The respiratory system provides gas exchange by taking in oxygen and removing carbon dioxide. It contains the nose, mouth, pharynx, larynx, trachea, bronchi, bronchioles and lungs. The lungs contain alveoli where gas exchange occurs through diffusion between the alveolar air and capillary blood. Inhalation is driven by contraction of the diaphragm which increases the thoracic cavity volume, lowering pressure and drawing air in. Exhalation is passive as the diaphragm and chest wall relax, reducing volume and raising pressure to push air out.

1. Chapter 18Chapter 18
Respiratory SystemRespiratory System

2. Functions of the RespiratoryFunctions of the Respiratory
SystemSystem
• 1. Provides for gas exchange-intake of1. Provides for gas exchange-intake of
oxygen for delivery to body cells-oxygen for delivery to body cells-
removal of carbon dioxideremoval of carbon dioxide
• 2. Helps regulate blood pH.2. Helps regulate blood pH.
• 3. Contains receptors for sense of3. Contains receptors for sense of
smell, filters warms and moistenssmell, filters warms and moistens
inspired air, produces sounds andinspired air, produces sounds and
excretes water and heat.excretes water and heat.

3. Name the organs of the respiratoryName the organs of the respiratory
systemsystem
• LungLung
• AlveoliAlveoli
• BronchioleBronchiole
• BronchiBronchi
• TracheaTrachea
• PharynxPharynx
• LarynxLarynx
• NoseNose
• MouthMouth
• epiglottisepiglottis

4. Respiratory OrgansRespiratory Organs
• Nose-internal and external-cartilage,Nose-internal and external-cartilage,
contains hairs, mucous membranescontains hairs, mucous membranes
• Pharynx- throat, passage of air and food,Pharynx- throat, passage of air and food,
houses tonsilshouses tonsils
• Larynx-voicebox- epiglottis covers duringLarynx-voicebox- epiglottis covers during
swallowing to keep food out, vocal chordsswallowing to keep food out, vocal chords

5. Respiratory OrgansRespiratory Organs
• Trachea- windpipe, lined with mucousTrachea- windpipe, lined with mucous
membranes, supported by cartilage,membranes, supported by cartilage,
pseudostratified columnar epithethium, basalpseudostratified columnar epithethium, basal
and goblet cells, divides into right and leftand goblet cells, divides into right and left
bronchi.bronchi.
• Bronchi and bronchioles- primary bronchi-Bronchi and bronchioles- primary bronchi-
secondary bronchisecondary bronchitertiarytertiary
bronchibronchibronchiolesbronchiolesterminal bronchiolesterminal bronchioles

6. Respiratory OrgansRespiratory Organs
• Lungs- pleural membrane encloses andLungs- pleural membrane encloses and
protects each lung, parietal membraneprotects each lung, parietal membrane
attaches lungs to diaphragm, inner layerattaches lungs to diaphragm, inner layer
visceral pleura, pleural cavity contains avisceral pleura, pleural cavity contains a
lubricating fluid, contains alveolilubricating fluid, contains alveoli

9. InhalationInhalation
• At rest (no breathing): pressure insideAt rest (no breathing): pressure inside
lungs and out equallungs and out equal
• Inhalation:Inhalation:
– Diaphragm contracts and dropsDiaphragm contracts and drops
– Volume of thoracic cavity increasesVolume of thoracic cavity increases
– Pressure inside lungs less than outsidePressure inside lungs less than outside
– Air rushes in and lungs expand/inflateAir rushes in and lungs expand/inflate

10. ExhalationExhalation
• Exhalation:Exhalation:
– Diaphragm relaxes and moves upDiaphragm relaxes and moves up
– Volume of thoracic cavity decreasesVolume of thoracic cavity decreases
– Pressure inside lungs greater thanPressure inside lungs greater than
outsideoutside
– Air rushes out and lungs deflateAir rushes out and lungs deflate

12. • What affect on breathing would occur ifWhat affect on breathing would occur if
there was a hole in the thoracic cavity?there was a hole in the thoracic cavity?

13. VocabularyVocabulary
• InhalationInhalation
• ExhalationExhalation
• diaphragmdiaphragm

15. Gas ExchangeGas Exchange
• AlveoliAlveoli
– Surfactant is fluid that lubricates and preventsSurfactant is fluid that lubricates and prevents
collapse of sacscollapse of sacs
– OO22 and COand CO22 exchange between alveolar wallsexchange between alveolar walls
and capillary walls by diffusionand capillary walls by diffusion

16. External respirationExternal respiration
– Diffusion of ODiffusion of O22 from air in alveoli to pulmonaryfrom air in alveoli to pulmonary
capillaries and COcapillaries and CO22 from capillaries to alveolifrom capillaries to alveoli
– PPO2O2 in alveoli < air, Pin alveoli < air, PCO2CO2 in alveoli > airin alveoli > air
– Travels to heart then to bodyTravels to heart then to body

17. Internal respirationInternal respiration
– Diffusion of ODiffusion of O22 from capillaries in to tissuefrom capillaries in to tissue
cells and COcells and CO22 from tissue cells to capillariesfrom tissue cells to capillaries
– PPO2O2 in cells < capillaries, Pin cells < capillaries, PCO2CO2 in cells >in cells >
capillariescapillaries
– Travels back to heartTravels back to heart

19. Factors affecting amount ofFactors affecting amount of
oxygen released by hemoglobinoxygen released by hemoglobin
• PPO2O2
– LowLow
• COCO22
– Higher COHigher CO22
• AcidityAcidity
– Lower pHLower pH
• TemperatureTemperature
– Greater temperatureGreater temperature

21. Transport of carbon dioxideTransport of carbon dioxide
• Dissolved in plasmaDissolved in plasma
– Least amountLeast amount
• Bound to amino acidsBound to amino acids
– Binds to amino groups of protein hemoglobinBinds to amino groups of protein hemoglobin
– High PHigh PCO2CO2 promotes bindingpromotes binding
• Bicarbonate ionsBicarbonate ions
– COCO22 + H+ H22OO  HH22COCO33  HH++
+ HCO+ HCO33
--

22. VocabularyVocabulary
• Gas exchangeGas exchange
• AlveoliAlveoli
• Internal respirationInternal respiration
• External respirationExternal respiration
• 7 total vocabulary words7 total vocabulary words