system
Given the following post, respond as if you're commenting on Reddit:
human
How does a 3 chambered Heart work vs a 4 chambered heart?

Im in a veterinary assistant program, and I learned that reptiles and amphibians have a 3 chambered heart. My teacher didn't go into much detail since I won't be working with a lot of reptiles, but I was just curious.

How does the 3 chambered heart function if it only has one ventricle?
How does "double circulation" work?
gpt
basically, in an amphibian heart there are two atria and one ventricle. Now as you'll know, humans have two ventricles to keep oxygenated and deoxygenated blood from mixing before it is pumped to the appropriate place. However, in amphibious hearts, there isn't an interventricular septum so you might think the blood mixes and the frog or whatever is going to be continuously cyanotic. It works though because there are ridges (trabeculae carnae) on the endocardial walls which turbulate and direct the flow of the blood to the appropriate vessels. Minimal mixing of oxygenated and deoxygenated blood occurs and everything's fine. In humans there is a rare congenital condition called 'cor triloculare biventriculare' in which there is just one atrium (i.e. a common atrium). you'd think that this would be very bad indeed but patients with this condition are pretty much asymptomatic and regularly get into their 20-30s undiagnosed. Yep, we have trabeculae carnae too. Without these 'meaty ridges' (as the latin literally translates to), the blood would stick to the walls, which is why we need the turbulation.