FACTS: About circulation

• Arteries
Blood flows out from the heart through large
blood vessels called arteries, which branch into
smaller arterioles and then into tiny capillaries.
• Veins
Blood flows back to the heart through small
venules that join to form larger veins. The load
of oxygen makes blood redder in the arteries
than the veins.
• Double circulation
There two systems of circulation in the body,
each pumped by a different half of the heart.
• Double circulation
The left of the heart drives the "systemic"
circulation, which carries oxygen-rich blood
from the lungs around the body. The right half
of the heart drives the "pulmonary" circulation,
which drives blood through the lungs to the
left side of the heart.
• Pulse
The pumping of the heart sends regular shock
waves through the circulation, detectable as a
pulse. To feel your pulse, lay two fingers gently
on the inside of your wrist. Counting the
number of pulses tells you how fast your heart
is beating.