Comparison of Vertebrate Hearts

Fish Heart Number of Chambers: 2 (one atrium and one ventricle) Gas Exchange: O2 and CO2 are dissolvable in H2O. Exchange occur at the gills (which contain tiny capillaries) O2-rich blood delivered to body cells via arteries and O2-poor blood returned to heart via veins. Blood goes into atrium. Heart relaxes and goes through a valve into ventricle. Ventricle contracts, pumps blood towards gills to get more of the O2-rich blood. Pumping force isn’t truly efficient = low pressure but adaptable to the fish’s needs as they are cold-blooded.

Frog Heart Number of Chambers: 3 (two atria and one ventricle) Gas exchange methods: skin (esp. when completely submerged in H2O) and lungs On land, lungs are only partially filled due to poor design. Right atrium holds O2-poor blood that come from the body cells and left atrium holds O2-rich blood that comes from the lung/skin. Both atrium empty into ventricle (which does have some narrow chambers to reduce the mixing of the two blood). Ventricle contracts and: O2-rich blood from LA pumped out to head and body. Blood going to body cells via aortic arches is less pure but has enough O2 in it. O2-poor blood from RA pumped out to lungs and skin where more O2 can be picked up.

The mammalian heart consists of a double pump separated by the septum. Composed of cardiac muscle tissue, nervous tissue, epithelial tissue and connective tissue. Each pump consists of a thin-walled atrium and a thick-walled ventricle. Therefore the mammalian heart has four chambers: Right atrium Right ventricle Left atrium Left ventricle The Heart

Deoxygenated blood (O2 poor) from body’s cells needs to go to lungs to be oxygenated – must pass heart! Oxygenated blood (O2 rich) from lungs needs to go to body cells to be used – must pass heart! 1. Deoxygenated blood from the body cells flows through the vena cava into the right atrium. 4. Oxygenated blood from the lungs travels to the heart via the pulmonary veins and enters the left atrium. 2. Deoxygenated blood flows through tricuspid valve into the right ventricle. 5. Oxygenated blood flows through the left atrioventricular valve into the left ventricle. 3. The right ventricle pumps the deoxygenated blood through the pulmonary valve into the pulmonary arteries where it travels to the lungs. 6. The muscular left ventricle pumps the oxygenated blood through the aortic valve into the aorta where it travels to the body cells. Arteries carry blood away from the heart with the exception of the pulmonary arteries. Veins carry blood to the heart with the exception of the pulmonary veins.