Download - 12-1 the Body's Transportation System Web
Circulation
Chapter 12
THE BODY’S TRANSPORTATION SYSTEMSection 1
Movement of Materials
The cardiovascular system- circulatory system that consists of the heart, blood vessels, and blood
The cardiovascular system carries needed substances to cells such as oxygen and glucose to produce energy
It carries waste products away from cells such as carbon dioxide
It transports white blood cells that attack disease-causing mico-organisms
Structure and Function of the HeartThe Heart’s Structure How the Heart Works
In the first phase the heart muscle relaxes as the atria fills with blood
In the second phase, the atria contracts and fills the ventricles ; ventricles then contract to pump blood forward
The heart has two sides- a right and left- separated by a wall of tissue
It has two upper chambers- atrium that receive blood that comes into the heart
Ventricles- two lower chambers that pump blood out of the heart
Valves- flap of tissue that prevents blood from flowing backward located between each ventricle and the blood vessels that carry blood away
Regulation of Heartbeat
Pacemaker- group of cells located in the right atrium, sends out signals that make the heart muscle contract
The pacemaker responds to the body’s oxygen needs by adjusting the heart rate
Pacemakers can become damaged, and an artificial one implanted
The Heart
Arteries- blood vessels that carry blood away from the heart
Capillaries- tiny vessels into which blood flows and substances are exchanged between the blood and body cells and back to the veins
Veins- Vessels that carry blood back to the heart
Two LoopsLoop One: to the Lungs and Back
Loop Two: to the Body and Back
In the second loop, blood is pumped from the heart throughout the body and then returns again to the heart
The left atrium fills with oxygenated blood from the lungs and that then moves to the left ventricle
Blood then flows into the aorta- the largest artery in the body
From the aorta, oxygen rich blood flows to the body and then back to the right atrium
In the first loop, blood travels from the heart to the lungs and then back to the heart
Blood flows from the body into the right atrium and contains little oxygen
Blood then flows to the right ventricle out to the lungs
From the lungs oxygen rich blood returns to the left side of the heart
The Force of the Ventricles The ventricles of the heart
exert a force on the blood inside them
The force moves blood out of your heart and into your arteries
The contraction of the left ventricle exerts a much stronger force than that of the right ventricle because it must move blood throughout the body while the right ventricle moves blood only to the lungs
Review What is the function of the cardiovascular system?
What function does the heart perform?
Describe the route that blood takes through the cardiovascular system. Begin with blood leaving the left ventricle.
What is the heart’s pacemaker? To what internal stimulus does the pacemaker respond?