Please answer the following questions:

1.- Where is located the primary heart pacemaker? What is its function? What is the normal heart rate for adults?

2.- Please name the vessels originated from the aortic arc.

3.- What is the Portal vein, and its importance? Please name the vessels that give origin to the Portal Vein.

4.- Please describe the blood flow in the pulmonary circuit.

5.- What is the lymphatic system? What are the main functions of the lymphatic system?