Transcript Cardiovascular System

Cardiovascular System
Lecture 5
General
• The cardiovascular system is a
series of tubes and a muscular
pump that provides a ONE-WAY
street for blood, oxygen, and
nutrients.
• Blood and nutrients travel
through blood vessels (arteries,
veins, and capillaries).
• The cardiovascular system is fueled
by a muscular pump called the heart.
The heart is actually two pumps
connected by a SEPTUM.
• The right side of the heart pumps
blood that is deficient in oxygen to the
lungs [Pulmonary Circulation].
• The left side of the heart pumps
blood that is rich in oxygen to the
body [Systemic Circulation].
Combining Forms
Angi/o
Vas/o
vessel
Angiogram (record)
Vasospasm (twitching)
aort/o
aorta
Aortostenosis
(narrowing)
Arterio/o
artery
Arteriosclerosis
(condition of hardening)
Ather/o
Fatty plaque
Atheroma
Atri/o
atrium
Atrial
Cardi/o
heart
Cardiomegaly
(enlargement)
Electr/o
electric
Electrocardiogram (record
of electric)
Phleb/o
Ven/o
vein
Phlebitis
Venous
Thromb/o
Blood clot
Thrombolysis
(destruction of a
clot)
Ventricul/o
Ventricle
(brain or
heart)
Interventricular
septum
(wall between the
two ventricles)
The Heart
• The heart has three distinct layers of
tissue.
1. endocardium
- deepest layer.
2. myocardium
- muscle
3. epicardium
- outermost layer
• The heart is a muscular organ
that pumps blood and is
enclosed in a membranous sac.
This sac allows the heart to beat
without friction.
• This sac is called the
PERICARDIUM. Peri- means
“around”, cardium refers to the
heart.
Peri/cardi/ectomy
- sx procedure excising the pericardium.
Peri/cardi/o/rraphy
- suturing a wound of the pericardium.
My/o/cardi/um
- the muscular layer of the heart.
• There are two sides of the heart.
• There are two vertical divisions of
the heart.
• The top compartments are ATRIA
• The bottom compartments are
VENTRICLES
• Therefore, there are right and left
atria and right and left ventricles.
Heart Chambers
Left
Atrium
Right
Atrium
Right
Ventricle
Left
Ventricle
Apex
• Abbreviations for chambers:
Right atrium
Right ventricle
Left atrium
Left ventricle
RA
RV
LA
LV
• The ventricles are larger than the
atria. This is because the
ventricles are responsible for
pumping blood a farther distance
than the atria.
• Of the two ventricles, the left is
larger than the right. This is
because the left ventricle must
pump blood to the entire body.
• A rapid contraction of the atrium
or ventricle is known as a
FLUTTER.
• Atrial flutter can cause chest
pain and shortness of breath
(SOB).
• The rule for forming plural words
from the singular that end in –
um is to drop the –um and add
an –a.
• The prefix “tachy-” refers to rapid.
a rapid heartbeat (pulse):
tachycardia
• The prefix “brady-” refers to slow.
a slow heartbeat (pulse):
bradycardia
• Arteries bring blood AWAY from the
heart.
• Veins bring blood TOWARD the
heart.
• Arteries usually carry blood with
much oxygen.
• Veins usually carry blood with little
oxygen.
• The RIGHT ATRIUM receives blood
from all tissues of the body through
veins. This blood is oxygen poor.
•
The blood brought back to the heart comes
from three sources:
1.
SUPERIOR VENA CAVA (SVC) brings
blood from the top part of the body.
INFERIOR VENA CAVA (IVC) brings blood
from the lower part of the body.
CORONARY SINUS brings blood from the
heart muscle.
2.
3.
All three sources empty into the RIGHT
ATRIUM.
• Once inside the right atrium, the
blood must travel to the right
ventricle. In order to do this, it must
pass through the TRICUSPID
VALVE.
• The function of all heart valves is to
allow one way travel of blood. It
would be dangerous to have blood
backflow because of different
oxygen concentrations.
Heart Valves
Pulmonary Veins
Mitral
Left
Tricuspid
Right
Apex
• Once inside the right ventricle, the
blood passes through the
PULMONARY SEMILUNAR VALVE
into the PULMONARY ARTERIES.
• The pulmonary arteries carry
oxygen-deficient blood to the lungs.
• Once inside the lungs, the blood
vessels branch until they reach one
cell layer thick. These
CAPILLARIES combine with the
ALVEOLI of the lungs for the
exchange of oxygen and carbon
dioxide.
• The blood now has much oxygen. It
returns to the heart by the
PULMONARY VEINS. There are four
pulmonary veins that empty into the
LEFT ATRIUM.
• The blood then must pass through the
MITRAL VALVE (BICUSPID VALVE)
into the left ventricle.
• From the left ventricle the blood
passes through the AORTIC
SEMILUNAR VALVE in the AORTA.
• The aorta is the largest artery of the
body.
• The contraction of the left ventricle
sends blood rich in oxygen all over
the body. There are three arteries
that bring blood to the head, neck,
and upper extremities. There is one
major vessel that brings blood to the
abdomen and lower extremities.
• Arteries are the large vessels that
bring blood away from the heart.
These vessels branch into smaller
ARTERIOLES which eventually
branch into CAPILLARIES which are
only one cell thick.
• The primary responsibility for
initiating the heartbeat is with the
SINOATRIAL NODE. This is located
on the posterior wall of the right
atrium.
• Once this electric current is
generated, atrial muscle contracts
forcing blood into the ventricles.
Once this occurs the heartbeat
moves to another region called the
ATRIOVENTRICULAR NODE.
• Once this occurs, the AV node sends
electrical impulses through a series
of BUNDLE BRANCHES ending in
PURKINJE FIBERS that stimulate
the ventricles to contract.
Blood Supply to Heart
• Coronary Artery System
– right coronary
– left coronary
• left anterior descending
• circumflex
The Cardiac Cycle and Heart
Sounds
• The CARDIAC CYCLE is the events
that occur in one complete heartbeat.
• The cardiac cycle has 2 phases:
1. contraction of the heart: SYSTOLE
2. relaxation of the heart: DIASTOLE
• The atria and ventricles have
different functions during the cardiac
cycle.
• When the atrium are contracting,
blood flows into the ventricles.
Therefore, the ventricles have to be
relaxing.
• When the atria are in systole, the
ventricles are in diastole.
• Electrical activity of the heart can be
measured by an electrocardiogram
(EKG or ECG).
• EKG’s are electrical tracings of
each part of the cardiac cycle.
• Each time a different part of the
heart contracts, an electrical
impulse can be recorded from
different areas on the thorax.
QRS complex
– signals
activity of
the Purkinje
fibers and
Bundle of His
P wave –
signals atrial
contraction
T wave signals
ventricular
relaxation
Microcardia
- small heart
Cardiomegaly (megalocardia)
- enlargement of heart
Myocardial Infarction (MI)
- heart attack
Hypertension
- high blood pressure
• ATHEROSCLEROSIS is a form of
ARTERIOSCLEROSIS and is
characterized by an abnormal
accumulation of fat and fibrous
tissue (scarring) in a blood vessel.
• This leads to a narrowing of the
LUMEN which causes a decrease in
blood flow to a part of the body.
• This condition can lead to
NECROSIS, or cellular death.
• To prevent blood clots, patients
may take an ANTICOAGULANT.
These are agents that delay blood
coagulation (clotting).
• Anticoagulants are used to prevent
THROMBUS formation
(THROMBOGENESIS).
• THROMBOLYSIS is accomplished
with THROMBOLYTIC AGENTS or
medications that destroy a clot.
• An ANEURYSM is a weakened blood
vessel wall caused by DILATION of the
vessel. This causes the vessel to
balloon and eventually burst.
• There are two types of aneursym:
1. Fusiform – the wall dilates equally
resulting in a tubular swelling.
2. Sacculated – a balloon is attached
to the vessel by a narrow stalk.