10.22.96------------begin lecture----------

announcements: exam to be returned today.
clinical correlation today w/bill someone, GI specialist.

Dr.Morrison: remarks that he is the proud inventor of the "cheesecloth on 
ruminant stomach" technique of learning the attachments of the omentum.
refer to p 4 of handout from yesterday. realize the gut tube starts out 
suspended from dorsal body wall by the mesentery

||||||||||||||||||||
|||||||||||||||||||| <----mesentery- dorsal mesogastrium in embryo, 
becomes
___	||||||||||||||||                   greater omentum
   \||||||||||||||||
  	----------------
                    <-----gut tube
	----------------
___/
|||||
||||| <---ventral mesentery - ventral mesogastrium-becomes lesser 
omentum.

liver develops out of lesser omentum/ventral mesogastrium, as a 
diverticulum of the stomach. recall that in the dog the greater omentum 
attaches to the dorsal body wall and the greater curvature of the 
stomach. in the cow, the greater omentum is attached to what used to be 
the dorsal midline of the simple stomach, and is now the right 
longitudinal groove. it also attaches to the caudal groove and around all 
the way to the left longitudinal groove and even all the way up to the 
reticulum (which develops as a pouch behind the pouch that the becomes 
the rumen). the reticulum only moves cranial to the rumen through 
developmental growth. the other end of the greater omentum is of course 
attached to the dorsal body wall. anyway, the non-body wall end is also 
attached to the greater curvature of the abomasum, and then you lose the 
attachment and the omentum continues on as the mesoduodenum. so, in the 
anatomical position, the dorsal sac of the rumen is not covered on both 
sides, by omentum, but the ventral sac is. also, note the omental bursa 
is 'covered' by the superomental bursa, which is made by the omentum as 
it wraps around from the left to the right side. also notice there is no 
greater omentum covering the omasum, which forms from the ventral midline 
of the original primitive stomach. it has no attachment to the greater 
omentum because of that. it IS covered by lesser omentum.