Pulmonary & systemic circulation

1. Pulmonary Circulation and Pulmonary Circulation and
Systemic CirculationSystemic Circulation
By: Vernice Chun and Dale Go

3. When a heart contracts and forces blood
into the blood vessels, there is a certain
path that the blood follows through the
body. The blood moves through pulmonary
circulation and then continues on through
systemic circulation.

4. Humans and other mammals have two-
circuit circulatory systems: one circuit is
for pulmonary circulation, and the other
circuit is for systemic circulation. As each
atrium and ventricle contract, blood is
pumped into certain major blood vessels,
and from there, continues through the
circulatory system.

5. Pulmonary circulationPulmonary circulation
The part of the circulatory system that
transports deoxygenated blood from the right
side of the heart to the lungs and returns
oxygenated blood to the left side of the heart.
Blood that is lacking oxygen is said to
be deoxygenated. This blood has just exchanged
oxygen for carbon dioxide across cell
membranes, and now contains mostly carbon
dioxide. Deoxygenated blood enters the right
atrium through the superior vena cava and the
inferior vena cava.
 

6. From the right atrium, the deoxygenated
blood drains into the right
ventricle through the tricuspid valve.
When the ventricles contract, the
tricuspid valve closes off the opening
between the ventricle and the atrium so
that blood does not flow back up into the
atrium.
.

7. As the right ventricle contracts, it forces the
deoxygenated blood through the pulmonary
semilunar valve and into the pulmonary
artery. Note that this is the only artery in the
body that contains deoxygenated blood; all
other arteries contain oxygenated blood. The
semilunar valve keeps blood from flowing
back into the right ventricle once it is in the
pulmonary artery.
The pulmonary artery carries the blood that
is very low in oxygen to the lungs, where it
becomes oxygenated.

9. The aorta leads to smaller arteries,
arterioles, and finally capillaries. Waste and
carbon dioxide diffuse out of the cell into
the blood and oxygen in the blood diffuses
out of the blood and into the cell, blood
then moves to venious capillaries, and then
the venae cavae: the lower inferior vena
cava and the upper superior vena cava,
through which the blood re-enters the heart
at the right atrium. in the liver.

10. Oxygenated blood enters the systemic circulation
when leaving the left ventricle, through the aortic
semilunar valve. The first part of the systemic
circulation is the aorta, a massive and thick-
walled artery. The aorta arches and branches into
major arteries to the upper body before passing
through the diaphragm, where it branches further
into arteries which supply the lower parts of the
body. After their passage through body tissues,
capillaries merge once again into venules, which
continue to merge into veins.

11. The venous system finally coalesces into two
major veins: the superior vena cava (roughly
speaking draining the areas above the heart)
and the inferior vena cava (roughly speaking
from areas below the heart). These two
great vessels empty into the right atrium of
the heart. The general rule is that arteries
from the heart branch out into capillaries,
which collect into veins leading back to the
heart..

12. Portal veins are a slight exception to this.
In humans the only significant example is
the hepatic portal vein which combines
from capillaries around the gut where the
blood absorbs the various products of
digestion; rather than leading directly
back to the heart, the hepatic portal vein
branches into a second capillary system in
the liver.

14. The End