Transcript Chapter 8

Human Biology Concepts and Current Issues
Seventh Edition
Michael D. Johnson
8
Heart and
Blood Vessels
© 2014 Pearson Education, Inc.
Lecture Presentations by
Robert J. Sullivan
Marist College
OBJECTIVES
•Describe the transportation route of blood
•Differentiate between blood vessels
• Describe the structure/function of the heart
• Describe normal/abnormal blood pressure
•Describe factors that contribute to the risk
of cardiovascular disease (CVD)
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Figure 8.9
Components of Cardiovascular System
Jugular vein
Carotid artery
Superior
vena cava
Inferior
vena cava
Renal vein
Common
iliac vein
Common
iliac artery
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Subclavian vein
Subclavian artery
Aorta
Renal artery
Femoral vein
Femoral artery
Great saphenous
vein
Figure 8.1
Compare and contrast
arteries and veins
Direction of
blood flow
Outer layer:
Connective
tissue
Middle layer:
Smooth
muscle with
elastic fibers
Vein
Inner layer:
Artery
Endothelium
Connective tissue
Smooth muscle
Endothelium
Venule
Arteriole
Capillary
Tissue cells
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Epithelial cells of
capillary endothelium
Blood Vessels (types)
Arteries:
-carry blood away from heart
-high pressure
-thick-walled (3 layers)
-largest: aorta
-Smallest: arterioles
-Control blood flow to
capillaries via “gates” called
precapillary sphincter)
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•Veins:
-carry blood to heart
-Larger lumen than arteries
-thinner walls
-low pressure
-Largest: vena cava
-Transport blood with help of:
-skeletal muscle contraction
-one-way valves stop
backflow
-breathing
 Blood flow
– Heart  Arteries  Arterioles  Capillaries
 Arterioles: control blood flow into capillaries
– Vasodilation:
– Relaxation of blood vessel smooth muscle
– Increases blood flow to capillaries
– Vasoconstriction:
– Contraction of blood vessel smooth muscle
– Decreases blood flow to capillaries
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Capillaries:
• Capillary beds:
extensive networks of
capillaries
•exchange of
substances with cells
via interstitial fluid
• Bridge arterioles
and venules
•Arterial side delivers
•Venous side picks up
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Figure 8.2
Heart: muscular fist-size pump
Blood
•Location: thoracic cavity
Vessels•Enclosed by: pericardium
•3 Layers: epicardium,
myocardium and endocardium
•4 chambers: 2 atria (L/R) and
2 ventricles (L/R)
•4 valves: L/R AV valve and L/R
semilunar valves
The heart is comprised primarily of myocardium
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The Heart Has Four Chambers and Four Valves
 Four chambers
– Two atria: upper chambers
– Two ventricles: lower chambers
– Septum, muscular partition separates right and left
sides of the heart
 Four valves—prevent backflow
– Two atrioventricular (AV) valves
– Tricuspid valve (right side)
– Bicuspid (mitral) valve (left side)
– Two semilunar valves
– Pulmonary valve
– Aortic valve
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Figure 8.7
Aorta
Superior
vena cava
Right pulmonary
artery
Left pulmonary artery
Pulmonary trunk
Left pulmonary veins
Pulmonary
semilunar valve
Right atrium
Right
atrioventricular
(AV) valve
Right ventricle
Inferior vena cava
Left atrium
Aortic semilunar valve
Left atrioventricular
(AV) valve
Left ventricle
Chordae tendineae
Papillary muscles
Septum
Epicardium
Myocardium
Endocardium
What are the purpose of the valves?
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Figure 8.8
Systemic Circuit
Head and
upper
limbs
Lung
capillaries
Pulmonary
Circuit
Heart
Lung
capillaries
Aorta
Torso and
Lower limbs
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Pulmonary Circuit vs. Systemic Circuit
Lung
P
O2
Pulmonary Arteries
Pulmonary Veins
Right Ventricle
S
Lung (+O2)
Left Atrium
Right Atrium
Left Ventricle
Vena Cava
Aorta
Body (-O2)
CO2
Body
What is the purpose of each circuit?
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Use Figure 8.7 to answer the following questions:
1.
What major vessels lead into the right atrium? Where do they come from? Are
they transporting mainly CO2 or O2?
2. The right atrium is connected to which other section?
3. What major vessels lead out of the right ventricle? Where do they go? Is it
transporting mainly CO2 or O2?
4. What major vessels lead into the left atrium? Where do they come from? Are they
transporting mainly CO2 (waste) or O2?
5. The left atrium is connected to which other section?
6. What major vessel leads out of the left ventricle? Where does it go? Is it
transporting mainly CO2 or O2?
7. Are the atria entrances to or exits out of the heart?
8. Are the ventricles entrances to or exits out of the heart?
9. Is the left side of the heart for oxygen rich blood?
10. Is the right side of the heart for oxygen poor blood?
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Figure 8.10
The heart must also
supply itself!
Aorta
Superior
vena cava
Pulmonary
trunk
Right
coronary
artery
Cardiac
vein
Left
coronary
artery
Cardiac
veins
Inferior
vena cava
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Coronary arteries supply
the heart muscle
Figure 8.11
The
Cardiac Cycle: The Heart
Contracts and Relaxes
Right atrium
Left atrium
Aortic semilunar valve
Pulmonary
semilunar valve
Left AV valve
Right AV valve
Left ventricle
Atrial systole.
Right ventricle
0.1 second
Diastole
Systole
0.4 second
The AV valves are open, and the
semilunar valves are closed.
Both atria contract, forcing blood
into the ventricles, completing
filling of ventricles
Aorta
Pulmonary trunk
0.3 second
Diastole. The ventricles
relax and begin to fill
passively with blood
through the open AV
valves. The semilunar
valves are closed, and the
atria remain relaxed.
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Ventricular systole. Both ventricles
contract, causing the AV valves to
close and the semilunar valves to open.
Blood is ejected into the pulmonary
trunk and aorta. The atria relax.
Heart Sounds Reflect Closing Heart Valves
 Lub-dub heart sounds
– Lub: closing of both AV valves
– Dub: closing of both semilunar valves
 Heart murmurs
– Caused when blood flow is disturbed
– May be a sign of a defective valve
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Cardiac Conduction System Coordinates Contraction
 Sinoatrial (SA) node— cardiac pacemaker
– Initiates the heartbeat spontaneously
– Pace can be modified by nervous system
 Atrioventricular (AV) node
– Relays impulse
 Atrioventricular (AV) bundle and Purkinje fibers
– Located in septum and ventricles
– Carry impulse to ventricles
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Figure 8.13
Sinoatrial
(SA) node
Atrioventricular
(AV) node
AV bundle
Bundle branches
Purkinje fibers
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Figure 8.14
Electrocardiogram (ECG)
Records the Heart’s
Electrical Activity
An ECG being recorded.
R
T
P
Q
S
A normal ECG recording.
Ventricular fibrillation.
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Blood Exerts Pressure Against Vessel Walls
 The force that the blood exerts on the wall of the
blood vessels
– Systolic pressure: highest pressure, as blood is
ejected during ventricular systole
– Diastolic pressure: lowest pressure, during
ventricular diastole
 Measurement
– Sphygmomanometer: device used to measure blood
pressure
– “Normal” readings
– Systolic pressure <120 mmHg
– Diastolic pressure <80 mmHg
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 Hypertension: High Blood Pressure Can Be Dangerous
 Sustained elevation in blood pressure
– Systolic pressure  140 mmHg
– Diastolic pressure  90 mmHg
 Risk factor for cardiovascular disease
 Hypotension: When Blood Pressure Is Too Low
 Low blood pressure
 If low enough, may cause dizziness or fainting
 May follow abrupt changes in body position
– Standing up suddenly
 May result from excessive blood loss or fluid loss from burns
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Cardiac Output
 Cardiac output is the amount of blood pumped by
heart in one minute
– Heart rate: 75 beats/minute
– Stroke volume: amount of blood pumped by heart in
one heart beat : 70 ml/beat
 Cardiac output  heart rate  stroke volume
 Resting cardiac output
– 75 bpm  70 ml/beat  5.25 liters/min.
 During exercise cardiac output (CO) is increased
– Non-athletes: up to 20–25 liters/min
– Trained athletes: up to 35 liters/min
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Cardiovascular Diseases (CVD)
 Angina (chest pains): narrowed coronary artery; temporary
 Myocardial Infarction (heart attack): Blockage of coronary
artery; death of heart muscle
 Congestive heart failure: inefficient pump; blood backs up into
veins-high capillary pressure; too much fluid exits capillaries
 Out of breath, swollen ankles, legs
 Embolism: piece of clot broken- causes blockage of blood
vessels (pulmonary, brain)
 Stroke : blood flow to part of brain shut off
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Reducing Your Risk of Cardiovascular Disease
 Don’t smoke
– Smokers have twice the risk of heart disease
 Watch cholesterol levels
– Risk increases with increasing blood cholesterol
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Engage in regular moderate exercise
Maintain a healthy weight
Keep diabetes under control
Avoid chronic stress
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Cardiac Anatomy Quiz
A
B
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Test Yourself, page 185