The Circulatory system

[AdaAda87]

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Hi Everyone,

I don't get the circulatory system for mammals, I haven't take physiology, so I'm learning all it the first time. What is don't get is how the blood pumps, i've read the kaplan bk and read it on wikipedia, but it doesnt seem to stick. Can someone explain it? Muchas Gracias!

 

[osimsDDS]

mammals have a 4 chambered heart, right atrium, right ventricle, left atrium, left ventricle...

Blood can come from 2 halves of your body, the inferior part (lower extremities) or the superior part (upper extremitites).

Lets trace the blood flow now coming from lower and upper extremeties:

1) Blood flows from lower and upper extremeties towards the heart via the inferior and superior vena cava, these are veins that come from the lower and upper extremeties of your body with deoxygenated blood because they want to dump out the waste (CO2) in the lungs.
2) So the blood from the inferior vena cava and superior vena cava dump the blood in the right atrium, right atrium pumps the blood into the right ventricle.
3) the right ventricle now pumps the blood into the pulmonary arteries (away from the heart but with deoxy blood) and the pulmonary arteries carry blood to the lungs in exchange for O2 and departure of CO2.
4) Now the lungs through the alveoli and capillary system in the lungs have fresh O2 which goes towards the heart via the pulmonary veines (oxygenated now).
5) the pulmonary veins reach the left atrium and then the left atrium pumps blood to the left ventricle.
6) finally the left ventricle pumps the blood into systemic (body) circulation to reach tissues via the Aorta.
7) the aorta (artery) reaches capillary beds in the body and exchanges O2 for CO2 there and the body starts the on going cycle again by branching into veins and taking the deoxy blood with CO2 and wastes to the right atrium via the inferior and superior vena cava...

The diastole is when the heart is at rest after the ventricles contract...when the ventricles contract that is systole.

Also this might be pretty advanced for right now, but after you get down the cycle and everything...try learning about the capillary beds with the arterioles and venoules. arterioles branch into the capillary beds and since the hydrostatic pressure is much higher than the osmotic pressure the nutrients and O2 leave the arteries and enter the interstitial fluid. At the other end of the capillary bed you have a venoule (veins but smaller) where the osmotic pressure is higher than the hydrostatic pressure and now you have fluid (with waste) going into the venules (veins)...

That is the basic stuff, sorry its a lot but its good to know

 

[yakuza]

It's difficult to explain without showing you pictures.

Your best bet is to look here
http://bcs.whfreeman.com/thelifewir...000|55000|56000|57000|58000|99000|00020|&ns=0
----scroll down to CH 49 and watch the video.

 

[Jim Halpert]

The obvious answer to this question is the heart, but I have a feeling thats not the part that is confusing you. The wall of the left ventricle is much more muscular than the walls of the other chambers, as it must pump blood through out the body. The contracting of these muscles lead to blood pumping out of the heart and into the aorta where blood is diverted to different areas of the body. The muscles of the heart is triggered by the sinoatrial node (SA node), which travels down the bundle of his and contracts the ventricles to contract. Im not sure if I completely answered your question. If you have a more specific question please pm message me or ask through the blog.

 

[AdaAda87]

Thanks everyone for responding! I kinda get it better, the the systems are just confusing, like how how it goes through the pulmonary system to bring the deoxgenated blood to the arteries to get oxygenated again to the veins. And so forth. Thanks again guys!