40. Circulatory System

Pressure is greatest in the ventricles when __________.

The SA node generates an electrical impulse from its location in __________.

The heart contains _____ which prevent the backflow of blood.

How many chambers are present in the human heart?

Approximately how many times does the average human heart beat in a lifetime?

Which of the following systems plays the largest role in regulating heartbeat when at rest?

Which of the following correctly lists the sequence of blood flow through the heart starting from the vena cava?

Which structure acts as the primary pacemaker of the heart?

Which hormone is released by heart muscle in response to excessive chamber volume?

Approximately how many times does the average human heart beat in one year?

What is the main function of the heart?

Approximately how many times does the average human heart beat in one day?

Why does the human heart never tire of constantly beating to pump blood throughout the body?

Approximately how many times does the average human heart beat in one day?

When we compare the structures and functions of arteries and veins, we find that the walls of arteries are __________, the blood pressure inside arteries is __________, and the blood in arteries is moving __________ the heart.