NURS 401 Exam 3 Questions And Correct Answers 2024-2025
Where in the heart do the electrical impulses originate? ("Pacemaker" of the heart)
-Answer SA Node
Fill in the blank:
Autorhythmic cells in the _____ node _____________ (depolarize/repolarize). The
de/repolarized charge travels through the _________ to the ____ node. The _____ node
________ (quickens/slows) electrical conduction by 0.1 seconds, allowing a break
between atrial and ventricular contraction. The electrical charge then goes to the
__________, which then divides into the __________, which then further subdivide into the
_____________. -Answer Auto-rhythmic cells in the SA node DEPOLARIZE. The
Depolarized charge travels through the INTERNODAL TRACTS to the AV node. The AV
node SLOWS electrical conduction by 0.1 seconds, thus allowing a break between atrial
and ventricular contraction. The electrical charge then proceeded to the BUNDLE OF
HIS, which then branched into the LEFT AND RIGHT BUNDLE BRANCHES, which then
furthered to the PURKINJE FIBERS.
Bundle of His sets a pulse rate of: - Answer 40-60 bpm
The Purkinje fibers set a pulse rate of: - Answer 20-40 bpm
The SA node is reflected in which part of an ECG? - Answer P wave
,The AV node slowing electrical impulses is reflected in which part of an ECG? - Answer
PR interval (0.1 seconds)
Why is the left bundle branch larger? - Answer Because the left side of the heart is
larger and requires more force/strength for contraction.
What does the P wave represent on an ECG? - An-swer Atrial depolarization
(contraction)
What does the QRS complex represent on an ECG? - An-swer Ventricular depolarization
(contraction)
What does the T wave represent on an ECG? - An-swer Ventricular repolarization
(relaxation)
What is the term for a normal electrical conduction rhythm on an ECG? - An-swer Sinus
Rhythm
What is sinus bradycardia? -Answer SA node rate is <60 BPM. Everything is normal, just
too slow.
What is sinus tachycardia? -Answer SA node rate is >100 BPM. Everything is normal,
just too fast
Where is the PR interval measured? What does it represent? -Answer Measured from
the beginning of the P wave to the beginning of the QRS complex.
Represents the time it takes for the Atrium to depolarize, send signal to AV node, AV
node to delay signal, then for the signal to travel to the purkinje fibers. (Atrium + AV
node + delay + purkinje fibers)
, Where is the PR segment measured? What does it represent? - Answer *think of it as a
SEGMENT of the PR interval
This should be measured from the end of the P wave to the beginning of the QRS
complex and should reflect a flat or isometric line.
This reflects the time it takes the signal to travel through the AV node, pause, then to the
purkinje fibers - AV node + delay + purkinje fibers.
*this should make sense- the p wave measures atrial depolarization; the PR segment
does not include the p wave in its measurement, so atrial depolarization is not included
in this like it is in the PR interval*
Where is the QRS complex measured? What does it represent? - Answer Measured from
the beginning of the Q to the end of the S.
Where is the ST segment measured? What does it represent? -Answer Measured from
end of QRS complex to beginning of T wave (should a flat/isometric line).
Represents early ventricular repolarization. If the segment is not flat, this suggests the
problem is likely related to something wrong w/ the ventricles.
Where is the measurement for the QT interval taken? What does this represent?
-Answer Measured from the beginning of the QRS complex to the end of the T wave.
Represents the time taken for the ventricles to completely contract and completely
relax.
What is the normal timing for a P wave? QRS complex? - Answer P wave should be no
greater than 5 small blocks (0.12-0.2 seconds)
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Easton. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.99. You're not tied to anything after your purchase.