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 decrease in peripheral vascular resistance decrease blood pressure or increase blood flow?

like peripheral vascular resistance is directly proportional to diastolic blood pressure but it is also inversely proportional to cardiac output(which is proportional to systolic blood pressure) So ...
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Can we apply ohm's law and poiseulle's law on blood exactly as it is?

Since blood pressure,resistance and blood flow are so dependent on each other,how do the above two laws fit. like blood flow has components dependent on blood pressure(after load) and furthermore ...
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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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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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Why does higher venous volume increase atrial pressure?

If the cardiac output stays the same, then why does higher venous volume increase right atrial pressure? Shouldn't the flow rate be conserved (with a constant cardiac output) so that the venous return ...
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Are there macrophages in the blood vessels and within the blood stream?

Monocytes are phagocytes that "evolve" or "differentiate" into macrophages. I read that there are monocytes in the blood stream and vessels and that macrophages are found mainly in other tissues and ...
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Absorption vs Secretion

Qouted from Junqueira's Basic Histology textbook : "Ion and water transport across epithelia can occur in either direc- tion, depending on the organ involved. (a) Absorption is the pro- cess of ...
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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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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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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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132 views

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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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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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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Does the body have a mechanism for cleaning plaque buildup in arteries?

Is there a self synthesized substance in the body, or a mechanism that can break down plaque in arteries ?
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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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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 body three ...
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Which types of blood vessels can regenerate in humans/mammals?

Which types of blood vessels can regenerate in humans/mammals? From what I understand, arteries and arterioles can be created later in life, while this is not necessarily the case with veins. However ...
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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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Do camels have nucleated RBCs or enucleated RBCs?

Most mammals have enucleated RBCs as an adaptation to facilitate the transport of oxygen. My text says that camels and llamas are exceptions to these. I was wondering why they are exceptions, and 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 ...
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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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increase in blood pressure can in turn decrease it?

increase in blood pressure can actually decrease it? bp=co*TP and cardiac output (co) decreases when after load increases, because with the increase of the after load, stroke volume decreases. ...
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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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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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1answer
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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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263 views

Can systemic intravascular thrombosis cause brain infarction?

I wonder if the thrombus can pass through the brain-blood barrier because I think small molecules like O2, CO2 and ethanol can pass it. Probably, in some diseases where the permeability of the barrier ...
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262 views

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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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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85 views

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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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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Are blood vessels organs?

Are blood vessels classified as organs? Organs compose of 2 or more tissues and perform a certain function. Blood vessels have 3 different tissues and perform a function (transport blood), yet I do ...
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Where does the human brain drain to?

When a brain has a aneurysm and the patient survives untreated then where does that blood drain to or how is it absorbed? How is the pain perceived?
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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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296 views

Relationship between mN and mg in vessel contraction studies?

What is the relationship between mN and mg as the units involved to measure the changes in contraction? A tool most widely used is an instrument called myograph. In these exoeriments, either units of ...
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217 views

Why are veins not blocked by plaques?

In my textbook, it is written that atheromatous plaques block the artery. This leads to heart attack and and heart failure. But my question is why do the plaques only block arteries and not the veins? ...
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Do fat people have more chances of developing nitrogen bends?

I was reading some text on deep sea physiology. I got to know that solubility of nitrogen in fat is five times that in water. The exact text from the book animal physiology adaptation and environment ...
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112 views

What are the effects of oxygen toxicity in human blood?

I was reading some text on deep sea Physiology, and for to know that diving to do could cause oxygen toxicity in the blood. This was the exact text from the book Textbook of Medical Physiology by ...
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Why are higher doses of atropine required to produce central effects?

Reason given in my book is restricted entry into the brain..is it something to do with the chemisty?
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In adverse effects of Heparin, why is bleeding from deeper organs more common?

The reason given in my book is that it i because it interferes with the secondary hemostasis..but i did not understand how that implies that bleeding from deeper organs is more common..
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“Blood circulation”. Why blood bleeds in atmosphere ?

If our body's blood pressure is 120 mm-Hg then why blood goes out of our body in 760 mm -Hg pressure if we have cuts?
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Does blood carry metallic nanoparticles?

I find this particular chart about constituents of blood very informative and interesting. Looking through the different components, I see metals such as copper, zinc, etc. Are these only carried as ...
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Why do we feel numbness and an electric sensation in our legs after standing for too long?

We have all felt that numbness while standing immobile for a while.It gets difficult to walk.It can also happen if we are just putting some pressure on our legs Why does this happen? I'd like to ...
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How does vasodilation slow blood flow?

During inflammation, cytokines and histamine cause vasodilation to increase blood flow to the inflamed area. However, it is also said that vasodilation slows blood flow which facilitates the adhesion ...
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If someone's arm is cut off, how does that affect blood circulation throughout their body?

Essentially what I'm asking is that if someone's arm is amputated, doesn't that cut off a significant part of their blood flow because the blood vessels that normally flowed up to the hand of the ...
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Is the amount of blood that flows through every vein and artery per minute really a constant?

I was listening lectures from Mark Saltzman via Open Yale Courses. Now, if I did not understand him wrong, he said that the amount of blood that travels through every vein and artery in our bodies per ...
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60 views

Blood pressure in the blood vessels

Why do the capillaries have a lower blood pressure than the arteries even though the capillaries lumen is much narrower. Wouldn't the narrowness of the blood vessel increase the pressure? Also the ...
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107 views

Red Blood Cell Size Vs White Blood Cell Size

I have just found out that white blood cells are larger than red blood cells and now I'm confused due to something I learnt in class. Basically, I was taught that there were spaces between the ...
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105 views

Blood Vessels (Artery Vs Arterioles)

I just have a quick question regarding what my textbook says. I have tried searching online but I have failed to find an answer. Basically, my textbook states that arterioles are smaller in diameter ...
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473 views

Cutting off circulation [closed]

How much force is required to cut off the blood circulation of, lets say the average human arm? I'm asking because i'm bored and want to try it on myself. I know that in just a couple of seconds with ...