10.18.96
the rest of the circulatory system.

counter current exchange mechanism for heat transfer in gazelle/sheep.

venous drainage from the olfactory region forms a capillary bed 
underneath a capillary bed formed by the internal carotid on the way to 
the brain. the cool venous blood absorbs the heat of the arterial blood 
and carries it back into the body. this cools the arterial blood on its 
way to the brain, so the brain can avoid being fried :) . while the 
capillary beds are not actually connected, they are intimately opposed, 
sitting on top of each other. this structure is called a RETE MIRABILE or 
wondrous rete. Also this one is called the carotid rete. arterial blood 
can go from 46 C to 41 C in this fashion, through this convective heat 
transfer. 

life as a fetus: lungs are collapsed, liver nonfunctional. get nutrients 
and gases from placenta instead. so there are necessary circulatory 
detours. from placenta, blood carried into fetus via umbilical vein. then 
it goes to the liver- 10-20% of blood shunts through the liver through 
ductus venosus and goes directly to the vena cava. in adult, ductus 
venosus becomes ligamentum venosum, and umbilical vein becomes the round 
ligament. additionally there is a pulmonary bypass because you don't need 
to send blood to lungs. so you have the foramen ovale and the ductus 
arteriosus. the foramen ovale, which is the fossa ovalis in the adult, 
shunts blood from R to L atrium. not ALL the blood is shunted, though. 
so, the blood that goes out the pulmonary trunk is mostly shunted to the 
aorta via the ductus arteriosus (6th aortic arch). in the adult, this 
becomes the ligamentum arteriosus. these shunts all normally close up 
after birth.

ORSINI

note: don't have to put all the legs back in the cooler, just leave them 
on the table.

diagram 6-11 in smallwood.
this shows a hyperflexed stifle, and indicates three separate joint 
capsules. each is a separate compartment: the femoropatellar joint 
capsule, and the two femorotibial joint capsules (lateral and medial). in 
the horse you do a lot of injections in the stifle, so it's important to 
know these are separate capsules. there is some communication between 
them, noted w/arrows in the diagram, but you really need to inject all 
three capsules to get good coverage.

when you dissect this, you can see a slit between the compartments of the 
medial femorotibial and the femoropatellar.

dissect these joints after looking at the muscles of the hindlimb.

couple of thoughts:

stay apparatus that allows horse or cow to stand while sleeping or 
relaxing. make sure to take a look at the stay apparatus. 

superficial digital flexor in horse/cow (not as much goat) looks really 
fibrous, ropelike. this is also seen in peroneous tertius.