The Circulatory System
Amazing Heart Facts
1. Your heart is about the same size as your fist.
2. An average adult body contains about five
quarts of blood.
3. All the blood vessels in the body joined end to
end would stretch 62,000 miles or two and a
half times around the earth.
4. The heart circulates the body's blood supply
about 1,000 times each day.
5. The heart pumps the equivalent of 5,000 to
6,000 quarts of blood each day
The job of
the
circulatory
system
The job of the circulatory
system
• is to move the oxygen out to the body, have
the cell take that oxygen and then take the
blood back up to the lungs to get more
oxygen.
• Blood carries oxygen and nutrients to every
cell of the body, carries away waste
products, and plays a central role in the
body's defense against intruders.
The body's
circulatory
system
really has
3 distinct
parts:
Circulatory Breakdown:
• 1. Pulmonary circulation, circulation through
the lungs, where blood goes from the heart to the
lungs and back to the heart, is when the blood
exchanges carbon dioxide and picks up oxygen.
The blood then returns to the left side of the
heart, which pumps it out to the rest of the body.
• 2. Systemic Circulation: What occurs here is
the flow of the blood from the heart to the rest
of the body and back to the heart.
Circulatory Breakdown:
• 3. Coronary Circulation: Like any other
organ, the heart itself needs blood to supply it
with nourishment and carry away wastes.
• The movement of blood through the
capillaries of the heart for these purposes is
called coronary circulation.
• BrainPop: the circulatory system
The Heart
• The heart which is a hollow muscle is charge of
pumping the blood.
• It is about the size of your fist.
• It is located slightly to the left of the center of
your chest.
The Heart in detail:
• The heart is basically shaped like a 4 pained
window.
• There is a right side, and a left side.
• There is a top half and a bottom half.
• Each side has specific responsibilities and
Right Atrium
Left Atrium
Right Ventricle
Left Ventricle
The right upper (right atrium)
receives blood from the body.
The right lower (right ventricle)
pumps blood to the lungs.
The left upper (left atrium)
receives blood from the lungs.
The left lower (left ventricle)
pumps blood to the rest of the
body.
The two halves of the heart are
separated by a membrane called
the septum.
This wall prevents the flow of
blood between the two atria or
the two ventricles.
The Heart
BrainPop
• Brainpop: The Heart
The heart is set up like a football team.
• You have receivers, quarterbacks
(who push the blood) and running
backs.
• The atriums RECEIVE the blood.
• The ventricles PUMP the blood out
to specific parts of the body and
• the veins and arteries are the
running backs who carry the
blood to where it needs to go.
• Veins carry DEOXYGENATED
blood.
• They carry blood TO the heart .
• The primary blood vessels that carry
the blood are called the upper and
lower VENA CAVAS
The Vena Cavas….
• One carries blood from the head
region to the heart, the other carries
blood from the body to the heart.
• This blood is designated as a blue
color to show that it is LACKING
oxygen “deoxygenated”
• Once the blood gets to the heart it is
RECEIVED by the right atrium.
• The right atrium then allows the blood
to go through a one-way valve to the
right ventricle.
• Once in the right ventricle it is this
“quarterback’s job “ to push (or
pump) the blood out to the lungs.
• The blood is pushed out to the lungs
by the right ventricle
• It is carried to the LUNGS by the
PULMONARY ARTERY.
• This is a rule breaker Number 1.
• What vessels carry what type of
blood?
• Veins carry DEOXYGENATED
blood to the heart and
• ARTERIES carry OXYGENATED
• But what type of blood do we have here???
Deoxygenated blood is being carried in an artery...
on it’s way to the lungs.
• Once it gets to the lungs, what’s going to happen??? The
blood is going to get oxygenated. It’s going to become
rich with oxygen. This is the blood that has to go out to the
body. This is the blood that the body needs. This is the
“red” blood of life.
• The blood gets oxygen, becomes oxygenated and then
heads back to the heart. It is carried to the heart by what
kind of vessel??
• What kind of vessels carry blood to the heart?? VEINS do.
This is rule breaker Number 2.
• The PULMONARY VEIN carries
OXYGENATED blood back to the
heart.
• This oxygenated blood is received in
the LEFT ATRIUM. (remember the
atriums as receivers.) It then goes
through another one way valve to the
LEFT VENTRICLE. If you look at a
heart it is this side which has the
greatest amount of muscle- because of
the quarter backing it must do!
• The LEFT VENTRICLE PUSHES
the blood into the AORTA (which is
the largest artery in the body).
• The AORTA then carries this
OXYGEN rich blood out to the various
parts of the body through the artery
system.
Valve Review
• Each chamber has a sort
of one-way valve at its
exit that prevents blood
from flowing backwards.
• When each chamber
contracts, the valve at its
exit opens.
• When it is finished
contracting, the valve
closes so that blood does
not flow backwards.
Valve Review
• The tricuspid valve
is at the exit of the
right atrium.
• The pulmonary
valve is at the exit of
the right ventricle.
• The mitral valve is
at the exit of the left
atrium.
• The aortic valve is at
the exit of the left
ventricle.
Heart Review
Blood
• The blood is carried to
the individual cells by
the capillary bridges
where the oxygenated
blood leaves its oxygen
and then is bridged to the
veins.
• The venous system
works together and meets
up with the VENA
CAVA and back to the
heart it goes, to start the
circulatory circle of life
again.
The heart pumps blood
in two phases.
• a. systolic phase: the ventricles contract,
pumping blood into the arteries.
• b. diastolic phase: or second phase, the
ventricles relax and blood flows into them
from the atria. These two phases of the
heartbeat are measured when the blood
pressure is taken..
Blood Vessels of the Systemic
Circulation
Blood
Arteries & Arterioles • 1. Arteries - arteries -> carry blood from heart to tissues - thick layer
of smooth muscle - no exchange of gases
• 2. Arterioles - arteries divide into smaller arterioles -> further
branch into microscopic capillaries
arterioles play a key role in regulating blood flow from arteries into
capillaries - no exchange of gases
Blood Vessels of the Systemic Circulation
3. Capillaries- microscopic in size; connect
arterioles and venules
- site of exchange of gases, nutrients and wastes
between blood and tissue cells
Blood Vessels of the Systemic Circulation
4. Venules- capillaries unite to form small venules, which in turn
merge and form veins - no exchange of gases
5. Veins - veins -> carry blood from tissues back to heart - blood
volume in rest -> 60 %
- veins usually have valves, which prevent back flow of blood compared to arteries, veins are thinner
- blood pressure in veins is considerably lower than in arteries
Size Comparison
VEINS
• veins: transports
the blood to the
heart this blood is
lacking in oxygen.
It is called
deoxygenated
blood
• and is typically
colored
as blue (it’s
actually a very
deep deep red
color)
ARTERIES
• arteries: this
transports blood
from the heart and is
rich in oxygen. It is
called oxygenated
blood
and is typically
CAPILLARIES
• capillaries: These
are the bridges
between the arteries
and the veins.
• Their jobs are to take
the oxygenated blood
directly to the cell,
and then pick up the
deoxygenated blood
and carry it to the
veins.
• - 60 % in
systemic veins and
venules
• - 15 % in
systemic arteries and
arterioles
• - 5 % in
systemic capillaries
-