Portal systems...

[doc3232]

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I think there are two of these...the hypophyseal one and some other one.
So these transport hormones, but I don't understand how the blood moves if it is just 2 capillary beds. Does skeletal muscle move the blood?

 

[Holopeachy1]

I think there are two of these...the hypophyseal one and some other one.
So these transport hormones, but I don't understand how the blood moves if it is just 2 capillary beds. Does skeletal muscle move the blood?

Yes the other one is the hepatic portal system. Skeletal muscle move the blood in veins, that is why when you sit for a long time in one position you want to move around. It's the contraction of the skeletal muscle sorrounding the veins and that move the blood and gravity of course. In arteries the blood is moved primarily by pressure.

 

[Albuterol]

doc,
not too sure about the flow of blood since it is between capillary-vein-capillary and they are both at low pressures. maybe movement like u suggested. but the hepatic portal vein (the other portal system) receives amino acids and carbohydrates from the duodenum.

 

[Holopeachy1]

Oh sorry I didnt understand the question right, but the blood moves in the hepatic portal system with the help of visceral smooth muscle in the sorrounding organs. With respect to the hypopheseal portal system, gravity moves the blood there since there are no skeletal muscles sorrounding it.

 

[doc3232]

Thanks...got it now.

 

[admap]

Actually, aren't there like 3 portal systems? Third one being to the kidney...? So there's Hepatic, hypophyseal and the kidney system.

 

[Albuterol]

admap you are correct, the kidney does have a portal system.

 

[admap]

Thanks for confirming 🙂

 

[Albuterol]

no problem, but the renal portal system is only found in fishes, amphibians, birds, reptiles. NOT mammals...good luck studying![SIZE=+1][/SIZE]

 

[doc3232]

taking a guess: is it the adrenal portal system?
so what does each one do?
Hepatic as someone previously said brings carbos and amino acids from the small intestine?
The hypophyseal one brings hormones from the hypothalamus to the anterior pituitary?
Kidney one brings toxins to the kidney from the blood?

 

[Albuterol]

doc, you are right on about the hepatic and hypophyseal portal systems.
Adrenal would mean it is above the kidney (think adrenal gland, which is positioned above the kidney)
the renal portal system is found only in fishes, amphibians, reptiles, and birds. its role is to bring blood from the posterior of the animal into the vena cava.