Portal System of Frog


Portal System of Frog

The portal system is defined as a system of blood vessels in which the veins carrying blood from a region is first broken up into capillaries in another organ like kidneys or liver and then the blood is collected by another set of capillaries which unite to form another vein which carries the blood to the heart. A portal vein is, therefore, originates from capillaries and terminates as capillaries. There are two types of portal system in frog. They are:

(i) Hepatic portal system and

(ii) Renal portal system.

(i) Hepatic portal system: The pelvic veins of both the hind limbs join together to form the anterior abdominal vein. It runs forwards in the mid-ventral line along the muscular layer of the abdominal wall. It also receives veins from urinary bladder and abdominal muscles in the course. It finally opens into the liver to form capillaries. Before entering liver it is connected with hepatic portal vein. Which is formed due to the joining of various veins coming from dift’erent parts of . alimentary canal. A gastric vein brings blood from the wall of the ‘{ontach. An intestinal vein brings blood from the,intestinal wall. Splenic vein and pancreatic vein return blood from spleen and pancreas respectively. All these veins join to form hepatic portal vein which enters the liver. Inside the Iiver hepatic portal vein breaks into capillaries. ‘fhe capillaries of hepatic vein and abdominal vein again join to form hepatic vein. The hepatic vein comes out from the.liver and unites with the post-caval which in turn open into sinus-venosus. Thus, blood from different parts of the alimentary canal is returned to the heart through the liver and post-caval. This is known as hepatic portal system.

(ii) Renal portal s_ystem: This sysrem is formed by dilferenr veins coming from hind limbs and abdomen. Venous blood of the hind-limb is collected by capillaries which combines to form femoral and sciatic vein. The femoral vein after enrering into the abdomjnal cavity divides to form renal portal and pelvic vein. The scialic vein of each side join with renal portal veins of their sides. The renal portal vein also receives dorso-lumber veins at the outer surface of the kidney. Inside the kidney, it branches and re-branches to form capillaries. The capillaries thenjoin to form four to six renal vein which open into the post-caval. The post-caval also receives a pair of gonadial veins. The post-caval run forward and opens into sinus-venosus. Thus, the venous blood returning from hind-lintbs and certain other posterior – regions is carried to kidney where rhe blood is purified due to the extraction of nitrogenous wastes and then it is returned to the heart. This is called renal portal system.

    • Linguol Mondibulor
      Externol iugulor
      Heolt Subclovion
      Right precovol
      lnlernol iugulor
      Subscopulor Left precovol
      Sinsus venusus
      Pulrnonory (ioslric
      llepolic portol
      Poncreolic Duodenol lntestinol Dorsolumbot Splenic
      Anterior obdominol
      Cloocol opeiture
      Genitol Renots
      Renol portol



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