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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628 views

Vo2 of the brain is 21% of Q=13% or of the entire blood?

I am reading now the book which states that the Q (blood flow per unit of time) of the brain is 13% while the Vo2 (relative Oxygen used per unit of time) is 21%. Now my question is if the Vo2 of the ...
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0answers
2k views

What is the surface area of the cardiovascular system?

In this question says: An adult human has been estimated to have some 60,000 miles (96,560 km) of capillaries with a total surface area of some 800–1000 m2 (an area greater than three tennis ...
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1answer
113 views

Cell nanoparticle dynamics within blood

I am trying to mathematically model the dynamics of a particular cell in circulation and its binding to another nanoparticle that is intravenously injected. The concentration of this cell is very low (...
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33 views

How do bats manage lymph fluids?

We all know that bats hang upside down to sleep. I was watching some sleep for a while, and they don't move much while asleep. If I fall asleep sitting in a chair my lower legs will swell. Lymph ...
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0answers
92 views

Does capillary blood pressure have any effect on how much oxygen or nutrient gets distributed to tissues?

From what I have read regarding blood pressure and blood flow, I've come to the conclusion that, apart from the osmolarity of blood, the only determinant of how much oxygen/nutrients the tissues get ...
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1answer
676 views

Is Infra Red light safe to use on your scalp? [closed]

I own an Anodyne Infrared therapy device which I use to treat ligament/tendon/muscular pains and it works nicely. I see other infrared products used to combat hair loss (e.g. https://www.amazon.com/...
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0answers
31 views

Is the CNS vascularized?

I was under the impression that the CNS is never penetrated by blood vessels, which explains why one never sees them in histological samples. However a google search reveals I am wrong. So can ...
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1answer
202 views

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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86 views

What is the circulation that allows for nutrient absorption and excrete of metabolic wastes in humans? [closed]

Pulmonary veins carry oxygenated blood from lungs to heart, while pulmonary arteries carry deoxygenated/CO2 rich blood from heart to lungs. On the other hand, systemic arteries carry oxygen-rich blood ...
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1answer
344 views

distribution of some injected materials/medicines through blood vessels [closed]

Fastest distribution of some injected materials/medicines & with no risk of any kind can be achieved by injecting it into - artery or vein?
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1answer
583 views

What is the relationship between stroke volume of blood and ventricular end-diastolic volume? [closed]

I do know what each term means. That is, i know that stroke volume is: the volume of blood pumped by each contraction of a ventricle, while ventricular end-diastolic volume is: the volume of blood in ...
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1answer
881 views

Why doesn't the rest of the body have something like the "blood-brain" barrier to protect itself from pathogens?

According to Wikipedia: "The blood–brain barrier acts very effectively to protect the brain from most pathogens". This is because the pathogens cannot pass through the tight junctions of the ...
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2answers
14k views

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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1answer
430 views

What would happen if blood flow wasn't periodic?

Blood pressure has its systolic and diastolic parts due to the beating heart and the body's used to that kind of thing. What would happen to a person supported by a blood-pumping machine that applies ...
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1answer
321 views

Why is it always Sodium that we talk of in blood pressure?

Why is that we emphasize so much on sodium in blood pressure? I understand that it is a major extracellular ion, but, it also is tightly regulated. So when something is that tightly regulated, won't ...
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288 views

Is the amount of blood same in the pulmonary and systemic foetal circulation?

We learn that the stroke volume is the same for the right and left side of the heart. So the amount of blood in either circulations should also be the same. (is it? I myself doubt this statement. As ...
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1answer
1k views

What is the oxygen carrying capacity of reticulocytes?

What is the oxygen carrying capacity of immature red blood cells, or reticulocytes? Is there any difference between oxygen carrying capacity of mature and immature red blood cells?
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1answer
227 views

When there's a wound, the end result is a thrombus or thrombosis?

When there's a wound, the blood vessels are damaged. To stop the loss of blood, the clotting cascade starts off and forms a clot. This clot is a thrombus, right? Seems like perfect physiology. Where ...
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57 views

Oncotic (Osmotic Pressure) in the blood pressure

I just wanted to ask, why is the oncotic pressure more negative in the blood plasma even though the hydrostatic pressure is higher since the blood comes from the pumping of the heart?
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370 views

How long does it take for blood to travel from the lungs to the fingertips?

I've noticed that a pulse oximeter at my fingertip lags my breathing effort by a noticable amount. I conclude that it takes some time for freshly oxygenated blood to travel from the lungs to the ...
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1answer
11k views

What is the speed of blood?

The speed of blood may vary from one place to another and may be quite low in the tiniest vessels compared to the biggest one. What is the speed of blood while exiting a normal human heart?
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2answers
733 views

Diffusion coefficient of cells in blood?

What's the diffusion coefficient of white cells in blood? Is it well defined, or are cells too large and few as to be treated as particles in this context? P.S. I have tried to look this up, but what ...
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1answer
2k views

How do cellular waste products enter arterial blood?

I recently learned that blood in renal arteries contains waste materials, which is filtered via nephrons in the kidneys. My question is, how are these waste materials getting into the arterial blood?...
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1answer
2k views

Why is alcohol purged from the body more slowly when we sleep?

It is a popular belief that when you get asleep after drinking alcohol, in the morning you have higher level in your blood than if you stayed awake the whole night. Is this true? If so, why? Is it ...
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1answer
8k views

what makes our body warm?

I would think that there would so many chemical reactions going inside our body,friction produced by blood in veins, subcutaneous and visceral fat acting as heat insulators. I was wondering to what ...
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2answers
171 views

By What Mechanism Does Heat Cause Muscle Relaxation?

Heat is commonly used "loosen" muscles, but what exactly is happening to relax the muscle? It wouldn't make sense that increased blood flow alone would relax muscle.
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Why is squeezing not recommended after a needle prick?

I've read some interesting things about the risk of infection after a needle prick (30% - hepatitis B, 1.8% - hepatitis C and 0.3% - HIV), but I've also saw that the local squeezing is not recommended....
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2answers
4k views

Why do veins undergo vasoconstriction during physical activity?

How would this help increase blood circulation?
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145 views

How do mosquitoes react to blood feeding on a highly ethanol intoxicated host?

Considering that a mosquito can consume up to five times its body weight in blood during a single meal (Encyclopedia of the Arctic, M.Nuttal), and considering a very strong alcoholic intoxication of ...
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86 views

Can bigger persons generally resist g-forces better?

I've seen a claim that bigger persons generally resist g-forces worse than smaller in an undergraduate biology book. However this claim was supported by the argument that blood has to travel a longer ...
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1answer
2k views

Is pulse rate measurable in the capillary bed and venous vasculature?

Pulse rate is easily felt when gently pressing the arteries in the wrist or neck region (Fig. 1). Fig. 1. Feeling the pulse at the radial artery. Source: Wikipedia Arteries supply the thin ...
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3answers
30k views

Why does the face turn pale in dangerous situations?

I know what the effects are of a dangerous situation on the brain, i.e., an activation of the hypothalamic-pituitary-adrenal (HPA) axis which eventually results in an increased heart rate and elevated ...
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3answers
27k views

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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1answer
1k views

Oxygenated hemoglobin in MRI

I have read the following sentence: Because this oxygenated hemoglobin is unaffected by magnetic fields, the response RF signal returned to the fMRI scanner is stronger when there is more brain ...
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1answer
996 views

Are there fishes with a double circulatory system?

Our courseware materials say there are such fishes, but my Internet searches suggests fishes only have a single circulatory system.
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1answer
128 views

Where does the exudate comes from during inflammation?

During inflammation transudate and exudate is formed by vessels. I would like to make sure if it comes from arterioles, venules, or both, and the reason why.
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513 views

Difference between pulse and blood pressure

I'm a very naive and biologically illiterate person, and from what I've read on the internet I'm not really sure I understand the difference between pulse and ...
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1answer
53k views

Why do fingers swell during cold winters?

When exercising, tissue in the hands may swell. This may be caused by the muscles generating heat, which leads to blood being pushed to the vessels closest to the surface of your body to dissipate the ...
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1answer
5k views

How does the brain cool itself?

Thoughout life everyone tells you that brain is essentially a computer but just like computers your brain would create immense amounts of heat by being in use, so if that's the case how does it cool ...
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1answer
2k views

How does the body respond to blood donation; are there any possible risks?

Can blood donation cause any harm to the donor? I have been told so, but cannot find any references supporting this claim. I have also learned that our body will replace the lost fluids within 24 ...
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4answers
2k views

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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0answers
102 views

Human leukocytes (re)circulation/migration in homeostatic state

One can easily find information on the topic of leukocytes trafficking between vessels and peripheral tissues during inflammation. But what happens during normal states when there is no pathology? ...
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1answer
701 views

How does Hemocytoblast constantly get formed into so many blood cells and yet remains there in the bone marrow throughout the lifetime?

I mean, Hemocytoblast is a stem cell which is constantly being differentiated into daughter cells and leads to formation of all the blood cells (having short and limited life spans), so how come those ...
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1answer
2k views

What creates the feeling of 'excess' blood pressure to an area of the body?

If I hang upside down, and feel blood rushing to my head, what structures are actually responsible for me "feeling" this excess flow of blood? Baroreceptors? Mechanoreceptors? Something else? ...
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1answer
3k views

Maximum RPM in zero-g before losing consciousness, spinning head-over-heels

There are more than a few scenes in Gravity that I find dubious. Specifically the ones where people are revolving very quickly, either about their own center of gravity or at the end of a rather long ...
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2answers
32k views

Blood circulation - How to expand blood capillaries?

Do blood capillaries expand? If yes, through what means can it be done? And can warm water also be used to expand blood capillaries?
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3answers
84k views

Why draw blood from veins rather than arteries?

Why draw blood from veins rather than arteries? Is it more convenient or safer?
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2answers
4k views

How long can the brain survive during ongoing cardiac arrest?

There was this interesting discussion on CPR and defib in response to the question "Why can't we defibrillate the heart within 1 minute after ventricular fibrillation by electroshock?". Now I was ...
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121 views

Is the molecule nitric oxide responsible for healing blood vessels?

Is the molecule nitric oxide responsible for healing blood vessels? How does nitric oxide heal the blood vessels? I watched a documentary about the healing effects of nitric oxide. In the video I saw ...
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1answer
15k views

Why is the Trendelenburg position used when placing and removing Central Venous Line catheters in the sub-clavian vein?

The title says it all. Why is it that patients are placed in the trendelenburg position when a catheter is inserted in the sub clavian vein? What would happen if the patient wasn't placed in the ...