The Pulmonary and systemic circulation. Functions of these circulations and difference between pulmonary and systemic circulation,

1. Pulmonary & Systemic
Circulation
By: Amen Ullah
Lecturer Surgical
KMU-IPMS

2. Introduction
• 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.

3. Overview
• Humans and other mammals have two circuit
circulatory systems:
• one circuit is for pulmonary circulation, and the
other circuit is for systemic circulation (the rest
of the body).
• As each atrium and ventricle contract, blood is
pumped into certain major blood vessels, and
from there, continues through the circulatory
system.

4. Pulmonary 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.

5. • From the right atrium, the deoxygenated blood
drains into the right ventricle through the
tricuspid valve.
• The tricuspid valve has three flaps in its structure.
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.
.

6. • As the right ventricle contracts, it forces the
deoxygenated blood through the pulmonary semilunar
valve and into the pulmonary artery.
• Semilunar means half-moon and refers to the shape of
the valve. 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.

7. Pulmonary circulation

8. Systemic circulation
• Systemic circulation is the part of the
cardiovascular system which carries oxygenated
blood away from the heart to the body, and
returns deoxygenated blood back to the heart.
• Systemic circulation refers to the part of the
circulatory system in which the blood leaves the
heart, services
the body's cells, and then re-enters the heart.
• Blood leaves through the left ventricle to the
aorta, the body's largest artery.

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 venous
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.

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 thickwalled 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.

13. Pulmonary & Systemic circulation

14. Pulmonary Edema
• Pulmonary edema is a condition
characterized by fluid accumulation in the
lungs caused by back pressure in the lung
veins.
• This results from malfunctioning of the
heart.

15. Pulmonary Capillary dynamics
1. Starling forces (ultra filtration)
1. Capillary hydrostatic P = 7 mmHg.
2. Interstitial hydrostatic P = -8 mmHg.
3. Plasma colloid osmotic P = 28 mmHg.
4. Interstitial colloid osmotic P = 14 mm
2. Filtration forces = 15 mmHg.
3. Reabsorption forces = 14 mmHg.
4. Net forces favoring filtration = 1 mmHg.
5. Excess fluid removed by lymphatics

16. Causes of pulmonary edema
• Pulmonary edema is a complication of a
myocardial infarction (heart attack), mitral
or aortic valve disease, cardiomyopathy, or
other disorders characterized by cardiac
dysfunction.

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