. Chordate morphology. Morphology (Animals); Chordata. occipital arch. FEUS TALPA Figure 11-34. Variations in venous drainage of mammals. (After von Gelderen, 1933) Bird The venous system of the bird is modified. Blood is shunted below the middle-ear cavity in an external jugular stem. The external jugular shunts of either side are inter- connected, and the right jugular is the larger (turkey). Drainage from the brain is by way of middle and posterior cerebral channels and out through the foramen magnum as well. The development of the venous channels can readily be observed in the chicken. The
. Chordate morphology. Morphology (Animals); Chordata. occipital arch. FEUS TALPA Figure 11-34. Variations in venous drainage of mammals. (After von Gelderen, 1933) Bird The venous system of the bird is modified. Blood is shunted below the middle-ear cavity in an external jugular stem. The external jugular shunts of either side are inter- connected, and the right jugular is the larger (turkey). Drainage from the brain is by way of middle and posterior cerebral channels and out through the foramen magnum as well. The development of the venous channels can readily be observed in the chicken. The 72-hour chick has a network of channels above and below the nerve roots and the otic capsule. The dorsal channel of the otic capsule has a divi- sion passing lateral to the capsule. The 96-hour chick has a single anterior cardinal channel which passes below the vagus, lateral to the glossopharyngeal, below the otic cap- sule, lateral to the facial, and below the trigeminal. This channel has the same branches as the 10-mm pig. Amphibians In the salamander or frog, the pattern of head veins is essentially that of the reptile. In the frog, there is a small inferior jugular which extends to the musculature of the throat; it has submental and shoulder branches. The anterior cardinal stem also has large subclavian and bran- chial stem, as the vena capitis lateralis, ex- tends into the head over the columella and through the cranioquadrate passage; it enters the orbit above the trigem- inal root. In the Bullfrog a posterior cerebral branch is lacking; the middle cerebral branch of the lateral head vein enters the skull and extends out on the dorsal surface of the optic lobes. The vessels of either side converge on the posterior half of the brain and are connected by a fine reticulum of vessels. These vessels pass through the foramen magnum, side by side, and back through the spinal canal on the dorsal sur- face of the cord. The lateral head vein of the Bullfrog also re
Size: 1705px × 1465px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiversity, bookleafnumber382
