4
votes
3answers
89 views

How does strength of a pulse related to EKG(ECG)?

There are variabilities in the heart rate as well as strength of heartbeats. I want to know if one can predict which heartbeat will be strong or weak based on the corresponding EKG/ECG signal. I am ...
0
votes
0answers
12 views

How Calcium regulated in myocardic AP and plateau phase?

The plateau phase is maintained by influx of calcium and outflux of potassium in the second stage: My conjuncture is that calcium transforms between two phases ionated phase (free calcium from ...
1
vote
1answer
29 views

Fast standing and the heart's insufficient accommodation of the increased venous return

Assume you are 45 minutes on the supine position. Furthermore: you stand all of a sudden and fast and without sympaticus activity. The venous return (smooth musculature of vessels) accommodates ...
0
votes
0answers
22 views

Projection space of ML II channel in ECG

I am trying to find the approximate effective 3D region of the heart that is drawn from the ML II channel of the standard ECG either by using many channels or using one channel only (not possible ...
1
vote
0answers
26 views

Is it okay to do carotid sinus massages during palpitations? [closed]

Is it okay to do carotid sinus massages during a palpitation to slow the heart down?
0
votes
1answer
70 views

What is atrial fibrillation?

I am wondering exactly what a-fib is (causes and symptoms). I would really appreciate having a sample of an EKG with it (because in my limited research, I have found it nearly impossible to find just ...
1
vote
0answers
35 views

What is the nature of action potentials in autonomic nervous system?

My conjuncture is that the natures of sympathetic and parasympathetic action potentials are different. My findings propose me that sympathetic action potential is little longer lasting than ...
0
votes
0answers
26 views

Are there naturally occurring Biological Pacemakers?

There are artificial biological pacemakers which express funny channels. I am thinking if it is possible to have also naturally occurring (only in recovery cases and in silent tissues) biological ...
0
votes
0answers
10 views

Mechanisms to start simultaneous depolarisation of two Pacemakers?

I am thinking the biochemical mechanisms of the simultaneous depolarisations of two pacemakers. My intuition Funny channels (but not alone) No autonomic nervous system (my conjencture) What are ...
0
votes
0answers
14 views

What are the mechanisms of disabling extrinsic control of heart?

I started this thread by thinking this question but I developed it further below What is the mechanism maintaining refractory period of pacemakers? My conjuncture is that the mechanism is the ...
0
votes
0answers
22 views

Which reflex arcs work in Heart with extrasystoles?

I am researching what is triggering the extrasystoles - initial idea from this thread about Which ionic channels of Pacemakers can work in very low frequencies in extrasystole? I am interested in the ...
0
votes
1answer
14 views

Which ionic channels of Pacemakers can work in very low frequencies in extrasystole?

At frequency 0-3 Hz. Like computer processors which can work at low frequencies and controlling under- and overvoltage. Normal most significant channels are Ca2+ and K+ that are changing. However, I ...
0
votes
0answers
14 views

Calling for Pressure pictures about Right and Left atrium

I am trying to understand the partially patent foramen ovale in patients with right-side heart failure. I am interested how the pressure in right and left atrium change in normal case in abnormal ...
0
votes
2answers
41 views

Is Sinus node conduction necessary for heart beating?

Assume a patient with previous cardial infaction which SA node not possible to activate action potential anymore. However, SA trying to beat unsuccessfully repeatedly waisting energy. Therefore, I ...
0
votes
0answers
20 views

Laser surgery to stop damaged Sinus node from beating

I am trying to find any publication about laser surgery to stop the damaged sinus node which cannot anymore beat. I could only find publications which modifies SA node function. I am not sure if it ...
0
votes
0answers
28 views

Normal Frequencies in Heart

I am trying to visualise possible ranges of frequencies from different structures of heart: different valves and their possible frequencies heart sounds I - IV and their normal frequencties what can ...
1
vote
0answers
32 views

How do the symptoms of Sepsis affect heart function?

I have intuition that Sepsis with infection can cause spastic functioning of heart during systole heart working spontaneously in snatches during systole atrial fibrillation first contraction of ...
-3
votes
1answer
36 views

Which chemical and hormonal effects on heart are by metabolites?

I am thinking which hormonal and chemical effects from: catecholamines thyroxin corticosteroids sex hormones prostaglandins Ca2+ Na+ K+ can be be regarded as metabolites i.e. intermediates or ...
0
votes
1answer
24 views

What is the quality rate of intrinsic autoregulation in the heart?

Autoregulation is the maintenance of constant blood flow to an organ in spite of fluctuations in Blood pressure. It involves the relaxation of myocardium and contraction. It is local. I know that ...
0
votes
1answer
25 views

Are there any forms of heart failure where cell size decreases?

I think hypertrophy happens in most of the cases. However, I am not sure if hypertrophy always happens. I started to think about wet lungs (pulmonary reason for the left-sided heart failure). Can the ...
0
votes
1answer
51 views

What is the difference between intracardiac and extracardiac reflexes in cardiac regulation?

The primary parameters of heart pumping are strength of contractility (inotropic positive; Frank-Starling relationship) rate of relaxation (lusitropic positive) heart rate (chronotropic positive) ...
2
votes
2answers
155 views

Why there is a very high drop in pressure from arteries to arterioles?

Laplace law explains why the pressure is the same in aorta and arteries (100). I am thinking why there is so big drop in pressure when going from arteries to arterioles (40-60). Why there is a great ...
0
votes
1answer
36 views

Late control mechanisms of blood pressure (arterial) level?

I first covered the fast and moderate control mechanisms which I think are Fast control: Baroreceptive reflex (tonus), Chemoreceptive reflex (CO$_2$). Moderate control: Bicarbonate (ECF), ...
0
votes
1answer
584 views

Which processes are during the latent period of ventricular contraction?

The latent period is the time between the start of depolarisation and the start of contraction. I know that the contraction of ventricles starts after sufficient influx of Ca2+ and threshold ...
0
votes
0answers
29 views

To define the total Resistance of Systemic Blood Circulation

Some systems are in parallel so let's just call those like $R_{\text{lungs}}$. I got this formula $$R_{\text{total}}=R_A+R_a+R_c+R_V+R_v$$ where $R_c$ capillaries, $R_a$ arterioles, $R_A$ Small ...
2
votes
1answer
71 views

Why does the arch of aorta coils?

My study materials use the word vesselcompression chamber of aorta to emphasize aorta's elastic property. The arch of the aorta only coils, not its straight part. I think the reason why the arch ...
1
vote
0answers
30 views

Voltage-gated Potassium channels in the action potential of cardiomyocyte?

There is one type of potassium voltage-gated channels open in Phase 1 too. Some call them early repolarization channels. I am not convinced that the channels are different in different phases: 0, 2, ...
0
votes
0answers
52 views

Why is the resting membrane potential of cardiomyocyte more stable than that of Pacemaker in Phase 4?

There must be some channels that keeps this very stable. It seems to be that the resting membrane potential of pacemaker cells is steadily increasing until the threshold voltage. I think the same must ...
0
votes
1answer
25 views

Why is Aorta sometimes called Compression chamber?

I find this statement that Aorta is called Compression Chamber in my study materials. Aorta can it keeps blood flowing it can accumulate potential energy for bumping and compression However, why ...
0
votes
1answer
62 views

Regional circulation and Cardiac output? [closed]

I am reading my study materials and think what is the systemic POV here Regional circulation Blood flow within the tissue/organs based on the functional demands of the tissue. E.g. The ...
0
votes
1answer
43 views

Can you approximate Cardiac Output by Ohm's law?

I found this sentence from my notes which I cannot understand PR < CO, CO $\uparrow$, PR > CO $\downarrow$ where ...
1
vote
1answer
68 views

Is end-systolic volume (ESV) the same as residual volume?

I am reading this site and my study materials. The end-systolic volume (ESV), 50-60 ml, is the volume of blood found in ventricles after systole and contraction of ventricles. I think ESV is the same ...
1
vote
0answers
72 views

Sodium levels and blood pressure

Why does low $\ce{Na+}$ levels cause hypotension (low blood pressure). Alternatively, why does excessive intake of $\ce{Na+}$ cause hypertension or high blood pressure? From what I ...
2
votes
1answer
813 views

fibroblast cells and fibers

I am interested in fibroblast cells in human arteries. Here are the things that I am not clear at the moment and I could not find any answer from the literature: What are the dimensions of these ...
2
votes
1answer
392 views

Why is the blood pressure in the superior vena cava during inhalation less than during the exhalation?

For further investigation into the progress of the blood pressure, we will measure a patient's blood pressure in the superior vena cava measured during inhalation and during an exhalation. His heart ...
16
votes
3answers
282 views

How is the blood volume of a living organism measured without killing it?

How is the blood-volume of an organism measured without killing it? NOTE: The blood-volume of an organism is defined as the total volume of blood present inside that organism.
8
votes
2answers
374 views

Why is blood pressure higher the more distal an artery is?

Why is blood pressure generally higher in more distal arteries?
3
votes
1answer
103 views

Are ectopic beats considered sinus rhythm for pNN50 purposes?

One quantification of the heart rate variability of an ECG is pNNx, i.e. the proportion of consecutive NN distances that differ by at least 50 ms. When a premature beat occurs, the preceding and ...
4
votes
1answer
148 views

Is a raised baseline between T and QRS normal in any ECG lead?

Here are excerpts from an unknown ECG lead. I find it weird that the "baseline" changes after the T wave and doesn't return until after the following QRS complex. Is that normal/expected for any lead? ...