Anatomy of the Heart
What is the purpose of a heart?
 Not all organisms have a heart, what is the
advantage of having a heart?
Different kinds of hearts
Aortic Arches
 The “hearts” of the
earthworm
 Blood is actually
pumped by the dorsal
into the aortic arches
arches
2 chambered heart
 Blood moves in one direction
 2 chambers – atrium and ventricle
3-chambered heart
 2 atriums, and 1
ventricle
 Oxygenated blood
comes into the left
atrium, and
deoxygenated blood
comes in from the
right atrium.
 Both atrium lead to
the same ventricle
4 Chambered heart
(Human heart)
 Has 2 atriums, and 2 ventricles
 4 valves
 Tricuspid, mitral, aortic, pulmonary
 Each side receives and sends its own blood to
its respective circuit
Think, pair, share
 Think of the advantages
disadvantages of each heart
 Pair up (with the person beside you)
and discuss you answers
 Share your answers with the class
Advantages/disadvantages
 2 chambered heart
 Low on energy
 Not very efficient
 3 chambered heart
 Low on energy
 Limits organisms
 4 chambered heart
 Very efficient, transports the most blood to the
cells
 High energy cost
How does it work?
 2 stages of the heart
 Systole – heart contraction
 First the atriums, then the ventricles
 Diastole heart at rest
Human Heart