Circulatory System
Function and Parts
Definition

It is a fluid-filled network of tubes (or
vessels) through which materials move
between the environment and the cells of a
multicellular animal.
Characteristics

It connects all parts of an organism in a way
that allows individual cells to thrive as well
as for organisms to function as a unit
 It is an entirely closed system
Function

Transport materials needed by cells
– Oxygen
– Glucose

Remove waste materials from cells
– Carbon dioxide
– urea
Major Components

Pump (heart)
– Continuously circulates blood

Network of tubes
– Arteries- blood away from heart
– Veins- blood back to the heart

Blood
– Fluid that fills the circulatory system
Specific parts





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Pulmonary arteries- transport blood to lungs
Pulmonary veins- transport oxygenated blood to
hear
Aortic arch and trunk- main arteries from heart
Common carotid artery- carries blood to brain
Renal vein and artery- connects to kidneys
Mesenteric veins- connects to intestine
Accessory Organs

Lungs- organ where oxygen is taken up and
CO2 is released
 Kidneys- organ where wastes are removed
from blood; critical in regulating fluids in
the body
 Small intestine- digestion
 Large intestine- water absorption
The Heart

The human heart has four chambers
– Left and right ventricle
– Left and right atrium

The left side of the heart pumps oxygenated
blood to the body while the right side of the
heart pumps deoxygenated blood to the
lungs where oxygen can be absorbed by the
hemoglobin carrying red blood cells
After passing through the capillaries of the lungs, the
blood which is now oxygenated returns to the heart in
the pulmonary veins.
From lungs
The left atrium receives blood from the pulmonary vein.
Blood passes through the mitral valve into the left
ventricle.
Contraction of the left ventricle pushes blood through the aortic
semilunar valve into the aorta. Blood travels to all regions of the
body where it feeds cells with oxygen picked up from the lungs
and nutrients from the digestive tract.
To rest of body
Deoxygenated blood returns from the rest of the body
through the superior and inferior vena cava.
The right atrium receives the deoxygenated blood.
Blood then enters the right ventricle through the
tricuspid valve.
Contraction of the right ventricle pushes blood through
the pulmonary semilunar valve into the pulmonary
arteries in which it travels to the lungs.
To lungs
Blood Pressure

Blood pressure is a measure of the force
exerted by the blood on the wall of the
arteries.
– An example is 120/80 (systolic
pressure/diastolic pressure.


Systolic pressure is the result of the contraction of
the ventricles (normal 110-140)
Diastolic pressure is during the ventricle relaxation
(normal 70-90)