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8 views

What is the realationship between arterial pressure and stroke volume

Frank-Starling Law says , When keep const Pvp (pulmonary venous pressure) and T ( heart period) and we increase Psa(aortic pressure or arterial pressure), Vd(end-diastolic volume) and Vr(residual ...
2
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0answers
29 views

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 ...
2
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0answers
50 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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0answers
40 views

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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1answer
49 views

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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1answer
4k views

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 ...
3
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1answer
144 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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4answers
4k views

Will the heart keep beating if it is 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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1answer
27 views

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?
2
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1answer
94 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.
10
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1answer
825 views

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 ...
3
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1answer
143 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 ...
4
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1answer
988 views

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 ...
2
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1answer
624 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 ...
4
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1answer
41 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 ...
1
vote
1answer
656 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, ...
1
vote
1answer
87 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) ...
2
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1answer
1k 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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0answers
70 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 ...