Module 8 Intro
1. Module 8 Intro
1.4. Page 2
Module 8—Circulation, Immunity, and Excretion
Explore
Watch and Listen
Major Components of the Circulatory System
Before you begin this lesson, read the bottom of page 268 in your textbook.
Inquiry into Biology (Whitby, ON: McGraw-Hill Ryerson, 2007), 269, fig. 8.2. Reproduced by permission.
Watch this animation. It shows both the heart’s structure and the blood flow through its chambers and associated blood vessels. The movement of blood through the heart is referred to as the cardiac cycle. As in the previous diagram of the heart, the right-hand side of your heart is referred to as left. It’s like you are facing someone else and looking at this person’s heart. As you are watching, take note of the heart’s division into two distinct sides.
The right side contains deoxygenated blood received from the body and is pumped from the heart toward the lungs. The left side contains oxygenated blood from the lungs, which is pumped out to supply the body’s tissues.
atria: one of the two upper chambers of the heart that collects blood flowing into the heart
The right atrium receives blood from systemic circulation, and the left receives blood from pulmonary circulation.
atrioventricular valve: a membranous extension of a vessel or the heart wall that opens and closes, ensuring one-way fluid flow; located between the atrium and ventricle
ventricle: one of the two lower chambers of the heart; each ventricle receives blood from one of the atria and pumps it into systemic or pulmonary circulation
Recognize that blood flows simultaneously into the top two chambers of the heart (the atria). The atria contract in unison to pass blood through the atrioventricular valves (more commonly referred to as A-V valves) and then pass blood into the ventricles. The ventricles also contract synchronously to push blood from the heart.