Transcript Circulatory Notes

Circulatory
Notes
The Anatomy of the Heart
• There are four chambers in the heart - two
atria and two ventricles.
• The atria are responsible for receiving blood
from the veins leading to the heart. When they
contract, they pump blood into the ventricles.
• It is the ventricles that are the real workhorses,
for they must force the blood away from the
heart with sufficient power to push the blood all
the way back to the heart.
• The muscle in the walls of the ventricles is much
thicker than the atria. The walls of the heart are
really several spirally wrapped muscle layers.
This spiral arrangement results in the blood
being forced out of the ventricles during
contraction.
• Between the atria and the ventricles are valves,
overlapping layers of tissue that allow blood
to flow only in one direction. Valves are also
present between the ventricles and the vessels
leading from it.
The Blood Vessels
There are three types of vessels:
1. Arteries - a muscular blood vessel that
carries blood away from the heart.
2. Veins - a blood vessel that carries blood to
the heart.
3. Capillaries – Small blood vessels, the walls
are so thin that oxygen and glucose can pass
through them and enter the cells. Waste
products, such as carbon dioxide, pass back into
the bloodstream via the capillaries to be carried
away and expelled from the body.
Flow of blood
Blood from the body flows:
• to the Superior and Inferior Vena Cava,
• then to the Right Atrium
• through the Tricuspid Valve
• to the Right Ventricle
• through the Pulmonary Valve
• to the Pulmonary Artery
• to the Lungs
The blood picks up oxygen in the lungs,
and then flows from the lungs:
• to the Pulmonary Veins
• to the Left Atrium
• through the Mitral valve
• to the Left Ventricle
• through the Aortic Valve
• to the Aorta
• to the body
Circulatory Problems
• Atherosclerosis is a degenerative disease that results in
narrowing of the coronary arteries.
• Coronary arteries can become clogged or occluded,
leading to damage to the heart muscle supplied by the
artery.
• Valvular regurgitation occurs when the valves become
so worn that they cannot close completely, and blood
flows back into the atria or the ventricles.
Stained cross sections through coronary
artery (left) and a coronary artery with lipid
deposits in its walls (right).
• Name the numbered
parts of the heart
• Using arrows, show
the path of blood
moving through the
heart
• Color the pathways of
deoxygenated blood
blue and oxygenated
blood pathways red.
Question
• Why is the human heart called a “double
loop”?