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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42
votes
3answers
74k views

Why draw blood from veins rather than arteries?

Why draw blood from veins rather than arteries? Is it more convenient or safer?
40
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4answers
10k views

Why are bruises not lethal?

Given the following: bruises are caused by minor trauma which breaks blood vessels beneath the skin, causing bleeding the mechanism by which bleeding stops is clotting blood clots inside the body ...
35
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2answers
12k views

How many mosquitoes would it take to “drain” enough blood to put a person into shock?

I'm just curious, how many mosquito "bites" (mosquitoes which have removed blood from a person) would it take to remove enough blood to put a person into shock? (Putting aside all reasons why it ...
24
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1answer
10k 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?
22
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3answers
26k 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 ...
14
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3answers
4k views

Where does extra blood come from to fill your muscles during exercise?

Let's say I go to the gym and lift some weights an hour. During this time my arms will grow due to the "pump" -- the extra blood rushing in to feed the muscles. For example, I've measured about 2-3 ...
12
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2answers
1k views

Why isn’t Haemoglobin a plasma protein, rather than being encompassed by the erythrocyte?

Erythrocytes (red blood cells) are a common feature of almost all vertebrates. What evolutionary advantage do they provide in containing haemoglobin, rather than it being just a plasma protein? In ...
10
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3answers
14k 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 ...
9
votes
1answer
1k 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? ...
9
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1answer
1k views

What causes Paresthesia (Pins and Needles) at a cellular level?

I've looked it up in plenty of places like the Wikipedia page and such, and it is clear that the most common cause of Paresthesia is either a fair amount of pressure on a specific patch of skin ...
8
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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 ...
8
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2answers
684 views

Why don't we see turbulence in the aorta even in normal situations?

I read about the Windkessel effect. Then I read about pulse pressure waves getting reflected from the periphery. If the pulse pressure wave is reflected during diastole and at the same time blood is ...
8
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1answer
720 views

How fast is the blood flow in various vessels?

How fast is the blood flow in different blood vessels, such as the aorta and capillaries?
7
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5answers
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 ...
7
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3answers
412 views

Why are diabetic people often overweight?

I was looking at diabetes the other day, and I noticed something strange. Lower amounts of lipase are a symptom of diabetes, as is overweightness. However, since lipase is the enzyme that breaks down ...
6
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2answers
22k views

What happens when you mix type A with type B blood (and v.v)

What happens when you mix different blood types that are not compatible? For example, if a patient has type A blood and receives type B blood, or v.v.?
6
votes
1answer
117 views

Blood cells penetration

Is there a type of blood cell that can reach all other body cells? By "reach", I mean to "touch" the surface of the target cell. If we look at the red blood cell for example, that moves in blood ...
6
votes
1answer
4k 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 ...
5
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1answer
1k views

Why do veins look blue?

I know that veins carry oxygen. Veins look blue because the oxygen-depleted blood in them is blue. Is this true??
5
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2answers
167 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. ...
5
votes
1answer
294 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 ...
5
votes
1answer
222 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, ...
5
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2answers
5k views

Why doesn't nitrogen diffuse into blood?

In school, I have learnt that the deoxygenated blood brought in to the Alveoli by Pulmonary Arteries contains Carbon Dioxide. And that Carbon Dioxide present in the blood diffuses into the Alveoli and ...
5
votes
1answer
10k 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 ...
5
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1answer
62 views

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 ...
5
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1answer
5k views

How does alum help in blood coagulation?

I recently came across a test in my chemistry book which says that potash alum, $\ce{K_2SO_4.Al_2(SO_4)_3.24H_2O}$ is used on cuts and bruises, because it coagulates the blood quickly. The explanation ...
5
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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 ...
5
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1answer
124 views

Are new blood vessels able to deliver oxygen to hypoxic tissue before the establishment of blood circulation?

Sprouting angiogenesis - the growth of new blood vessels from a preexisting vasculature - can be triggered by cells in hypoxia in order to re-stablish the oxygen and nutrients supply to the tissue. ...
5
votes
2answers
958 views

Why does our face get red during anger?

My attempt: This site says that it is due to flight or fight mechanism, which results in more amount of blood being passed to face causing red face. But isn't it wasteful for our body to send more ...
4
votes
1answer
190 views

Is a one ventricle heart feasible?

So this is derived from a lesson at Khan Academy. The mind activity assumes that the one ventricle heart pumps blood to the lungs for oxygenation then rest of the body. However, the problem is that ...
4
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2answers
29k 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?
4
votes
1answer
215 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/...
4
votes
1answer
687 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 ...
4
votes
1answer
51 views

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 ...
4
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1answer
932 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 ...
4
votes
1answer
872 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?
4
votes
1answer
91 views

Thrombus and Embolii

Can treatment of thrombus cause embolism, in case of very high blood pressure, that may even lead to a heart attack ? As the very high Blood pressure may cause some of the enzymes not act completely ...
4
votes
1answer
851 views

How are blood vessels affected by UV and infrared radiation?

The lining of the blood vessel as an interface and boundary layer is of existential necessity to the life-support of mammals. My question is: How are major blood vessels and the blood vessel lining ...
4
votes
1answer
281 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 ...
4
votes
0answers
131 views

Is there a naturally occurring mechanism in the body for cleaning plaque buildup in arteries?

Is there a naturally occurring mechanism in the body for cleaning plaque buildup in arteries ?
4
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0answers
97 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? ...
3
votes
4answers
254 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 ...
3
votes
2answers
72 views

Isolating the vasculature of an organ?

Is there a chemical or process that would dissolve or remove all other tissues in an organ and leave all the vasculature intact? I am planning to make a shelf display of the blood vessels in the heart ...
3
votes
1answer
2k 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 ...
3
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2answers
3k views

Why do veins undergo vasoconstriction during physical activity?

How would this help increase blood circulation?
3
votes
1answer
595 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 ...
3
votes
1answer
7k views

How do nutrients get to the cells they need to get to?

I understand the basics of digestion. I know that nutrients get absorbed by the microvilli, enter the bloodstream and travel to the liver but after all that, what is the biological mechanism that ...
3
votes
1answer
8k views

Do body lotions enter into bloodstream of people? And how do they do it?

I found this very disturbing: bombastic tabloid-style writing in capital and the content is doubtful. If it was correct or close "does it really take something like 26 seconds for a body lotion ...
3
votes
1answer
41 views

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 ...
3
votes
1answer
212 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 ...