Page 203 - Biology_F5

Biology for Advanced Level Secondary Schools

through the pancreas. The pancreas lies and later discharge into the duodenum. In
between the stomach and the duodenum. the mesentery near the duodenum lies a
The secretions are discharged into the bile spherical red structure called spleen, which
duct, which become hepato-pancreatic duct has no digestive role (Figure 3.63).

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Oesophagus
Stomach
Liver
Gall bladder
Pancreas
Duodenum Mesentery

Ileum

Rectum

Cloaca

Figure 3.63: The digestive system of a frog

Urinogenital system of a male frog possibly secreted by the blood vessels
A male frog is slender, with nuptial pads from its wall, which acts as a reserve of
on the first finger which is one of the water during dry seasons. Cloaca is an
morphological features that distinguish outlet that serves as the only opening for
it from female frog, which is fat, with an digestive, reproductive and urinary tracts.
expanded abdomen due to the presence Also, a frog has two testes, each suspended
of eggs in the ovisacs. A male frog has by a double fold of mesorchium. They
two kidneys, which are dark red, oval, lie ventrally below the front part of
and somehow flattened, located near the kidneys, and from them there are
to the testes, ventrally and below the several fine vasa efferentia that cross the
ureter. The ureter passes along the outer mesorchium and enter the anterior kidney
border of each kidney, and opens into the tubules, which convey sperms to the
cloaca. The bladder is a thin sac arising ureter. In both left and right ureters, there
as a ventral outgrowth, the cloaca, with is a pouch-like gland situated on each
its outlet closed by a sphincter. Since the side of the male urinary bladder (vesicula
ureter is not opening to the bladder, it is seminalis), which store sperms until the
not a urinary bladder, but contains fluids breeding period (Figure 3.64).

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