Cardiac Quiz

[Code 3]

It's no secret that cirriculums for EMT-B drastically vary from program to program. However, it's interesting to see what some of these differences may be. Try your best to answer the following question. Please do not use the internet or any other forms of research in order to find the answer. You can, however, use your textbook if the information is provided and it was discussed in class. The object is to see if this information was given to you during lecture. Please do not hestitate to post vague answers if that is all you know. Good luck!

What are the primary functions of the Sinoatrial Node (SA Node) and Atrioventricular Node (AV Node)?

Extra credit points for those of you that can identify the roles of the Bundle of His and Purkinje Fibers.

 

[tydek07]

Hi,

I will not answer this, as I am a medic... and well, we learn this stuff inside and out.

I will however tell you that I would not have been able to answer this question before I went to medic school! I would have had no clue haha

This information was not covered in my EMT-Basic class at all.

Take Care,

 

[Sapphyre]

Sticking my neck out here, because, well, this was discussed in class, but, for some reason I doubt it was properly discussed.

The SA and AV nodes are, essentially, the heart's internal pacemaker. The electrical signal telling the heart to contract originates at the SA node. The AV node helps to regulate the rate.

Bundle of His I've never heard of. Purkinje Fibers, um, are those the ones that control the valves?

 

[rhan101277]

We learned this in class, I will give it a shot. The SA node is the hearts pacemaker, the electrical impulse starts here. Then it moves onto to the AV node, where just after that point there is some sort of resistance which slows down the signal before it moves onto the bundle of his, giving time for the ventricles to fill. Then it moves down the septum and across all the purkunji fibers causing the ventricles to contract. We also learned that in some cases where the SA node cells malfunction that the heart can be paced by the AV node, which results individuals having heart rates of 60bpm rested.

I hope I am not way off base, but our class is extremely stringent so I hope I got it right. This material was covering in class in detail.

 

[micsaver]

What are the primary functions of the Sinoatrial Node (SA Node) and Atrioventricular Node (AV Node)?
I remember them talking about it briefly in class and then I did some research on my own to learn more. This was a little while ago. I think the SA Node starts the beat rhythm and is the fastest. It sends the signal to the AV node which slows the conduction / beat speed.

Extra credit points for those of you that can identify the roles of the Bundle of His and Purkinje Fibers. The BofH and PF are along the the center and bottom of the Ventricles. The AV node sends the signal to the BofH and PF causing the ventricles to contract.

 

[jochi1543]

Urgh, without using the book all I can say is that they are pacemakers. SA node is capable of generating the fastest beat, I believe it can make the heart go above 60 bpm? If SA is damaged, AV is able to maintain the heartbeat at a slower rate, I'm tempted to say something like 40-60 bpm. Purkinje fibers are the last resort and they maintain a very slow HR when SA and AV nodes both fail (I think <20? Or 20-40 bpm?). I think they also serve to conduct impulses from the nodes to the heart muscle.

I have no recollection of the function of bundle of His whatsoever, although I definitely studied it in my A&P class before.:wacko:

 

[Noctis Lucis Caelum]

SA Node = Pacemaker, electrical impulse starts and travels to the
AV Node = Regulator, tells SA to slow down if its too fast

I have no idea about the bundle of his and that fibers

Notes are in my backpack, 2 lazy to take'em out but thats whats on my mind right now

 

[AnthonyM83]

Doubt most people in my class (probably including me) could answer that two months after the course...possibly not even during the course. I'm sure it was briefly covered.

Of course, one should continue their education on their own after EMT class....

 

[seanm028]

I know that the sinoatrial node is the primary pacemaker for the heart, and that the atrioventricular node takes over if the SA node's rate drops below a certain level.

I believe that the Bundle of His and the Purkinje Fibers are conduction pathways, but I can't tell you their functions besides that.

I learned all this from a book someone gave me called "Basic Arrhythmias". I don't believe we discussed it in EMT-B class, but I could have just forgotten exactly where I learned it first. I think we might have gone over the fact that the SA node is the pacemaker.

 

[PapaBear434]

What are the primary functions of the Sinoatrial Node (SA Node) and Atrioventricular Node (AV Node)?

Extra credit points for those of you that can identify the roles of the Bundle of His and Purkinje Fibers.

Yeah, I didn't even hear of any of this stuff until my ALS classes. I just completed EMT-B as of March, so it's not like I went through it a long while ago. They just don't teach this.

Pretty much what I learned, some of which you've probably seen on those joke lists before:

If it's bleeding, push on it until it stops.

If it's warm, wet, sticky, and not yours, don't touch it without a glove.

Oxygen. You can't go wrong with Oxygen. Lot's and lots of oxygen. O2 is good, blue is bad.

Air goes in and out,blood goes round and round, any variation on this is a bad thing and should be corrected ASAP.

The address is never clearly marked.

The end. Asking about nodes of the heart is a bit out of the scope of practice. The only thing we have to worry about regarding the heart is what the little man in the AED tells us in that oh-so-polite but insistent voice.

 

[JPINFV]

The end. Asking about nodes of the heart is a bit out of the scope of practice. The only thing we have to worry about regarding the heart is what the little man in the AED tells us in that oh-so-polite but insistent voice.

Education is never out a level's scope of practice.

 

[EMERG2011]

What are the primary functions of the Sinoatrial Node (SA Node) and Atrioventricular Node (AV Node)?

Extra credit points for those of you that can identify the roles of the Bundle of His and Purkinje Fibers.

SA Node - Primary pacemaker of the heart. Located at the apex of the right atrium. Normally discharges action potentials at a rate of 100/minute, causing the heart to beat.

AV Node - Located between atria and the ventricles of the heart, at the origin of the bundle of his. The AV node normally works as a capacitor for the action potential released by the SA node, delaying the transmission of the impulse to the ventricles so that the atria have sufficient time to discharge. In abnormal function, the AV node can act as the primary pacemaker of the heart, and discharges at a rate of 80( think thats right...) beats per minute.

His and Purkinje Fibers - electroconductive fibers of the heart (think: wiring). Transmit the impulse from the SA and AV nodes to the muscle tissues of the heart.

And no - I didnt have to look this up!

 

[stephenrb81]

Education is never out a level's scope of practice.

Agreed

As an EMT, I was constantly bugging medics "What is that drug" "How does it work" "What does that bump on the monitor mean".

Most were happy to teach, I did work with one that always replied "It's beyond your scope of practice, don't worry about it" but he was a <Insert male genitalia here>

My eagerness to learn before entering a paramedic program helped me fly through pharmacology and cardiac A&P

Again to quote JPINFV: Education is never out of a level's scope of practice

 

[PapaBear434]

Education is never out a level's scope of practice.

You misunderstand. I am currently in my ALS classes, so I am furthering my education. But the actual training that goes into EMT-B doesn't cover this stuff.

 

[stephenrb81]

You misunderstand. I am currently in my ALS classes, so I am furthering my education. But the actual training that goes into EMT-B doesn't cover this stuff.

True, in most cases it isn't but some instructors do add a little advanced A&P to facility understanding. My basic course actually did cover a little of this so that we had a little more understanding of Vfib/Vtach and how an AED worked. Granted it wasn't required but it was nicer than simply saying "This shocks the heart to stop it and we hope like hell it starts again"

Now I didn't have a clue about automaticity and such until Medic school

 

[mycrofft]

SA: ignition coil. AV: distributor. Sort of.

OK, check these out:

"WPW syndrome"
"Pre-cordial thump"

(No ,the latter is not what you do to someone before they drink a liqeur to make them choke).-_-

 

[AbsoluteZzZero]

The SA node is where the electrical signal first starts. The signal travels from the SA node across the atria and then travels down the middle of the heart(cant remember the correct name for that) and stimulates the AV node where the signal is "regrouped" and sent across the ventricles.

I just typed that from what I remember from class. Didn't read any of these posts or look in my text. But yes, it was definitely explained before we went into "Cardiac Emergencies". Also, just to throw this out, I just graduated from a 3 week intensive course. It was definitely intensive, but super thorough as well!

 

[VentMedic]

just graduated from a 3 week intensive course. It was definitely intensive, but super thorough as well!

Some of those words don't go together.

Oh wait, you're from Florida.

Okay, me bad.

Back to the subject of the thread.

 

[JPINFV]

Since it's quiz time, here's one.

The sympathetic nervous system causes three changes in the heart whereas the parasympathetic only causes two changes in the heart. The two effects of the parasympathetic innervation are directly opposite of the sympathetic nervous system. Which effect of the sympathetic nervous system is not counteracted by the parasympathetic nervous system?

 

[Sasha]

OK, check these out:

"WPW syndrome"
"Pre-cordial thump"

(No ,the latter is not what you do to someone before they drink a liqeur to make them choke).-_-

Pre-cordial thump is when you witness a pt go into v-fib/v-tach but dont have a defibrillator immediately handy but its on its way ( think AH! Get the defibrillator/crash cart out of room 6!! ) and it delivers around 5J, I think, of energy. Its not part of protocol anymore, is it?

WPW, Wolff Parkinson White syndrome is a rare, congenital heart problem. Isnt that where there are extra accessory pathways between the atria and the ventricles? Arent they usually tachy? Verapamil and digoxin are contraindicated for WPW.