The Circulation System of the Heart:
> Blood Circulates continously round and round in your body through an intricate series of tubes called blood vessels, Bright red oxygene rich blood is pumped from the left side of the heart through vessels called arteries. Purplish-blue, low in oxygene blood returns to the right of the heart through veins and venules.
> Your circulation is the system of tubes called blood vessels which carries blood out from your heart to all your body cells and back again.
> Each of the body's 600 billion cells gets fresh blood once every few minutes or less, on the way out from the heart, blood is pumped through vessels called arteries and arterioles.
***FACT***
It takes less than 90 seconds on average for the blood to circulate trhough all the body's 100,000 km of blood vessels.
> On the way back to the heart, blood flows through venules and veins
> Blood flows from the arterioles to the venules through the tiniest tubes caled called capillaries
The blood circulation has two parts: The Pulmonary and the Systemic
1) Pulmonary Circulation- is the short section that carries blood which is low in O2 (oxygene) from the right side of the heart to the lungs for "refuelling". It then returns O2 rich blood to the left side of the heart.
2) Systemic Circulation - This circulation carries O2 rich blood from the left side of the heart all around the body and returns blood which is low in O2 to the right side of the heart.
***Inside the blood, oxygene is carried by the haemoglobin in red blood cells
***Red Blood Cells can actucally be brown in color, but they turn bright scarlet when their Haemoglobin is carrying oxygene. After the haemoglobin passes its oxygene to a cell, it fades to dull purple. So oxygene rich blood from the heart is red, while oxygene-poor blood that is returning to the heart is a purplish-blue in color.
***FACT***
During an average lifetime , the HEART pumps 200 million liters of blood - enough to fill New Yorks Central Park to a dept of 15 m.