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Questions tagged [circulatory-system]

The organ system consisting of both the cardiovascular system and lymphatic system which allows for the circulation of blood and lymph, respectively.

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Is there any evidence of causation for breathing rate to affect blood pressure in a human?

I did some research and trials, and with 5 trials for a normal heart rate and 5 done 45 seconds into breath holding, the results came back showing that my heart rate of 116/65 mmHg increased to 138/90 ...
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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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How does LDL leave the circulatory system and enter the interstitial fluid to deliver cholesterol to cells?

I have read that small molecules like oxygen and carbon dioxide diffuse through the capillaries, but larger structures can't fit through. This answer indicates that some proteins go through via ...
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Hydrostatic Pressure at the Venous End of Capillaries

Why is hydrostatic pressure much lower at the venous end? I have read that it is due to the fact that fluid has left the capillary, but I have also read that at a point in the capillary (around mid-...
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232 views

Veins collapse when empty

Veins collapse when empty. That's because they have thin and almost inelastic walls. What has inelasticity and thinness of the walls to do with the collapsing of the veins?
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Do blood vessels expand during angiogenesis?

I know that there are two usual ways of creating new blood vessels: A new vessel sprouts from the wall of an old one, A wall of cells grows down the middle of a vessel, splitting it into two. I also ...
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250 views

Pressure change in atria

Background:It is said that during the phase of isovolumetric contraction , due to sharp rise in the ventricular pressure, there occurs bulging of AV valves into the atria producing a small but sharp ...
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Arteries used for inserting catheter

For catheter purpose, femoral and subclavian arteries are mostly used as starting point. Why? Are there other arteries which are used for the purpose?
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What's so special about Chassaignac tubercle?

1-How does massaging of carotid artery at chassaignac tubercle( anterior tubercle of transverse process of C6 vertebra ) can relieve the symptoms of Supraventricular Tachycardia? My attempt: I think ...
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Question regarding circulatory system of the body

Does the highlighted part in the picture mean that if you take a single blood cell, it traverses through all the veins in the circulatory system ? (Including all the organs)
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Can an octopus survive if one of its three hearts stops working?

While reading the book "The Soul of an Octopus" by Sy Montgomery, I learnt that Octopuses have three hearts. This is very fascinating. According to a Wikipedia article, two of the three are used to ...
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231 views

Do blood vessel walls have blood vessels in them?

If so, do those blood vessels have no walls because they don't need them because they're in the same tissue as that of a blood vessel wall? Are the cells alligned diffently at the edge of the blood ...
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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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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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Why does liver wrap around inferior vena cava?

As shown in the image, the liver wraps around inferior vena cava, which takes blood from liver via hepatic veins. Is there an advantage of having the inferior vena cava closer to the liver rather than ...
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Is dextrocardia congenital? [closed]

Dextrocardia is displacement of human heart to the right side. Does it occur during the life span of a human being or right from birth?
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Why is there a structural difference between the bicuspid and tricuspid valve?

There are three cusps in the tricuspid valve and only two in the bicuspid valve? Why is there such a structural difference? Does it have anything to do with that there is oxygenated blood on the left ...
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544 views

Why do earthworms have 4 hearts?

I was reading about earthworms and came to know that they have 4 hearts. Why is there a need for a 4 heart system? What advantages would it have over a 1 heart circulatory system except for pumping ...
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How did the double circulatory system evolve from the single circulatory system

I already learned how the mammal circulatory system (double circulatory system) evolved from the reptilian circulatory system. How did natural selection evolve the reptilian circulatory system and the ...
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How does the brain regulate its temperature?

I recently ran into a bio-physical paradox while trying to solve an engineering problem, using nature's way as a guide; namely the brain. I'm working on designing a totally new system of liquid/gas ...
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Why is the brain white?

I have read many articles about how the brain is the most power-hungry organ in any living complex organism, requiring about 70% of it's oxygen supplies in the resting state. Since the usual medium ...
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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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Will the heart keep beating if it's separated from the body?

The heart is a vital organ in our body, as it drives blood circulation. I was wondering if a heart keeps beating if it is separated from the body? If yes, then why?
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Who is organizing the heartbeat and its roles in the body?

Throughout the decades we heard that the heart is the only muscle whose nervous system is not acting. So who is he responsible for organising the heartbeat and its roles?
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662 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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Where is the aneurysm in this picture?

I'm a curious person, I've never had any medical training, but I wish to know some more about aneurysms. Aneurysms are basically weakened spots in the elastic artery wall. This can eventually result ...
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1answer
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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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1answer
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How does most of lymph get back into the blood stream? (I don't mean the lymphatic system)

I once read that it was because of osmotic pressure that it returns to the blood stream, by entering the venules. But why? If lymph originated as plasma how come that the solute concentration is ...
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1answer
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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 ...
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59 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 ...
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1answer
2k views

In an open circulatory system, how is blood moved?

In the mollusks section, the powerpoint mentioned that gastropods and bivalves have an open circulatory system. According to the note, this means that the blood does not travel in vessels. How, then, ...
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1answer
181 views

Why are new vessels more permeable in microvasculature?

I know for microvasculature New microvasculature (arterioles, venules) are always more permeable as they lack pericytes. and then I have this sentence about new blood vessels (not specific) ...
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1answer
3k views

Valves in the heart

I am confused regarding the presence of valves in the superior vena cava. The superior vena cava does not possess valves unlike inferior vena cava, which possesses Eustachian Valve. Then where are ...
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408 views

What parts of the brain are involved in regulating blood pressure in mammals?

I'm reading this Wikipedia article on blood pressure and its regulation, and it mentions that medulla is involved. however, I vaguely remember reading another article on Wikipedia and it mentioned ...