mm sections |
| Horizontal spacing | .04 sec at 25 mm/sec |
| Bold lines | .04 x 5 |
| Vertical lines | 10 mvolts |
| 10 mm | 100 mvolts |
| upward deflections | positive |
| downward deflection | negative |
| Normal P wave time | .11 sec long, 2-3 mm tall |
| PR normal interval time | .12-.20 sec |
| QRS normal interval time | .05-.10 sec |
| Q wave norm time | .04 sec, ¼ -1/3 height of R wave |
| What is S wave? | ventricular depolarization away from electrode |
| QT seg norm time | .4 to .44 sec |
| What is J point? | where ST takes off from Q |
| A longer QRS complex time may mean ________ | conduction block |
| Each little horizontal box ( 1 mm ) is the equivalent of how many seconds when the ECG is running at 25 mm/ sec? | .04 sec |
| A normal PR interval time is… | .12 to .20 |
| A set of limb leads is…. | aVL, ll, and lll |
| For normocardia, the HR must be… | 60-100bpm |
Created by:
sbush0804
Popular Anatomy sets