Chapter 11

© 2009 The McGraw-Hill Companies, Inc. All rights reserved

27-1

The Cardiovascular SystemThe Cardiovascular System


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Introduction The cardiovascular system consists of heart,

blood vessels, and blood

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


Functions of the Heart

Generating blood pressure

Routing blood Heart separates pulmonary and systemic circulations

Ensuring one-way blood flow Heart valves ensure one-way flow

Regulating blood supply Changes in contraction rate and force match blood

delivery to changing metabolic needs


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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


Size, Shape, Location of the Heart

Size of a closed fistShape

Apex: Blunt rounded point at the bottom pointing towards left hip.Base: Flat part at opposite of end of cone

Located in thoracic cavity in mediastinum

© 2009 The McGraw-Hill Companies, Inc. All rights reserved7

Coverings of the Heart: Anatomy

Pericardium – a double-walled sac around the heart composed of:

1. A superficial fibrous pericardium2. A deep two-layer serous pericardium

a. The parietal layer lines the internal surface of the fibrous pericardium

b. The visceral layer or epicardium lines the surface of the heart

They are separated by the fluid-filled pericardial cavity that helps to minimize friction during heart beats.


Pericardial Layers of the Heart

Figure 18.2


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Heart walls: Epicardium (visceral layer)

Outermost layer Fat to cushion heart

Myocardium Middle layer Primarily cardiac muscle Actually contracts

Endocardium Innermost layer Thin and smooth Stretches as the heart pumps

Click for Larger View


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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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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


Location of Heart Valves


Heart Valves

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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

Left Atrium

BicuspidValve

Left Ventricle

PulmonaryValve

TricuspidValve

AorticSemilunar

Valve

LungsBody


Systemic and PulmonaryCirculation


Myocardial Thickness and Function

Thickness of myocardium varies according to the function of the chamber

Atria are thin walled, deliver blood to adjacent ventriclesVentricle walls are much thicker and stronger

right ventricle supplies blood to the lungs (little flow resistance) left ventricle wall is the thickest to supply systemic circulation


Thickness of Cardiac Walls

Myocardium of left ventricle is much thicker than the right.


Pathway of Blood Through the Heart and Lungs

Figure 18.5



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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


Cardiac Cycle


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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

Third heart sound (occasional) Caused by turbulent blood flow into ventricles and detected near end of first

one-third of diastole


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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


Electrocardiogram

Action potentials through myocardium during cardiac cycle produces electric currents than can be measured

Pattern P wave

Atria depolarization QRS complex

Ventricle depolarization

Atria repolarization T wave:

Ventricle repolarization


Heart Excitation Related to ECG

Figure 18.17


Cardiac Arrhythmias

Tachycardia: Heart rate in excess of 100bpm Bradycardia: Heart rate less than 60 bpm Sinus arrhythmia: Heart rate varies 5% during

respiratory cycle and up to 30% during deep respiration

Premature atrial contractions: Occasional shortened intervals between one contraction and succeeding, frequently occurs in healthy people


Alterations in Electrocardiogram


Events during Cardiac Cycle


Mean Arterial Pressure (MAP)

Average blood pressure in aorta MAP=CO x PR

CO is amount of blood pumped by heart per minute CO=SV x HR

SV: Stroke volume of blood pumped during each heart beat HR: Heart rate or number of times heart beats per minute

Cardiac reserve: Difference between CO at rest and maximum CO

PR is total resistance against which blood must be pumped

© 2009 The McGraw-Hill Companies, Inc. All rights reservedChapter 18, Cardiovascular System

35

Cardiac Output: Example

CO (ml/min) = HR (75 beats/min) x SV (70 ml/beat)

CO = 5250 ml/min (5.25 L/min)


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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 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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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.


Gross Anatomy of

Circulatory System


44

Coronary Circulation Coronary circulation is the functional blood

supply to the heart muscle itself Collateral routes ensure blood delivery to

heart even if major vessels are occluded


Coronary Circulation: Arterial Supply

Figure 18.7a


46

Coronary Circulation: Venous Supply

Figure 18.7b


Circle of Willis = Cerebral Arterial Circle

= Ring of vessels surrounding pituitary gland - supplies cerebrum and cerebellum

Brain can receive blood from carotids or vertebrals (significance?)

v

ic

Fig 22.13


Circle of Willis


Fig 22.9

Right ventricle into pulmonary trunk to pulmonary arteries to lungs

Return by way of 4 pulmonary veins to left atrium

Pulmonary Circuit

© 2009 The McGraw-Hill Companies, Inc. All rights reservedFigure 21-20

Major Systemic Arteries

The Systemic CircuitContains 84% of blood volumeSupplies entire body: except for pulmonary circuitSupplies entire body:

except for


Systemic Arteries

Blood moves from left ventricle: into ascending aorta


The Aorta The ascending aorta:

rises from the left ventricle curves to form aortic arch turns downward to become descending aorta

Branches of the Aortic Arch deliver blood to head and neck: brachiocephalic trunk left common carotid artery left subclavian artery


The Common Carotid Arteries Carry blood to head and neck Each common carotid divides into:

external carotid artery-Supplies structures of: Neck, lower jaw, face

internal carotid artery-Enters skull and divides into: opthalmic artery, anterior cerebral artery, middle cerebral artery


Brachiocephalictrunk1

Left commoncarotid

Left subclavian3

2

Aortic ArchAortic Arch


Descending aorta• thoracic aorta• abdominal aorta

Abdominal aorta

Common iliac

External iliac

Femoral


The Abdominal Aorta Divides at terminal segment of the aorta into:

left common iliac artery right common iliac artery


Descending Aorta - Thoracic Area

Bronchial arteries - supply bronchi and lungs

Pericardial arteries - supply pericardium

Mediastinal arteries - supply mediatinal structures

Esophageal arteries - supply esophagus

Paired intercostal arteries- thoracic wall

Superior phrenic arteries - supply diaphragm


Descending Aorta - Abdominal Area

Celiac trunck - 3 branches – to liver, gallbladder, esophagus, stomach, duodenum, pancreas, and spleen

Superior mesenteric– to pancreas and duodenum, small intestine and colon

Paired suprarenal - to adrenal glands

Paired renal – to kidneys

Paired gonadal – to testes or ovaries

Inferior mesenteric – to terminal colon and rectum

Paired lumbar – to body wall Fig 22.17

© 2009 The McGraw-Hill Companies, Inc. All rights reservedFigure 21-27

Major Systemic Veins

All Systemic VeinsDrain into either:

Superior vena cava (SVC) or Inferior vena cava (IVC)


The Superior Vena Cava (SVC) Returns blood to the heart from:

head neck chest shoulders upper limbs


Veins of the Neck Temporal and maxillary veins:

drain to external jugular vein Facial vein:

drains to internal jugular vein


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Dural Sinuses In The Cranium

Superior sagittalsinusFalx cerebri

Inferior sagittalsinusStraight sinusCavernous sinusJunction of sinusesTransverse sinuses

Jugular foramen

(b)

Right internaljugular vein

Sigmoid sinus


The Inferior Vena Cava (IVC) Returns blood to the heart from:

Regions inferior to the diaphram


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Dissection of the posterior abdominal wall

Diaphragm

Right Left

Inferiorvena cava

Hepaticveins

Renal veins

Commoniliac veins

Abdominalaorta

© 2009 The McGraw-Hill Companies, Inc. All rights reservedFigure 21-33a

Placental Blood Supply

Blood flows to the placenta:through a pair of umbilical arterieswhich arise from internal iliac arteries and enter umbilical cord

Blood returns from placenta:in a single umbilical veinwhich drains into ductus venosus

Ductus venosus:empties into inferior vena cava


Atrial Septal Defect Present at birth Treated naturally

Surgery Or catheterization

68


Treatment of patent foramen oval aka “Atrial Septal Defect”

27-69


Ventricular Septal Defect

Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc

UNDERSTANDING YOURUNDERSTANDING YOURBLOOD PRESSUREBLOOD PRESSURE


NEW RESEARCH STATES…NEW RESEARCH STATES…

So…high blood pressure is a condition that most people So…high blood pressure is a condition that most people will have at some point in their lives.will have at some point in their lives.

that at age 55 or older, those who do not have that at age 55 or older, those who do not have high blood pressure have a 90% chance of high blood pressure have a 90% chance of developing it during their lifetimes.developing it during their lifetimes.

1 in 3 American adults have high blood pressure1 in 3 American adults have high blood pressure

““Silent Killer”Silent Killer”65 million adults have high blood pressure in this country.65 million adults have high blood pressure in this country.

What Is Blood Pressure?What Is Blood Pressure?

Blood pressureBlood pressure is is the force of blood the force of blood pushing against pushing against

the arteries.the arteries.

Blood is carried to Blood is carried to all parts of your all parts of your body in vessels body in vessels called arteries.called arteries.


Each time the heart beats Each time the heart beats (about 60-70 times a (about 60-70 times a

minute at rest), it pumps minute at rest), it pumps out blood into the arteries. out blood into the arteries.

What Is Blood Pressure?What Is Blood Pressure?

Your blood pressure is at Your blood pressure is at its highest when the heart its highest when the heart beats, pumping the blood.beats, pumping the blood.

When the heart is When the heart is at rest, between at rest, between

beats, your blood beats, your blood pressure falls.pressure falls.

Your blood pressure is always given as these two numbers Your blood pressure is always given as these two numbers with one above or before the other.with one above or before the other.

This is called This is called SYSTOLICSYSTOLIC pressure. pressure.120/120/To

p

num

ber

8080This is calledThis is called DIASTOLIC DIASTOLIC pressure.pressure.

Bottom number

http://www.hsfpe.org/


CategoryCategorySystolicSystolic

(Top Number)(Top Number)

DiastolicDiastolic

(Bottom Number)(Bottom Number)

NormalNormal Less than 120Less than 120 Less than 80Less than 80

What Is Normal Blood Pressure?What Is Normal Blood Pressure?

““Normal” blood pressure is when both Normal” blood pressure is when both numbers arenumbers are lower lower than 120/80. than 120/80.


““Prehypertension”Prehypertension”

This category was created to alert people to their risk of developing This category was created to alert people to their risk of developing high blood pressure so they could make lifestyle changes that may high blood pressure so they could make lifestyle changes that may

help to avoid developing this condition.help to avoid developing this condition.

Which of the Which of the following blood following blood

pressure readings are pressure readings are considered considered

“prehypertensive”?“prehypertensive”?

80-8980-89120-139120-139PrehypertensionPrehypertension

138/82138/82 128/89128/89118/78118/78

Top NumberTop Number Bottom NumberBottom Number

NEW!!!

NEW!!!


If your blood pressure is in the prehypertensive range:If your blood pressure is in the prehypertensive range:

It means that you don’t have high blood pressure now, It means that you don’t have high blood pressure now, but you are likely to develop it in the future.but you are likely to develop it in the future.

Unless you take Unless you take ACTIONACTION to prevent it! to prevent it!

““Prehypertension”Prehypertension”

PrehypertensionPrehypertension 120-139120-139 80-8980-89


What Is High Blood Pressure?What Is High Blood Pressure?When blood pressure stays elevated over a long period of When blood pressure stays elevated over a long period of time it is called time it is called high bloodhigh blood pressure or “ pressure or “hypertensionhypertension”.”.

High blood pressure is dangerous because High blood pressure is dangerous because it makes the heart work too hard and it makes the heart work too hard and

contributes to hardening of the arteries contributes to hardening of the arteries (atherosclerosis). (atherosclerosis).

http://diseases-explained.com/


What Is High Blood Pressure?What Is High Blood Pressure?

A blood pressure of A blood pressure of 140/90140/90 is considered high blood pressure. is considered high blood pressure.

High Blood PressureHigh Blood Pressure SystolicSystolic DiastolicDiastolic

Stage 1Stage 1 140-159140-159 90-9990-99

Stage 2Stage 2 160 or higher160 or higher 100 or higher100 or higher

““Hypertension”Hypertension”


High Blood PressureHigh Blood Pressure

Warning Signs:Warning Signs:

1.2.3.4.““Silent Killer”

Silent Killer”

““Silent Killer”

Silent Killer”


Why Is High Blood Pressure Important?Why Is High Blood Pressure Important?

Increases your risk for :Increases your risk for :

Heart disease & StrokeHeart disease & Stroke – –Heart disease & StrokeHeart disease & Stroke – – the the 1st1st and and 3rd3rd leading causes of leading causes of death for Americans.death for Americans.

the the 1st1st and and 3rd3rd leading causes of leading causes of death for Americans.death for Americans.

If left uncontrolled, high blood pressure can also cause:If left uncontrolled, high blood pressure can also cause:

Heart failureHeart failure

Heart AttackHeart Attack

Kidney diseaseKidney disease

BlindnessBlindness


What can high blood pressure do to your body?What can high blood pressure do to your body?

Heart AttackHeart Attack

High blood pressure is a High blood pressure is a major risk factor for major risk factor for

heart attack. The heart attack. The arteries bring oxygen-arteries bring oxygen-carrying blood to the carrying blood to the heart muscle. If the heart muscle. If the

heart cannot get enough heart cannot get enough oxygen, chest pain, can oxygen, chest pain, can

occur. If the flow of occur. If the flow of blood is blocked, a heart blood is blocked, a heart

attack results.attack results.

BlindnessBlindnessHigh blood pressure can High blood pressure can eventually cause blood eventually cause blood

vessels in the eye to burst or vessels in the eye to burst or bleed. Vision may become bleed. Vision may become

blurred or otherwise impaired blurred or otherwise impaired and can result in blindness.and can result in blindness.

Kidney diseaseKidney diseaseKidneys act as filters to Kidneys act as filters to rid the body of waste. rid the body of waste.

High blood pressure can High blood pressure can narrow and thicken the narrow and thicken the

blood vessels of the blood vessels of the kidneys. The kidneys kidneys. The kidneys

filter less fluid and waste filter less fluid and waste builds up in the blood. builds up in the blood. The kidneys may fail The kidneys may fail

altogether.altogether.

High blood pressure is the most High blood pressure is the most important risk factor for stroke. Very important risk factor for stroke. Very high pressure can cause a break in a high pressure can cause a break in a weakened blood vessel, which then weakened blood vessel, which then bleeds in the brain. This can cause a bleeds in the brain. This can cause a stroke. If a blood clot blocks one of stroke. If a blood clot blocks one of

the narrowed arteries, it can also the narrowed arteries, it can also cause a stroke. cause a stroke.

StrokeStroke

As people get older, As people get older, arteries throughout the arteries throughout the

body "harden," body "harden," especially those in the especially those in the

heart, brain, and heart, brain, and kidneys. High blood kidneys. High blood

pressure is associated pressure is associated with these "stiffer" with these "stiffer"

arteries. This, in turn, arteries. This, in turn, causes the heart and causes the heart and

kidneys to work harder.kidneys to work harder.

ArteriesArteries

Heart failureHeart failure

The heart is unable to pump enough blood to supply the body's

needs.


The Good News is…The Good News is…You can take action to prevent getting high blood pressure You can take action to prevent getting high blood pressure

or take steps to control it!or take steps to control it!

See your doctor for regular blood pressure check upsSee your doctor for regular blood pressure check ups

Maintaining a healthy weightMaintaining a healthy weight

Get physically activeGet physically active

Eat a healthy diet rich in Eat a healthy diet rich in vegetables and fruits, and low vegetables and fruits, and low fat dairy foodsfat dairy foodsChoose and prepare foods with less saltChoose and prepare foods with less salt

If you drink alcoholic beverages, drink If you drink alcoholic beverages, drink in moderationin moderation

If you smoke, think about quittingIf you smoke, think about quitting


Factors that affect Blood Pressure

1. Neural factors: Sympathetic nervous system causes vasoconstriction or narrowing of blood vessels.

2. Kidneys: release renin which triggers angiotensin a potent vasoconstrictor.

3. Temperature: Cold is vasoconstricting Heat is the opposite.

4. Chemicals: Medication, nicotine, alcohol

5. Diet: salt, fat, and cholesterol balance

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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 The more blood it will pump out


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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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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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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



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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



By-pass Graft


Percutaneous Transluminal Coronary Angioplasty


Artificial Heart

Chapter 11

Documents

normal blood pressure

blood vessels

high blood pressure

force of blood

blood pressureneural

heart beats

heart work

heart disease