1. Circulatory System Review of the digestive system
Review of the digestive system

2. Main functions of the Circulatory system
Delivers Materials
Removes wastes
Regulates body temperature
Fights disease

3. Heart
Heart is a hollow muscular organ that pumps blood to the body through blood vessels
Atrium – upper sections that receive blood
Ventricle – lower sections that pump blood out

4. How the Heart Works Valves separate the atria from the ventricles
Prevents blood from flowing backward

5. Path of Blood Flow There are two loops
First, blood travels from the heart, to the lungs, then back to the heart
Then, Blood is pumped from the heart, through the body, then back to the heart

6. Three kinds of blood vessels
Arteries carry blood away from the heart
Capillaries – tiny vessels where substances are exchanged to the cells
Veins – carry blood back to heart

7. Blood Blood has 4 components Red blood cells Platelets Plasma
White Blood cells

8. Red Blood Cells
Take up oxygen in the lungs and deliver it to the cells of the body
Mature red blood cells have no nuclei so they cannot reproduce or repair
Red blood cells are produced in bone marrow

9. Hemoglobin A red blood cell is made mostly of hemoglobin
This is a protein that contains iron and combines chemically with oxygen molecules in the lungs
Oxygen makes blood cells bright red – without it they are dark red

10. Plasma Most materials transported in blood travel in the plasma
Proteins in the plasma make it look pale yellow
Some form blood clots, fight disease, and regulate water

11. White Blood Cells Are produced in bone marrow Body’s disease fighters
Larger than red blood cells and contain nuclei
May live for days, months, or even years

12. Platelets Cell fragments that help form blood clots
When a vessel is cut, platelets collect and stick to the vessel at the wound
Fibrin weaves a net of tiny fibers that trap platelets and blood cells