CIRCULATION
Chap. 12-1
The Body’s Transport System
Cardio-Vascular System
• Also called the circulatory system.
• Consist of the heart, blood vessels, and blood.
• The cardiovascular system carries……..
Needed substances to all cells
Waste products away from cells
Cells that fight disease. White blood cells
Movement of Materials
• Needed materials:
Blood carries oxygen from lungs to the cells
Blood carries glucose to cells for energy
• Waste products:
Blood carries carbon dioxide from cells to lungs.
• Disease fighters
White blood cells attack disease causing
microorganisms.
Structure and Function
• The heart is a hollow, muscular organ,
about the size of your fist. It is located behind the sternum and inside the ribs.
• Average heart beats per minute rate is 70-75 B.P.M.
• Each heart beat pumps approximately 60 ml. (1/4 of a cup) of blood thru the
vessels of your body.
• DEMO:
Can your hands work as fast as your heart?
Try this at home. You need two containers.
Fill one with water. Find a very small bowl
that holds about ¼ of a cup. Every second
use the small bowl to transfer water from
one container to the other. How long can you las
last?
Structure and Function
• The heart has 2 sides (right and left)
Separated by wall of muscle called the septum.
Each side has 2 chambers.
• The upper chambers (called atria)
receive blood coming into the heart.
• The lower chambers (called ventricles)
pump blood out of the heart.
• Each atrium is separated from its ventricle
by a one way valve that keeps blood from flowing
backwards. One way valves also separate the
ventricles from the two major arteries where blood
Is pumped out of the heart.
Demo: View arm one way valve
Heart Works in 2 Phases
• In phase 1, the heart atria relax and the atria are filled with blood.
• In phase 2, the atria contract and fill the ventricles with blood, and the
ventricles contract to pump the blood forward.
• The “lubb-dubb” sound of the heartbeat is made as the valves slam shut.
The Pacemaker
• The pacemaker is a group of nerve cells located in the right atrium.
• The pacemaker sends out electrical signals that makes the heart beat.
• The pacemaker constantly receives stimuli from the brain about the
body’s oxygen needs, and responds by adjusting the heartbeat to match
the need.
Two Loops
• After leaving the heart, the blood travels three types
of vessels thru-out the body
Arteries take blood away from the heart
Capillaries connect arteries to veins
Veins bring blood back to heart
• The pattern of the flow is like a figure 8.
• Heart to lungs and back to heart
• Blood thru aorta to cells of the body and back to heart
Blood Vessels & Blood