Download The Heart - Aroma Hut Institute

The Heart
The Heart
The Heart
The heart is made up of four chambers. These are called the atria (left atrium,
right atrium also known by the term auricles) and the left and right ventricles. The
atria collect the blood. The ventricles pump the blood out of the heart.
To prevent blood from flowing backwards, each chamber is equipped with a valve.
The two sides of the heart are separated by the septum.
The right side of the heart pumps de-oxygenated blood (blood not containing oxygen)
to the lungs to pick up oxygen. The left side of the heart pumps the oxygenated blood
from the lungs around the rest of the body.
Take a minute to consider the difference between the circulatory system and the
lymphatic system. Circulation has the heart to pump it while the lymph depends on
muscular tone to compress it.
Blood Vessels
Blood is carried throughout the body through blood vessels. In an average day, the
heart will pump around 36,000 quarts of blood through 12,450 miles of blood vessels.
An adult has around 5-6 quarts of blood within.
There are three types of vessels:
Arteries
These are the largest of the three and have very thick muscular walls.
These create a very high pressure environment for the blood and carry blood away
from the heart (this is always oxygenated with the exception of the pulmonary artery
which goes to the lungs). The small passageways that allow the blood to flow through
are called the internal lumen.
Veins
Smaller, veins have thinner walls and a larger internal lumen. The blood in the veins
is contained under much lower pressure which also have valves to prevent back flow.
Veins carry blood to the heart. In the case of veins, the blood is always de-oxygenated
apart from the pulmonary vein which goes away from the lungs to the heart.
Capillaries
Capillaries are teeny weeny, measuring only one cell in thickness and constrict the
blood under very low pressure. These are found in both the muscles and the lungs.
Gas exchange takes place in the capillaries. Oxygen passes through the capillary wall
and then pervades into the tissues. Carbon dioxide then passes from the tissues and is
taken into the blood.