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hi doctors iam astudent doctor at the first year in medical school i want to ask you aquestion please,we all know that when the heart ends from the reduced ejection phase in the cardiac cycle,there are 5ml of blood remain in the left ventricle the question that i want to ask is why this amount of blood remain in the ventricle some of my doctors told me that if this amount of blood vanished the ventricle would collapse :rolleyes:but my mind cannot accept that as the ventricle is a muscular wall how could it be collapsed?:confused::confused:thanks alot............
 

Rollo

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I think it's reserves in cases like during exercise, the heart can increase its cardiac output by increasing the stroke volume without having to increase the heart rate too much.
 

CaliSurferDoc

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I think Rollo is correct. When you exercise, your EDV will decrease slightly because of an increased HR (the time between pumps shortens).

SV = EDV - ESV
CO = SV * HR
 
OP
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thanks for replying doctor but i think that in cases of exercise the venous return increases as the cardiac output increases so these 5 ml of blood are still there without approaching to them is that right?
 

CaliSurferDoc

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The 5ml is not static. If the same 5ml was left inside the LV after every pump, different pathogens will have the opportunity to grow and invade the myocardial tissue, causing pathology.
 
OP
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yes i know that doctor what i mean is the volume of the 5ml is the same but not the same blood so the blood of this 5ml change during the cardiac cycle but the volume is still 5ml so it will not result in pathology or myocardial damage that is what i understand is that true?
 

sindadel

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Venous return will increase, but it takes a little time (at least one cycle). It's useful to have that extra blood there to increase your cardiac output immediately in the case of e.g. seeing a bear and needing to run. So transiently, there is an imbalance, but it resolves quickly.
 

turkeyjerky

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yes i know that doctor what i mean is the volume of the 5ml is the same but not the same blood so the blood of this 5ml change during the cardiac cycle but the volume is still 5ml so it will not result in pathology or myocardial damage that is what i understand is that true?
lol, what?

where do you get 5 ml from? maybe if you had like a 95% ef, but that just doesn't happen (or a heart the size of a humingbird's) also, quit calling people doctor--it's just weird
 
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First of all, your writing is atrocious, 8th grade level. To answer your question, it just does. My guess is that larger hearts have a larger esv, and smaller hearts have a smaller esv, not a constant 5 ml across all heart sizes. Now you are asking why is there 5 ml left. I think there are 2 factors to consider. First is the afterload, which also determines the LVP at esv, and also the length tension relationship of cardiac muscle. At short lengths, the cardiac muscle tension is at equilibrium with the afterload, which results in the incomplete ejection of blood that you see.


hi doctors iam astudent doctor at the first year in medical school i want to ask you aquestion please,we all know that when the heart ends from the reduced ejection phase in the cardiac cycle,there are 5ml of blood remain in the left ventricle the question that i want to ask is why this amount of blood remain in the ventricle some of my doctors told me that if this amount of blood vanished the ventricle would collapse :rolleyes:but my mind cannot accept that as the ventricle is a muscular wall how could it be collapsed?:confused::confused:thanks alot............
 

Disinence2

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Hello,

Think of it the same as your reserve volume when it comes to breathing.

I'm not an expert but 5ml seems a bit low.

You can't have a ejection fraction of 100% so there will always be some blood left over.

I doubt understanding "why" this happens will come up on your exams or step 1.

Best of luck
 

Droopy Snoopy

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First of all, your writing is atrocious, 8th grade level.
The guy's a medical student asking a good question about cardiac physiology. Maybe give him the benefit of the doubt and assume he's got English as a 2nd or 3rd language, not lazy or stupid?

That, or just refrain from being an a-s-s-hole altogether.
 

gracie369

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"Cofuse" Does that mean you along with another person are confused? "Professor Smith, David and I are both cofused."
 

chiz2kul

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The guy's a medical student asking a good question about cardiac physiology. Maybe give him the benefit of the doubt and assume he's got English as a 2nd or 3rd language, not lazy or stupid?

That, or just refrain from being an a-s-s-hole altogether.
:thumbup:
 

AbbyNormal

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hi doctors iam astudent doctor at the first year in medical school i want to ask you aquestion please,we all know that when the heart ends from the reduced ejection phase in the cardiac cycle,there are 5ml of blood remain in the left ventricle the question that i want to ask is why this amount of blood remain in the ventricle some of my doctors told me that if this amount of blood vanished the ventricle would collapse :rolleyes:but my mind cannot accept that as the ventricle is a muscular wall how could it be collapsed?:confused::confused:thanks alot............
Not a doctor, I am a critical care RN.

Prior to the start of systole, the LV is filled with blood to the capacity known as end diastolic volume (EDV) during the filling phase or diastole. During systole, the LV contracts and ejects blood until it reaches its minimum capacity known as end systolic volume (ESV), it does not empty completely. The ventricle stops ejecting blood at the end of systole when the pressure in the aorta equals the pressure within the heart which causes the aortic valve to close which stops blood from traveling backward into the heart.

I believe you misunderstood your instructor saying only 5 ml of blood would remain in the LV. That is too low for an adult human heart.

Typical values are end-diastolic vol = 120 ml; end-systolic vol = 50 mil

stroke vol = EDV - ESV
thus 70 ml = 120 ml - 50 ml

Those values are an average adult heart at rest without disease.

I disagree a bit with Rollo and CalisurferDoc. They are not completely wrong though.

When the body needs increased oxygen/blood most of the increase in cardiac output is due to an increase in heart rate (HR). Change of posture, increased sympathetic nervous system activity, and decreased parasympathetic nervous system activity can also increase cardiac output. HR can vary by a factor of approximately 3, between 60 and 180 beats per minute, while stroke volume (SV) can vary between 70 and 120 ml, a factor of only 1.7. Again we are talking about a healthy heart without disease.

Clear as mud?
 

Knicks

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The guy's a medical student asking a good question about cardiac physiology. Maybe give him the benefit of the doubt and assume he's got English as a 2nd or 3rd language, not lazy or stupid?

That, or just refrain from being an a-s-s-hole altogether.
Win.
 
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Oh no! was someone an ahole on the internet???

OP, i apologize for hurting your feelings. I must have irreparably destroyed your self worth without even realizing it. I really am a bad person.

Nice job tic, for your contribution to this thread. :thumbup:

The guy's a medical student asking a good question about cardiac physiology. Maybe give him the benefit of the doubt and assume he's got English as a 2nd or 3rd language, not lazy or stupid?

That, or just refrain from being an a-s-s-hole altogether.
 

AbbyNormal

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Oh no! was someone an ahole on the internet???

OP, i apologize for hurting your feelings. I must have irreparably destroyed your self worth without even realizing it. I really am a bad person.

Nice job tic, for your contribution to this thread. :thumbup:





 
OP
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ok guys thanks to all of u but i wanted to mention that the word (cofuse)was a typing mistake and i know it is (confuse) so this is not abig deal and thanks for explanation finally i know that (why)wouldnot be asked in my 1st year exams but i just wanted to understand .thanks alot again:):love:
 
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OP
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Oh no! was someone an ahole on the internet???

OP, i apologize for hurting your feelings. I must have irreparably destroyed your self worth without even realizing it. I really am a bad person.

Nice job tic, for your contribution to this thread. :thumbup:
thanks for apologizing doctor but save it to your self, i donnot need it .
and there is something i wanted to tell u (my feelings werenot hurt,as i ignore any rude reply):nono::nono:thanks again...:p:D
 

ChimpanzeeMinky

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Oh no! was someone an ahole on the internet???

OP, i apologize for hurting your feelings. I must have irreparably destroyed your self worth without even realizing it. I really am a bad person.

Nice job tic, for your contribution to this thread. :thumbup:
What strikes me as odd is that not only is her English terrible, but she doesn't know how to use a space bar. 2nd language English speakers use space bars for their own languages, don't they?
 
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Well, spaces, capitalizations, and punctuations are highly overrated. I for one am glad to see they finally got rid of them in foreign english classes. And run on sentences really do make you say seem like a likeable person. No wonder I've always felt like hugging and cuddling incoherent foreigners every time they say something nonsensical.

Tic, I see you agree that such writing makes you appear lazy or stupid, even if you are not. These days, it is quite fashionable to appear to be so, wouldn't you say?
 

Rollo

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Never did I imagine that discussion about cardiac physiology would turn into grammar debate...

:laugh:
 

richse

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Not a doctor, I am a critical care RN.

Prior to the start of systole, the LV is filled with blood to the capacity known as end diastolic volume (EDV) during the filling phase or diastole. During systole, the LV contracts and ejects blood until it reaches its minimum capacity known as end systolic volume (ESV), it does not empty completely. The ventricle stops ejecting blood at the end of systole when the pressure in the aorta equals the pressure within the heart which causes the aortic valve to close which stops blood from traveling backward into the heart.

I believe you misunderstood your instructor saying only 5 ml of blood would remain in the LV. That is too low for an adult human heart.

Typical values are end-diastolic vol = 120 ml; end-systolic vol = 50 mil

stroke vol = EDV - ESV
thus 70 ml = 120 ml - 50 ml

Those values are an average adult heart at rest without disease.

I disagree a bit with Rollo and CalisurferDoc. They are not completely wrong though.

When the body needs increased oxygen/blood most of the increase in cardiac output is due to an increase in heart rate (HR). Change of posture, increased sympathetic nervous system activity, and decreased parasympathetic nervous system activity can also increase cardiac output. HR can vary by a factor of approximately 3, between 60 and 180 beats per minute, while stroke volume (SV) can vary between 70 and 120 ml, a factor of only 1.7. Again we are talking about a healthy heart without disease.

Clear as mud?
Thank you! I was reading through the previous responses and wondering why no one was correcting all the bad info. This is exactly what I just learned in cardiac physio so I am inclined to believe it is 100% correct.
 

username456789

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Definitely assumed this was a troll just by hovering on the thread on the main forum and seeing the atrocious writing coupled with the screen name. Add in the frequent addressing of obvious med students (and nurses) as "doctor" despite being corrected, and I'm still not convinced I'm wrong.

Oh well, carry on.