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