Page 546 - Anatomy and Physiology of Farm Animals, 8th Edition

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Lymphatic System blood supply (one renal artery per lobe)
and renal venous return (Fig. 30‐9). This
VetBooks.ir Avian lymph vessels are less numerous system receives venous blood from the

caudal body via the external iliac vein and
and less widely distributed than the
analogous structures in mammals. They distributes it into a second capillary system
run satellite to blood vessels and most in the interlobular spaces with return to
ultimately converge on paired thoracic the venous system via the renal vein.
ducts that, in turn, empty into the paired Two valves, located at the junction of the
cranial venae cavae. Only Anseriformes
possess true encapsulated lymph nodes; v a
in these species, the cervicothoracic
lymph nodes are found within the tho-
racic inlet and the lumbar lymph nodes
ventral to the vertebral column in the ta
region of the kidneys. Lymph nodules are
found abundantly associated with most
organs and in the walls of the gastrointes- ar
tinal tract. These are especially prominent e ae
in the ceca of chickens, where they may be
referred to as cecal tonsils.
The cloacal bursa has already been 1
mentioned as a diverticulum of the proc-
todeum. It is well developed in young r e1
birds and disappears following sexual p
maturation. During its short existence, it 2
is an important lymphatic organ, being
the maturation site for B‐lymphocytes.
The avian spleen lies in contact with dd 3
the right lobe of the liver adjacent to the
gizzard. In addition to its important role
in erythrocyte physiology, the spleen u
produces lymphocytes that are clustered
in sheaths around splenic arterioles (the
so‐called white pulp of the spleen).

Urinary System

Avian kidneys lie on the ventral surface of
the synsacrum. Each kidney is divided c
into cranial, middle, and caudal lobes cre-
ated by external grooves associated with
large vessels that cross the renal surface Figure 30-9. The genitourinary organs and
(Fig. 30‐9). Collecting ducts empty directly associated structures of a male cockerel. a, abdom-
into the ureter adjacent to the cranial lobe inal aorta; ae, epididymal artery; ar, cranial renal
of the kidney; there is neither renal pelvis artery; c, cloaca; e, epididymis; ei, external iliac
vein; p, caudal renal portal vein; r, renal vein; t, tes-
nor renal calyces as in other domestic tis; ta, testicular artery; u, ureters; v, caudal vena
species. Right and left ureters terminate in cava; dd, ductus deferens; 1, 2, and 3, cranial, mid-
the dorsal part of the urodeum. dle and caudal lobes of the kidney, respectively.
Birds possess a renal portal system Source: adapted from Reece, 2015. Reproduced
in addition to the expected renal arterial with permission of John Wiley & Sons, Inc.