Cardiovascular System

Cardiovascular System
Cardiovascular System
 Includes
the heart, blood vessels and blood. (add
blood to your notes)
 Vital for survival, without circulation the tissues
lack oxygen and nutrients and waste will
Average Heart 13
centimeters long and 9 cm
 As a kid, the size of your
fist. As an adult…closer
to twice the size of your
 Vary along with body size.
A hollow, cone-shaped,
muscular pump located
within the mediastinum of
the thorax and resting
upon the diaphragm.
The heart is bordered by
the lung, posteriorly by the
spinal cord, and anteriorly
by the sternum.
Put your hand on your
heart. Did you place your
hand on the left side of
your chest?
 Many people do, but the
heart is actually located
almost in the center of the
chest, between the lungs.
It's tipped slightly so that a
part of it sticks out and
taps against the left side of
the chest, which is what
makes it seem as though it
is located there.
Layers of the Heart
 Pericardium-
Covering that encloses the heart and
the proximal ends of the large blood vessels to
which it attaches. The outer fibrous pericardium is
a tough, protective sac largely composed of dense
connective tissue.
Wall of the Heart (3 distinct layers)
Epicardium- corresponds with the visceral pericardium. It
is protective serous membrane that consists of connective
tissue covered by epithelium, and it includes blood
 Myocardium- thick and largely consists of the cardiac
muscle tissue that pumps blood out of the heart chambers.
 Endocardium- Inner most layer that consists of epithelium
and connective tissues that contains many elastic and
collagenous fibers. Also contains blood vessels and some
specialized cardiac muscle fibers.
Structure of the Heart
Major Parts of the Heart
The heart is divided into four hollow champers, two on the
left and two on the right.
 Atria- (Atrium)These are the upper chambers of the heart
which have thin walls and receive blood returning to the
 Ventricles- The lower chambers which force blood out of
the heart into the arteries.
 Blood flow will go like this…right atrium, right ventricle,
other stuff…left atrium to the left ventricle.
Major Parts of the Heart
 Superior
 These
Vena Cava and Inferior Vena Cava-
are two large veins that enter the right
 They are carrying blood that is low in oxygen from
tissue in the body.
Major Parts of the Heart
Throughout the heart circulation you will be responsible
for 4 valves…
Tricuspid, Bicuspid, Pulmonary and Aortic Valves
Regardless of location… all valves in the heart have
essentially the same purpose which is to allow blood to
flow in the correct order and preventing blood from
flowing backwards as the heart contracts and relaxes.
Major Parts of the Heart
 Tricuspid
Valve- guards the atrioventricular
orifice between the right atrium and right ventricle.
Valve permits the blood to move from the right
atrium to the right ventricle. (may need to be fixed
on guided reading notes)
 Bicuspid Valve (aka mitral valve)- blood goes
from the left atrium into the left ventricle through
this atrioventricular orifice.
Major Parts of the Heart
Pulmonary Valve- the flaps
between the right ventricle and
the pulmonary artery.
When the ventricle relaxes, the
valves closes, preventing the
back flow of blood from the
pulmonary artery to the right
Aortic valve- This is the valve
that the blood will flow
through as it moves from the
left ventricle to the aorta.
This prevents blood from
moving or back flowing from
aorta back into the left
ventricle during ventricular
The crazy things they do!
Throughout the body’s circulation system the following
holds true..
Veins always carry oxygen poor blood to the heart!
 Arteries always carry oxygen rich blood to the heart or
throughout the body!
The pulmonary circulation system is the flow of blood from the
heart to the lungs and then back again! Just the opposite holds
true here!!
Major Parts of the Heart
Pulmonary Arteries- the
blood vessel that carries
oxygen-poor blood from
the right ventricle of the
heart to the lungs.
Pulmonary Veins- the
blood vessel that carries
oxygen-rich blood from
the lungs to the left atrium
of the heart.
 The
coloring “concept” will remain constant
 Always
color oxygen poor veins or arteries BLUE
 Always color oxygen rich veins or arteries RED!
Major Parts of the Heart
 The
oxygen poor blood leaves the heart through
the pulmonary value and the pulmonary artery to
the lungs. You have 2 pulmonary valves. (right
and left)
 Left atrium receives the blood from the lungs
through four pulmonary veins (2 from the right
lung 2 from the left lung)
Major Parts of the Heart
 Aorta-
is the largest diameter artery in the body.
( It is almost the diameter of a garden hose.) It
extends upward from the left ventricle, arches over
the heart to the left and descends just anterior and
to the left of the vertebral column.
 You have an ascending and a descending aorta.
 It takes blood away from the heart.
Major Parts of the Heart
 Septum-
The muscular wall that separates the left
and right sides of the heart.
Basic Structure of the Heart
The human heart is primarily a shell. There are four
cavities, or open spaces, inside the heart that fill with
blood. Two of these cavities are called atria (atrium).
The other two are called ventricles. The two atria
form the curved top of the heart. The ventricles meet
at the bottom of the heart to form a pointed base
which points toward the left side of your chest. The
left ventricle contracts most forcefully, so you can
best feel your heart pumping on the left side of your
Main Arteries of the Heart
The top of the heart connects to a few large blood
vessels. The largest of these is the aorta, or main
artery, which carries nutrient-rich blood away from
the heart. Another important vessel is the pulmonary
artery which connects the heart with the lungs as
part of the pulmonary circulation system. The two
largest veins that carry blood into the heart are the
superior vena cava and the inferior vena cava. They
are called "vena cava" because they are the "heart's
veins." The superior is located near the top of the
heart. The inferior is located beneath the superior.
How Blood Flows Through the Heart
Day and night, the muscles of your heart contract and
relax to pump blood throughout your body. When blood
returns to the heart, it follows a complicated pathway. If
you were in the bloodstream, you would follow these
steps one by one.
You will need to write this down these steps and include
as part of your notes…Not in the guided reading
This is a vital part of this chapter!
How Blood Flows Through the Heart
1. Oxygen-poor blood flows from the body into the superior and
inferior Vena Cava
2. The Vena Cava’s dump the blood into the right atrium.
3. Blood flows through the right atrium into the right
ventricle by way of the Tricuspid Valve.
4. The right ventricle pumps the blood to the Pulmonary Trunk through
the Pulmonary Valve.
5. The oxygen poor blood will the go through the 2 Pulmonary
Arteries (right and left) to the lungs.
How Blood Flows Through the Heart
6. Once the lungs have saturated the blood with oxygen it then will
travel back to the heart through the 4 Pulmonary Veins (right and
7. The newly oxygen-rich blood enters the left atrium.
8. From the left atrium it will go to the left ventricle by way of the
bicuspid valve.
9. From the left ventricle the blood will then go the aorta via the aortic
10.The aorta will then pump the oxygen-rich blood to all parts of the
 Circulation
Blood Vessels
 The
blood vessels are organs of the cardiovascular
system and they form a closed circuit of tubes that
carries blood from the heart to cells and back
 These vessels include arteries, arterioles,
capillaries, venules, and veins.
Arteries and Arterioles
 Arteries
are strong, elastic vessels that are adapted
for carrying the blood away from the heart under
high pressure.
 These vessels subdivide into progressively thinner
tube and eventually give rise to the finer branched
 Capillaries
are the smallest diameter blood vessels.
(Capillaries are so small that it takes ten of them to
equal the thickness of a human hair.)
 They connect the smallest arterioles and the
smallest venules.
 They are extensions of the inner linings of
arterioles in that their walls are endothelium ( a
single layer of epithelial cells)
Venules and Veins
 Venules
are the microscopic vessels that continue
from the capillaries and merge to form veins.
 The veins which carry blood back to the atria,
follow pathways that roughly parallel those of the
Paths of Circulations
Pulmonary Circuitconsists of vessels that
carry blood from the heart
to the lungs and back to
the heart.
Systemic Circuit- Carries
blood from the heart to all
body parts, except the
lungs, and back again.
Pulse Rate
Feel your pulse by placing
two fingers at pulse points
on your neck or wrists.
The pulse you feel is
blood stopping and
starting as it moves
through your arteries.
As a kid, your resting
pulse might range from 90
to 120 beats per minute.
As an adult, your pulse
rate slows to an average of
72 beats per minute.
Blood Pressure
Blood Pressure is the
pressure of the blood
against the walls of the
 It results from two forces.
One by the force created
as the heart pumps blood
into the arteries.
 The other is the force of
the arteries as they resist
the blood flow
Blood Pressure
 Elevated:
Cool Facts
Your body has about 5.6
liters (6 quarts) of blood.
This 5.6 liters of blood
circulates through the
body three times every
minute. In one day, the
blood travels a total of
19,000 km (12,000
miles)—that's four times
the distance across the
U.S. from coast to coast.
The heart pumps about 1
million barrels of blood
during an average
lifetime—that's enough to
fill more than 3 super
Cool Facts
Your heart beats about
100,000 times in one day
and about 35 million times
in a year. During an
average lifetime, the
human heart will beat
more than 2.5 billion
lub-DUB, lub-DUB, lubDUB. Sound familiar? If
you listen to your heart
beat, you'll hear two
sounds. These "lub" and
"DUB" sounds are made
by the heart valves as they
open and close.

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