The Circulatory System

Why do we need it? Transportation system by which oxygen and nutrients reach the body's cells, and waste materials are carried away. Also carries substances called hormones, which control body processes, and antibodies to fight invading germs.

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Parts of the Circulatory System Divided into 3 major parts: 1. Heart 2. Blood 3. Blood Vessels

1. The Heart It is a muscular pump Size of your fist Thick muscular walls Divided into 4 chambers (compartments)

Chambers of the Heart Upper chambers – right and left atria receives blood coming IN from the veins (singular: atrium) Lower chambers – right and left ventricles push blood OUT into the arteries

VALVES Flaps that open and close as blood moves through chambers Prevent backflow Heart “sounds” are made by the valves as they open and close

2. Blood Pumped by your heart Carries nutrients, water, oxygen and waste products around body. Made up of liquids, solids and small amounts of O2 and CO2 gases.

4 Parts of Blood Red blood cells White blood cells Platelets Plasma

Red Blood Cells Carry O2 from the lungs to all the cells of the body Take CO2 waste from cells back to lungs About 5,000,000 RBC’s in 1 drop of blood!

White Blood Cells Defend against germs Actively attack and destroy germs Have “memory” to recognize germs

Platelets Stop bleeding when vessels or skin is broken

Plasma Liquid part of the blood Carries the blood cells throughout the body Plasma is made in the liver.

Hollow tubes that bloods travels through 3.Blood Vessels Hollow tubes that bloods travels through 3 Kinds of Blood Vessels Arteries Capillaries Veins

Arteries Carry blood AWAY from the heart Main artery called the aorta Aorta divides and branches into many smaller arteries

Carry oxygenated blood! Shown in RED Arteries Carry oxygenated blood! Shown in RED

Capillaries Very thin tubes RBC’s must go through “single file!” Connect arteries to veins EXCHANGE HAPPENS HERE! Food and O2 released to the body cells CO2 and waste products returned to the bloodstream

After blood leaves the capillaries, it is now deoxygenated and full of waste products.

Veins Receives blood from the capillaries Carry blood to the heart

Veins Carry deoxygenated blood! Shown in BLUE

Why is it called the CIRCULATORY system? The heart, the blood vessels, and LUNGS make 1 huge circle that blood constantly travels through.

Circulation Heart is a double pump blood from the right side is deoxygenated and going to the LUNGS (to get oxygen) blood from the left side is oxygenated and going to the body cells

Label & COLOR your diagram (must use red & blue!) LUNGS LEFT SIDE RIGHT SIDE BODY CELLS