Their are 2 heart chambers.
atrioventricular bundle
Clams have the most complex heart of the mollusks, with 3 chambers.
Sharks have 2 chambers
A snails heart has 2 chambers.
the 2 lower chambers of the heart
The left atrium and right atrium receive blood coming into the heart.
The human heart has four chambers connected by valves. We have 2 smaller chambers on the upper half of our heart and two larger chambers on the bottom of our heart. The smaller chambers are called atria; the larger chambers are called ventricles. So we refer to these chambers as right and left atrium, and right and left ventricle.
Fish
2 atria and 2 ventricle
There are 4 chambers/rooms in the heart of bird/mammal.Here are some others...Fish-2 chambers/roomsLizard-3 chambers/rooms
there are 4 chambers; the top 2 of the heart (right and left) are called the atria and the bottom 2; the ventricles.