Chapter 7Chapter 7

The Respiratory SystemThe Respiratory System

Chapter 7Chapter 7The Respiratory SystemThe Respiratory System

7.1 Structures of the Respiratory System7.1 Structures of the Respiratory System

7.2 Breathing and Respiration7.2 Breathing and Respiration

7.3 Respiratory Health7.3 Respiratory Health

Chapter 7 The Respiratory Chapter 7 The Respiratory SystemSystem

In this chapter, you will learn:In this chapter, you will learn:The upper respiratory tract filters, warms, and moistens oxygen-containing air, and The upper respiratory tract filters, warms, and moistens oxygen-containing air, and channels it into the lungs.channels it into the lungs.The lower respiratory tract is made up of specialized structures that exchange oxygen The lower respiratory tract is made up of specialized structures that exchange oxygen for carbon dioxide in the bloodstream.for carbon dioxide in the bloodstream.Humans ventilate their lungs by the mechanism of breathing, which involves inspiration Humans ventilate their lungs by the mechanism of breathing, which involves inspiration and expiration.and expiration.The volume of air that is taken into the lungs can increase if the need for oxygen The volume of air that is taken into the lungs can increase if the need for oxygen increases, such as during exercise.increases, such as during exercise.External respiration takes place in the lungs, between the air in the alveoli and the blood External respiration takes place in the lungs, between the air in the alveoli and the blood in the capillaries.in the capillaries.Internal respiration takes place between the blood in the capillaries and tissue cells.Internal respiration takes place between the blood in the capillaries and tissue cells.Gas exchange occurs through the processes of simple diffusion and facilitated diffusion.Gas exchange occurs through the processes of simple diffusion and facilitated diffusion.Some disorders are specific to the respiratory system. Technologies are available to Some disorders are specific to the respiratory system. Technologies are available to treat respiratory disorders, but they may not be able to restore the respiratory system to treat respiratory disorders, but they may not be able to restore the respiratory system to optimal health.optimal health.Smoking causes respiratory diseases. Technologies can help some symptoms of Smoking causes respiratory diseases. Technologies can help some symptoms of smoking, but many symptoms are untreatable.smoking, but many symptoms are untreatable.

7.1 Structures of the 7.1 Structures of the Respiratory SystemRespiratory System

In this section, you will:In this section, you will:

identify identify the principal structures of the respiratory the principal structures of the respiratory systemsystem

identify identify the principal functions of the respiratory the principal functions of the respiratory systemsystem

observe observe and and identify identify the major respiratory the major respiratory structuresstructures

Respiratory SystemRespiratory System

RespirationRespiration

cellular respirationcellular respiration– at the cellular level involves the oxidation of glucoseat the cellular level involves the oxidation of glucose

respiration at the multicellular level (breathing)respiration at the multicellular level (breathing)– involves taking oxygen from the environment and involves taking oxygen from the environment and

returning carbon dioxide to it (breathing)returning carbon dioxide to it (breathing)– breathing is necessary to bring enough nutrients breathing is necessary to bring enough nutrients

and oxygen to all cells in a multicellular organism and oxygen to all cells in a multicellular organism (where diffusion just isn’t enough)(where diffusion just isn’t enough)

Respiration: Stages & StructuresRespiration: Stages & Structures• • BreathingBreathing involves two basic processes: involves two basic processes: inspiration (breathing in, or inhaling) and inspiration (breathing in, or inhaling) and expiration (breathing out, or exhaling). expiration (breathing out, or exhaling). Inspiration moves air from the external Inspiration moves air from the external environment to the lungs inside the body. environment to the lungs inside the body. Expiration moves air from the lungs back Expiration moves air from the lungs back to the external environment.to the external environment.

• • External respirationExternal respiration is the exchange of is the exchange of oxygen and carbon dioxide between the air oxygen and carbon dioxide between the air and the blood.and the blood.

• • Internal respirationInternal respiration is the exchange of is the exchange of oxygen and carbon dioxide between the oxygen and carbon dioxide between the body’s tissue cells and the blood.body’s tissue cells and the blood.

• • Cellular respirationCellular respiration is the series of is the series of energy-releasing chemical reactions that energy-releasing chemical reactions that take place inside the cells. Cellular take place inside the cells. Cellular respiration is the final stage in respiration. respiration is the final stage in respiration. It is the sole means of providing energy for It is the sole means of providing energy for all cellular activities, and it helps the body all cellular activities, and it helps the body maintain homeostasis.maintain homeostasis.

BreathingBreathing

brings oxygen to where diffusion can take brings oxygen to where diffusion can take place (bulk flow)place (bulk flow)

facilitates diffusion into the transport facilitates diffusion into the transport systemsystem

the circulatory system brings the oxygen to the circulatory system brings the oxygen to the cells (bulk flow)the cells (bulk flow)

oxygen is brought into cells by diffusion oxygen is brought into cells by diffusion across the membraneacross the membrane

The Respiratory SystemThe Respiratory System

as air passes through the nasal cavity, it is as air passes through the nasal cavity, it is warmed and moistenedwarmed and moistened

the passages are lined with hair and later the passages are lined with hair and later cilia and mucous to help trap foreign cilia and mucous to help trap foreign invaders and sweep them into the pharynx invaders and sweep them into the pharynx where they are swallowed, sneezed or where they are swallowed, sneezed or coughed outcoughed out

the warmed air passes by the epiglottis the warmed air passes by the epiglottis and down the trachea which is lined with and down the trachea which is lined with cartilage to prevent the trachea from cartilage to prevent the trachea from collapsing or being damagedcollapsing or being damaged– the opening (slit) to the trachea is called the the opening (slit) to the trachea is called the

glottisglottis– the air passes by the enlargement of the the air passes by the enlargement of the

trachea, the larynx, where the vocal cords are trachea, the larynx, where the vocal cords are locatedlocated

the trachea is also lined with the trachea is also lined with ciliacilia and and mucous-secreting cells mucous-secreting cells – which beat 20x per minute to move the which beat 20x per minute to move the

trapped particles up to the pharynxtrapped particles up to the pharynxSmokers ciliaSmokers cilia

just above the heart, the trachea branches just above the heart, the trachea branches into two bronchi into two bronchi

Bronchi branch again into bronchioles Bronchi branch again into bronchioles which branch smaller and smaller – only which branch smaller and smaller – only the smallest of the bronchioles lack the smallest of the bronchioles lack cartilagecartilage

at the end, the terminal bronchioles (the at the end, the terminal bronchioles (the last ones) end at a group of alveolar ducts last ones) end at a group of alveolar ducts and sacs called and sacs called alveolialveoli – the specialized structures for gas exchangethe specialized structures for gas exchange

the lungs are each encased in a double-the lungs are each encased in a double-membraned sac, the membraned sac, the pleurapleura which allow which allow the lungs to expand and contract freelythe lungs to expand and contract freely

the diaphragm separates the lungs (in the the diaphragm separates the lungs (in the thoracic cavity) from the peritoneal cavity, thoracic cavity) from the peritoneal cavity, where the digestive organs are locatedwhere the digestive organs are located

AlveoliAlveoli

are specialized for optimal diffusionare specialized for optimal diffusion– moist membranemoist membrane– large surface arealarge surface area– thin walls for diffusion (1thin walls for diffusion (1m across)m across)– immediately adjacent to pulmonary capillaries, immediately adjacent to pulmonary capillaries,

which are just large enough for a RBC to get which are just large enough for a RBC to get throughthrough

– the inner surface of the alveoli are covered with a the inner surface of the alveoli are covered with a single layer of lipid called single layer of lipid called surfactantsurfactant

which reduces the surface tension in the alveoli allowing which reduces the surface tension in the alveoli allowing them to easily expand to twice their size with each breaththem to easily expand to twice their size with each breath

when a baby is born, the first cry and when a baby is born, the first cry and breath must expand the alveoli without the breath must expand the alveoli without the aid of surfactant aid of surfactant – the lipid layer is immediately formed making the lipid layer is immediately formed making

breathing easier, and oxygen diffusion more breathing easier, and oxygen diffusion more efficient (by efficient (by surface area since surfactant surface area since surfactant aids in the expansion of the alveoli)aids in the expansion of the alveoli)

– for premature babies, the lungs may not be for premature babies, the lungs may not be completely mature. Doctors must support completely mature. Doctors must support breathing until the baby’s lungs develop by breathing until the baby’s lungs develop by giving them air with a higher oxygen giving them air with a higher oxygen concentrationconcentration

-Each bronchiole ends in several clusters of alveoli. -Each bronchiole ends in several clusters of alveoli. -Surrounding each alveolus is a fine network of -Surrounding each alveolus is a fine network of capillaries from the circulatory system. capillaries from the circulatory system. -Gas exchange occurs between the blood in the -Gas exchange occurs between the blood in the capillaries and the air in the alveolus, so that blood capillaries and the air in the alveolus, so that blood leaving the lungs has a high oxygen content.leaving the lungs has a high oxygen content.

7.2 Breathing and Respiration7.2 Breathing and Respiration

In this section, you will:In this section, you will:

explain explain the mechanics of breathingthe mechanics of breathing

explain explain how gases are exchanged between the how gases are exchanged between the human respiratory system and the external human respiratory system and the external environmentenvironment

perform perform an experiment to determine your an experiment to determine your respiratory volumerespiratory volume

perform perform an experiment to examine factors that an experiment to examine factors that affect the rate of respirationaffect the rate of respiration

Mechanics of BreathingMechanics of Breathing

breathing involves two processes, inhalation breathing involves two processes, inhalation and exhalationand exhalation– Inhalation:Inhalation: an active process (using energy) an active process (using energy)

where one breath is drawn into the lungs with the where one breath is drawn into the lungs with the aid of muscle contractionsaid of muscle contractions

air is drawn into the lungs when the thoracic air is drawn into the lungs when the thoracic cavity expands in size, and since the pleural cavity expands in size, and since the pleural cavity is sealed, decreasing the pressure of the cavity is sealed, decreasing the pressure of the cavity, which pulls air in from the environmentcavity, which pulls air in from the environment

depending on the depth of breathing, depending on the depth of breathing, a number of muscles will be involveda number of muscles will be involved

–Diaphragm:Diaphragm: contracts, moving contracts, moving downwarddownward

– intercostal musclesintercostal muscles (between the ribs): (between the ribs): contract, expanding the chest cavitycontract, expanding the chest cavity

–neck muscles:neck muscles: contract, raising the top contract, raising the top two ribstwo ribs

– Exhalation:Exhalation: generally a passive process generally a passive process (unless breathing very deeply) where one (unless breathing very deeply) where one breath is expelled as the muscles above relaxbreath is expelled as the muscles above relax

as the muscles relax, the size of the as the muscles relax, the size of the thoracic cavity is decreased, increasing the thoracic cavity is decreased, increasing the pressure, forcing the gas out of the lungspressure, forcing the gas out of the lungs

when breathing deeply, more air may be when breathing deeply, more air may be exhaled with the contraction of the exhaled with the contraction of the abdominal musclesabdominal muscles

The The Mechanics Mechanics of Breathingof Breathing

Lung VolumesLung Volumes

the lung volume (the lung volume (total lung capacitytotal lung capacity) of the ) of the average male is 5.7 L, the average female, average male is 5.7 L, the average female, 4.2 L, including the residual volume4.2 L, including the residual volumeresidual volumeresidual volume is the amount of air that is the amount of air that remains in the lungs after maximum remains in the lungs after maximum expiration, keeping the lungs partially expiration, keeping the lungs partially inflated (about 1 L) inflated (about 1 L) during quiet breathing, lungs generally during quiet breathing, lungs generally inflate from 2.2 L to 2.7 L (the amount of inflate from 2.2 L to 2.7 L (the amount of air inhaled during quiet breathing, about air inhaled during quiet breathing, about 500 mL is the 500 mL is the tidal volumetidal volume))

The largest breath you can take is called The largest breath you can take is called vital capacityvital capacity – involves expanding the lungs to a greater involves expanding the lungs to a greater

extent than normal (recruiting the diaphragm, extent than normal (recruiting the diaphragm, intercostals and neck muscles), and exhaling intercostals and neck muscles), and exhaling actively by recruiting the abdominal musclesactively by recruiting the abdominal muscles

Vital capacity includes tidal volume, the Vital capacity includes tidal volume, the extra you can inhale (extra you can inhale (inspiratory reserve inspiratory reserve volumevolume) and the extra you can exhale ) and the extra you can exhale ((expiratory reserve volumeexpiratory reserve volume))

Of the 500 mL inhaled with every normal Of the 500 mL inhaled with every normal breath, only about 0.35 L reaches the alveoli breath, only about 0.35 L reaches the alveoli (the rest fills the trachea, bronchi and (the rest fills the trachea, bronchi and bronchioles)bronchioles)– with an average respiratory rate (# with an average respiratory rate (#

breaths/minute) of 10, the amount of air breaths/minute) of 10, the amount of air exchanged per minute is 3.5Lexchanged per minute is 3.5L

Lung volumes will be affected by height and Lung volumes will be affected by height and gender in that thoracic cavity size will be gender in that thoracic cavity size will be affected which affects the lung sizeaffected which affects the lung size

Exercise performed over an extended Exercise performed over an extended period of time will strengthen the muscles period of time will strengthen the muscles involved in breathing which will increase involved in breathing which will increase tidal volume and vital capacitytidal volume and vital capacity

Illness can reduce vital capacity and tidal Illness can reduce vital capacity and tidal volume by affecting the number of alveoli volume by affecting the number of alveoli that can successfully exchange oxygen, or that can successfully exchange oxygen, or by weakening the muscles in breathingby weakening the muscles in breathing

A Typical SpirographA Typical Spirograph

External vs. Internal RespirationExternal vs. Internal RespirationA) A) External respirationExternal respiration

- occurs between alveoli and the capillaries - occurs between alveoli and the capillaries next to them.next to them.- As blood moves away from the body tissues, - As blood moves away from the body tissues, it is oxygen-poor and carbon dioxide-rich. it is oxygen-poor and carbon dioxide-rich. - As it moves through the lung capillaries, - As it moves through the lung capillaries, oxygen from the air in the alveoli diffuses into oxygen from the air in the alveoli diffuses into the capillaries and carbon dioxide diffuses out the capillaries and carbon dioxide diffuses out of the blood. of the blood.

B) B) Internal respiration Internal respiration - occurs between the capillaries and the body - occurs between the capillaries and the body tissues. tissues. - Oxygen diffuses from the blood into the - Oxygen diffuses from the blood into the oxygen-poor tissues while carbon dioxide oxygen-poor tissues while carbon dioxide diffuses from the tissues into the blood.diffuses from the tissues into the blood.

Gas Exchange and TransportGas Exchange and Transport oxygen and carbon dioxide must diffuse through the layer of oxygen and carbon dioxide must diffuse through the layer of cells lining the alveolus and the layer of cells lining the cells lining the alveolus and the layer of cells lining the pulmonary capillary to enter/exit the blood. pulmonary capillary to enter/exit the blood.

The gas must also diffuse across the membrane of the The gas must also diffuse across the membrane of the RBC to attach to a hemoglobin moleculeRBC to attach to a hemoglobin molecule

OxygenOxygen98.5% of oxygen is carried on the heme 98.5% of oxygen is carried on the heme group of the hemoglobin on the RBCgroup of the hemoglobin on the RBC

oxygen binds reversibly to hemoglobin to oxygen binds reversibly to hemoglobin to form oxyhemoglobin (HbOform oxyhemoglobin (HbO22) in a reversible ) in a reversible

reactionreaction

the attaching of oxygen to hemoglobin is the attaching of oxygen to hemoglobin is

affected by the followingaffected by the following– concentration of oxygenconcentration of oxygen – – oxygen, oxygen, binding, binding,

oxygen, oxygen, binding (allows oxygen to be released binding (allows oxygen to be released and diffuse into tissues over the entire capillary and diffuse into tissues over the entire capillary length – gradually)length – gradually)

– pH pH - - pH, pH, binding ( binding ( pH means pH means CO CO22))

– temperaturetemperature - - temp, temp, binding binding– these conditions favour the release of oxygen in these conditions favour the release of oxygen in

tissues that are metabolically active (undergoing tissues that are metabolically active (undergoing lots of cellular respiration)lots of cellular respiration)

Carbon DioxideCarbon Dioxide

is transported three ways in the bloodis transported three ways in the blood– 7% dissolved in the blood plasma7% dissolved in the blood plasma– 23% carried on the hemoglobin molecule as 23% carried on the hemoglobin molecule as

carbaminohemoglobin (HbCOcarbaminohemoglobin (HbCO22))

– 70% is carried as carbonic acid/carbonate ion 70% is carried as carbonic acid/carbonate ion equilibriumequilibrium

– EquationEquation

COCO22(g) + H(g) + H22O(l) O(l) → → HH22COCO33(aq) (aq) → → HCOHCO33-(aq) + H+(aq)-(aq) + H+(aq)

with the aid of the enzyme carbonic anydrase, with the aid of the enzyme carbonic anydrase, the reaction between carbon dioxide and water the reaction between carbon dioxide and water is enhanced, which removes the carbon dioxide is enhanced, which removes the carbon dioxide from the plasma, maintaining the concentration from the plasma, maintaining the concentration gradient from the tissues to the plasma, gradient from the tissues to the plasma, ensuring diffusionensuring diffusion

the HCOthe HCO33-(aq)/ H-(aq)/ H22COCO33(aq) behaves as a blood (aq) behaves as a blood buffer to help maintain the appropriate pH for buffer to help maintain the appropriate pH for enzyme activityenzyme activity

Controlling Breathing RateControlling Breathing Rate

to deliver the optimal quantity of oxygen to the tissues, to deliver the optimal quantity of oxygen to the tissues, the body will the body will HR and alter BP (via baroreceptors HR and alter BP (via baroreceptors and chemosensors) but unless the breathing rate is and chemosensors) but unless the breathing rate is matched, oxygen transport will not be effectivematched, oxygen transport will not be effectivethe nervous system will match rate and magnitude of the nervous system will match rate and magnitude of breathing to the heart rate and blood pressurebreathing to the heart rate and blood pressure– the medulla oblongata will control breathing ratethe medulla oblongata will control breathing rate– the pons smoothes out the rhythm of the respirationthe pons smoothes out the rhythm of the respiration– chemoreceptors monitor pH (chemoreceptors monitor pH ( CO CO22(g) (g) pH) pH)– receptors in the aorta and carotid arteries monitor receptors in the aorta and carotid arteries monitor

OO22(g) in arterial blood(g) in arterial blood

7.3 Respiratory Health7.3 Respiratory Health

In this section, you will:In this section, you will:

identify identify specific diseases that are associated with specific diseases that are associated with the respiratory systemthe respiratory system

identify identify technologies that may be used to treat technologies that may be used to treat these respiratory diseasesthese respiratory diseases

summarize summarize the physiological effects of smoking the physiological effects of smoking and the limitation of technologies to address these and the limitation of technologies to address these effectseffects

Upper Respiratory Tract InfectionsUpper Respiratory Tract InfectionsTonsillitis Tonsillitis is an infection of the tonsils, which are located in the is an infection of the tonsils, which are located in the pharynx. A viral infection, rather than a bacterial infection, is the pharynx. A viral infection, rather than a bacterial infection, is the more common cause of tonsillitis. The tonsils can be removed more common cause of tonsillitis. The tonsils can be removed surgically if the infections are frequent and breathing is surgically if the infections are frequent and breathing is impaired. In the past, many children had their tonsils removed impaired. In the past, many children had their tonsils removed as a precaution, but this surgery is no longer as common. The as a precaution, but this surgery is no longer as common. The tonsils help to prevent bacteria and other foreign pathogens tonsils help to prevent bacteria and other foreign pathogens from entering the body, so removing them can increase the from entering the body, so removing them can increase the number of infections later in life.number of infections later in life.Laryngitis Laryngitis is an inflammation of the larynx. Recall that the is an inflammation of the larynx. Recall that the larynx contains the vocal cords. The most common cause of larynx contains the vocal cords. The most common cause of laryngitis is a viral infection; allergies and overstraining of the laryngitis is a viral infection; allergies and overstraining of the voice can also lead to laryngitis. When the larynx is inflamed, voice can also lead to laryngitis. When the larynx is inflamed, the vocal cords are not able to vibrate as they normally do. This the vocal cords are not able to vibrate as they normally do. This reduces the ability to speak in a normal voice or even to speak reduces the ability to speak in a normal voice or even to speak at all. Symptoms of laryngitis include a sore throat and at all. Symptoms of laryngitis include a sore throat and hoarseness.hoarseness.

Lower Respiratory Tract InfectionsLower Respiratory Tract InfectionsBronchitis is a disorder that causes the bronchi to become inflamed and filled Bronchitis is a disorder that causes the bronchi to become inflamed and filled with mucus, which is expelled by coughing.with mucus, which is expelled by coughing.

Pneumonia is a disease that occurs when the alveoli in the lungs become Pneumonia is a disease that occurs when the alveoli in the lungs become inflamed and fill with liquids. This interferes with gas exchange, and the body inflamed and fill with liquids. This interferes with gas exchange, and the body becomes starved for oxygen.becomes starved for oxygen.

Pleurisy is a lung disorder that is caused by the swelling and irritation of the Pleurisy is a lung disorder that is caused by the swelling and irritation of the pleura, the membranes that surround the lungs.pleura, the membranes that surround the lungs.

Emphysema is an obstructive respiratory disorder in which the walls of the Emphysema is an obstructive respiratory disorder in which the walls of the alveoli break down and lose their elasticity. This reduces the surface area for alveoli break down and lose their elasticity. This reduces the surface area for gas exchange and causes oxygen shortages in the tissues.gas exchange and causes oxygen shortages in the tissues.

Cystic fibrosis is a serious genetic condition that affects the lungs. Cystic Cystic fibrosis is a serious genetic condition that affects the lungs. Cystic fibrosis is caused by an abnormal gene that disrupts the function of the cells fibrosis is caused by an abnormal gene that disrupts the function of the cells lining the passageways of the lungs.lining the passageways of the lungs.

Asthma is a chronic obstructive lung disease that affects the bronchi and Asthma is a chronic obstructive lung disease that affects the bronchi and bronchioles, making breathing difficult or impossible because of reduced air bronchioles, making breathing difficult or impossible because of reduced air flow.flow.

Lung cancer is the uncontrolled and invasive growth of abnormal cells in the Lung cancer is the uncontrolled and invasive growth of abnormal cells in the lungs. It is the leading cause of cancer deaths for men and women in Canada.lungs. It is the leading cause of cancer deaths for men and women in Canada.

Lower Respiratory Tract Lower Respiratory Tract DisordersDisorders

Normal Lungs vs. Diseased LungsNormal Lungs vs. Diseased Lungs

(A) These normal lungs have healthy red tissue. (The heart (A) These normal lungs have healthy red tissue. (The heart is visible near the lower centre.) (B) These diseased lungs is visible near the lower centre.) (B) These diseased lungs have black tissue caused by heavy smoking. The white have black tissue caused by heavy smoking. The white areas are tumours, or carcinomas.areas are tumours, or carcinomas.

Carcinoma of the LungCarcinoma of the Lung

The large ball of cells in the centre of the image is a The large ball of cells in the centre of the image is a carcinoma that has developed from the interior carcinoma that has developed from the interior surface cells of the human lung. The carcinoma surface cells of the human lung. The carcinoma continues to grow and invade surrounding tissues, continues to grow and invade surrounding tissues, including the lymphatic and blood vessels in the including the lymphatic and blood vessels in the lung. The lymphatic and blood vessels circulate lung. The lymphatic and blood vessels circulate through the body and carry the cancerous cells, or through the body and carry the cancerous cells, or metastatic cells, to new locations where they can metastatic cells, to new locations where they can grow and invade new tissues.grow and invade new tissues.

Chapter 7 ReviewChapter 7 ReviewCreate a flowchart or diagram showing the Create a flowchart or diagram showing the path of oxygen through the respiratory path of oxygen through the respiratory system.system.

Explain how each of the major respiratory Explain how each of the major respiratory structures function.structures function.

What is cellular respiration?What is cellular respiration?

Compare and contrast a normal lung with Compare and contrast a normal lung with smoker’s lung.smoker’s lung.

Identify three respiratory diseases. Briefly Identify three respiratory diseases. Briefly describe their symptoms and how they are describe their symptoms and how they are diagnosed.diagnosed.

Concept OrganizerConcept Organizer

Chapter 7 SummaryChapter 7 Summary

Respiration enables the body to take oxygen from Respiration enables the body to take oxygen from the external environment and process it for the external environment and process it for delivery to the cells and, at the same time, rid itself delivery to the cells and, at the same time, rid itself of carbon dioxide.of carbon dioxide.

Chapter 7 SummaryChapter 7 SummaryOxygen is delivered to the cells and carbon dioxide is Oxygen is delivered to the cells and carbon dioxide is removed from the cells and the body in a number of removed from the cells and the body in a number of exchanges. exchanges. Inspiration (breathing in, inhaling) and expiration Inspiration (breathing in, inhaling) and expiration (breathing out, exhaling) exchange air between the (breathing out, exhaling) exchange air between the environment and the lungs. environment and the lungs. External respiration exchanges oxygen and carbon External respiration exchanges oxygen and carbon dioxide between the air in the lungs and the blood. dioxide between the air in the lungs and the blood. Internal respiration exchanges oxygen and carbon Internal respiration exchanges oxygen and carbon dioxide between the blood and the body’s tissue cells. dioxide between the blood and the body’s tissue cells. Cellular respiration is the final step, when the oxygen Cellular respiration is the final step, when the oxygen delivered to the cells is used to provide the energy for delivered to the cells is used to provide the energy for all cellular activities; carbon dioxide is the waste all cellular activities; carbon dioxide is the waste product of cellular respiration. product of cellular respiration.

Chapter 7 SummaryChapter 7 SummaryThe respiratory tract is the passageway for air to move The respiratory tract is the passageway for air to move from the external environment into the lungs. from the external environment into the lungs. The upper respiratory tract begins at the nostrils and The upper respiratory tract begins at the nostrils and includes the nasal passages, pharynx, larynx, and includes the nasal passages, pharynx, larynx, and trachea. trachea. These passageways all clean and warm the air as it These passageways all clean and warm the air as it passes through. passes through. The lower respiratory tract consists of two bronchi that The lower respiratory tract consists of two bronchi that each lead to a lung. each lead to a lung. Within the lungs are small, fine tubes called Within the lungs are small, fine tubes called bronchioles, where the air continues to be cleaned bronchioles, where the air continues to be cleaned and warmed. and warmed. The exchange of gases takes place in a cluster of tiny The exchange of gases takes place in a cluster of tiny sacs at the end of each bronchiole, called alveoli, sacs at the end of each bronchiole, called alveoli, where the oxygen diffuses through the membranes of where the oxygen diffuses through the membranes of the alveoli into the capillaries of the circulatory system.the alveoli into the capillaries of the circulatory system.

Chapter 7 SummaryChapter 7 Summary

A number of disorders of the respiratory A number of disorders of the respiratory tract can impair the delivery of oxygen to tract can impair the delivery of oxygen to the cells, including bronchitis, pneumonia, the cells, including bronchitis, pneumonia, pleurisy, emphysema, cystic fibrosis, pleurisy, emphysema, cystic fibrosis, asthma, and lung cancer. asthma, and lung cancer.

These are all disorders of the lower These are all disorders of the lower respiratory tract. respiratory tract.

Infections of the upper respiratory tract, Infections of the upper respiratory tract, such as tonsillitis and laryngitis are short such as tonsillitis and laryngitis are short term infections that do not obstruct term infections that do not obstruct breathing.breathing.