The Circulatory System CRCT Coach Book: pgs. 59-60

Circulatory System Vocabulary heart 9. red blood cells atrium 10. white blood cells ventricle 11. platelets artery vein capillary plasma

The Circulatory System PURPOSE: The circulatory system is a transport system that uses blood to carry nutrients and oxygen to the cells of the body. It also carries waste products such as carbon dioxide away from the cells. The circulatory system transports chemical messages between cells and different parts of the body. It also carries cells and substances that fight disease.

Organs of the Circulatory System Heart Blood Vessels Blood

The Heart The heart is the main organ of the circulatory system. It is a muscular organ that consists of two pumps working side by side. When the heart muscles contract, they push the blood forward on its path. Each pump involves two chambers.

The Heart continued… The upper chamber of each pump is called the atrium (atria – plural). The lower chamber of each pump is called the ventricle. The left side of the heart receives oxygen-rich blood from the lungs and pumps it to then rest of the body. The right side of the receives oxygen-poor blood from the rest of the body and pumps it to the lungs.

Blood Vessels Blood vessels are the tube like structures through which the blood flows. There are three types of blood vessels: Arteries – carry blood away from the heart Veins – carry blood toward the heart Capillaries – are tiny vessels that connect arteries to veins. They exchange substances such as gases and nutrients between the blood and the body cells.

Arteries in Red – away from the heart Veins in Blue – back to the heart

Did you know????? Blood is never blue! Veins look blue because the blood in veins is dark due to low oxygen levels. Arteries look red because the blood is bright red due to its high oxygen content.

Composition Blood is composed of two main parts: Plasma Blood cells Plasma is a yellowish liquid that is mostly water. It contains nutrients, minerals, salts, and gases. The blood cells are components that float in the plasma.

Composition continued… There are three different types of blood cells: Red blood cells – carry oxygen to the cells of the body and carry carbon dioxide away. White blood cells – help the body fight disease. They attack invading microorganisms and make antibodies that fight disease. Platelets – are fragments of cells that help form blood clots to stop bleeding.

Working Together The circulatory and respiratory systems work together to bring oxygen into the body and deliver it to cells. They also work together to carry carbon dioxide away from cells and remove it from the body.

O2 O2 O2 O2 CO2 CO2 CO2 CO2 CO2 CO2 CO2 CO2

O2 O2 O2 O2 O2 CO2 O2 CO2 Body Cells CO2 CO2 CO2 CO2

CO2 CO2 CO2 O2 O2 CO2 O2 O2 O2 O2 O2 CO2 O2 CO2 O2 CO2 O2 O2 O2 CO2 O2 CO2 O2 CO2 O2 O2 O2

Blood travels through the body and ends up in a capillary!

move through capillaries Red Blood Cells move through capillaries one at a time! Artery Vein Body Cells

Now the O2 gets off, and the CO2 gets on!

CO2 CO2 CO2 O2 O2 O2 O2 O2 O2 CO2 CO2 CO2

The CO2 goes back to the lungs where it gets breathed out!