antagonism by the high concentrations of progesterone that occur in this condition.
Such effects may increase the need for osmoregulation, but do not constitute a part
of the process.
8. The Adrenal (Suprarenal) Glands
The adrenal glands in mammals, birds and reptiles are usually discrete paired structures lying adjacent to the kidneys. In the Amphibia the adrenal tissues are attached
to the ventral surface of the kidney, either in a continuous layer as in the Anura,
or in scattered patches as in the U rodela. In the tetrapods the adrenal gland consists
of two anatomically, embryologically and physiologically distinct regions; the adrenocortical (or interrenal) and chromaffin tissues. In mammals the chromaffin tissue makes up an internal medullary region, while the interrenal cells surround
this to form the cortex of the gland (hence adrenocortical tissue). In non-mammalian tetrapods these two tissues are mingled with each other, so that there is no
Anuran
Mammalian
OD
Avian
Urodele
Teleost
Lacertilian
Ophidian
Elasmobranch
,.
, ~ -.
..
Fig. 2.6 Types of vertebrate adrenals and their association with the kidneys, in ventral view.
Solid black indicates chromaffin tissue, dense stippling indicates interrenal tissue, and light
stippling indicates kidney. Teleost kidneys show postcardinal venous drainage; anuran and
ophidian kidneys show postcaval venous drainage . Teleost interrenal and chromaffin tissues
are embedded in "head" kidney . Adrenals are shown as if in section . (From GORBMAN and
BERN, 1962).
68
Such effects may increase the need for osmoregulation, but do not constitute a part
of the process.
8. The Adrenal (Suprarenal) Glands
The adrenal glands in mammals, birds and reptiles are usually discrete paired structures lying adjacent to the kidneys. In the Amphibia the adrenal tissues are attached
to the ventral surface of the kidney, either in a continuous layer as in the Anura,
or in scattered patches as in the U rodela. In the tetrapods the adrenal gland consists
of two anatomically, embryologically and physiologically distinct regions; the adrenocortical (or interrenal) and chromaffin tissues. In mammals the chromaffin tissue makes up an internal medullary region, while the interrenal cells surround
this to form the cortex of the gland (hence adrenocortical tissue). In non-mammalian tetrapods these two tissues are mingled with each other, so that there is no
Anuran
Mammalian
OD
Avian
Urodele
Teleost
Lacertilian
Ophidian
Elasmobranch
,.
, ~ -.
..
Fig. 2.6 Types of vertebrate adrenals and their association with the kidneys, in ventral view.
Solid black indicates chromaffin tissue, dense stippling indicates interrenal tissue, and light
stippling indicates kidney. Teleost kidneys show postcardinal venous drainage; anuran and
ophidian kidneys show postcaval venous drainage . Teleost interrenal and chromaffin tissues
are embedded in "head" kidney . Adrenals are shown as if in section . (From GORBMAN and
BERN, 1962).
68