Download The Cardiovascular System

The Cardiovascular System
Mrs. Jessica Dean, RN, BSN
The Cardiovascular System:
Heart Anatomy Introduction/Overview
Daily Objectives:
1. Describe the location of the heart and
trace its outline on the surface of the
chest.
2. Discuss the external and internal anatomy
of the chambers of the heart.
3. Describe the structure
and function of the valves
of the heart.
I. Heart Anatomy: Location/Size
-
The heart is about the
size of your cupped
hands.
-
It is hollow, cone-shaped,
and weighs less than 1
pound
-
The heart rests on the
diaphragm, near the
midline of the thoracic
cavity in the mediastinum
and is flanked on each
side by the lungs.
-
About two-thirds of the
mass of the heart lies to
the left of the body’s
midline.
-The pointed end of the heart is the apex and is directed
towards the left hip.
-The wider end is called the base and it points towards the
right shoulder and lies beneath the 2nd rib.
Heart Anatomy : Coverings / Wall
- The membrane that surrounds and
protects the heart is the
pericardium. It confines the heart
to its position in the mediastinum,
while allowing sufficient freedom of
movement for vigorous and rapid
contraction.
-The heart wall consists of three layers:
the pericardium, the myocardium, and the
endocardium.
-Pericardium(external layer) = also called
the visceral layer, is the thin, transparent
outer layer of the wall.
-Myocardium (middle layer) = cardiac
muscle tissue, makes up the bulk of the
heart and is responsible for its pumping
action.
-Endocardium (inner layer) = is a thin layer
of endothelium overlying a thin layer of
connective tissue . It provides a smooth
lining for the chamber of the heart and
covers the valves of the heart.
Heart Anatomy: Chambers of the
Heart
- The heart contains
four chambers.
- The two uppers
chambers are the
atria and the two
lower chambers are
the ventricles.
- The right atrium
forms the right
border of the heart.
-The right atrium receives
blood from three veins:
superior vena cava, inferior
vena cava, and coronary sinus.
-Between the right atrium and
left atrium is a thin partition
called the interatrial septum. A
prominent feature of this
septum is an oval depression
called the fossa ovalis, which is
an opening in the interatrial
septum of the fetal heart that
normally closes soon after
birth.
- Blood passes from the right atrium into the
right ventricle through a valve called the
tricuspid valve (contains three cusps).
-The right ventricle
forms most of the
anterior surface of the
heart.
-The right ventricle is
separated from the left
ventricle by a partition
called the
interventricular septum.
-Left atrium forms
most of the base of the
heart. It receives blood
from the lungs through
four pulmonary veins.
- Blood passes from the left atrium into the left ventricle
through the bicuspid (mitral) valve (has two cusps).
-The left ventricle forms the apex of the heart.
- Blood passes from the left ventricle into the largest
artery of the body, the ascending aorta through the
aortic valve.
The Cardiovascular System: Blood Vessels
Daily Objectives:
1. Contrast the structure and
function of arteries, arterioles,
capillaries, venules, and veins.
2. Discuss blood formation and
function.
II. Composition and Functions of
Blood:
- Recall blood is the only fluid connective tissue
that constitutes the transport medium of the
circulatory system.
- Blood has three functions:
1. Transports nutrients, dissolved (oxygen
and carbon dioxide), enzymes, hormones,
and waste materials.
2. Regulate body temperature, fluids, pH,
and electrolytes.
3. Defend the body against disease.
-Approximately 55 % of blood is made up of a fluid
portion called plasma.
-Plasma is a straw-colored liquid and is 90% water and
10% dissolved fats, salts, sugars, and proteins.
-Red blood cells (Erythrocytes) = RBCs are the most
numerous of the blood cells and account for about 45%
of total volume. Approx. 5 million per mm3 of blood.
-RBCs are biconcave (narrower at the center than along
the edges).
-White blood cells (Leukocytes) = outnumbered by RBCs
almost 1000 to 1. Approx. 4,000-10,000 per mm3 of
blood and less than 1% of volume.
-WBCs are produced in bone red marrow, lymph
nodes, and spleen.
-The main function of WBCs is to protect the
body against invasion by foreign cells, viruses,
parasites, and tumor cells.
III. Blood Vessels:
-Blood vessels form a closed system of tubes that
carries blood away from the heart, transports it to the
tissue of the body, and then returns it to the heart.
-Arteries are vessels that carry blood AWAY from the
heart to the tissues. Large, elastic arteries leave the
heart and divide into medium-sized, muscular arteries
that branch out into the various regions of the body.
Medium- sized arteries then divide into smaller arteries
called arterioles.
-As arterioles enter a tissue, they branch into countless
microscopic vessels called capillaries.
-Substances are exchanged
between the blood and body
tissues through the thin
walls of the capillaries.
- Before leaving the tissue,
groups of capillaries unite to
form small veins called
venules, which merge to
form progressively larger
blood vessels called veins.
- Veins then convey blood
from the tissues back to the
heart.
The Cardiovascular System:
Daily Objectives:
1. Describe the flow of blood through
the chambers of the heart and
through the systemic and pulmonary
circulations.
2. Describe the phases, timing, and
heart sounds associated with a
cardiac cycle
IV. Blood Circulation:
-With each beat, the heart pumps blood
into two closed circuits- the
systemic circulation and the
pulmonary circulation.
-The left side of the heart is the pump
for the systemic circulation; it
receives freshly oxygenated blood
from the lungs.
-The left ventricle ejects blood into the
aorta. From the aorta, the blood
divides into smaller systemic
arteries that carry blood to all the
organs throughout the body (except
the air sacs in the lungs).
- Exchange
of nutrients and gases occurs across the thin
capillary walls: Blood unloads oxygen and picks up carbon
dioxide. Venules carry deoxygenated blood away from
tissues and merge to form larger systemic veins, and
ultimately the blood flows back to the right atrium.
-The right side of the heart is the pump for the
pulmonary circulation; it receives all the deoxygenated
blood returning from the systemic circulation.
-Blood ejected from the right ventricle flows into the
pulmonary trunk, which branches into pulmonary arteries
that carry blood to the right and left lungs.
-Blood then unloads carbon dioxide, which is exhaled, and
picks up oxygen.
- The freshly oxygenated blood then flows into pulmonary
veins and returns to the left atrium.
Cardiac Cycles:
-A single cardiac cycle includes
all the events associated with
one heartbeat. In each cardiac
cycle, the atria and ventricles
alternately contract and relax,
forcing blood from areas of
higher pressure to areas of
lower pressure.
-Systole = phase of
contraction
-Diastole = phase of relaxation
Heart Sounds:
-The act of listening to sounds
within the body is called
auscultation, and it is usually done
with a stethoscope.
-The sound of the heartbeat comes
primarily from blood turbulence
caused by the closing of the heart
valves.
-During each cardiac cycle, four
heart sounds are generated, but in
a normal heart only the first and
second heart sounds are loud
enough to be heard by listening
through a stethoscope.
-Heart sounds provide valuable information about the
mechanical operation of the heart.
-A heart murmur is an abnormal sound consisting of a
rushing or gurgling noise that is heard before, between, or
after the normal heart sounds, or that may mask the
normal heart sounds.
-Although some heart murmurs are “innocent,” meaning
they are not associated with a significant heart problem,
most often a murmur indicates a valve disorder.
The Cardiovascular System:
Daily Objectives:
1. Discuss various dysfunctions / disorders of
the Cardiovascular System.
2. Identify some common methods of assessing
the heart.
V. Cardiovascular System Dysfunctions / Disorders
-Hypertension = persistently high blood pressure, is
defined as systolic pressure of 140mm Hg or greater and
diastolic blood pressure of 90 mm Hg or greater.
-Recall that a blood pressure of 120/80 is normal and
desirable in a healthy adult. (Although, the American
Heart Association now suggest: Systolic less than 130 and
Diastolic less than 70).
-Hypertension is the most common disorder affecting the
heart and blood vessels; it is a major cause of heart
failure, kidney disease, and stroke.
-90-95% of all cases of hypertension are classified as
primary hypertension, which is a persistently elevated
blood pressure that cannot be attributed to any cause.
Lifestyle Changes to Reduce
Hypertension:
1. Lose weight
2. Limit alcohol intake
3. Exercise
4. Reduce intake of sodium
5. Don’t smoke
6. Manage stress
7. Maintain dietary intake of
potassium, calcium, and magnesium.
Pulse Rates:
-Tachycardia: An abnormally rapid resting heartbeat or
pulse rate over (100/min).
-Bradycardia: A slow resting heart rate or pulse rate
under (60/min).
-Normal sitting pulse rate is between 70-80
-Heart
Attack: A blockage in the heart's
arteries may reduce or completely cut off
the blood supply to a portion of the heart.
-This can cause a blood clot to form and
totally stop blood flow in a coronary artery,
resulting in a heart attack (also called an
acute myocardial infarction or MI).
-Irreversible injury to the heart muscle
usually occurs if medical help is not received
promptly. Unfortunately, it is common for
people to dismiss heart attack symptoms.
Symptoms of a Heart Attack
• Uncomfortable pressure,
fullness, squeezing or pain in
the center of the chest
lasting more than a few
minutes.
• Pain spreading to the
shoulders, neck or arms. The
pain may be mild to intense.
It may feel like pressure,
tightness, burning, or heavy
weight. It may be located in
the chest, upper abdomen,
neck, jaw, or inside the arms
or shoulders.
•
Chest discomfort with
lightheadedness,
fainting, sweating, nausea or
shortness of breath.
•
Anxiety, nervousness and/or
cold, sweaty skin.
•
Paleness or pallor.
•
Increased or irregular heart
rate.
•
Feeling of impending doom.
Heart Attack Statistics:
-1.5 million heart attacks occur in the United States
each year with 500,000 deaths.
-More than 233,000 women die annually from
cardiovascular disease.
-A heart attack occurs about every 20 seconds
with a heart attack death about every minute.
-Sudden death is more common among women with heart
attack.
-Almost 14 million Americans have a history of heart
attack or angina.
-Only 31% of women know that cardiovascular
disease is the leading cause of death in the USA.
-On the average, women take 2-4 hours longer than
men to respond to symptoms of heart attack,
limiting the beneficial use of some newer
treatments like clot busters that work best within
the first hour after onset of pain or discomfort.
-Chewing an uncoated aspirin right away, at the first
sign of chest discomfort or distress, can reduce the
amount of damage to the heart muscle during a
heart attack.
-Studies show the most common time for a heart attack
to occur is Monday morning. Saturday morning ranks
second. Another common time is during the early
morning hours, when blood platelets are stickier.
-About 50% of deaths occur within one hour of the
heart attack ––outside a hospital.
Congestive Heart Failure (CHF)
• Heart muscles do not beat adequately
to supply blood needs of the body
• May involve either right or left side of
heart
• Symptoms: edema, dyspnea, cyanosis,
weak and rapid pulse
• Treatment: diuretics, elastic support
hose to improve circulation, oxygen
therapy, low sodium diet
Arteriosclerosis
• Hardening or thickening of walls of
arteries
• Causes loss of elasticity and
contractility
• Commonly occurs as result of aging
• Causes hypertension and can lead to
aneurysm or cerebral hemorrhage
Atherosclerosis
• Fatty plaques, frequently cholesterol,
deposited on walls of arteries
• Causes narrowing of opening, which
reduces or eliminates the flow of blood
• If plaques break loose, they can
circulate through the blood stream as
emboli
• Treatment: low-cholesterol diet,
exercise
Aneurysm
• Ballooning out or saclike formation on wall of
artery
• Causes: disease, congenital defects, injuries
leading to a weakening of structure of wall of
artery
• Symptoms: some cause pain and pressure and
some have none
• Common sites are cerebral, aortal, and
abdominal
• If ruptures, hemorrhage occurs, can cause
death
• Treatment: surgical removal and replacement
with a graft or another blood vessel
Embolus
• Foreign substance circulating in blood
stream
• Can be air, blood clot, bacterial clumps,
fat globule
• Blockage of vessel occurs when embolus
enters an artery or capillary too small
for passage
Phlebitis
• Inflammation of vein, frequently in leg
• Symptoms: pain, edema, redness,
discoloration at site
• Treatment
– Anticoagulants and pain med
– Elevate affected area
– Support hose
– Surgery to remove clot
Varicose Veins
• Dilated, swollen vein that have lost
elasticity and cause a stasis or decrease
blood flow
• Frequently occur in legs
• Result from pregnancy, prolonged
sitting or standing, and hereditary
factors
• Treatment: exercise, support hose,
eliminating tight-fitting or restrictive
clothing, surgery to remove vein
Anemia
– Inadequate # of erythrocytes, hemoglobin
or both
– Symptoms: pallor, fatigue, dyspnea, rapid
heart rate
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Acute blood loss anemia
Iron deficiency anemia
Aplastic anemia
Pernicious anemia
Sickle cell anemia
Acute blood loss anemia
• Caused by hemorrhage or rapid blood
loss
• Corrected by blood transfusion
Iron deficiency anemia
• Caused by inadequate amount of iron to
form hemoglobin in erythrocytes
• Treatment: iron supplements and
increased iron intake from green leafy
vegetables
Aplastic anemia
• Caused by injury or destruction of bone
marrow
• Results in poor or no formation of
erythrocytes
• Fatal unless damage can be reversed
Pernicious anemia
• Caused by lack of intrinsic factor which
results in poor absorption of vitamin B12
• Results in formation of inadequate and
abnormally large erythrocytes
• Treatment: replacing intrinsic factor
and administering B12 injections
Sickle Cell Anemia
• Chronic inherited anemia
• Production of abnormal
crescent-shaped erythrocytes that
carry less oxygen, break easily, and
block blood vessels
• Occurs almost exclusively among
African Americans
• Treatment: transfusions of packed cells
and supportive therapy during a crisis
Leukemia
• Malignant disease of bone marrow or lymph
tissue
• Results in large # of immature WBC
• Different types—some acute, some chronic
• Symptoms: fever, pallor, swelling of lymph
tissue, fatigue, anemia, joint pain, excessive
bruising
• Treatment
– Varies, can be chemo, radiation and bone marrow
transplant
Hemophilia
• Inherited disease
• Occurs almost exclusively in males but
carried by females
• Blood not able to clot due to lack of
plasma protein (prolonged or internal
bleeding)
• Treatment: transfusions, administration
of missing protein factor
Heart Studies
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Stethoscope
ECG/EKG
Catheterization
Fluoroscope
Ultrasound
Echocardiography
Treatments of Heart Disease
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Artificial pacemakers
Heart surgery
Coronary bypass surgery
Angioplasty
Valve replacement
Surgical transplantation