Circulatory System
Health and Wellbeing
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Circulatory System
Major structures:
1. Heart
2. Blood Vessels
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Heart
Two Major Functions:
1. Pump blood to the lungs for
oxygenation (pulmonary loop)
2. Pump blood to all tissues in the
body (systemic loop)
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Heart- Pulmonary Loop
Pulmonary means “lungs”- circulates blood to the lungs and
back to the heart again.
● Right side of the heart pumps to lungs
● Blood picks up oxygen (low oxygen blood becomes oxygenated)
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Heart- Systemic Loop
Systemic refers to body systems
- circulates blood to tissues
all over your body.
● Left side of the heart pumps
to the body
● Delivers oxygen and picks
up carbon dioxide waste
(oxygenated blood becomes
de-oxygenated)
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Heart Chambers
Atria - collect blood coming into
the heart from the blood vessels
Ventricles - pump blood out of the
heart to the pulmonary or systemic
loops
* The tan part of the diagram is muscular tissue. What do you notice about the
muscle tissue around the atria compared to the ventricles? Why?
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Heart Valves
The heart valves slam shut after blood has passed through
them.
This keeps blood from moving backwards and forces it to flow
in only one direction.
The valves opening and closing are also responsible for the
“lub dub” heartbeat sounds!
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Blood Vessels
Three major categories of blood vessels:
1. Arteries
2. Veins
3. Capillaries
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Blood Vessels
Arteries:
●
●
Carry blood AWAY from the heart (artery=away)
Have thick, strong walls to resist high pressure
Veins:
●
●
Carry blood back to the heart
Have thin walls because there is little or no pressure
Capillaries:
●
●
Found in lungs and tissues that need oxygen
Very thin walls so gases can move in and out easily
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Blood Vessels
Arteries, capillaries, and
veins are attached in
sequence:
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Circulatory System
This animation puts everything together: Ventilation and
Circulation
Video of a single cardiac cycle
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Circulatory System
Explore the system using
this interactive anatomy site
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