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© 2010 Pearson Education, Inc.
• The cardiovascular system of vertebrates consists of the:
– Heart
– Blood vessels
© 2010 Pearson Education, Inc.
• In the heart the:
– Atrium receives blood
– Ventricle pumps blood away from the heart
© 2010 Pearson Education, Inc.
• Blood is confined to three main types of blood vessels:
– Arteries carry blood away from the heart
– Capillaries are the site of exchange between blood and interstitial fluid
– Veins return blood back to the heart
© 2010 Pearson Education, Inc.
The Path of Blood
• Humans and other terrestrial vertebrates have a double circulation system.
• A double circulation system consists of a:
– Pulmonary circuit between the heart and lungs
– Systemic circuit between the heart and the rest of the body
© 2010 Pearson Education, Inc.
How the Heart Works
• The human heart:
– Is a muscular organ about the size of a fist
– Has four chamberLocated in the thoracic cavity (between the lungs and the sternum)
– s
© 2010 Pearson Education, Inc.
The Heart
Structure
Chambers: two atrias, two ventricles
Valves
• Two atrioventricular valves: tricuspid and bicuspid (mitral)
• Two semilunar valves: pulmonary and aortic
© 2010 Pearson Education, Inc.
Pulmonary Circuit: Oxygenation of Blood
Pathway
• Deoxygenated blood through the vena cava to the right atrium
• Deoxygenated blood through the right atrioventricular valve to the right ventricle
• Deoxygenated blood through the pulmonary semilunar valve to the pulmonary trunk and the lungs
• Oxygenated blood through the pulmonary veins to the left atrium
• Oxygenated blood through the left atrioventricular valve to the left ventricle
© 2010 Pearson Education, Inc.
Systemic Circuit: Delivery of Oxygenated Blood to Tissues and Return of Blood to the Heart
Pathway
• Oxygenated blood through the aortic semilunar valve to the aorta
• Oxygenated blood through branching arteries and arterioles to the tissues
• Oxygenated blood to the capillaries
• Deoxygenated blood from capillaries into venules and veins
• Ultimately to the vena cava and into the right atrium
© 2010 Pearson Education, Inc.
Frombody Venae
cavae
Rightatrium
Leftatrium
Rightventricle
Leftventricle
Pulmonaryarteries
Pulmonaryveins
Tolungs
Fromlungs
Tobody
Aorta
Figure 23.UN3
O2-rich blood
O2-poor blood
Right atrium Left atrium
Leftventricle
RightventricleFrom
body
Rightlung
Leftlung
Frombody
Tobody
Valves Valves
Figure 23.4
© 2010 Pearson Education, Inc.
The Cardiac Cycle
• The heart relaxes and contracts throughout our lives.
– Diastole is the relaxation phase of the heart cycle.
– Systole is the contraction phase.
Blast Animation: Cardiac Cycle Overview
Heart is relaxed.Blood flows in.
Diastole
0.4sec
Atria contract. Blood isforced into ventricles.
0.1sec
Systole
Ventricles contract.Blood is pumped out.
0.3sec
0.8sec
Figure 23.5-3
© 2010 Pearson Education, Inc.
The Pacemaker and the Control of Heart Rate
• The pacemaker, or SA (sinoatrial) node:
– Sets the tempo of the heartbeat
– Is composed of specialized muscle tissue in the wall of the right atrium
Blast Animation: Electrical Coordination of the Cardiac Cycle
Pacemaker(SA node)
Rightatrium
AV node
Right ventricle
Wire leadingto SA node
Artificialpacemaker
Heart
Pacemakergenerateselectricalimpulses.
Impulsesspreadthroughatria.
Impulsesreachventricles.
(b) Artificial pacemaker(a) The heart’s natural pacemaker
Figure 23.6
Pacemaker(SA node)
Rightatrium
AV node
Right ventricle
Pacemakergenerateselectricalimpulses.
Impulsesspreadthroughatria.
Impulsesreachventricles.
(a) The heart’s natural pacemaker
Figure 23.6a
Wire leadingto SA node
Artificialpacemaker
Heart
(b) Artificial pacemakerFigure 23.6b
© 2010 Pearson Education, Inc.
• In certain kinds of heart disease, the heart fails to maintain a normal rhythm.
• The remedy for this failure of the electrical control of the heart is:
– An artificial pacemaker, a small electronic device surgically implanted near the SA node
© 2010 Pearson Education, Inc.
Blood Vessels
• If the heart is the body’s “pump,” then the “plumbing” is the system of arteries, veins, and capillaries.
– Arteries carry blood away from the heart.
– Veins carry blood toward the heart.
– Capillaries allow for exchange between the bloodstream and tissue cells.
© 2010 Pearson Education, Inc.
Blood Flow through Arteries
• The force that blood exerts against the walls of blood vessels is blood pressure.
– Blood pressure is the main force driving the blood from the heart to the capillary beds.
– A pulse is the rhythmic stretching of the arteries caused by the pressure of blood forced into the arteries during systole.
© 2010 Pearson Education, Inc.
• Optimal blood pressure for adults is below 120 systolic and below 80 diastolic.
• High blood pressure, or hypertension, is:
– Persistent systolic blood pressure higher than 140 and/or
– Diastolic blood pressure higher than 90
© 2010 Pearson Education, Inc.
Blood
• An adult human has about 5 L (11 pints) of blood.
• By volume, blood is about:
– 45% cells and
– 55% plasma, consisting of about:
– 90% water
– 10% dissolved salts, proteins, and other molecules
Plasma(55%)
Water (90%of plasma)
Dissolved salts(such as sodium,potassium, calcium)
Substances beingtransported (such as
O2, CO2, nutrients,
wastes, hormones)
Cellularelements (45%)
Red blood cells(erythrocytes)
White blood cells(leukocytes)
Platelets
BloodProteins
Figure 23.11
Plasma(55%)
Water (90%of plasma)
Dissolved salts(such as sodium,potassium, calcium)
Substances beingtransported (such as
O2, CO2, nutrients,
wastes, hormones)
Cellularelements (45%)
Red blood cells(erythrocytes)
White blood cells(leukocytes)
Platelets
Proteins
Figure 23.11a
© 2010 Pearson Education, Inc.
Red Blood Cells and Oxygen Transport
• Red blood cells (erythrocytes) are:
– Shaped like discs with indentations in the middle
– The most numerous type of blood cell
Red Blood Cells(cells that carry oxygen)
Co
lori
zed
SE
M
Figure 23.12a
© 2010 Pearson Education, Inc.
Hemegroup
Ironatom
Polypeptide chain
O2 loaded
in lungs
O2 unloaded
in tissues
O2
O2
Figure 23.23
White Blood Cells(cells that fight infection)
Co
lori
zed
SE
M
Figure 23.12b
Platelets(bits of membrane-enclosedcytoplasm that aid clotting)
Fibrin
Red blood cell
Co
lori
zed
SE
M
Co
lori
zed
SE
M
Figure 23.12c
© 2010 Pearson Education, Inc.
• Each red blood cell contains large amounts of the protein hemoglobin, which:
– Contains iron
– Transports oxygen throughout the body
© 2010 Pearson Education, Inc.
• Anemia may result from:
– An abnormally low amount of hemoglobin or
– A low number of red blood cells
• The hormone EPO boosts production of red blood cells.
© 2010 Pearson Education, Inc.
White Blood Cells and Defense
• White blood cells (leukocytes) fight:
– Infections
– Cancer
• .
© 2010 Pearson Education, Inc.
Platelets and Blood Clotting
• Blood contains two components that aid in clotting:
– Platelets
– Clotting factors released from platelets that convert fibrinogen, a protein found in plasma, into a threadlike protein called fibrin
© 2010 Pearson Education, Inc.
• Cardiovascular disease:
– Includes all diseases affecting the heart and blood vessels
– Accounts for 40% of all deaths in the United States
– Kills more than 1 million people each year
© 2010 Pearson Education, Inc.
• Coronary arteries:
– Supply the heart muscle
– Can narrow or close, contributing to a heart attack
Coronary artery(supplies oxygento the heart muscle)
Dead muscletissue
Blockage
Aorta
Figure 23.13
© 2010 Pearson Education, Inc.
• Atherosclerosis:
– Is a chronic cardiovascular disease
– Results from the buildup of cholesterol and other substances in the walls of arteries
– Gradually narrows arteries throughout the body
Connectivetissue
Smoothmuscle
Epithelium
Normal artery
Figure 23.14a
Plaque
Artery partially blocked by plaqueFigure 23.14b
© 2010 Pearson Education, Inc.
• Heart disease:
– Involves inherited factors but
– Can be reduced by:
– Not smoking
– Exercising regularly
– Eating a heart-healthy diet
© 2010 Pearson Education, Inc.
THE HUMAN RESPIRATORY SYSTEM• The human respiratory system has three phases of gas exchange:
– Breathing
– Transport of oxygen from the lungs to the rest of the body via the circulatory system
– Removal of oxygen from the blood and release of CO2 into the blood by cells of the body
Lungs(localized internal organs)
Model of a pair of human lungs
Figure 23.17d
The Structure and Function of the Human Respiratory System• Air moves sequentially from the mouth and nose:
– To the pharynx, where digestive and respiratory systems meet
– To the larynx (voice box) and trachea (windpipe)
– To the bronchi (one bronchus to each lung)
– To the bronchioles, the smallest branches of the tubes within the lungs and
– To the alveoli, the air sacs where gas exchange primarily occurs
© 2010 Pearson Education, Inc.
Larynx (voice box)
Trachea(windpipe)
(a) Overview of the human respiratory system
Pharynx
Right lung
Bronchus
Bronchiole
Diaphragm
Esophagus
Nasal cavity
Left lung
Heart
Figure 23.19a
(b) The structure of alveoli
Bronchiole
Bloodcapillaries
Fromheart
Toheart
Alveoli
O2-rich
blood
O2-poor
blood
O2CO2
Figure 23.19b
© 2010 Pearson Education, Inc.
Taking a Breath• Breathing is the alternating process of:
– Inhalation
– Exhalation
© 2010 Pearson Education, Inc.
• During inhalation, the chest is expanded by the:
– Upward movement of the ribs
– Downward movement of the diaphragm
• Air moves into the lungs:
– By negative pressure breathing
– As the air pressure in the lungs is lowered by the expansion of the chest
Inhalation(Air pressure is
higher in atmospherethan in lungs.)
Exhalation(Air pressure is
lower in atmospherethan in lungs.)
Diaphragmrelaxes(moves up)
Diaphragmcontracts(movesdown)
Rib cageexpands asrib musclescontract
Rib cage getssmaller asrib musclesrelax
Airinhaled
Airexhaled
Lung
Figure 23.20
© 2010 Pearson Education, Inc.
How Smoking Affects the Lungs• Breathing exposes your respiratory tissues to potentially
damaging chemicals, including one of the worst pollutants, tobacco smoke.
© 2010 Pearson Education, Inc.
• Tobacco smoke:
– Irritates the cells that line the bronchi and trachea
– Inhibits their ability to remove foreign substances from the airways
© 2010 Pearson Education, Inc.
• Smoking:
– Kills half of all people who smoke, about 440,000 Americans every year,
– Causes 90% of all lung cancer (one of the deadliest forms of cancer)
– Causes more deaths than the combined total of:
– All accidents
– Alcohol and other drug abuse
– HIV
– Murders
(a) Healthy lungs (nonsmoker)
Lung
Heart
Figure 23.24a
(b) Cancerous lungs (smoker)
Lung
Heart
Figure 23.24b
© 2010 Pearson Education, Inc.
• The lifestyle choice with the greatest impact on your long-term health is choosing not to smoke.
The Heimlich maneuver:
– Involves quick thrusts to the diaphragm
– Compresses the lungs
– Forces air rapidly out of the chest
– May dislodge food or other objects obstructing the breathing pathway
© 2010 Pearson Education, Inc.
© 2010 Pearson Education, Inc.
• The food and air passageways pass through a common tube in the rear of the pharynx.
• Choking results when food or other substances get diverted from the food to the air pathway.
© 2010 Pearson Education, Inc.
• The common passageway of food and air reflects the remodeling of the food passageway during the evolution of the respiratory system in shallow-water fishes.
• Choking is thus a consequence of the evolutionary remodeling of the throat.
Figure 23.25
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