Download The Heart

11
The Cardiovascular
System
Lesson 11.1: Heart Anatomy;
Function of the CV System
Lesson 11.2: Regulation of the Heart
Lesson 11.3: Blood Vessels & Circulation
Lesson 11.4: Heart Disease
Chapter 11: The Cardiovascular System
Lesson 11.1
Heart Anatomy;
Function of the
Cardiovascular System
Anatomy and the Function of the
Cardiovascular System
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Heart: location and size
Four chambers of the heart
Heart valves
Blood flow through the heart
Walls of the heart
Cardiac cycle
Cardiac output
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The Heart: Location and Size
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Thoracic cavity
Above diaphragm
Between lungs
Size of a clenched fist
Weighs 8–12 ounces
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The Heart: Location and Size
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The Four Chambers of the Heart
• Right atrium
• Right ventricle
• Left atrium
• Left ventricle
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The Heart Valves
• Atrioventricular (AV) valves
– Tricuspid
• Right atrium  Right ventricle
– Bicuspid (mitral)
• Left atrium  Left ventricle
• Semilunar valves
– Pulmonary
• Right ventricle  Lungs
– Aortic
• Left ventricle  Body
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Blood Flow through the Heart
1. Deoxygenated blood flows from the body to the
inferior and superior vena cavae to right atrium
2. Right atrium contracts, forcing blood through the
tricuspid valve to right ventricle
3. Right ventricle contracts, forcing blood through
the pulmonary valve, to the pulmonary artery
4. Blood exits to the lungs
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Blood Flow through the Heart (continued)
5. Oxygenated blood from lungs travels through the
pulmonary veins to the left atrium
6. Left atrium contracts, forcing blood through the
mitral valve to the left ventricle
7. Left ventricle contracts, forcing blood through the
aortic valve
8. Blood passes to the aorta
9. Blood travels out to parts of the body
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Blood Flow through the Heart
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Walls of the Heart
• Epicardium
– Outermost layer
– Aka: pericardium
• Myocardium
– Middle layer
• Endocardium
– Inner layer
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Cardiac Cycle
• Diastole
– Ventricle relax, atria contract
• Systole
– Ventricles contract, atria relax
• Mean arterial pressure
– Overall pressure within cardiovascular system
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Filling of Heart Chambers
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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Cardiac Output
• Amount of blood pumped by heart in 1 minute
measured in liters/minute
• Stroke volume
– Amount of blood pumped in 1 beat
• Activity – Increases speed blood enters
• Injury – blood loss decreases SV
• Disease – muscle disease decreases SV
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Cardiac Output (continued)
• Heart rate
– Number of beats per minute
– Factors
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Body temp
Emotions
Age
Gender
– Males = 70-72 bpm
– Females = 78-82 bpm
• Activity
• Physical Condition
• Heart Disease
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Chapter 11: The Cardiovascular System
Lesson 11.2
Regulation of the Heart
Internal Control of the Heart
• Sinoatrial node (SA node)
– Pacemaker
– Sends electrical impulse
– Tells heart to beat 60–100 bpm
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AV node
Bundle of His
Bundle branches (right & left)
Purkinje fibers
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Figure 11.5
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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External Control of the Heart
• Cardiac center
– Sympathetic nerve system speeds up
– Parasympathetic nerve system slows down
• Endocrine system
– Some hormones speed up
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Regulation of Heart Rate
• Increased heart rate
–Sympathetic nervous system
• Crisis
• Low blood pressure
–Hormones
• Epinephrine
• Thyroxine
–Exercise
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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Slide
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Regulation of Heart Rate
 Decreased heart rate
 Parasympathetic nervous system
 High blood pressure or blood volume
 Decreased venous return
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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Slide
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Electrocardiogram
• ECG or EKG
– Electrical activity of the heart
– Depolarize = contract
– Repolarize = relax
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Cardiac Arrhythmias
• Normal contractility condition
– Sinus rhythm
• Abnormal contractility condition
– Arrhythmia
• Ventricle or atria contraction is not normal
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Cardiac Arrhythmias
• Bradycardia
– Slow heart beat
• Tachycardia
– Fast heart beat
• Premature atrial contraction (PACs)
– Atria contracts before SA node
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Cardiac Arrhythmias
• Atrial fibrillation
– Atria contract faster than 350 bpm
• Premature ventricular contractions (PVCs)
– Ventricles contract too soon
• Ventricular tachycardia (VT)
– Ventricles, rather than SA node, cause beat
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Cardiac Arrhythmias
• Ventricular fibrillation (VF)
– Ventricles contract faster than 350 bpm
• Heart block
– Impulse from SA node to AV node
• First–impulse delayed
• Second–intermittently blocked
• Third–completely blocked
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Defibrillators and Life-Threatening
Arrhythmias
• Automatic external defibrillator (AED)
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Electric shock
Stops heart
Allows heart to start normal rhythm
Anyone can use one
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Review and Assessment
Fill in the blanks with: Tachycardia, Atrial fibrillation,
Bradycardia, or Defibrillator.
1. ___________ is fast heart beat.
2. ___________ is slow heart beat.
3. ___________ is atria beating more than 350 bpm.
4. A(n) ___________ stops the heart so it can reset.
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Chapter 11: The Cardiovascular System
Lesson 11.3
Blood Vessels and
Circulation
Blood Vessels and Circulation
• Blood vessels
– Transport network
• Circulation
– Moving blood around the body
• Taking vital signs
– Know your numbers
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Blood Vessels: The Transport Network
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Three Layers of Blood Vessels
• Tunica intima
– Innermost layer
• Tunica media
– Middle layer
• Tunica externa
– Outermost layer
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Arteries vs. Veins
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Capillaries
• Exchange vessels
– Gas moves between tissue and blood
• Capillary bed
– Network of exchange vessels
• Pre-capillary sphincters
– Close off capillary bed as needed
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Circulation: Moving Blood
• Cardiopulmonary circulation
– Between heart and lungs
• Systemic circulation
– Between heart and body
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Circulation: Moving Blood around the
Body
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Cardiac Circulation
Coronary arteries
– Left
– Right
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Arteries
Veins
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Taking Vital Signs
• Heart Rate (pulse)
– Radial, carotid, brachial artery
– Count beats for 15 seconds, multiply by 4
• Blood Pressure
– Stethoscope, sphygmomanometer
– Systolic/diastolic pressure
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Know Your Numbers
• Weight
– Body mass index (weight/height2)
• Blood pressure
– Systolic/Diastolic (120/80 mmHg)
• Cholesterol
– LDLs and HDLs
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Chapter 11: The Cardiovascular System
Lesson 11.4
Heart Disease
Heart Disease
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valve abnormalities
diseases ending in -itis
heart failure
diseases of the arteries
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Heart Disease
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heart attack
hypertension
peripheral vascular disease
stroke
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Valve Abnormalities
• heart murmurs
– valves do not close properly
• valvular stenosis
– narrowed, stiff heart valve
• mitral valve prolapse
– mitral valve does not fully close
• palpitations
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Diseases Ending in -itis
• pericarditis
– inflammation of heart sac
• myocarditis
– inflammation of heart muscle
• endocarditis
– inflammation of heart lining and valves
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Heart Failure
• heart cannot pump blood
• fluid backs up in
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lungs
liver
limbs
gastrointestinal tract
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Diseases of the Arteries
• aneurysms
– weakened artery bulges,
may break
• coronary artery disease
– atherosclerosis
– angina pectoris
– ischemia
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Heart Attack
• myocardial infarction
– plaque blocks a cardiac artery
• treatment
– aspirin as soon as symptoms appear
– 20–60 minute window for treatment
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Heart Attack
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Heart Disease
• hypertension
– blood pressure above 140/90 mmHg
• peripheral vascular disease
– lack of circulation in legs
• stroke
– blockage of brain blood flow
• ischemic stroke
• hemorrhagic stroke
• transient ischemic attack (TIA)
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Review and Assessment
True or False?
1. Hypertension is 120/80 mmHg.
2. Aspirin helps in a heart attack.
3. An aneurysm is a weakened artery.
4. Myocarditis affects the heart wall.
5. In a heart murmur the valves do not close
properly.
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