9
votes
Accepted
Is a one ventricle heart feasible?
Alternative Heart Morphologies
Amphibians and some reptiles have a three-chambered heart, with 2 atria and a single ventricle. There are still separate circulatory pathways for the lungs and the rest ...
- 46.5k
6
votes
How do physics notions of fluid dynamics relate to pressure gradients in circulation?
As far as we know so far, biology isn't able to break any laws of physics.
However, biology isn't passive: biological systems react to changing environments to maintain some level of homeostasis. ...
- 46.5k
6
votes
Accepted
How to understand the biophysics and math behind a 0.2 second delay between the pulse in my arm and my ankle?
So it turns out that your estimate is not bad, by simple velocity calculation, I get it to be a little over 50% out (see below), but as you say, there is some error in your measurement. However, it ...
- 12.9k
6
votes
Accepted
Why do people perceive blood pressure as the force that moves the blood forwards (see details)?
In the vascular system, pressure is what moves blood forwards, at least in an analogous manner to voltage...just like voltage, pressure itself doesn't move things, but a pressure gradient does. You ...
- 46.5k
5
votes
Osmotic Pressure in Capillaries
Fluid movements across capillary wall is determined by 2 main factors.
Hydrostatic Pressure (Blood Pressure) - tends to push fluid out of the blood vessel
Osmotic Pressure - Tends to pull fluid back ...
5
votes
Accepted
Why does high blood pressure not damage the body during exercise?
Actually it can. See https://clinicalhypertension.biomedcentral.com/articles/10.1186/s40885-016-0052-y for instance:
Deleterious effects of HRE [hypertensive response to exercise] on structure and ...
- 3,062
4
votes
Accepted
Do afterload and stroke volume form part of a negative feedback loop in blood pressure regulation?
However, it then seems that hypertension, which increases afterload, would lead to a decrease in blood pressure and form a negative feedback loop. Is this in fact what happens in the human body?
Yes ...
- 25.9k
4
votes
Accepted
Consequences of abnormal blood pressure unrelated to cardiac output?
Blood pressure, as you noted, is just a means to an end: the flow of blood through tissues. The trouble is, many of the body's regulatory systems use blood pressure (rather than flow) as an index of ...
- 1,307
3
votes
How do physics notions of fluid dynamics relate to pressure gradients in circulation?
First, you are misapplying Bernoulli's law. At each point, Bernoulli's law says that $$\text{constant}=P+\frac{\rho v^2}{2}$$ But remember, that constant is not constant in time for unsteady flows; ...
- 131
3
votes
How does sodium ion increase blood pressure?
Sodium acts on the juxtaglomerular cells of the kidney, which are then activated to produce and secrete renin. Renin hydrolyses angiotensinogen into angiotensin I. Next angiotensin converting enzyme (...
- 2,482
3
votes
High Blood Pressure - Na or NaCl?
High blood pressure is caused by an excessive amount of fluid circulating in the blood vessels, or an excessively small mean blood vessel diameter. The later is more associated with stress situations ...
- 631
3
votes
What could an increase in systolic blood pressure and decrease in diastolic mean?
First, a couple of considerations
Heart rate (HR) is lower when seating, and even lower when lying. I assume that participants were seated when the first measure was taken.
Cardiac output is not ...
- 31
2
votes
Do afterload and stroke volume form part of a negative feedback loop in blood pressure regulation?
Not really following your logic at all, but maybe it helps to think that the parameter that needs to be held constant to deliver sufficient/constant blood to tissues is cardiac output.
All you need is ...
- 46.5k
2
votes
Accepted
How are limits determined for systotic and diastotic blood pressure?
120/80 are not upper limits on blood pressure - many people have blood pressures far in excess of those numbers. Instead, these are numbers beyond which studies have shown connections to negative ...
- 46.5k
2
votes
Accepted
Cardiac cycle and atrial contraction
While blood is flowing into the ventricle, it can never be at a higher pressure than where blood is flowing from: if it was, the flow would be going in the other direction. Flow is always from higher ...
- 46.5k
2
votes
Accepted
Why does the formula for blood velocity hold true?
In the capillaries the A must be extremely low
For a single capillary yes, the area is small.
However, these statements are not referring to a single capillary! They are referring to the entire ...
- 46.5k
2
votes
Why does the formula for blood velocity hold true?
The trick here is that 1 mL = 1 cm3 (or cc). So if you divide cm3/s by cm2 the result will be in cm/s. What that means is that the blood volume has three dimensions - if you picture the vessel as a ...
- 2,485
1
vote
Accepted
why dead mouse doesn't bleed when we cut their skin?
From personal experience, extracting organs/tissues of over 1000 mice I can give some hints:
Mice blood coagulates quite fast after death. If you need to extract blood, you are under time-pressure and ...
- 1,597
1
vote
What terms or concepts are used to describe the morning metabolic phenomenon involving glucocorticoids, glucose, and blood pressure?
Morning surge, Prewaking surge, Sleep-trough surge, Rising surge.
Example of article using the terms:
"Morning Surge in Blood Pressure and Cardiovascular Risk"
https://www.ahajournals.org/...
- 113
1
vote
The blood pressure when blood comes out of body
Blood pressure is the pressure above barometric pressure. When you pump up a blood pressure cuff, or a tire for that matter, you don't have a gauge with a line at 760 torr / mmHg; you're measuring ...
- 2,485
1
vote
Accepted
Why is angiotensin converting enzyme localized in the lungs
ACE is present on the luminal surface of vascular endothelia throughout the body and is abundantly present in the endothelium-rich lungs.
ACE in the kidney—particularly in the endothelial cells of ...
- 4,836
1
vote
Accepted
Blood pressure in the blood vessels
Answer: You are right that if you had one big pipe that was getting progressively narrower, the pressure in that pipe would increase. In the vascular system, you have one big pipe emptying into ...
- 26
Only top scored, non community-wiki answers of a minimum length are eligible