© 2009 the mcgraw-hill companies, inc. all rights reserved 27-1 the cardiovascular system...
TRANSCRIPT
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
27-1
The Cardiovascular SystemThe Cardiovascular SystemPowerPoint® presentation to accompany:
Medical AssistingThird Edition
Booth, Whicker, Wyman, Pugh, Thompson
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© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Learning Outcomes
27.1 Describe the structure of the heart and the function of each part.
27.2 Trace the flow of blood through the heart.
27.3 List the most common heart sounds and what events produce them.
27.4 Explain how heart rate is controlled by the electrical conduction system of the heart.
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Learning Outcomes (cont.)
27.5 List the different types of blood vessels and describe the functions of each.
27.6 Define blood pressure and tell how it is controlled.
27.7 Trace the flow of blood through the pulmonary and systemic circulation.
27.8 List the major arteries and veins of the body and describe their locations.
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Learning Outcomes (cont.)
27.9 List and describe the components of blood.
27.10 Give the functions of red blood cells, the different types of white blood cells, and platelets.
27.11 List the substances normally found in plasma.
27.12 Explain how bleeding is controlled.
27.13 Explain the differences among blood types A, B, AB, and O.
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Learning Outcomes (cont.)
27.14 Explain the difference between Rh-positive blood and Rh-negative blood.
27.15 Explain the importance of blood typing and tell which blood types are compatible.
27.16 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the cardiovascular system.
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Introduction The cardiovascular system consists of heart and
blood vessels
Sends blood to Lungs for oxygen Digestive system for nutrients
CV system also circulates waste products to certain organ systems for removal from the blood
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The Heart: Structures
Cone-shaped organ about the size of a loose fist
In the mediastinum Extends from the level
of the second rib to about the level of the sixth rib
Slightly left of the midline
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The Heart: Structures (cont.)
Heart is bordered: Laterally by the lungs Posteriorly by the vertebral
column Anteriorly by the sternum
Rests on the diaphragm inferiorly
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The Heart: Structures (cont.)
Heart coverings Pericardium
Covers the heart and large blood vessels attached to the heart
Visceral pericardium Innermost layer Directly on the heart
Parietal pericardium Layer on top of the
visceral pericardium
Heart walls: Epicardium
Outermost layer Fat to cushion heart
Myocardium Middle layer Primarily cardiac muscle
Endocardium Innermost layer Thin and smooth Stretches as the heart
pumps
Click for Larger View
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The Heart: Structures (cont.)
Four chambers Two atria
Upper chambers Left and right Separated by
interatrial septum
Two ventricles Lower chambers Left and right Separated by
interventricular septum
Click for View of
Heart
Atrioventricular septum separates the atria from the ventricles
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The Heart: Structures (cont.)
Tricuspid valve – prevents blood from flowing back into the right atrium when the right ventricle contracts
Bicuspid valve – prevents blood from flowing back into the left atrium when the left ventricle contracts
Pulmonary valve – prevents blood from flowing back into the right ventricle
Aortic valve – prevents blood from flowing back into the left ventricle
Click for View of
Heart
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The Heart: Blood Flow
Deoxygenated blood in from
bodyOxygenated
blood in lungs
Atria Contract Ventricles Contract
Deoxygenated blood out to lungs
Oxygenated blood out to
body
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The Heart: Blood Flow (cont.)
Right Atrium
Right Ventricle
PulmonarySemilunar
Valve
Left Atrium
BicuspidValve
Left Ventricle
PulmonaryValve
TricuspidValve
AorticSemilunar
Valve
LungsBody
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The Heart: Cardiac Cycle
Right atrium contracts Tricuspid valve opens Blood fills right ventricle
Right ventricle contracts Tricuspid valve closes Pulmonary semilunar valve
opens Blood flows into pulmonary
artery
Left atrium contracts Bicuspid valve opens Blood fills left ventricle
Left ventricle contracts Bicuspid valve closes Aortic semilunar valve
opens Blood pushed into aorta
One heartbeat = one cardiac cycle Atria contract and relax Ventricles contract and relax
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The Heart: Cardiac Cycle (cont.)
Influenced by Exercise Parasympathetic nerves Sympathetic nerves Cardiac control center Body temperature Potassium ions Calcium ions
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The Heart: Heart Sounds
One cardiac cycle – two heart sounds (lubb and dubb) when valves in the heart snap shut Lubb – First sound
When the ventricles contract, the tricuspid and bicuspid valves snap shut
Dubb – Second sound When the atria contract and the pulmonary and aortic
valves snap shut
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The Heart: Cardiac Conduction System Group of structures that send electrical impulses through the heart
Sinoatrial node (SA node) Wall of right atrium Generates impulse Natural pacemaker Sends impulse to AV node
Atrioventricular node (AV node) Between atria just above ventricles Atria contract Sends impulse to the bundle of His
Bundle of His Between ventricles Two branches Sends impulse to Purkinje
fibers
Purkinje fibers Lateral walls of ventricles Ventricles contract
Link to Diagram
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© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your KnowledgeMatch the following:
__ Tricuspid valve A. Two branches; sends impulse to Purkinje fibers
__ Bicuspid valve B. Covering of the heart and aorta
__ Pericardium C. Between the right atrium and the right ventricle
__ SA node D. In the lateral walls of ventricles
__ Bundle of His E. Natural pacemaker
__ Purkinje fibers F. Between the left atrium and the left ventricle D
A
E
B
F
CANSWER:
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Blood Vessels: Arteries and Arterioles Strongest of the
blood vessels Carry blood away
from the heart Under high pressure
Vasoconstriction Vasodilation
Arterioles Small branches of
arteries Aorta
Takes blood from the heart to the body
Coronary arteries Supply blood to heart
muscle
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Blood Vessels: Veins and Venules Blood under no pressure in
veins
Does not move very easily
Skeletal muscle contractions help move blood
Sympathetic nervous system also influences pressure
Valves prevent backflow
Venules
Small vessels formed when capillaries merge
Superior and inferior vena cava
Largest veins
Carry blood into right atrium
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Blood Vessels: Capillaries
Branches of arterioles
Smallest type of blood vessel
Connect arterioles to venules
Only about one cell layer thick
Oxygen and nutrients can pass out of a capillary into a body cell
Carbon dioxide and other waste products pass out of a body cell into a capillary
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Apply Your Knowledge
How do arteries control blood pressure?
ANSWER: The muscular walls of arteries can constrict to increase blood pressure or dilate to decrease blood pressure.
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Blood Pressure Force blood exerts on the inner walls of blood vessels
Highest in arteries Lowest in veins
Systolic pressure Ventricles contract Blood pressure is at its greatest in the arteries
Diastolic pressure Ventricles relax Blood pressure in arteries is at its lowest
Reported as the systolic number over the diastolic number
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Blood Pressure (cont.)
Control is based mainly on the amount of blood pumped out of the heart
The amount of blood entering should equal the amount pumped from the heart
Starling's law of the heart Blood entering the left ventricle stretches the wall of the ventricle The more the wall is stretched
The harder it will contract and tTe more blood it will pump out
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Blood Pressure (cont.)
Baroreceptors Also help regulate blood pressure Located in the aorta and carotid arteries High blood pressure in aorta message to
cardiac center in brain decreases heart rate lowers blood pressure
Low blood pressure in aorta message to cardiac center in the brain increases heart rate increases blood pressure
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© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
What is the difference between the systolic pressure and diastolic pressure?
ANSWER: Systolic pressure is the result of the contraction of the ventricles increasing the pressure in the arteries. Diastolic pressure is the result of the relaxation of the ventricles lowering the pressure in the arteries.
Good Answer!
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Circulation Pulmonary circuit
right atrium right ventricle pulmonary artery trunk pulmonary arteries lungs pulmonary veins heart (left atrium)
Systemic circuitleft atrium left ventricle aorta arteries
arterioles capillaries venules veins vena cava heart (right atrium)
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Circulation (cont.)
Arterial system Carry oxygen-rich blood
away from the heart
Pulmonary arteries carry oxygen-poor blood
Paired – left and right artery of the same name
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Circulation (cont.)
Venous system Carries oxygen-
poor blood toward the heart
Except pulmonary veins
Most large veins have the same names as the arteries they are next to
Hepatic portal system Collection of veins
carrying blood to the liver
Click for Larger View
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Apply Your Knowledge
ARTERIES: Pulmonary arteries carry oxygen-poor blood.
Do pulmonary arteries carry blood with high levels of oxygen or low levels of oxygen?
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Blood A type of connective tissue
Red blood cells (erythrocytes)
White blood cells (leukocytes)
Platelets – cell fragments
Plasma – fluid part of blood
Average-sized adult has 4 to 6 liters of blood
Amount depends on: Size of person Amount of adipose tissue Concentrations of ions Females have less than
males
Average-sized adult has 4 to 6 liters of blood
Amount depends on: Size of person Amount of adipose tissue Concentrations of ions Females have less than
males
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Blood Components
Hematocrit The percentage of red blood
cells Normal is about 45%
White cells and platelets = 1%
Plasma = 55%
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Blood Components: Red Blood Cells Erythrocytes Transport oxygen throughout the body Small biconcave-shaped cells Hemoglobin is a pigment in RBCs
Oxyhemoglobin carries oxygen; bright red Deoxyhemoglobin does not carry oxygen; darker red
Carries carbon dioxide, so also called carboxyhemoglobin Anemia – low RBC count
Erythropoietin – regulates production of RBCs
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Blood Components: Red Blood Cells (cont.)
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Blood Components: White Blood Cells Granulocytes
Neutrophils (55%) –destroy bacteria, viruses, and toxins in the bloodstream (phagocytes)
Eosinophils (3%) – get rid of parasitic infections such as worm infections
Basophils (1%) – control inflammation and allergic reactions
Agranulocytes Monocytes (8%) – destroy bacteria, viruses, and toxins in
blood Lymphocytes (33%) – provide immunity for the body
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Blood Components: White Blood Cells (cont.)
WBC count normally 5000 to 10,000 cells per cubic millimeter of blood Leukocytosis
Elevated WBC count Usually due to infection
Leukopenia Low WBC count Some viral infections and other conditions
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Blood Components: Platelets
Fragments of cells found in the bloodstream Also called thrombocytes Important in the clotting process of blood Normal count
130,000 to 360,000 platelets per cubic millimeter of blood
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Blood Components: Plasma
Liquid portion of blood composed mostly of water
Proteins Albumins
Smallest plasma proteins Pull water in to help
maintain blood pressure Globulins – transport lipids
and fat-soluble vitamins Fibrinogen – needed for
blood clotting
Nutrients Amino acids Glucose Nucleotides Lipids from the digestive
tract
Gases – oxygen, carbon dioxide, and nitrogen
Electrolytes Waste products
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Blood: Bleeding Control Hemostasis – the control
of bleeding
Three processes of hemostasis
Blood vessel spasm Platelet plug formation Blood coagulation
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Blood Types Types are distinguished
by antigen and antibodies
Agglutination Clumping of red blood
cells Antigens on surface of
RBCs bind to antibodies in plasma
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Blood Types (cont.)
Blood Type Antigen Present
Antibody Present
Blood That Can Be Received
A A B A and O
B B A B and O
AB AB None A, B, AB, and O
O None A and B O
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Blood Types (cont.)
Rh antigen – protein on RBCs
Rh-positive RBCs contain the
Rh antigen
Rh-negative RBCs do not contain
the Rh antigen
Rh-positive blood is given to Rh-negative person Antibodies form
If Rh-negative person receives more Rh-positive blood Antibodies bind to the
donor cells Agglutination occurs
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© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your KnowledgeTrue or False:
__ Hematocrit is the percentage of WBCs in the blood.
__ Neutrophils destroy bacteria, viruses, and toxins in the bloodstream.
__ Platelets are important to the clotting process.
__ Albumin is a small plasma protein that pushes water out of the bloodstream.
__ Hemostasis is the control of bleeding.
__ A person with type AB blood can only receive type AB blood.
__ Blood should be matched for Rh factor.
pulls water into
RBCs
can receive any type of blood
T
T
F
T
F
T
F
ANSWER:
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Chest Pain Cardiac
Myocardial infarction Angina Pericarditis Coronary spasm
Non-cardiac Heartburn Panic attacks Pleurisy Costochondritis Pulmonary embolism Sore muscles Broken ribsTake all complaints of
chest pain seriously!
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Chest Pain (cont.)
Determine cause Electrocardiogram Stress tests Blood tests Chest x-ray Nuclear scan Coronary
catheterization Echocardiogram Endoscopy
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Diseases and Disorders of the Cardiovascular System
Disease Description
Anemia The blood does not have enough red blood cells or hemoglobin to carry an adequate amount of oxygen to the body’s cells
Aneurysm A ballooned, weakened arterial wall
Arrhythmias Abnormal heart rhythms
Carditis Inflammation of the heart
Endocarditis Inflammation of the innermost lining of the heart, including valves
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Disease Description
Myocarditis Inflammation of the muscular layer of the heart
Pericarditis Inflammation of the membranes that surround the heart (pericardium)
Congestive Heart Failure
Weakening of the heart over time; heart is unable to pump enough blood to meet body’s needs
Coronary Artery Disease (CAD)
Atherosclerosis; narrowing of coronary arteries caused by hardening of the fatty plaque deposits within the arteries
Diseases and Disorders of the Cardiovascular System (cont.)
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Disease Description
Hypertension High blood pressure; consistent resting blood pressure equal to or greater than 140/90 mm Hg
Leukemia Bone marrow produces a large number of abnormal WBCs
Murmurs Abnormal heart sounds
Myocardial Infarction
Heart attack; damage to cardiac muscle due to a lack of blood supply
Diseases and Disorders of the Cardiovascular System (cont.)
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Disease Description
Sickle Cell Anemia
Abnormal hemoglobin causes RBCs to change to a sickle shape; abnormal cells stick in capillaries
Thalassemia Inherited form of anemia; defective hemoglobin chain causes, small, pale, and short-lived RBCs
Thrombophlebitis Blood clots and inflammation develops in a vein
Varicose Veins Twisted, dilated veins
Diseases and Disorders of the Cardiovascular System (cont.)
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Apply Your Knowledge
ANSWER: Anemia is a condition in which a person does not have enough red blood cells or hemoglobin in the blood to carry an adequate amount of oxygen to body cells.
The doctor has told your patient she has anemia. How would you explain this to the her?
Bravo!
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In Summary Cardiovascular system
Transport system for body Heart, arteries, veins, and capillaries
Blood Transport medium RBCs, WBCs, platelets, plasma
Medical assistant Assists patients in understanding prevention and
treatments for cardiovascular problems