1. The Circulatory System

2. Function of the Circulatory System
Transports materials such as oxygen, carbon dioxide, food molecules, and other materials to cells of the body.
Regulates body temperature
Carries white blood cells that protect the body from disease.
Body temperature regulation – capillaries can grow/shrink beneath the surface of skin – allows more/less body heat to escape

3. The Blood Transports nearly everything in the body Made up of :
Blood is the only liquid tissue
Transports nearly everything in the body
Made up of :
55% plasma (liquid)
45% cells (red blood cells, white blood cells, and platelets [cell fragments])
~5 L blood (10 pints?)

4. Blood Vessels
The human body has about 60,000* miles of blood vessels inside of it... enough to circle the Earth two and a half times!
One RBC travels 1,440 times through the body in one day. It will travel through multiple arteries, arterioles, capillaries, venules, and veins.
60, ,000 miles of blood vessels (equator is 25,000 miles)

5. Blood Vessels Arteries: Carry blood away from the heart High pressure
Elastic, muscular walls that enable them to expand and contract with surges of blood flow.

6. Blood Vessels Capillaries: Smallest of all blood vessels
Only one cell thick!
Where all diffusion takes place
Blood moves slowly and loses its pressure.
No cell of the body is more than a few cell diameters away from a capillary
Loses pressure – capillaries have many branches, so capillaries have a greater capacity for blood than arterioles/venules

7. Blood Vessels Veins: Carry blood to the heart, No blood pressure
Need valves so blood flows in one direction
Blood returning to heart from capillaries extremely low, not enough to propel blood back to heart, so valves to help and contraction of muscles drives blood through
Sometimes valves do not work properly and the result is a varicose vein. When valves do not work, blood tends to build up in the vein causing it to stretch and twist.

9. The Heart
Atrium – upper chamber of heart that receives blood, pumps blood to the ventricle.
Ventricle – lower chamber of heart that receives blood from atrium, pumps blood out of the heart.
Contractions force blood through the vessels – 70 ml blood/contraction (a little more than ¼ cup ~2.36 oz), 72 pumps/min – in one year pumps more than enough blood to fill an olympic sized swimming pool (pool = 2mill L, heart: 2.6 mill L)

10. The Heart The right side of the heart pumps oxygen-poor blood
The left side of the heart pumps oxygen-rich blood
The left and right sides of the heart are separated by the septum, which prevents the oxygen-poor and oxygen-rich blood from mixing
Contractions force blood through the vessels

11. Pathway of blood through the body – a summary:
Right side of heart
Lungs
Left side of heart
Body cells
Pathway of blood through the body – in detail...

12. Deoxygenated blood from body tissues
Vena cava 
Right atrium
Right ventricle 
Pulmonary artery 
LUNGS 
Blood is now oxygenated
Pulmonary vein 
Left atrium 
Left ventricle 
Aorta 
Body cells

13. Animations
Heart Map

14. Pathway of Blood Through Heart

15. Heart Facts … your heart:
The aorta, is almost the diameter of a garden hose. Capillaries, on the other hand, are so small that it takes ten of them to equal the thickness of a human hair.
Your body has about 5.6 liters (6 quarts) of blood that circulates through the body 3X/minute.
In one day, your blood travels a total of 12,000 miles-- that's four times the distance across the US from coast to coast.
Is located almost in the center of the chest, between the lungs.
Is about as big as two fists together
Beats about 100,000 times in one day and about 35 million times in a year. During an average lifetime, the human heart will beat more than 2.5 billion times.
Even at rest, the muscles of the heart work hard--twice as hard as the leg muscles of a person sprinting.