Questions tagged [blood-circulation]

Tag for questions regarding the circulation of blood through out the organism and issues that may arise from dysfunction of systemic circulation.

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Does your blood stop moving in between heart beats?

Does blood stop moving in between heart beats or does it move continuously?
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1 answer
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How do I calculate a "full-life" from a half-life of substance elimination? [closed]

The half-time of carbon monoxide disappearance from blood under normal recovery conditions while breathing air showed considerable between-individual variance. For carboxyhaemoglobin concentrations of ...
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What is the connection between LDL, liver, and saturated fat?

I've been trying to learn about cholesterol, lipoproteins, and fats, but unfortunately, there is an ocean of confusing information on the internet. I don't have any solid background in biology, so ...
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2 votes
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Why does distention of the veins not decrease their resistance in the first case but decrease it in the second?

Here are two quotes from Guyton and Hall Textbook of Medical Physiology, Chapter 20 (emphasis mine): Why is venous resistance so important in determining the resistance to venous return? The answer ...
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Why does vasodilation increase blood flow in the capillaries, but decrease it in the chest during inspiration?

From Guyton and Hall Textbook of Medical Physiology: Every time a person inspires, the pressure in the thoracic cavity becomes more negative than usual, causing the blood vessels in the chest to ...
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What does equilibrium curve signify?

While learning about gas exchange, I came across the haldane effect. Then i came across the CO2 -dissociation curve. Apparently the curves are "equilibrium curves". Does it mean that the ...
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Why is pressure in renal artey higher than aorta?

I am preparing for an exam. I have come across this question recently that pressure in aorta is less than that in renal artery. I am aware of the effect of gravity on venous pooling and high venous ...
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Can blood vessels be weakend [closed]

Lets say everyday you fall off your bike and your leg starts bleeding at the same spot everytime. Do the bloodvessels at this spot get weakend and if yes, does less blood reach your foot because the ...
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How to understand the biophysics and math behind a 0.2 second delay between the pulse in my arm and my ankle?

I recently had a test with six blood pressure cuffs; 2 each on arms, ankles and big toes. During the test I could feel the pulses in my arms and legs, and noticed a distinct ~0.2 second delay between ...
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How does increased resistance to flow decrease blood pressure?

I have recently encountered this question: Waldenström's macroglobulinemia is a condition which causes increased blood viscosity due to high protein content in the blood. How would Waldenström's ...
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Why is heparin contraindicated in patients with severe uncontrolled hypertension?

Heparin is a parenteral anti coagulant- prevents clot formation by inhibiting factors 2 a and 10 a mainly. Now, patients with severe uncontrolled hypertension- have persistent bp of more than 140/90. ...
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Can small differences in blood pressure affect our cognition?

For my school work I'm doing a project on chaos theory and one of the chaotic systems in the body is blood pressure and the cardio vascular system as a whole. And I'm trying to research the effects ...
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Is there a closed path through the circulatory system that never passes through the liver?

I know the liver is responsible for doing lots of stuff to the blood, including both adding glucose and removing "weird stuff" (stuff destroyed by hepatocytes). And I know that ...
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Where is coagulation factor v produced?

My textbook (Physiology 9th edition, People's Medical Publishing House, Beijing) tells me that coagulation factor V is produced in endothelial cells and platelets, which is different from some other ...
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How do physics notions of fluid dynamics relate to pressure gradients in circulation?

I'm having a hard time comprehending why sometimes physiology notions seem to contradict each other and contradict physics teachings. More specifically I don't understand why aortic coarctation causes ...
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why dead mouse doesn't bleed when we cut their skin?

When we are pricked by a needle, we bleed nevertheless it's so small wound. But when we do mouse anatomy, it doesn't bleed even if we cut their whole abdominal skin. Other student asked about that, ...
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renal portal system

I am a high school student. In my textbook it is written that Mammals don't have renal portal system because they have four chambered heart. I understand that the four chambered heart keeps the ...
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External "lungs" that process your blood the same as your real lungs do - would that stop your need for breathing?

So say your blood goes with a tube out of your body. In an external device all the chemical/biological magic would happen and it would be fed back to your body. Of course this doesn't exist (yet), but ...
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Are antibodies removed before blood transfusion

I am an O blood group person meaning, I can donate my blood to all as I don't have any Antigen A and B. But my body does contain antibodies A and B right? If they were along with the donor blood, ...
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Does alcohol really helps to get substances get faster into the bloodstream? [closed]

I saw the video where Arnold Schwarzenegger cooks some protein cocktail and adds Austrian Schnapps to the mix, saying that it's to make everything get faster to the blood. Is it true or some kind of a ...
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Why does the formula for blood velocity hold true?

v = Q/A where v = velocity (cm/s) Q = blood flow (ml/s) A = cross sectional area (cm2) So the greater the cros sectional area, the lower the velocity, assuming that the cardiac output is a constant ...
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How does blood reach skin cells and other closely packed cells?

When I see diagrams of cellular structures such as the layers of the skin, these diagrams show the cells as being closely packed together. For example here is a typical such diagram: So, it shows the ...
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Concept of mean systemic filling pressure

Mean circulatory filling pressure (MCFP) in humans was defined by Guyton as "the pressure that would be measured at all points in the entiere circulatory system if the heart were stopped suddenly ...
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Ostium: insects circulatory system

What is this? Is this a part of the tubular heart? Does it pump hymolymph? Does it have ostium?
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Why is the blood thick in Wet Cupping / Hijama

I have just witnessed the wet cupping procedure being performed and have questions regarding the blood that is seen in the cups. I understand there are no studies that show cupping is an effective ...
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Consequences of abnormal blood pressure unrelated to cardiac output?

A question from Kaplan's MCAT Biology Review asks: In bacterial sepsis (overwhelming bloodstream infection), a number of capillary beds throughout the body open simultaneously. What effect would this ...
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16 votes
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Why are the pulmonary vein and artery not like the rest of circulatory system?

I'm learning anatomy. What I learnt is that we have arteries that have oxygenated blood which appears red in color, and branch blood to arterioles to deliver blood to cells via capillaries from where ...
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Why do arteries have a small lumen? [closed]

My biology textbook says that arteries have a small lumen relative to the thickness of their walls. I understand why they need thick walls, to withstand high pressure and stretch etc. But when ...
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What was the evolutionary benefit of enclosing hemoglobin in cells?

The ancestral solution to oxygen transport is with hemoglobin (or, similar proteins) dissolved in blood (or, "hemolymph", but, basically, dissolved in water. ) What was the advantage of enclosing the ...
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Why don't we bleed interstitial fluid?

Interstitial fluid is the fluid between cells in tissues - forming the medium between cells and capillaries. From what I gather, the typical human has 5L of blood and 11L of interstitial fluid. This ...
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Diastole/systole pressure in transcapillary circulation

The Starling equation factors in hydrostatic pressure and oncotic pressure. Given that the hydrostatic pressure in capillaries is pulsed, alternating between systole and diastole, does reabsorption ...
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Why is angiotensin converting enzyme localized in the lungs

I understand that it's also found elsewhere, such as in renal capillaries, but I can't see logic behind it being located in the lungs. Isn't ACE's function, through making more angiotensin II, causing ...
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Why does a stronger heart cause blood pressure go down

Intuitively, why does a stronger heart cause blood pressure to go down? The answers I've found from a cursory google search seem to indicate that it has to "work less hard" to pump the blood and that ...
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why do our eyes not go red in response to body temperature?

I know that blood flow increases/decreases in response to temperature change, which is why (lighter-skinned) people go red when they are hot. I know that the eye contains lots of blood vessels. Why ...
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A question about L-Citrulline

I know that L-Citrulline enters in the second step of urea cycle in the liver mitochondria and I wonder if a person takes an overdose of L-Citrulline wouldn't that cause mild hyperammonemia or at ...
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Why does higher venous volume increase atrial pressure?

If the cardiac output stays the same (hypothetically, although obviously it doesn't stay the same), then why does higher venous volume increase right atrial pressure? Shouldn't the flow rate be ...
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Why does glomerulus don't allow white blood cells to leave?

The glomerulus in nephrons are just a ball of capillaries, so why can't it allow the white blood cells to squeeze though the epithelial cells into Bowman's capsule just like the formation of tissue ...
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8 votes
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Is there any justification for the claim that blood travels 12,000 miles per day?

An oft-quoted "fact" on the internet1,2,3 (and at least once in print4) is the claim: Your body has about 5.6 liters (6 quarts) of blood. This 5.6 liters of blood circulates through the ...
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How much does capillary action contribute to blood flow to the human brain?

The BBC News Universal Wonders short video Why water is one of the weirdest things in the universe says after 01:50: Water molecules can float upwards against the ...
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4 votes
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How are monocytes larger than capillaries?

I have read that the average size of a capillary is about 8 micrometers. How is it possible that the 15 micrometer or so monocytes in blood do not block these vessels? https://en.m.wikipedia.org/wiki/...
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Cardiac cycle and atrial contraction

During atrial contraction ("a" in the figure), why does the ventricular pressure match the atrial pressure? The ventricular pressure generally stays the same throughout passive filling until it ...
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Why does muscle blood flow decrease during exercise?

My questions semi-relates to these two items: Where does extra blood come from to fill your muscles during exercise? , and Blood pressure during exercise . While reading Exercise Physiology by Dr. ...
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Coronary circulation

It is said that the coronary artery that gives the posterior descending artery(PDA) determines if the heart is right dominant(most cases) or left dominant. Is there any reason to this? Why PDA?
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Mechanism of redirected blood

I've read several fitness articles mentioning redirected blood flow to muscles that are in use. However, they never mention how it works. Is it local and specific to the muscles in use? Or, for ...
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When endothelial cells in blood vessels (arteries or veins) are damaged, does atheroma form first or blood clot?

I have learnt from Khan Academy's video on atheresclerosis that when the endothelial cells of an artery are damaged, atheroma forms at the site, and if the atheroma’s fibrous cap is ruptured, ...
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4 votes
2 answers
349 views

Why is urea not converted to ammonia in the body?

After the liver processes metabolites to produce urea and other by-products, these travel in the blood to the heart, then they are oxygenated, and some travel through the renal artery to the kidneys. ...
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2 votes
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How do veins's valve pocket sinus tend to become hypoxic?

For context, this question relates to the formation of deep vein thrombosis as I read that hypoxemia in vein can trigger coagulation cascade and cause a thrombus to form in vein. I read that vein's ...
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3 votes
2 answers
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Reaction of the body to heat

In massage school we are being taught hydrotherapy -- applying cold and heat to specific areas. It says that when applying cold, first the body goes through vasoconstriction, and then later ...
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Why does atheroma contain thromplastin/tissue factor?

From my understanding, when the endothelial lining of arteries is damaged, atheroma is formed at the site of the damaged area. If the atheromas is ruptured, thromboplastin contained in atheroma is ...
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The detail about the exact time of heart attack

Storage of cholesterol in coronary artery tends to heart attack. But in which phase heart attack occurs? Why only a definite time is called heart attack? Why this is the extreme point of coronary ...
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