Urinary system in Bird

موضوع: Urinary system in Bird الثلاثاء مايو 25, 2010 10:23 pm

Urinary system

Birds have paired kidneys recessed into bony
depressions in the synsacrum, the renal fossae.
There are three lobes, with no distinct medulla
or cortex. Avian kidneys have both reptilian
and mammalian features, with the renal lobule
containing two types of nephrons:
1 The cortical type with no loop of Henle,
which are uricotelic (i.e. produce uric acid
as the end product of nitrogen excretion)
2 The less common medullary type with a
loop descending into the medullary region
of the lobule, which produce urine.
Blood supply to the kidneys comes from two
sources. Arterial blood from the aorta is the
only source for the renal corpuscle. The renal
portal system supplies two-thirds of the
blood, and comes as venous blood from the
large intestines and pelvic limbs. It enters the
peritubular capillary network within the cortical
region of the lobule, where it mixes with
arterial blood from the renal corpuscle. All of
the renal blood drains via efferent veins to the
common iliac vein or caudal vena cava.
Infections of the feet, legs or lower intestines
may drain to kidneys and cause septic
nephritis. Renal neoplasia or infection may
cause venous stasis of the pelvic limbs or
paralysis due to pressure on the sciatic nerves.
Injections into birds’ legs of drugs that are
cleared by the kidneys should be avoided
because, due to the renal portal system, such
drugs may be excreted before entering the
general circulation or before the therapeutic
agent has been diluted by the general blood
circulation. Unfortunately, some avian species,
such as ratites, may have to be injected in
the large leg muscles.
Urine is drained by ureters, which empty
into the urodeum; it is then moved by
retroperistalsis into the rectum, where resorption
of water and salt takes place.
Uric acid is produced by the liver, transported
in the blood, and excreted by means of
glomerular filtration and tubular secretion. In
the collecting tubules it forms a colloidal
solution which allows transport through the
kidney without precipitation.

موضوع: رد: Urinary system in Bird الجمعة مايو 28, 2010 6:57 pm

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موضوع: رد: Urinary system in Bird السبت مايو 29, 2010 10:38 am

Hi my sister Dr. Majida!

Thousand thanks for your answer, I'm really happy for your response, I hope that the articles were happy with your desire

sincerely,
Dr. Hazin

موضوع: رد: Urinary system in Bird السبت مايو 29, 2010 5:21 pm

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