Download AP - Cardiovascular

Unit 5
Cardiovascular System
 Introduction
A. The cardiovascular system consists of the heart
and three types of blood vessels.
- arteries
- capillaries
- veins
B. A functional cardiovascular system is vital for
supplying oxygen and nutrients to tissues and
removing wastes from them.
C. Deoxygenated blood is carried by the pulmonary
circuit to the lungs, while the systemic circuit sends
oxygenated blood to all body cells.
Structure of the Heart
A. The heart is a hollow, cone-shaped,
muscular pump within the thoracic cavity.
B. Size and Location of the Heart
1. The average adult heart is 14 cm long and 9 cm
wide.
2. The heart lies in the mediastinum under the
sternum; its apex extends to the fifth intercostal space.
Structure of the Heart
C. Coverings of the Heart
1. The pericardium encloses
the heart.
2. It is made of two layers: the
outer, tough connective
tissue fibrous pericardium
surrounding a more delicate
visceral pericardium
(epicardium) that surrounds
the heart.
Remember the
perimysium?
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Structure of the Heart
D. Wall of the Heart
1. The wall of the heart
is composed of three
distinct layers.
- epicardium
- myocardium
- endocardium
(the endocardium contains the
Purkinje fibers)
What are Purkinje Fibers?
• Located in the inner
ventricular walls of the
heart, just beneath the
endocardium. These
fibers are specialized
myocardial fibers that
conduct an electrical
stimulus or impulse
that enables the heart
to contract in a
coordinated fashion.
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Chambers of the Heart
• The heart contains four
compartments called
chambers.
• The two upper chambers
are called the right and
left atriums.
• The two lower chambers
are called the right and
left ventricles, they are
separated by a septum
with an apex at the base.
Atrium
Ventricle
Atrium
Ventricle
Anatomy of the Heart
• The atrioventricular valves (AV valve) separate
the atrium and ventricle on each side of the heart.
• The AV valves have flaps of tissues, called
leaflets or cusps, which open and close to ensure
that the blood flows only in one direction and
does not backflow into the atriums.
Anatomy of the Heart
• The AV valve on the right
side of the heart is called
the tricuspid valve because
it has three leaflets
(cusps).
• The AV valve on the left
side of the heart is called
the bicuspid valve (or mitral
valve) because it has two
leaflets.
Atrium
Atrium
Bicuspid
Valve
Tricuspid
Valve
Ventricle
Ventricle
Apex
Blood Vessels
• The blood vessels form
a closed tube that
carries blood away from
the heart, to the cells,
and back again.
– Arteries/Arterioles
– Capillaries
– Veins/Venules
Arteries
• Arteries – Blood vessels that carry blood away from the
heart. They have thick, elastic walls made of connective
tissue and smooth muscle tissue.
Main Arteries Connected to the
Heart
• The right ventricle of the
heart is connected to the
pulmonary artery (moves
blood toward the lungs).
• The left ventricle of the
heart is connected to the
aorta (move blood toward
other body tissues).
Aorta
Pulmonary
Artery
Atrium
Ventricle
Atrium
Ventricle
Arteries
• As the arteries extend away from the heart, they branch
out into smaller arteries called arterioles.
• The smaller arteries’ walls are composed of large
amounts of smooth muscle instead of the elastic tissue.
• Arterioles branch into smaller vessels called capillaries.
Capillaries
• Capillaries – Arteries and veins are connected by
microscopic blood vessels. The walls of
capillaries are only one cell thick. Nutrients and
oxygen diffuse from body cells into capillaries.
Capillaries
• The semi-permeable membrane of capillary
walls allows nutrients, oxygen, and water to
diffuse from the blood to the tissues.
• Waste products, like carbon dioxide, diffuse from
the tissues into the blood.
Capillaries
• Once blood passes through the capillary beds, it
begins its return to the heart.
• Capillaries unite to form small veins called
venules.
• The venules join together to form larger veins,
which have thin walls and are collapsible.
Blood Vessels
• Veins – Blood vessels that carry blood back
to the heart. Veins have one-way valves that
keep blood moving toward the heart.
Main Veins that are Connected to
the Heart
• The superior vena cava
returns blood from your
head and neck.
• The inferior vena cava
returns blood from your
abdomen and lower
body.
Superior Vena
Cava
Atrium
Ventricle
Inferior
Vena
Cava
Atrium
Ventricle
Main Veins that are Connected to
the Heart
• Right and left
pulmonary veins bring
blood from lungs back
to the heart.
Pulmonary
Veins
Pulmonary
Veins
Right
Atrium
Right
Ventricle
Left
Atrium
Left
Ventricle
Veins
• Veins have valves that aid the return flow of blood and
prevent the blood from reversing flow.
• These valves allow for muscle contractions and movement
of body parts.
• The valves also assist the return flow of blood to the heart
when blood pressure is low.
Superior Vena
Cava
Aorta
Left
Pulmonary Artery
Right
Pulmonary Artery
Pulmonary
Veins
Pulmonary
Valve
Right
Atrium
Tricuspid
Valve
Right
Ventricle
Inferior
Vena
Cava
Pulmonary
Veins
Left
Atrium
Aortic
Valve
Left
Ventricle
Apex
Bicuspid
Valve
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The Largest Heart and Blood
Vessels
Parts of the Circulatory System
The total circulatory system is
divided into two main parts:
• Pulmonary circulation
• Systemic circulation
Pulmonary Circulation System
Red portion of heart and red blood vessels carry oxygen-rich blood.
Blue portion of heart and blue blood vessels carry oxygen-poor blood.
Pulmonary Circulation
Pulmonary circulation:
 takes the blood from the heart to the lungs
 blood is oxygenated, then its returned to the heart
The main parts of the pulmonary circulation system
include the:
-
Heart
Pulmonary Arteries
Pulmonary Veins
Alveolar Capillaries
Pulmonary Circulation
Oxygen Poor Blood
Oxygen Rich Blood
Picks up oxygen
from the LUNGS
Flow of Blood in Pulmonary Circulation
1. Unoxygenated blood
enters the right atrium:
- From upper body via
superior vena cava
- From lower body via
inferior vena cava.
Flow of Blood in Pulmonary Circulation
2. From atrium, blood goes
thru tricuspid valve into
right ventricle.
3. Ventricle contracts,
pushed blood into
pulmonary artery.
4. Pulmonary artery branch
apart, sending blood to the
right or left lung.
Flow of Blood in Pulmonary Circulation
5. At lung, blood
becomes oxygenated
by diffusion between
the alveoli and
capillaries.
Flow of Blood in Pulmonary Circulation
6. Oxygenated blood
goes back to the
heart through the
pulmonary vein.
- Pulmonary veins
returns blood into the
left atrium.
The Flow of Blood Through the
Systemic Circulatory System
Systemic Circulation:
 takes oxygen-rich blood from heart to all organs
and body tissues
 oxygen-poor blood returns to the heart. This is
the largest section of your circulatory system.
The main parts of the pulmonary circuit are the:
-
Aorta
Veins
Capillaries
Arteries
Systemic Circulation
Oxygen Rich Blood
Oxygen Poor Blood
Gives Oxygen to
Body Cells
Flow of Blood in Systemic Circulation
1. Oxygenated blood
from left atrium goes thru
bicuspid valve to left
ventricle.
Flow of Blood in Pulmonary Circulation
2. Ventricle contracts,
pushes blood into
aorta under high
pressure.
Flow of Blood in Systemic Circulation
3. Aorta sends blood
throughout body to
be used by all body
cells.
- Blood gets filtered
in the kidneys.
Flow of Blood in Systemic Circulation
4. Blood becomes
deoxygenated by diffusion
in the capillaries.
5. Deoxygenated blood
goes back to the heart via
the two vena cava.
Don’t Forgot…
In the pulmonary system, un-oxygenated blood is
carried by the pulmonary arteries and oxygenated
blood is carried by pulmonary veins.
In the systemic system, arteries carry oxygenated
blood and veins carry un-oxygenated blood.
Coronary Circulation
• The left and right coronary arteries immediately branch
from the aorta and carry fresh blood to the heart muscle
itself.
• The coronary veins quickly return that blood back to the
heart.
Heart Action
A. The cardiac cycle consists of the atria
beating in unison (atrial systole) followed by
the contraction of both ventricles,
(ventricular systole) then the entire heart
relaxes for a brief moment (diastole).
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Cardiac Cycle
1. During the cardiac cycle, pressure
within the heart chambers rises and falls
with the contraction and relaxation of atria
and ventricles.
2. When the atria fill, pressure in the atria
is greater than that of the ventricles, which
forces the A-V valves open.
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Heart Sounds
1. Heart sounds are due to vibrations in
heart tissues as blood rapidly changes
velocity within the heart.
2. Heart sounds can be described as a
"lubb-dupp" sound.
Heart Sounds
3. The first sound (lubb) occurs as ventricles
contract and A-V valves are closing.
4.The second sound (dupp) occurs as
ventricles relax and aortic and pulmonary
valves are closing.
Electrocardiogram
1. An electrocardiogram is a recording of the
electrical changes that occur during a
cardiac cycle.
a. The first wave, the P wave, corresponds to the
depolarization of the atria.
b. The QRS complex corresponds to the depolarization
of ventricles and hides the repolarization of atria.
c. The T waves ends the ECG pattern and
corresponds to ventricular repolarization.
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What is a Heart Attack
• Heart attacks most often occur as a result
of coronary heart disease, in which a waxy
substance called plaque (plak) builds up
inside the coronary arteries.
• When plaque builds up in the arteries, the
condition is called atherosclerosis (ath-ero-skler-O-sis). The buildup of plaque
occurs over many years.
What is a Heart Attack
• Eventually, an area of plaque can rupture (break
open) inside of an artery. This causes a blood
clot to form on the plaque's surface. If the clot
becomes large enough, it can mostly or
completely block blood flow through a coronary
artery.
• If the blockage isn't treated quickly, the portion
of heart muscle fed by the artery begins to die.
Healthy heart tissue is replaced with scar tissue.
This heart damage may not be obvious, or it
may cause severe or long-lasting problems.
Coronary Artery Stint Surgery
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Blood Pressure
• The surge of blood that occurs with
ventricular contraction can be felt at certain
points in the body as a pulse.
Irregular Heart Rate
• Pulse rate is recorded by an electrocardiogram (EKG). It
is a recording of the electrical changes that occur during
a cardiac cycle.
Irregular Heart Rate
• Slow Heart Rate
– bradycardia
• Rapid Heart Rate
– tachycardia
Blood Pressure
• Blood pressure or hypertension, is the force of
blood against the inner walls of blood vessels
anywhere in the cardiovascular system,
although the term "blood pressure" usually refers
to arterial pressure.
Means
ARTERY….refers to
blood leaving the
heart!
Blood Pressure
• Blood pressure is highest as its leaves the heart
through the aorta and gradually decreases as it
enters smaller and smaller blood vessels
(arteries, arterioles, and capillaries)
Blood Pressure
• Arterial Blood Pressure
- Arterial blood pressure rises and falls following a
pattern established by the cardiac cycle.
a.During ventricular contraction,
arterial pressure is at its highest (systolic
pressure).
b.When ventricles are relaxing, arterial pressure
is at its lowest (diastolic pressure).
Blood Pressure Readings
• Normal blood pressure less than 120/80
• Pre-hypertension 120-139/ 80-89
• High blood pressure (stage 1) 140-159/90-99
• High blood pressure (stage 2) higher than
160/100
Risks of High Blood Pressure
• According to research studies, the risk of
dying of a heart attack is directly linked to
high blood pressure, particularly systolic
hypertension. The higher your blood
pressure, the higher the risk.
• Maintaining lifelong control of hypertension
decreases the future risk of complications
such as heart attack and stroke.
Causes of High Blood Pressure
• Age: The older a person is, the greater the likelihood
that he or she will develop high blood pressure,
• Race: African Americans develop high blood pressure
more often than Caucasians.
• Socioeconomic status: High blood pressure is found
more commonly among the less educated and lower
socioeconomic groups.
• Family history (heredity): The tendency to have high
blood pressure appears to run in families.
Causes of High Blood Pressure
• Birth control pills (oral contraceptive use): Some
women who take birth control pills develop high blood
pressure.
• Lack of exercise (physical inactivity): A sedentary
lifestyle contributes to the development of obesity and
high blood pressure.
• Medications: Certain drugs, such as amphetamines
(stimulants), diet pills, etc.
Causes of High Blood Pressure
• Gender: Generally men have a greater likelihood of
developing high blood pressure than women.
• Obesity: As body weight increases, the blood pressure
rises.
• Sodium (salt) sensitivity: Some people have high
sensitivity to sodium (salt), and their blood pressure
increases if they use it.
• Alcohol use: Drinking more than one to two drinks of
alcohol per day.