Chapter 7Chapter 7

The Respiratory SystemThe Respiratory System

Goals for this Chapter:Goals for this Chapter:

1.1. Explain how the upper respiratory tract Explain how the upper respiratory tract filters, moistens, and directs air.filters, moistens, and directs air.

2.2. Describe the composition, structure, and Describe the composition, structure, and function of the lower respiratory system.function of the lower respiratory system.

3.3. Describe how the mechanical action of Describe how the mechanical action of breathing moves gases into and out of breathing moves gases into and out of the lungs.the lungs.

4.4. Explain how gases are exchanged Explain how gases are exchanged between the respiratory system and the between the respiratory system and the environment.environment.

5.5. Identify factors that affect the rate Identify factors that affect the rate of respiration.of respiration.

6.6. Identify diseases that are Identify diseases that are associated with the respiratory associated with the respiratory system.system.

7.7. Identify technologies used to Identify technologies used to identify and treat diseases and identify and treat diseases and disorders of the respiratory system.disorders of the respiratory system.

7.1 – Structures of the 7.1 – Structures of the Respiratory SystemRespiratory System• Respiration actually involves a 4-stage Respiration actually involves a 4-stage

process:process:1.1. Breathing – the movement of air into & out Breathing – the movement of air into & out

of the lungsof the lungs2.2. External respiration – the exchange of External respiration – the exchange of

oxygen and carbon dioxide within the lungsoxygen and carbon dioxide within the lungs3.3. Internal respiration – the exchange of Internal respiration – the exchange of

oxygen and carbon dioxide within the oxygen and carbon dioxide within the blood and body tissuesblood and body tissues

4.4. Cellular respiration – the oxidation of Cellular respiration – the oxidation of glucose for energyglucose for energy

Respiratory StructuresRespiratory Structures

Respiratory StructuresRespiratory Structures

• Air enters via the nasal cavities and Air enters via the nasal cavities and mouthmouth

• The nasal cavities contain hairs and The nasal cavities contain hairs and mucus that traps particles and keeps cells mucus that traps particles and keeps cells moistmoist

• At the same time, the large number of At the same time, the large number of blood vessels inside the nose also warm blood vessels inside the nose also warm the incoming airthe incoming air

• The air then travels through the The air then travels through the pharynxpharynx, , which separates the which separates the trachea (windpipe)trachea (windpipe) and the esophagusand the esophagus

• When eating, an When eating, an enlarged flap of enlarged flap of cartilage called the cartilage called the epiglottis covers epiglottis covers the trachea to the trachea to prevent food from prevent food from enteringentering

• Food and drink that Food and drink that enter the trachea enter the trachea stimulates stimulates ciliacilia that that lines the respiratory lines the respiratory tract, producing a tract, producing a coughcough

• Beyond the pharynx is the Beyond the pharynx is the larynxlarynx, , which is composed of thin sheets of which is composed of thin sheets of elastic ligamentselastic ligaments

• When air passes past the larynx, When air passes past the larynx, sounds are produced (these are the sounds are produced (these are the vocal cords)vocal cords)

• During speech, muscles contract and During speech, muscles contract and move these cords closer togethermove these cords closer together

• Males have thicker vocal cords, Males have thicker vocal cords, which results in a deeper voicewhich results in a deeper voice

The LungsThe Lungs• The lungs are surrounded by the pleural The lungs are surrounded by the pleural

membrane, which attaches the lungs to membrane, which attaches the lungs to the thoracic cavitythe thoracic cavity

• The trachea branches into two The trachea branches into two bronchibronchi, , one for each lungone for each lung

• These bronchi then continue to branch into These bronchi then continue to branch into bronchiolesbronchioles

• The bronchioles, unlike the bronchi and The bronchioles, unlike the bronchi and trachea, lack rings of cartilagetrachea, lack rings of cartilage

• Smooth muscle can change the diameter Smooth muscle can change the diameter of the bronchiolesof the bronchioles

AlveoliAlveoli

Gas ExchangeGas Exchange

• The alveoli walls are very thin and The alveoli walls are very thin and are surrounded by capillariesare surrounded by capillaries

• Carbon dioxide and oxygen transfer Carbon dioxide and oxygen transfer between the alveoli and capillaries between the alveoli and capillaries through diffusionthrough diffusion

• You have about 150 million alveoli, You have about 150 million alveoli, whose total combined surface area whose total combined surface area could cover a tennis court!could cover a tennis court!

Section 7.2 – Breathing and Section 7.2 – Breathing and RespirationRespiration

• Recall that breathing and respiration Recall that breathing and respiration are differentare different

• Breathing is the mechanical action Breathing is the mechanical action that brings air into the lungsthat brings air into the lungs

• Respiration is the exchange of gases Respiration is the exchange of gases

Breathing and MusclesBreathing and Muscles

• Pressure differences between the Pressure differences between the chest cavity and the atmosphere chest cavity and the atmosphere move gases into and out of the lungs move gases into and out of the lungs (atmospheric pressure is constant, (atmospheric pressure is constant, but the lung pressure changes)but the lung pressure changes)

• Gases move from high pressure Gases move from high pressure areas to low pressure areasareas to low pressure areas

• When you inspire (breathe in), the When you inspire (breathe in), the pressure inside the lungs is lower than pressure inside the lungs is lower than the outsidethe outside

• When you expire (exhale), the pressure When you expire (exhale), the pressure within the lungs is higher than the within the lungs is higher than the atmospheric pressureatmospheric pressure

• The change in lung pressure is created The change in lung pressure is created by changing the volume of the lungsby changing the volume of the lungs

• The The diaphragmdiaphragm, a band of muscle , a band of muscle beneath the lungs, is responsible for beneath the lungs, is responsible for thisthis

• When you inhale, the diaphragm When you inhale, the diaphragm contracts and flattens, and the lungs contracts and flattens, and the lungs expandexpand

• The atmospheric pressure is now The atmospheric pressure is now higher than the lung pressure, and air higher than the lung pressure, and air moves into the lungsmoves into the lungs

• When you exhale, the diaphragm When you exhale, the diaphragm relaxes and becomes dome-shapedrelaxes and becomes dome-shaped

• As a result, the lung volume is reducedAs a result, the lung volume is reduced• The atmospheric pressure is now lower The atmospheric pressure is now lower

than the lung pressure, and air moves than the lung pressure, and air moves out of the lungsout of the lungs

• The diaphragm is assisted by the The diaphragm is assisted by the movement of the ribsmovement of the ribs

• Between the ribs are bands of Between the ribs are bands of intercostal muscleintercostal muscle

• When you inhale, these muscles pull When you inhale, these muscles pull the ribs upwards and outwards the ribs upwards and outwards (increasing lung volume)(increasing lung volume)

• When you exhale, the muscles pull When you exhale, the muscles pull the ribs inwards and downwards the ribs inwards and downwards (decreasing lung volume)(decreasing lung volume)

The Mechanics of BreathingThe Mechanics of Breathing

Respiratory VolumeRespiratory Volume

• You do not always use your full lung You do not always use your full lung volume while breathingvolume while breathing

• If our bodies need more oxygen, then our If our bodies need more oxygen, then our lungs can accommodate a greater volume lungs can accommodate a greater volume of airof air

• The normal volume of air that is exhaled The normal volume of air that is exhaled and inhaled is known as our and inhaled is known as our tidal volumetidal volume

• The total volume of air that our lungs can The total volume of air that our lungs can contain is known as our contain is known as our vital capacityvital capacity

A Spirograph:A Spirograph:

Gas ExchangeGas Exchange• Gases are exchanged between Gases are exchanged between

the air in the alveoli and the the air in the alveoli and the blood of the capillariesblood of the capillaries

• OO22 will diffuse out of the will diffuse out of the alveoli and into the capillary alveoli and into the capillary while COwhile CO2 2 moves in the moves in the opposite directionopposite direction

• About 30% of the OAbout 30% of the O22 transfer transfer occurs through facilitated occurs through facilitated diffusion to increase the rate diffusion to increase the rate of exchangeof exchange

• Within tissues, COWithin tissues, CO22 and and OO22 are also exchanged are also exchanged

• OO22 leaves the blood and leaves the blood and diffuses into the tissuediffuses into the tissue

• COCO22 diffuses out of the diffuses out of the tissue and into the bloodtissue and into the blood

OO22 and CO and CO22 Transport in the Transport in the BloodBlood• Only 1% of OOnly 1% of O22 in the blood is dissolved in in the blood is dissolved in

blood plasmablood plasma• 99% of the O99% of the O22 is bonded to hemoglobin is bonded to hemoglobin

moleculesmolecules• Hemoglobin allows red blood cells to carry Hemoglobin allows red blood cells to carry

70 times more oxygen than cells without 70 times more oxygen than cells without hemoglobinhemoglobin

• You would only be able to maintain life for You would only be able to maintain life for about 4.5 seconds without hemoglobin about 4.5 seconds without hemoglobin (we can go without oxygen for about 5 (we can go without oxygen for about 5 minutes!)minutes!)

• COCO2 2 can also be transported by can also be transported by hemoglobin, but only about 23% of hemoglobin, but only about 23% of all COall CO22 is carried in this fashion is carried in this fashion

• The blood plasma only carries about The blood plasma only carries about 7% of the CO7% of the CO22

• 70% of the CO70% of the CO22 in your blood is in the in your blood is in the form of the bicarbonate (HCOform of the bicarbonate (HCO33

-- ion) ion)

Carbon Dioxide & Carbon Dioxide & BicarbonateBicarbonate• When COWhen CO22 is added to water, is added to water,

carbonic acid (Hcarbonic acid (H22COCO33) is formed) is formed• This loses an HThis loses an H++ ion, which is picked ion, which is picked

up by hemoglobinup by hemoglobin• The remaining HCOThe remaining HCO33

-- ion remains in ion remains in the blood plasmathe blood plasma

• When the plasma reaches the lungs, When the plasma reaches the lungs, the hemoglobin gives up its Hthe hemoglobin gives up its H++, and , and the sequence reverses – COthe sequence reverses – CO22 is is formed and releasedformed and released

7.3 – Respiratory Health7.3 – Respiratory Health

• Respiratory health problems can be Respiratory health problems can be identified as conditions that affect identified as conditions that affect either the upper respiratory tract, or either the upper respiratory tract, or the lower respiratory tractthe lower respiratory tract

• Many disorders are preventable – Many disorders are preventable – particularly those that are caused by particularly those that are caused by smokingsmoking

Upper Respiratory InfectionsUpper Respiratory Infections

1.1. Tonsillitis: This is caused by bacterial Tonsillitis: This is caused by bacterial or viral infections. Typically, bacterial or viral infections. Typically, bacterial infections are treated with antibiotics.infections are treated with antibiotics.

2.2. Laryngitis: This is an inflammation of Laryngitis: This is an inflammation of the larynx caused by infection, the larynx caused by infection, allergies, or straining of the voice. As allergies, or straining of the voice. As a result, the vocal cords become a result, the vocal cords become inflamed and do not vibrate properly.inflamed and do not vibrate properly.

Lower Respiratory Tract Lower Respiratory Tract DisordersDisorders

1.1. Bronchitis: Bronchitis:

• This is an inflammation of the bronchi. This is an inflammation of the bronchi.

• It can be classified as acute (usually a It can be classified as acute (usually a bacterial infection) or chronic (caused by bacterial infection) or chronic (caused by irritants). irritants).

• During chronic bronchitis, the cilia lining During chronic bronchitis, the cilia lining the bronchi can become damaged. the bronchi can become damaged.

• The most common cause of chronic The most common cause of chronic bronchitis is smoking.bronchitis is smoking.

2.2. PneumoniaPneumonia

• A condition where the alveoli fill with A condition where the alveoli fill with fluidfluid

• Can affect an entire lobe of the lung Can affect an entire lobe of the lung (lobular), or be found in small patches (lobular), or be found in small patches (bronchial)(bronchial)

• Lobular pneumonia is caused by Lobular pneumonia is caused by bacteria and is typically more serious bacteria and is typically more serious than viral pneumoniathan viral pneumonia

• There are vaccines for bacterial There are vaccines for bacterial pneumoniapneumonia

• AIDS patients often die because of a AIDS patients often die because of a rare bacterial form of pneumoniarare bacterial form of pneumonia

3.3. PleurisyPleurisy

• This is a swelling of the pleuraThis is a swelling of the pleura

• May be caused by infection, blood May be caused by infection, blood clots, or cancerclots, or cancer

• A common symptom is a localized A common symptom is a localized sharp, stabbing painsharp, stabbing pain

• Treatment of pleurisy often focuses Treatment of pleurisy often focuses on reducing the swellingon reducing the swelling

4.4. EmphysemaEmphysema

• Emphysema is a loss of elasticity in Emphysema is a loss of elasticity in the alveoli wallthe alveoli wall

• As a result, the surface area for As a result, the surface area for absorption is reducedabsorption is reduced

• Most cases of emphysema are Most cases of emphysema are associated with smokingassociated with smoking

5.5. Cystic FibrosisCystic Fibrosis

• Genetic condition that prevents the Genetic condition that prevents the formation of sodium channels in cell formation of sodium channels in cell wallswalls

• This disrupts the water balance in This disrupts the water balance in the lung cellsthe lung cells

• As a result, the normally runny As a result, the normally runny mucus in the lungs becomes very mucus in the lungs becomes very thick and cannot be expelledthick and cannot be expelled

6.6. AsthmaAsthma• This is a chronic obstructive disease This is a chronic obstructive disease

which reduces the diameter of the which reduces the diameter of the bronchi & bronchiolesbronchi & bronchioles

• Environmental triggers and stress Environmental triggers and stress can often cause asthma attackscan often cause asthma attacks

• Bronchial dilators are used to treat Bronchial dilators are used to treat asthmaasthma

• Most of these drugs are administered Most of these drugs are administered through inhalers which produce a through inhalers which produce a mist or fine powder that contains the mist or fine powder that contains the drugdrug

7.7. Exercise Induced BronchospasmExercise Induced Bronchospasm

• This condition produces symptoms This condition produces symptoms similar to asthma which are only similar to asthma which are only brought on by exercisebrought on by exercise

• In most cases, dry, dusty and cold In most cases, dry, dusty and cold environments trigger this conditionenvironments trigger this condition

• Patients with EIB can use bronchial Patients with EIB can use bronchial dilators before exercise to avoid dilators before exercise to avoid symptomssymptoms

8.8. Lung CancerLung Cancer• This (like all cancers) is an This (like all cancers) is an

uncontrolled, abnormal growth of uncontrolled, abnormal growth of invasive cellsinvasive cells

• The tumors that form reduce the The tumors that form reduce the available volume of the lung for gas available volume of the lung for gas exchangeexchange

• Often carcinogens (chemicals that Often carcinogens (chemicals that cause cancer) trigger the production cause cancer) trigger the production of tumors in the lungsof tumors in the lungs

• Carcinogens are found in cigarette Carcinogens are found in cigarette smoke, but also include asbestos and smoke, but also include asbestos and radonradon

Technologies for Detection and Technologies for Detection and Treatment of Lung DisordersTreatment of Lung Disorders

• Diagnosis of disorders such as Diagnosis of disorders such as cancer, and some other infections cancer, and some other infections (such as inhalational anthrax and (such as inhalational anthrax and tuberculosis) are typically done using tuberculosis) are typically done using X-rays and CT scansX-rays and CT scans

• Lung CancerLung Cancer

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http://www.lakeridgehealth.on.ca

•Tuberculosis

• DNA analysis can be used to identify DNA analysis can be used to identify if genes for cancer are presentif genes for cancer are present

• Cancers can be treated in several Cancers can be treated in several ways, including radiation therapy and ways, including radiation therapy and chemotherapychemotherapy

• In some cases, liposomes (small, In some cases, liposomes (small, hollow sacks of lipids) are filled with hollow sacks of lipids) are filled with cancer-fighting drugscancer-fighting drugs

• These liposomes follow the spread of These liposomes follow the spread of the cancer cells and attack them the cancer cells and attack them before they start new growth in a before they start new growth in a new area of the bodynew area of the body