1. Chapter 12-2 pages
By Isaac, Noah and Nick

2. Cardiac Muscle Cells
In one heartbeat, the entire heart contracts in a coordinated manner so blood flows in the correct direction at the right time
Have longer refractory period than skeletal muscle
Relax long enough so that the hearts chambers can refill with blood

3. Cardiac Muscle Cells
Contractile Cells - produce a powerful contraction that propels blood
Conducting System – controls and coordinates the activities of the contractile cell

4. Contractile Cells Form the bulk of the hearts muscle tissue
Forms 99% of all cardiac muscle cells

5. Contractile Cells Rapid Depolarization Plateau Repolarization
Voltage gated sodium channels open, and the influx of sodium ions rapidly depolarizes the sarcolemma
Plateau
As the cell begins to actively pump sodium ions out, voltage gated calcium channels open and extracellular calcium ions enter the sarcoplasm
Repolarization
As the calcium channels begin to close, potassium channels open and potassium ions rush out

6. Conducting System

7. Conducting System
Conducting Cells – distribute the contractile stimulus to the general myocardium
Nodal Cells – responsible for establishing the rate of cardiac contraction
Pacemaker Cells – nodal cells that reach threshold first