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Please Help - The Heart

Debate and discussion of any biological questions not pertaining to a particular topic.

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Please Help - The Heart

Postby PleaseHelp » Sun Feb 21, 2010 10:03 pm

Hi,

I was given a take-home open book open notes open anything test in my Biology class. It was 12 pages long so please realize I'm not dumping all of my homework here.

I've been having an extremely difficult time figuring out the answers for 5 of the questions regarding the heart (2,3, 5, 9, 10). I've read the definitions in our text book and researched online but am stilled confused. If anyone is able to help I'd really appreciate it! Here are the problems, I'm copying the whole section including the ones in the section that I believe I've already got right:

Fill In the Blank:

Atrial Systole
Cardiac Output
Atrioventricular Node
Cardiac Sounds
Autonomic Nervous System
Diastole
Bundles & Conductive Fibers
EKG
Cardiac Cycle
Sinoatrial Node
Ventricular Systole

1. Sinoatrial Node the heart’s “pacemaker”, a mass of conductive tissue which produces the signal that initiates each new heart beat.
2. ___________________________ a mass of conductive tissue which generates the signal that initiates ventricular depolarization
3. ___________________________ the conductive tissues that conduct the signal for depolarization throughout the ventricular myocardium
4. EKG a clinical recording of the electrical energies created by depolarization and repolarization of the atrial and ventricular myocardium
5. ___________________________ its sympathetic division increases heart rate and its parasympathetic division slows heart rate
6. Cardiac Sounds “Lub” as the AV valves close, “dup” as the semilunar valves close
7. Cardiac Output Heart Rate X Stroke Volume; the amount of blood pumped into systemic circulation in 1 minute
8. Cardiac Cycle all the events associated with a single “heart beat”
9. __________________________ that stage of the Cardiac Cycle when the SA Node fires and the atrial myocardium depolarizes and contracts
10.__________________________ that stage of the myocardium that the heart pumps blood into systemic and pulmonary circulation
11. Diastole the time during each cardiac cycle that the heart is “at rest”.

Thanks!
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Re: Please Help - The Heart

Postby mamoru » Mon Feb 22, 2010 12:21 am

PleaseHelp wrote:Hi,
I've read the definitions in our text book and researched online but am stilled confused.

Are you sure about that? Because the definitions in any reasonable textbook or even the Wikipedia article on hearts will give almost identical definitions to those in the test questions.

Here, try this. Look up the definitions of the words on the word list again, and post the definitions you find next to the words, either by editing your original post or by replying. Because, really, this should be as simple as a dictionary search, google lookup, or a reading from your book on the chapter about heartbeat and circulation.
"Empathise with stupidity, and you're halfway to thinking like an idiot." - Iain M. Banks
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Postby mith » Mon Feb 22, 2010 12:24 am

surely if you know diastole, you know systole?
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Enjoying one moment at a time;
Accepting hardships as the pathway to peace;
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Re: Please Help - The Heart

Postby PleaseHelp » Mon Feb 22, 2010 1:15 am

Yes. I'm sure. I've spent hours trying to figure out this stupid thing. I've only found the answer for number 5.

Can you please tell me if these are correct?

2. bundles and conductive fibers
3. atrioventricular node
5. autonomic nervous system
9. atrial systole
10. ventricular systole

Definitions:
bundles and conductive fibers - These fibers are specialized myocardial fibers that conduct an electrical stimulus or impulse that enables the heart to contract in a coordinated fashion.

atrioventricular node - is a part of electrical control system of the heart that co-ordinates heart rate. It electrically connects atrial and ventricular chambers.[1] The AV node is an area of specialized tissue between the atria and the ventricles of the heart, specifically in the posteroinferior region of the interatrial septum near the opening of the coronary sinus, which conducts the normal electrical impulse from the atria to the ventricles.

atrial systole - is the contraction of myocardium of the left and right atria. Atrial systole occurs in late part of ventricular diastole, but it is important to note that the main force driving blood from the atria to the ventricles is not atrial contraction, but decreased ventricular pressure in ventricular diastole, atrial systole plays a minor, and additive role in forcing blood into the ventricles.

ventricular systole - contraction of the atria by which blood is forced into the ventricles; it precedes the true or ventricular systole.

depolarization - is a change in a cell's membrane potential, making it more positive, or less negative.
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Re: Please Help - The Heart

Postby mamoru » Mon Feb 22, 2010 1:29 am

PleaseHelp wrote:Yes. I'm sure. I've spent hours trying to figure out this stupid thing. I've only found the answer for number 5.

Can you please tell me if these are correct?

2. bundles and conductive fibers
3. atrioventricular node
5. autonomic nervous system
9. atrial systole
10. ventricular systole

I think your #2 and #3 are reversed. Otherwise you look fine. I'm surprised you didn't learn the name "Purkinje fibers" for the tissue that conducts the impulse the the bottom of the ventricles, but what's in a name, eh? ;) Anyway, the AV node is what "gathers" and slightly delays the impulse and conducts it to the Purkinje Fibers (bundles and conductive fibers), which then transmit the impulse to the bottom of the ventricles so they contract from the bottom up to push the blood out into the aorta and pulmonary arteries.
"Empathise with stupidity, and you're halfway to thinking like an idiot." - Iain M. Banks
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Postby jwalin » Mon Feb 22, 2010 3:44 am

Mamoru is right when he says
2 and 3 are reversed
it isn't what you do that matters but it is how you do it
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