Transcript Transport System

Transport System
Human Heart
• Designed as a pair of side-byside pumps
• Each side has a collection
chamber for blood moving from
veins = thin walled, muscular
chambers are atria
• Each side also has a thick-walled
pump called a ventricle to force
blood out of the heart (blood
pressure)
Two Main Structures
1.
2.
3.
4.
5.
6.
7.
Large artery
Smaller artery branches
An arteriole (smallest
type of artery)
Capillary bed
A venule (smallest type
of vein)
Larger veins
Large vein which takes
blood back to the heart
be pumped out once
again
Blood path as it’s pumped
out of the heart
• Right side of the heart sends blood along a route that is
called your pulmonary circulation
• Here the capillary bed is in one of your lungs, and blood
picks up oxygen and releases carbon dioxide
• Left side of sends blood along a route that is called your
systemic circulation
• The artery in this part is your aorta
• Branches of the aorta carry blood to almost every organ and
cell type in your body
• Here the capillary bed is in one of your organs or tissues,
and blood picks up carbon dioxide and releases oxygen
Two Routes
• First found in a large vein that bring blood to the right
atrium
• RBC needs oxygen before it can go around the body
again
• From right atrium goes through a valve (R
atrioventricular valve) into the R ventricle
• One a volume of blood collects from atrium to ventricle
by muscle contractions in the heart, then the ventricle will
start its contractions
Pulmonary Circulation
(as if following 1 RBC)
• Closure of the atrioventricular valve to prevents back
flow to the R atrium (the closing of valves that produces
the characteristic “lubdub” sounds heard through a
stethoscope)
• Dramatic increase in blood pressure inside R ventricle
which opens the R semilunar valve allowing blood to
enter the pulmonary artery
• Due to increase in pressure, blood leaves the heart
through the pulmonary artery
Ventricle contractions
initiate:
• Now its leading to an artery leading to one of the two
lungs going through smaller and smaller arteries (the
smallest being the arterioles)
• Arterioles lead to a capillary bed where the gas exchange
will take place
• Now the RBC will head back to the heart oxygenated
• Will pass into larger and larger veins until the largest of
those veins takes our RBC directly to the left atrium
Still on the path of our
RBC
• One our RBC has entered the left atrium, it goes through
a series of events much like the pulmonary circulation
(build up in artery, pass through valve, enter the ventricle)
(both sides of the heart work simultaneously)
• Once ventricle has a pool of blood the:
• Atrioventricular valve closes to prevent backflow into
atrium
• Dramatic increase in blood pressure inside the left ventricle
will open the semilunar valve and allow blood to leave aorta
• Due to increase in pressure, blood leaves the heart through
the aorta
Systemic Circulation
• The RBC now is in the largest artery of our body, the aorta,
which has many branches that leads to all tissues in our body
• One of the first branches from the aorta allows blood to enter
the coronary arteries (will branch out into the heart muscle
itself and supplying the heart with oxygen and nutrients)
• Obviously, our RBC can only go down one branch…the end
result of any branch will be a capillary bed somewhere in the
body for another set of gas exchange.
• Following one RBC…will only take 1 or 2 min to complete the
entire process
Leaving the heart