Chapter 18Chapter 18

Respiratory SystemRespiratory System

Functions of the Respiratory Functions of the Respiratory SystemSystem• 1. Provides for gas exchange-intake of 1. 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 of 3. Contains receptors for sense of

smell, filters warms and moistens smell, filters warms and moistens inspired air, produces sounds and inspired air, produces sounds and excretes water and heat.excretes water and heat.

Name the organs of the respiratory Name the organs of the respiratory systemsystem

• LungLung• AlveoliAlveoli• BronchioleBronchiole• BronchiBronchi• TracheaTrachea• PharynxPharynx• LarynxLarynx• NoseNose• MouthMouth• epiglottisepiglottis

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 during Larynx-voicebox- epiglottis covers during

swallowing to keep food out, vocal chordsswallowing to keep food out, vocal chords

Respiratory OrgansRespiratory Organs• Trachea- windpipe, lined with mucous Trachea- windpipe, lined with mucous

membranes, supported by cartilage, membranes, supported by cartilage, pseudostratified columnar epithethium, basal pseudostratified columnar epithethium, basal and goblet cells, divides into right and left and goblet cells, divides into right and left bronchi.bronchi.

• Bronchi and bronchioles- primary bronchi-Bronchi and bronchioles- primary bronchi-secondary bronchisecondary bronchitertiary tertiary bronchibronchibronchiolesbronchiolesterminal bronchiolesterminal bronchioles

Respiratory OrgansRespiratory Organs• Lungs- pleural membrane encloses and Lungs- pleural membrane encloses and

protects each lung, parietal membrane protects each lung, parietal membrane attaches lungs to diaphragm, inner layer attaches lungs to diaphragm, inner layer visceral pleura, pleural cavity contains a visceral pleura, pleural cavity contains a lubricating fluid, contains alveoli lubricating fluid, contains alveoli

InhalationInhalation

• At rest (no breathing): pressure inside At 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

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 than Pressure inside lungs greater than

outsideoutside– Air rushes out and lungs deflateAir rushes out and lungs deflate

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

VocabularyVocabulary

• InhalationInhalation• ExhalationExhalation• diaphragmdiaphragm

Gas ExchangeGas Exchange

• AlveoliAlveoli– Surfactant is fluid that lubricates and prevents Surfactant is fluid that lubricates and prevents

collapse of sacscollapse of sacs– OO22 and CO and CO22 exchange between alveolar walls exchange between alveolar walls

and capillary walls by diffusionand capillary walls by diffusion

External respirationExternal respiration– Diffusion of ODiffusion of O22 from air in alveoli to pulmonary from air in alveoli to pulmonary

capillaries and COcapillaries and CO22 from capillaries to alveoli from capillaries to alveoli

– PPO2O2 in alveoli < air, P in alveoli < air, PCO2CO2 in alveoli > air in alveoli > air– Travels to heart then to bodyTravels to heart then to body

Internal respirationInternal respiration

– Diffusion of ODiffusion of O22 from capillaries in to tissue from capillaries in to tissue cells and COcells and CO22 from tissue cells to capillaries from tissue cells to capillaries

– PPO2O2 in cells < capillaries, P in cells < capillaries, PCO2CO2 in cells > in cells > capillariescapillaries

– Travels back to heartTravels back to heart

Factors affecting amount of Factors affecting amount of oxygen released by hemoglobinoxygen released by hemoglobin• PPO2O2

– LowLow• COCO22

– Higher COHigher CO2 2

• AcidityAcidity– Lower pHLower pH

• TemperatureTemperature– Greater temperatureGreater temperature

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 PCO2 CO2 promotes bindingpromotes binding

• Bicarbonate ionsBicarbonate ions– COCO22 + H + H22O O H H22COCO3 3 H H++ + HCO + HCO33

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VocabularyVocabulary

• Gas exchangeGas exchange• AlveoliAlveoli• Internal respirationInternal respiration• External respirationExternal respiration

• 7 total vocabulary words7 total vocabulary words