powerlecture: chapter 11 the respiratory system. learning objectives understand how body processes...

PowerLecture:PowerLecture:Chapter 11Chapter 11

The Respiratory SystemThe Respiratory System

Learning ObjectivesLearning Objectives

Understand how body processes generate Understand how body processes generate a need to acquire oxygen and dispose of a need to acquire oxygen and dispose of carbon dioxide.carbon dioxide.

Describe the gradients that the respiratory Describe the gradients that the respiratory gases follow in their routes into and out of gases follow in their routes into and out of the body.the body.

Understand how the human respiratory Understand how the human respiratory system functions and how it works in system functions and how it works in coordination with other systems of the body. coordination with other systems of the body.

Learning Objectives (cont’d)Learning Objectives (cont’d)

Explain the controls over the breathing Explain the controls over the breathing processes.processes.

List some of the things that can go wrong List some of the things that can go wrong with the respiratory system and explain the with the respiratory system and explain the mechanisms through which the breakdown mechanisms through which the breakdown in the system occurs.in the system occurs.

Impacts/IssuesImpacts/Issues

Down in SmokeDown in Smoke


Smoking poses a threat to human health Smoking poses a threat to human health and survival.and survival.

Cilia that line the respiratory Cilia that line the respiratory airways and normally sweep airways and normally sweep away pollutants and microbes away pollutants and microbes are immobilized for hours.are immobilized for hours.

Smoke kills white blood cells Smoke kills white blood cells that defend the respiratory tract.that defend the respiratory tract.

Smoking puts the body at Smoking puts the body at increased risk for cancer, high blood pressure, increased risk for cancer, high blood pressure, and elevated levels of “bad” cholesterol.and elevated levels of “bad” cholesterol.


The respiratory system functions to bring The respiratory system functions to bring oxygen into, and carbon dioxide out of, the oxygen into, and carbon dioxide out of, the body.body.

Fig. 11.14a, p. 206Fig. 11.14a, p. 206

How Would You Vote?How Would You Vote?To conduct an instant in-class survey using a classroom response To conduct an instant in-class survey using a classroom response system, access “JoinIn Clicker Content” from the PowerLecture main system, access “JoinIn Clicker Content” from the PowerLecture main menu. menu.

As tobacco use by its citizens declines, should the As tobacco use by its citizens declines, should the United States encourage international efforts to United States encourage international efforts to reduce tobacco use?reduce tobacco use? a. Yes, tobacco use is costly both in terms of personal a. Yes, tobacco use is costly both in terms of personal

health and societal financial burden. The United States health and societal financial burden. The United States should encourage international efforts to reduce should encourage international efforts to reduce tobacco use.tobacco use.

b. No, the United States should not encourage b. No, the United States should not encourage international efforts to reduce tobacco use. Tobacco international efforts to reduce tobacco use. Tobacco use, though deleterious to health, is a personal choice use, though deleterious to health, is a personal choice that individuals have a right to make on their own.that individuals have a right to make on their own.

Section 1Section 1

The Respiratory System—The Respiratory System—Built for Gas ExchangeBuilt for Gas Exchange

The Respiratory System – The Respiratory System – Built for Gas ExchangeBuilt for Gas Exchange

Airways are pathways for oxygen and Airways are pathways for oxygen and carbon dioxide.carbon dioxide.

The The respiratory systemrespiratory system brings in oxygen that brings in oxygen that each body cell requires and takes away carbon each body cell requires and takes away carbon dioxide that every cell generates.dioxide that every cell generates.

Through the Through the nasal cavitiesnasal cavities of the nose, air of the nose, air enters and leaves the respiratory system; the enters and leaves the respiratory system; the nasal cavities are separated by a septum of nasal cavities are separated by a septum of cartilage and bone.cartilage and bone.


• Hair and ciliated epithelium filter dust and particles Hair and ciliated epithelium filter dust and particles from the air.from the air.

• Blood vessels warm the air and mucus moistens it.Blood vessels warm the air and mucus moistens it.• The The paranasal sinusesparanasal sinuses lie just above the cavities lie just above the cavities

and are linked to them by channels.and are linked to them by channels.

Figure 11.2Figure 11.2


Air moves via this route: nasal cavities >>> Air moves via this route: nasal cavities >>> pharynx >>> larynx >>> vocal cords (the gap pharynx >>> larynx >>> vocal cords (the gap between the cords is the between the cords is the glottisglottis) >>> trachea ) >>> trachea >>> bronchi (one >>> bronchi (one bronchusbronchus goes to each lung). goes to each lung).

• The trachea leads from the larynx downward to The trachea leads from the larynx downward to branch into two bronchi, which are lined with cilia and branch into two bronchi, which are lined with cilia and mucus to trap bacteria and particles.mucus to trap bacteria and particles.

• The vocal cords at the entrance of the larynx vibrate The vocal cords at the entrance of the larynx vibrate when air passes through the glottis, allowing us to when air passes through the glottis, allowing us to make sounds; during swallowing, the glottis is closed make sounds; during swallowing, the glottis is closed to prevent choking.to prevent choking.

© 2007 Thomson Higher Education Fig. 11.3, p. 197

vocal cords

glottis (closed)

epiglottis

tongue’s base

glottis (open)


Lungs are elastic and provide a large Lungs are elastic and provide a large surface area for gas exchange.surface area for gas exchange.

Human Human lungslungs are a pair of organs housed in are a pair of organs housed in the rib cage above the the rib cage above the diaphragmdiaphragm; the two ; the two lungs are separated by the heart.lungs are separated by the heart.

Each lung is enclosed by a pair of thin Each lung is enclosed by a pair of thin membranes called membranes called pleuraepleurae (singular: pleura); (singular: pleura); the pleural membrane is folded in a manner that the pleural membrane is folded in a manner that forms a forms a pleural sacpleural sac leaving an leaving an intrapleural intrapleural spacespace filled with a lubricating filled with a lubricating intrapleural fluidintrapleural fluid..


Inside the lungs, bronchi narrow to form Inside the lungs, bronchi narrow to form bronchiolesbronchioles ending in ending in respiratory respiratory bronchiolesbronchioles..

• Tiny clustered sacs called Tiny clustered sacs called alveolialveoli (singular: (singular: alveolusalveolus) bulge out from the walls of the respiratory ) bulge out from the walls of the respiratory bronchioles.bronchioles.

• Together the alveoli provide a tremendous surface Together the alveoli provide a tremendous surface area for gaseous exchange, with the blood located in area for gaseous exchange, with the blood located in the dense capillary network surrounding each the dense capillary network surrounding each alveolar sac.alveolar sac.

bronchiole

alveolar duct

alveoli

alveolar sac(sectioned) alveolar

sac

pulmonarycapillary

Fig. 11.1bc, p. 196

Nasal Cavity

Pharynx (throat)

Epiglottis

Larynx (voice box)

Trachea (windpipe)

Lung (one of a pair)

Bronchial Tree

Pleural Membrane

Oral Cavity (mouth)

Intercostal Muscles

Diaphragm

Fig. 11.1, p. 196

bronchiole

alveolar duct

alveoli

alveolar sac(sectioned)

alveolarsac

pulmonary capillary

Section 2Section 2

Respiration = Gas Respiration = Gas ExchangeExchange

Respiration = Gas ExchangeRespiration = Gas Exchange

RespirationRespiration is the overall exchange of is the overall exchange of inhaled oxygen from the outside air for inhaled oxygen from the outside air for exhaled carbon dioxide waste.exhaled carbon dioxide waste.

This exchange occurs in the alveoli; This exchange occurs in the alveoli; afterward, the cardiovascular system is afterward, the cardiovascular system is responsible for moving gases in the body.responsible for moving gases in the body.

In-text Fig., p. 198

O2

CO2

O2

CO2

Cellular respiration in mitochondria Whole body respiration

Fig. 11-4, p. 198

RESPIRATORYSYSTEM

food, water intake

eliminationof carbondioxide

elimination ofexcess water,salts, wastes

water,solutes

carbondioxide

oxygen

nutrients,water,salts

eliminationof foodresidues

rapid transportto and from allliving cells

oxygen intake

DIGESTIVESYSTEM

CARDIOVASCULARSYSTEM

URINARYSYSTEM

Section 3Section 3

The “Rules” of Gas The “Rules” of Gas ExchangeExchange

The “Rules” of Gas ExchangeThe “Rules” of Gas Exchange

Respiratory systems rely on the diffusion of Respiratory systems rely on the diffusion of gases down gases down pressure gradientspressure gradients..

Air is 78% nitrogen, 21% oxygen, 0.04% carbon Air is 78% nitrogen, 21% oxygen, 0.04% carbon dioxide, and 0.96% other gases.dioxide, and 0.96% other gases.

• Partial pressuresPartial pressures for each gas in the atmosphere for each gas in the atmosphere can be calculated; for example, oxygen’s is 160 mm can be calculated; for example, oxygen’s is 160 mm Hg.Hg.

• Oxygen and carbon dioxide diffuse down pressure Oxygen and carbon dioxide diffuse down pressure gradients from areas of high partial pressure to areas gradients from areas of high partial pressure to areas of low partial pressure.of low partial pressure.

760 mm Hg

Fig. 11.5, p. 198

78% N2

Partial pressure ofN2 = 600 mm Hg

21% O2

Partial pressure ofO2 = 160 mm Hg

1% CO2, other gases

Total atmospheric pressure = 760 mm Hg


Gases enter and leave the body by diffusing Gases enter and leave the body by diffusing across thin, moist across thin, moist respiratory surfacesrespiratory surfaces of of epithelium; the speed and extent of diffusion epithelium; the speed and extent of diffusion depends on the surface area present and on depends on the surface area present and on the partial pressure gradient.the partial pressure gradient.


When hemoglobin binds oxygen, it helps When hemoglobin binds oxygen, it helps maintain the pressure gradient.maintain the pressure gradient.

Hemoglobin is the main transport protein.Hemoglobin is the main transport protein. Each protein binds four molecules of oxygen in Each protein binds four molecules of oxygen in

the lungs (high oxygen concentration) and the lungs (high oxygen concentration) and releases them in the tissues where oxygen is releases them in the tissues where oxygen is low; by carrying oxygen away from the lungs, low; by carrying oxygen away from the lungs, the gradient is maintained.the gradient is maintained.


Gas exchange “rules” Gas exchange “rules” change when oxygen is change when oxygen is scarce.scarce.

HypoxiaHypoxia occurs when occurs when tissues do not receive tissues do not receive enough oxygen; at high enough oxygen; at high altitudes the partial altitudes the partial pressure of oxygen is pressure of oxygen is lower than at sea level, lower than at sea level, so that so that hyperventilationhyperventilation may occur.may occur.

Figure 11.6aFigure 11.6a


Underwater, divers must Underwater, divers must breathe pressurized air breathe pressurized air from tanks and avoid from tanks and avoid nitrogen narcosisnitrogen narcosis, , where nitrogen dissolves where nitrogen dissolves into the body, including into the body, including the brain; divers must the brain; divers must also ascend to the also ascend to the surface slowly to prevent surface slowly to prevent nitrogen bubbles in the nitrogen bubbles in the blood—the “bends” or blood—the “bends” or decompression decompression sicknesssickness..

Figure 11.6bFigure 11.6b

Section 4Section 4

Breathing—Breathing—

Air In, Air OutAir In, Air Out

BreathingBreathing

When you breathe, air pressure gradients When you breathe, air pressure gradients reverse in a cycle.reverse in a cycle.

The The respiratory cyclerespiratory cycle is the continuous in/out is the continuous in/out ventilation of the lungs and has two phases:ventilation of the lungs and has two phases:

• InspirationInspiration (inhalation) draws breath into the (inhalation) draws breath into the

airways.airways.• ExpirationExpiration (exhalation) moves a breath out of (exhalation) moves a breath out of

the airways.the airways.

BreathingBreathing

During the cycle, the volume of the chest cavity During the cycle, the volume of the chest cavity increases, then decreases, and the pressure increases, then decreases, and the pressure gradients between the lungs and outside air gradients between the lungs and outside air reverse.reverse.

• This works because the air in the airways is the This works because the air in the airways is the

same pressure as the outside atmosphere.same pressure as the outside atmosphere.• Pressure in the alveoli (Pressure in the alveoli (intrapulmonary pressureintrapulmonary pressure) )

is also the same as the outside air.is also the same as the outside air.

Fig. 11.7, p. 200

INWARD BULKFLOW OF AIR

OUTWARD BULKFLOW OF AIR

Inhalation Diaphragm contracts and moves down. The external intercostal muscles contract and lift the rib cage upward and outward. The lung volume expands.

Exhalation Diaphragm and external intercostal muscles return to the resting positions. Rib cage moves down. Lungs recoil passively.

BreathingBreathing

The basic respiratory cycle.The basic respiratory cycle.• To inhale, the diaphragm contracts and flattens, To inhale, the diaphragm contracts and flattens,

muscles lift the rib cage upward and out ward, the muscles lift the rib cage upward and out ward, the chest cavity volume increases, internal pressure chest cavity volume increases, internal pressure decreases, air rushes in.decreases, air rushes in.

• To exhale, the actions listed above are reversed; the To exhale, the actions listed above are reversed; the elastic lung tissue recoils passively and air flows out elastic lung tissue recoils passively and air flows out of the lungs.of the lungs.

• Active exhalation involves contraction of the Active exhalation involves contraction of the abdominal muscles to push the diaphragm upward, abdominal muscles to push the diaphragm upward, forcing more air out.forcing more air out.

BreathingBreathing

Another pressure gradient aids the process.Another pressure gradient aids the process.• The lungs are stretched to fill the thoracic cavity by a The lungs are stretched to fill the thoracic cavity by a

slight difference between the intrapulmonary slight difference between the intrapulmonary pressure (higher) and the intrapleural pressure pressure (higher) and the intrapleural pressure (lower).(lower).

• In a collapsed lung (In a collapsed lung (pneumothoraxpneumothorax), air enters the ), air enters the pleural cavity, disrupting the normal expansion and pleural cavity, disrupting the normal expansion and contraction of the lungs.contraction of the lungs.

BreathingBreathing

How much air is in a “breath”?How much air is in a “breath”? About 500 ml of air (About 500 ml of air (tidal volumetidal volume) enters and ) enters and

leaves the lungs with each breath.leaves the lungs with each breath.• A human can forcibly inhale 3,100 ml of air A human can forcibly inhale 3,100 ml of air

((inspiratory reserve volumeinspiratory reserve volume) and forcibly exhale ) and forcibly exhale 1,200 ml (1,200 ml (eexpiratory reserve volumexpiratory reserve volume).).

• The maximum volume that can be moved in and out The maximum volume that can be moved in and out is called the is called the vital capacityvital capacity (4,800 ml for males, (4,800 ml for males, 3,800 ml for females).3,800 ml for females).

inspiratoryreserve volume

expiratoryreserve volume

tidal volume

vital capacity

total lung capacity

Fig. 11.8, p. 201

time

Lu

ng

vo

lum

e (m

illi

lite

rs)

6,000

1,000

2,000

3,000

4,000

5,000

0

residualvolume

BreathingBreathing

A A residual volumeresidual volume of about 1,200 ml remains of about 1,200 ml remains in the lungs and cannot be forced out.in the lungs and cannot be forced out.

Sometimes food enters the trachea rather than Sometimes food enters the trachea rather than the esophagus; it can be forced out by the the esophagus; it can be forced out by the Heimlich maneuverHeimlich maneuver,, which forces the which forces the diaphragm to elevate, pushing air into the diaphragm to elevate, pushing air into the trachea to dislodge the obstruction.trachea to dislodge the obstruction.

Fig. 11.9a, p. 201

a Place a fist just above the choking person’s navel, with the flat of your thumb against the abdomen.

Fig. 11.9b, p. 201

b Cover the fist with your other hand. Thrust both fists up and in with enough force to lift the person off his or her feet.

Section 5Section 5

How Gases Are How Gases Are Exchanged and Exchanged and

TransportedTransported

How Gases Are How Gases Are Exchanged and TransportedExchanged and Transported

VentilationVentilation moves gases into and out of moves gases into and out of the lungs; it is different from respiration, the lungs; it is different from respiration, which is the actual exchange of gases which is the actual exchange of gases between the blood and cells.between the blood and cells.

In In external respirationexternal respiration, oxygen moves from , oxygen moves from the alveoli to the blood; carbon dioxide moves the alveoli to the blood; carbon dioxide moves in the opposite direction.in the opposite direction.

In In internal respirationinternal respiration, oxygen moves from the , oxygen moves from the blood into tissues and vice versa for carbon blood into tissues and vice versa for carbon dioxide.dioxide.


Alveoli are masters of gas exchange.Alveoli are masters of gas exchange. Each alveolus is only a single layer of epithelial Each alveolus is only a single layer of epithelial

cells surrounded by a thin basement membrane cells surrounded by a thin basement membrane and a net of lung capillaries, also with thin and a net of lung capillaries, also with thin basement membranes.basement membranes.

• Between the two basement membranes is a film of Between the two basement membranes is a film of fluid.fluid.

• Together the system forms the Together the system forms the respiratory respiratory membranemembrane..

• The partial pressure gradients are sufficient to move The partial pressure gradients are sufficient to move oxygen in and carbon dioxide out of the blood, oxygen in and carbon dioxide out of the blood, passively.passively.


Pulmonary surfactantPulmonary surfactant is a secretion produced is a secretion produced by the alveoli that reduces the surface tension by the alveoli that reduces the surface tension of the film to prevent collapse of the alveoli; of the film to prevent collapse of the alveoli; infant respiratory distress syndromeinfant respiratory distress syndrome occurs occurs in premature babies who lack the ability to in premature babies who lack the ability to make the surfactant. make the surfactant.

Fig. 11.10, p. 202

a Surface view of capillaries associated with alveoli

b Cutaway view of one alveolus, showing the respiratory membrane

c Closer view of the respiratory membrane’s structure

pore for air flow between adjoining alveoli

respiratory membrane

space inside alveolus

alveolar epithelium

capillary endothelium

fused- together basement membranes of both epithelia

red bloodcell

Fig. 11.10a, p. 202

a. Surface view of capillaries associated with alveoli

pore for air flow between adjoining alveoli

red blood cell

spaceinsidealveolus

pore for airflowbetween adjoining alveoli

respiratory membrane

Fig. 11.10b, p. 202

(see next slide)

b. Cutaway view of one alveolus,showing the respiratory membrane

alveolar epithelium

fused-together basement membranes of both epithelia

capillary endothelium

Fig. 11.10c, p. 202

c. Closer view of the respiratory membrane’s structure


Hemoglobin is the oxygen carrier.Hemoglobin is the oxygen carrier. Blood cannot carry sufficient oxygen and Blood cannot carry sufficient oxygen and

carbon dioxide in dissolved form as the body carbon dioxide in dissolved form as the body requires; hemoglobin helps enhance its requires; hemoglobin helps enhance its capacity to carry gases by transporting oxygen.capacity to carry gases by transporting oxygen.

• Oxygen diffuses down a pressure gradient into the Oxygen diffuses down a pressure gradient into the blood plasma >>> red blood cells >>> hemoglobin blood plasma >>> red blood cells >>> hemoglobin where it binds at a ratio of four oxygens to one where it binds at a ratio of four oxygens to one hemoglobin to form hemoglobin to form oxyhemoglobinoxyhemoglobin..

• Hemoglobin gives up its oxygen in tissues where Hemoglobin gives up its oxygen in tissues where partial pressure of oxygen is low, blood is warmer, partial pressure of oxygen is low, blood is warmer, and pH is lower; all three conditions occur in tissues and pH is lower; all three conditions occur in tissues with high metabolism.with high metabolism.

© 2007 Thomson Higher Education

alveolar sacs

cells of body tissue

MOISTEXHALED AIR

pulmonaryarteries

start ofsystematic

veins

DRYINHALED AIR

pulmonaryveins

start ofsystematiccapillaries

O2 104 CO2 40

O2 40

Fig. 11.11, p. 203

O2 160CO2 0.3

O2 120

CO2 27

CO2 45O2 100

CO2 40

O2 less than 40CO2 more than 45

O2 100CO2 40

O2 40CO2 45


When tissues are chronically low in oxygen, red When tissues are chronically low in oxygen, red blood cells produce DPG (2,3-blood cells produce DPG (2,3-diphosphoglycerate), which decreases the diphosphoglycerate), which decreases the affinity of hemoglobin for oxygen, allowing more affinity of hemoglobin for oxygen, allowing more oxygen to be released to the tissues. oxygen to be released to the tissues.

Hemoglobin and blood plasma carry carbon Hemoglobin and blood plasma carry carbon dioxide.dioxide.

Because carbon dioxide concentration is higher Because carbon dioxide concentration is higher in the body tissues rather than in blood, it in the body tissues rather than in blood, it diffuses into the blood capillaries.diffuses into the blood capillaries.


• Seven percent remains dissolved in plasma, 23% Seven percent remains dissolved in plasma, 23% binds with hemoglobin (forming binds with hemoglobin (forming carbaminohemoglobincarbaminohemoglobin) and 70% is in ) and 70% is in bi carbonatebi carbonate form.form.

• Bicarbonate and carbonic acid formation is enhanced Bicarbonate and carbonic acid formation is enhanced by by carbonic anhydrasecarbonic anhydrase, an enzyme located in the , an enzyme located in the red blood cells.red blood cells.

Reactions that make bicarbonate are reversed Reactions that make bicarbonate are reversed in the alveoli where the partial pressure of in the alveoli where the partial pressure of carbon dioxide is low.carbon dioxide is low.

Section 6Section 6

Homeostasis Depends Homeostasis Depends on Controls over on Controls over

BreathingBreathing

Homeostasis Depends on Homeostasis Depends on Controls Over BreathingControls Over Breathing

A respiratory pacemaker controls the A respiratory pacemaker controls the rhythm of breathing.rhythm of breathing.

Automatic mechanisms ensure a regular cycle Automatic mechanisms ensure a regular cycle of ventilation.of ventilation.

• Clustered nerve cells in the medulla coordinate the Clustered nerve cells in the medulla coordinate the signals for the timing of exhalation and inhalation; the signals for the timing of exhalation and inhalation; the pons fine tunes the rhythmic contractions.pons fine tunes the rhythmic contractions.

• The nerve cells are linked to the diaphragm muscles The nerve cells are linked to the diaphragm muscles and the muscles that move the rib cage; during and the muscles that move the rib cage; during normal inhalation, nerve signals travel from the brain normal inhalation, nerve signals travel from the brain to the muscles causing them to contract and allowing to the muscles causing them to contract and allowing the lungs to expand.the lungs to expand.


Normal exhalation follows relaxation of muscles Normal exhalation follows relaxation of muscles and elastic recoil of the lungs.and elastic recoil of the lungs.

When breathing is deep and rapid, stretch When breathing is deep and rapid, stretch receptors in the airways send signals to the receptors in the airways send signals to the brain control centers, which respond by brain control centers, which respond by inhibiting contraction of the diaphragm and rib inhibiting contraction of the diaphragm and rib muscles, forcing you to exhale.muscles, forcing you to exhale.


brain stem(pons and medulla)

vagus nerve

diaphragm

motor pathways via spinal cord

phrenic nerve to diaphragm

intercostal nerves to rib muscles

stretch receptors in alveoli of lungs

Fig. 11.12, p. 204

neurons (pacemaker for respiration)

COCO22 is the trigger for controls over the rate is the trigger for controls over the rate

and depth of breathing.and depth of breathing. The nervous system is more sensitive to levels The nervous system is more sensitive to levels

of carbon dioxide and uses this gas to regulate of carbon dioxide and uses this gas to regulate the rate and depth of breathing.the rate and depth of breathing.

• Sensory receptors in the medulla detect hydrogen Sensory receptors in the medulla detect hydrogen ions produced when dissolved carbon dioxide leaves ions produced when dissolved carbon dioxide leaves the blood and enters the the blood and enters the cerebrospinal fluidcerebrospinal fluid bathing the medulla.bathing the medulla.

• The drop in pH in the cerebrospinal fluid triggers The drop in pH in the cerebrospinal fluid triggers more rapid and deeper breathing to reduce the levels more rapid and deeper breathing to reduce the levels of carbon dioxide in the blood.of carbon dioxide in the blood.


Changes in the levels of carbon dioxide, Changes in the levels of carbon dioxide, oxygen, and blood pH are also detected by oxygen, and blood pH are also detected by carotid bodiescarotid bodies, located near the carotid , located near the carotid arteries, and arteries, and aortic bodiesaortic bodies, located near the , located near the aorta; both receptors signal increases in aorta; both receptors signal increases in ventilation rate to deliver more oxygen to ventilation rate to deliver more oxygen to tissues. tissues.



brain-stem (pons and medulla) receptors detect decreases in pH of cerebrospinal fluid (due to rising CO2 in blood)

carotid bodies(CO2, O2

receptors)

aortic bodies (O2 receptors)

heart

lungs

spinal cord

Fig. 11.13, p. 205

Chemical controls in alveoli help match air Chemical controls in alveoli help match air flow to blood flow.flow to blood flow.

When the rate of blood flow in the lungs is When the rate of blood flow in the lungs is faster than the air flow, the bronchioles dilate to faster than the air flow, the bronchioles dilate to enhance the air flow and thus the rate of enhance the air flow and thus the rate of diffusion of the gases.diffusion of the gases.

When the air flow is too great relative to the When the air flow is too great relative to the blood flow, oxygen levels rise in the lungs and blood flow, oxygen levels rise in the lungs and cause the blood vessels to dilate, increasing cause the blood vessels to dilate, increasing blood flow.blood flow.


Apnea is a condition in which breathing Apnea is a condition in which breathing controls malfunction.controls malfunction.

ApneaApnea is a brief interruption in the respiratory is a brief interruption in the respiratory cycle; breathing stops and then resumes cycle; breathing stops and then resumes spontaneously.spontaneously.

Sleep apneaSleep apnea is a common problem of aging is a common problem of aging because the mechanisms for sensing changing because the mechanisms for sensing changing oxygen and carbon dioxide levels gradually oxygen and carbon dioxide levels gradually become less effective over the years.become less effective over the years.


Section 7Section 7

Disorders of the Disorders of the Respiratory SystemRespiratory System

Disorders of the Respiratory SystemDisorders of the Respiratory System

Tobacco is a major threat.Tobacco is a major threat. Smoking has both immediate effects (for Smoking has both immediate effects (for

example, loss of cilia function) and long term example, loss of cilia function) and long term effects, such as effects, such as lung cancerlung cancer..

Even one cigarette can cause Even one cigarette can cause

you damage as well as hurt those you damage as well as hurt those

around you through secondhand around you through secondhand

smoke.smoke. A variety of pathogens can infect the A variety of pathogens can infect the

respiratory system.respiratory system.Figure 11.17Figure 11.17

Fig. 11.14b, p. 206


PneumoniaPneumonia occurs when inflammation in lung occurs when inflammation in lung tissue and the buildup of fluids makes breathing tissue and the buildup of fluids makes breathing difficult; pneumonia can sometimes occur when difficult; pneumonia can sometimes occur when infections that start in the nose and throat, such infections that start in the nose and throat, such as from as from influenzainfluenza, spread., spread.

TuberculosisTuberculosis arises from infection by the arises from infection by the bacterium bacterium Mycobacterium tuberculosisMycobacterium tuberculosis; the ; the disease destroys patches of lung tissue and disease destroys patches of lung tissue and can cause death if untreated.can cause death if untreated.

HistoplasmosisHistoplasmosis is caused by a fungus; is caused by a fungus; treatment is possible, but the infection can treatment is possible, but the infection can sometimes spread to the eyes, causing sometimes spread to the eyes, causing impairment or blindness.impairment or blindness.


Irritants cause other disorders.Irritants cause other disorders. BronchitisBronchitis, caused by air pollution, cigarette , caused by air pollution, cigarette

smoke, or infection, leads to increased mucus smoke, or infection, leads to increased mucus secretions, interference with ciliary action, and secretions, interference with ciliary action, and eventual inflammation and possible scarring of eventual inflammation and possible scarring of the bronchial walls.the bronchial walls.


Fig. 11.18a, p. 210


If bronchitis progresses so that more of the If bronchitis progresses so that more of the bronchi become scarred and blocked with bronchi become scarred and blocked with mucus, mucus, emphysemaemphysema may result; here alveoli may result; here alveoli also begin to break down, further eroding the also begin to break down, further eroding the ability to breathe.ability to breathe.

Fig. 11.15, p. 207


AsthmaAsthma occurs in response to various occurs in response to various allergens; smooth muscles in the bronchiole allergens; smooth muscles in the bronchiole walls contract in spasms, mucus rushes in, and walls contract in spasms, mucus rushes in, and breathing becomes difficult. Steroid inhalers breathing becomes difficult. Steroid inhalers may be needed to relieve symptoms.may be needed to relieve symptoms.


powerlecture: chapter 11 the respiratory system. learning objectives understand how body processes...

Documents

respiratory system slide

tobacco use

respiratory airways

respiratory cilia

respiratory gases

respiratory tract

smoke slide

body cell