Heart/BP question (How it works)

burnsmh

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I seem to be having trouble on getting down how the heart works and how it relates to blood pressure.

Tell me what I have right and wrong please, any hints or help would be nice. Thanks.

Blood enters the right atrium, leaves the right ventricle for the lungs for oxidation.
Blood leaves the lungs into the left atrium then out the left ventricle for the tissues to give them oxygen.

Systole (Pumping) = Top number - Blood leaving the left ventricle to the tissue.
Diastole (At rest) = Bottom number - Blood entering the heart for oxygen via the right ventricle.

Where I get really confused is what is contracting and what is relaxing during each of the phases...

I have been taking practice test on medictests.com and I keep missing these questions and I keep re-reading the section...But I must not be understanding something.
 

cprted

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Think of the cardiovascular system as Pump, Pipes, and Fluid. The heart is a reciprocating pump and can be in one of two states, contraction (Systole) or relaxation (Diastole). Systole is the pressure wave of the heart contracting and pumping blood. Diastole is the relaxation of the heart where both sides of the heart refill with blood ready for the next contraction. Both sides of the heart contract and relax together. Really, the heart is two pumps working simultaneously.

Try watching this video https://www.khanacademy.org/science/biology/human-biology/circulatory-pulmonary/v/circulatory-system-and-the-heart It starts with discussing hemoglobin in the lungs, but does get on to circulation after a few minutes.
 
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burnsmh

burnsmh

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Both sides of the heart contract and relax together. Really, the heart is two pumps working simultaneously.

I am in my OSHA class right now, but I will watch that as soon as I get home. But this sentence cleared up a lot of what I had in my head. I was thinking when the right atrium contracts to send blood out the left atrium was filling. When the Right Ventricles were contacting sending blood to the lungs for air the left ventricles were relaxing. Kinda like when the left contracts the right rest.

But this cleared up a big problem in my head, thank you!
 

Ewok Jerky

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Small correction: its oxygenation not oxidation. Oxidation is a chemical reaction.

You have an OK basic understanding. It's just plumbing, with 2 circuits. There are 4 chambers. I think of the ventricles as pumps and atria as primers (small pumps).

You might look at "preload" and "afterload" for a better understanding of blood pressure readings and systole and diastole.

Diastole (bottom number) represents systemic vascular resistance, the pressure the left ventricle is pushing against.

Systole (top number) represents the force of the left ventricle pumping blood into the vascular system.

During diastole everybody is relaxed and filling passively. Just before systole the atria contract, giving the ventricles a 20% boost in volume. Systole is when the ventricles contract.

Google "Wigger's diagram".
 

Ewok Jerky

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Really? I'm still trying to understand that thing myself :)

Maybe I'm a visual learner?

Circulation and cardiac function can be very confusing. The Wigger's puts it all there: what's contracting, what's flapping, what's making noise, what's making the EKG go bloop, and what pressures are building.
 

Clare

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What you are getting confused on is the cardiac cycle; i.e. what valve is open or closed and which chamber is doing what.

I am sure there is a diagram out there somewhere or something to help you; ask Dr YouTube.

Also, blood is oxygenated not oxidised; oxidation is some sort of chemical reaction like when an apple goes brown because the flesh is exposed.
 
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