The study of the physiology and pathology of the cardiovascular system
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3answers
210 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.
9
votes
2answers
163 views
Does arterial blood always flow away from the heart?
Is there a negative net flow of blood in human arteries at any point of the cardiac cycle? I realise that blood flow can be turbulent, e.g. in the aorta or around stenotic arteries, but then the ...
8
votes
2answers
360 views
How does sodium in one's diet affect blood pressure?
Due to high blood pressure, my doctor has recommended I go on a low-sodium diet. So, that got me wondering what it is about sodium that drives this recommendation?
What does sodium do to a body ...
8
votes
2answers
275 views
Why do people say that trans fatty acids are bad for your health?
I've heard from several sources that trans FAs are bad for you and their consumption will lead to cardiac problems, and that they are indigestible.
But I also learned from biochemistry that they are ...
8
votes
3answers
182 views
Why is blood pressure higher the more distal an artery is?
Why is blood pressure generally higher in more distal arteries?
7
votes
2answers
429 views
What effect does ambient temperature have on the cardiovascular system?
I am sorry if this is not appropriate for this site, but I think it fits so I am asking it here:
I went for a run yesterday, and it was about -8 degrees Celsius. I was wearing a couple pairs of ...
5
votes
3answers
288 views
When to measure resting heart rate and blood pressure for following day-to-day trend?
I'd like monitor my resting heart rate and blood pressure to see how they are affected by regular cardiovascular training and other events in life.
When should I take the measurements in order to ...
4
votes
1answer
86 views
How quickly can the human heart rate rise and fall?
How quickly can the human heart rate rise and lower?
For example lets say a human heart rate is rested and is at 60BPM and that person is suddenly scared to trigger their fight or flight reaction. ...
4
votes
1answer
96 views
intravenous (IV) in the tail vein of an anaesthetized mouse
I trained myself to do intravenous injection on live mice. However, on anaesthetized mice you don't see the flux of your product showing that your injection was successful. In the same way, on live ...
4
votes
1answer
98 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?
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3
votes
1answer
117 views
How do insects such as crickets circulate blood through their antennae?
Some insects, like the crickets pictured below, have such slender antennae it seems no blood could fit. How do they get blood through their antennae?
3
votes
1answer
47 views
Does the Heart Require Gold?
I distinctly remember an episode of NOVA from the early 1980’s that concerned itself with gold. One of the points that was made was that there are trace amounts of gold in the human body, ...
3
votes
1answer
94 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 ...
3
votes
2answers
31 views
Can stress echocardiography show coronary blood flow difference before and after exercise?
Stress echocardiography means a pair of cardiac ultrasound imaging examinations, before and after exercise. I assume that coronary blood flow is increased after exercise. Is cardiac ultrasound ...
3
votes
0answers
32 views
What percentage of human capillaries are located in the skin?
As in the subject line, what percentage of capillaries in a human (expressed in terms of total length, I suppose) are located in the skin, as opposed to internal organs? Google scholar has not turned ...
2
votes
1answer
67 views
What is the surface area of the human heart?
I heard that the human heart had a surface area of 1000 square feet, and I thought that that cannot be true. So what is the surface area of the human heart and what are the different ways it can be ...
2
votes
1answer
54 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 ...
2
votes
1answer
54 views
Why is elevated homocysteine considered a risk factor for angina?
Elevated homocysteine levels are listed among risk factors for angina. How is homocysteine related to the heart? Or the coronary arteries? How do these relationships make it a risk factor for angina?
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1
vote
1answer
130 views
Is it possible that the recipient of a heart transplant would display some of the donor's personality traits, as if the heart has memories?
I've read somewhere that after a person has a heart transplant, it is possible that his/her attitude, action or behavior would change slightly or significantly, as though he/she possesses some aspects ...
1
vote
1answer
121 views
Amount of neurons in the heart
Finding numbers for the amount of neurons in the brain is quite easy. Finding them for other human organs is harder. How many neurons are there in the human heart?
1
vote
1answer
15 views
Do nerve cells cause action potential in cardiac muscle?
I think the answer is no, but I am not 100% sure.
If it was yes, then the dendrite of the nerve cell should each time receive a stimulus causing Na+ channels to open, when the contraction happen.
...
1
vote
1answer
26 views
What's seen when stress echocardiography shows ischaemia? Can this happen without angina?
What can be seen on the screen when stress echocardiography (a pair of heart ultrasounds before and after exercise) suggests ischaemia? Can this happen without chest pain?
Illustration from ...
1
vote
0answers
28 views
If a receptor is inhibited throughout embryogenesis, could there be observable phenotypic differences in the adult?
So I read a journal article entitled "Maternal hypoxia and caffeine exposure depress fetal CV function during primary organogenesis" (Momoi, et al., 2012) and in essence the article speaks of the ...
1
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0answers
22 views
Can we make any judgements about sleep or readiness to sleep from a heart rate metric and/or pulse oxymetry?
I'm looking at inexpensive and un-intrusive ways to quantify the state of human body/mind . One of these is Actigraphy, which is a study of human motion over time. This can be done with an iPhone ...
