Describe the three main types of cardiac muscle tissue and their functions in the heart.

The heart is made of three main types of cardiac muscle:

1. Atrial muscle and ventricular muscle: These are the main contractile muscles that pump blood. They contract similarly to skeletal muscles, but their contractions last much longer.
2. Specialized excitatory and conductive muscle fibers: These fibers don't contract strongly because they have few contractile fibrils. Instead, their job is to generate and conduct electrical signals (action potentials) throughout the heart. This forms an excitatory system that controls the heart's rhythmic beating.