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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14 votes
3 answers
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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 ...
CaptainCodeman's user avatar
43 votes
3 answers
86k views

Why draw blood from veins rather than arteries?

Why draw blood from veins rather than arteries? Is it more convenient or safer?
ZZZ's user avatar
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9 votes
1 answer
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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 ...
Ethan's user avatar
  • 193
7 votes
2 answers
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 ...
rishab bairagi's user avatar
21 votes
3 answers
31k 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 ...
Probably's user avatar
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13 votes
2 answers
2k 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 ...
Polisetty's user avatar
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4 votes
2 answers
533 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. ...
Sudhanva's user avatar
  • 327
3 votes
1 answer
285 views

What happens during a Raynauds episode?

Raynaud's phenomenon can be a serious health issue, as the blood flow to the extremities, mainly the fingers is compromised, causing fingers to blanche, and then turn blue. Severe Raynaud's can cause ...
user avatar
2 votes
1 answer
273 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 ...
Bøbby Leung's user avatar
2 votes
0 answers
405 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 ...
Adam Davis's user avatar
1 vote
1 answer
787 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? ...
Asif Iqubal's user avatar
1 vote
1 answer
135 views

Manifestations of open foramen ovale in adults

I read that foramen ovale opens in 30% of adults. I do not know how much of these openings can then close again. Probably, none. It is not pathogenic if no symptoms. It allows blood to enter from ...
Léo Léopold Hertz 준영's user avatar
1 vote
1 answer
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 ...
Jayachandran's user avatar
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0 votes
1 answer
826 views

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 ...
Rome's user avatar
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0 votes
1 answer
222 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?
ADP's user avatar
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