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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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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194 views

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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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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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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2answers
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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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54 views

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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54 views

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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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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226 views

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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158 views

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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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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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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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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243 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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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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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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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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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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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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106 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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561 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 ...
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why is erythrocyte sedimentation rate higher in females?

erythocyte sedimentation rate should be independent of the sex. what is the reason behind this sex bias and why does it increase during pregnancy and how does age influence it.
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Flow diversion for cerebral aneurysms or stabilizing the hemodynamics?

I'm doing research of flow diverter for cerebral aneurysms applications and I'm wondering the reason behind stent placement underneath of cerebral aneurysms is to divert the flow or stabilize the ...
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205 views

How does vasoconstriction retain heat?

I am reading on vasoconstriction on wikipedia. The article states that: When blood vessels constrict, the flow of blood is restricted or decreased, thus retaining body heat or increasing vascular ...
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Is a large tumor is more likely to develop hypoxic regions?

It is known that cancerous tumors in humans can develop hypoxic regions where no blood nor oxygen arrive to some volume of its cells, creating a dead lump inside or around the tumor. See Wikipedia - ...
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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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“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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Turbulence in blood

Turbulence in blood flow is known to indicate diseased or obstructed arteries. Techniques to measure turbulence in blood flow are mostly based on turbulence kinetic energy measurments using MRI [e.g., ...
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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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How does blood react to heat when inside the body

I was wondering: What are the possible dangers of being burned on the surface of the skin. Does it congeal (that's what my intuition tells me)? At which temperature would that happen? How heat-...
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How much blood flows to female breasts?

How much of the entire blood in the body blood flows to the breast (while resting). If you know the percentage or absolute values , as well as the total cardiac output, I would appreciate it answers ...