2. The cardiovascular system consists of a network of
vessels that circulates blood throughout the body,
motored by the action of the heart. We’ll be talking
about specifics of the heart in a separate lesson, so
will concentrate here on the circulatory system.
3. The inferior vena cava is
the largest vein of the body.
It carries de-oxygenated
blood back from the lower
part of the body to the right
atrium of the heart. This
blood is carrying carbon
dioxide.
The superior vena cava is above the heart and
carries de-oxygenated blood from the head and
arms to the right atrium of the heart.
4. From the right
atrium, the blood
flows through the
tricuspid valve to
the right ventricle
and then onto the
lungs through the
pulmonary valve
and pulmonary
artery.
5. In the lungs, the blood exchanges the carbon
dioxide it is carrying for oxygen.
7. The oxygenated
blood leaves the
left atrium through
the mitral
(bicuspid) valve
into the left
ventricle, gets
pumped from the
left ventricle
through the aortic
valve to the aorta.
8. The aorta is the
largest artery of the
body. The
ascending aorta
leaves the heart,
curves in an
inverted ‘U’ shape
making an arch,
and then descends
downward.
9. At the arch of the aorta, 3
branches extend upward…
1. The brachiocephalic
artery (or innominate
artery) quickly divides into
the right subclavian artery
that supplies blood to the
right arm and upper torso
AND the right common
carotid artery that supplies
the head and neck.
10. At the arch of the aorta, 3
branches extend upward…
2.The left common carotid
artery supplies the head
and neck.
3.The left subclavian artery
supplies the left arm and
upper torso. ‘Subclavian’
means it is located below
the clavicle… or collarbone.
11. The descending aortic
artery leads downward
through the diaphragm
and chest…and into the
abdomen. About 1/5 to 1/3
of the blood passes
through the renal artery
into the kidney. The
kidney is a filter, and takes
some water and waste
products out of the blood.
The kidneys excrete the waste products and
water out of the body as urine.
12. The descending
aortic artery
continues downward
into the abdomen. It
then splits into two
major branches. This
split is called the
aortic bifurcation;
the two branches are
called iliac arteries.
13. The left iliac
artery supplies
blood to the left
pelvis and leg;
the right iliac
artery supplies
blood to the right
pelvis and leg.
The iliac artery continues down
into the leg as the femoral artery
and its branches.
14. Arteries are elastic tubes that carry
blood in pulsating waves. The blood
exerts pressure against the walls of
the arteries as it passes through. The
peak pressure occurs during the
heart’s contraction, and is called
systolic pressure. The minimum
pressure occurs between
contractions when the heart expands
and refills, and is called diastolic
pressure. This pressure variation
within the artery produces a pulse.
All arteries have a pulse.
15. Common pulse sites used to
check circulation are:
1. TEMPORAL (TEM por ul) - side of
forehead
2 & 3. CAROTID (kuh RAH did) - neck
4. BRACHIAL (BRAY kee ul) - inside
the elbow
5. RADIAL - thumb side of wrist
6. FEMORAL (FEM er all) - groin
7.POPLITEAL (pah plah TEE ul) -
behind the knee
8 & 9. DORSALIS PEDIS (dor SAL us
PED iss) - upper surface of foot
16. Count the number of beats for
15 seconds x 4 = pulsations per minute.
The average
pulse rate for a
person who is
‘resting’, would
be 70. During
exercise, that
number might
increase to
between 130
and 140 beats
per minute.
17. Systolic and diastolic
blood pressure can be
measured in the brachial
artery just above the
elbow with an instrument
called a
sphygmomanometer
(sfig mō mah MOM ah ter) and a
stethoscope. Two
measurements are taken,
and are expressed in
millimeters of mercury
(the chemical symbol for
mercury is Hg).
The two blood pressure
measurements are
written as a ratio…
systolic over diastolic.
18. In the average adult,
systolic pressure usually
ranges between 100 to
140 mm Hg. Diastolic
pressure usually ranges
between 60 to 90 mm Hg.
A typical blood pressure
reading would be expressed as
120/80… 120 over 80. A reading
of 140/90 would be considered
‘high’ blood pressure, and may
pose health risks.
19. Arterioles act like adjustable
nozzles in the circulatory system,
so they have the greatest
influence over blood pressure.
The arteries
branch off
into even
smaller
vessels called
arterioles,
and then to
smaller
vessels yet
called
capillaries.
20. The capillaries are the
smallest of the blood
vessels, and the walls
are so thin that
molecules can pass
through them. They
branch out from the
arterioles, passing
next to the organs,
intestines, and
through all the
cellular tissue.
In the cellular tissue, the
capillaries provide the
means of exchange,
through the process of
absorption.
21. The capillaries
branching away
from the arteries in
the abdomen pass
by the liver and
intestines, picking
up nutrients and
water.
The capillaries in the cellular tissue exchange
their oxygen, nutrients, and water… and pick up
carbon dioxide and other wastes.
The capillaries
branching away
from the arteries in
the lungs absorb
oxygen.
Nutrients
Water
Oxygen
22. The capillaries,
now carrying
carbon
dioxide and
cell wastes,
start merging
into bigger
vessels called
venules (VEEN or VEN
yoo als) The venules
widen even further,
emptying into
24. Veins are the vessels
that are used to
remove blood from the
body for analysis.
This procedure is called a
venipuncture (VEEN ah punk chur)
and the medical personnel
that specializes in this
procedure is called a
phlebotomist (flah BOTT ah mist).
25. The veins carry the
blood BACK toward the
heart. The blood still
carries a small amount
of oxygen along with
cellular waste, but has
fairly low pressure
compared to blood in
arteries. It finally travels
through the superior
and inferior vena cava,
and back into the right
atrium of the heart.
Circulation is complete, and starts over again.
