Answer
Fig. 20.9
An anastomosis is a direct connection between two tubular structures :in the body this is the point of convergence between two blood vessels, other than capillaries. The vascular system has several types of anastomoses: arteriovenous anastomoses, venous anastomoses, and arterial anastomoses.
Arterial anastomoses:
The Circle of Willis of the brain
Coronary anastomosis
Joint anastomoses, such as the shoulder joint (the
scapular),the knee (the geniculate) and the hip
(circumflex).
Anastomoses of the arterial arches of the hand and foot.
Work Step by Step
Venous Anastomoses:
Basal veins of the brain, the jugular veins, the azygous
system, mesenteric veins, venous networks of hand and
foot.
Arterial-venous Anastomoses
Thoroughfare channels:
Thorough channels are found in the micro-circulation of
kidneys, skin, muscles,liver, eyes and ears.
Portal Systems
In portal systems, blood is shunted from one capillary system
to another without going through veins. Examples of portal
systems are the hepatic portal system, and the hypophyseal
portal system.
