The Circulatory System The Heart and Blood Vessels
What does the Circulatory System do for us? • It transports materials from one part of the body to another • It’s kind of like a busy highway system!
Circulatory System (arteries, veins & capillaries): like a network of roads that you see above Blood Cells: like the vehicles that travel on the road
What do the blood cells transport? • Food to the Cells • Water to the Cells • Oxygen to the Cells • Carbon Dioxide AWAY from the Cells • Other materials
The Heart • Organ that, by contracting, pushes the blood through the circulatory system • Beats (or contracts) about 70-75 times/minute • Consists of 4 Chambers (rooms) • Atria (left and right) • Ventricles (left and right)
The Pathway of blood flow through the heart – animation - https://www.youtube.com/watch?v=BEWjOCVEN7M
Questions for Thought: • 1. Look at the picture of the heart on page 569. What do you notice about the walls of the right ventricle compared to walls of left ventricle? • The walls of the left ventricle are MUCH thicker. • Why do you think this is true? • The left ventricle must contract with enough force to force the blood throughout the ENTIRE BODY AND BACK AGAIN. That’s a LOT of force needed! The walls of the left ventricle must have more muscular strength to contract hard enough to force the blood from the heart through the whole body. On the other hand, the right ventricle must only get the blood to the lungs and back. Not as much force is needed, so not as much muscular strength needed.
Questions for Thought: • 1. After looking at the picture of the blood vessels, what do you notice about the walls of the arteries compared to walls of the veins? • The walls of the arteries are MUCH thicker. • Why do you think this is true? • The walls of the arteries carry the blood AWAY from the heart and so, have all the force of the ventricle contraction behind the blood. The walls of the arteries must be thick to withstand the pressure of that force without breaking.
Valves • In the circulatory system, valves keep the blood flowing in the direction that it is supposed to go: • In the heart • located between the atria and the ventricles • located between right ventricle and pulmonary artery • located between left ventricle and the aorta • In the veins • Located in lower extremity veins to keep blood moving UP toward heart, flowing AGAINST gravity • https://www.youtube.com/watch?v=hXrZI4P4hYg
Types of Circulation Systemic • network of vessels that carry blood from the heart to the body and from the body back to the heart.
Types of Circulation Cornary • Network of arteries and veins that supply blood to all cells of the heart. • Question: Why can’t the heart cells get oxygen and nutrients from the blood that travels through the heart?
Types of Circulation • Pulmonary Circulation– network of vessels that carries blood from heart to the lungs and from the lungs back to the heart.
Circulatory Illnesses • 1. Hypertension – Know the definition • 2. Atherosclerosis – Know the definition? • 3. Heart Attack – Know the definition? • 4. Heart Failure – Know the definition? • 5. Stroke – Know the definition?