The Respiratory SystemThe Respiratory System

Major Function of the Respiratory System: Major Function of the Respiratory System: To supply the body with OTo supply the body with O22 and dispose of CO and dispose of CO22

Processes involved in respirationProcesses involved in respiration VentilationVentilation-movement of air into and out of the lungs-movement of air into and out of the lungs

External respirationExternal respiration-- gas exchange between the gas exchange between the blood (pulmonary capillaries) and the airsacs (alveoli) blood (pulmonary capillaries) and the airsacs (alveoli) in the lungsin the lungs

Transport of respiratory gasesTransport of respiratory gases-- movement of O2 movement of O2 and CO2 between the lungs and the tissues and CO2 between the lungs and the tissues

Internal respirationInternal respiration-- gas exchange between the blood gas exchange between the blood (tissue capillaries) and tissue cells(tissue capillaries) and tissue cells

* * cellular respirationcellular respiration-- utilization of O2 by cells for utilization of O2 by cells for energy (ATP) production via energy (ATP) production via oxidative phosphorylationoxidative phosphorylation

Basic Anatomy of the Respiratory Basic Anatomy of the Respiratory SystemSystem

Figure 22.1

Basic Anatomy of the Respiratory Basic Anatomy of the Respiratory SystemSystem

Upper Respiratory Tract OrgansUpper Respiratory Tract Organs

nasal cavity, pharynx, larynxnasal cavity, pharynx, larynx

Accessory structures: oral cavity, sinusesAccessory structures: oral cavity, sinuses

Lower Respiratory Tract OrgansLower Respiratory Tract Organs

trachea, bronchi, bronchioles, alveolitrachea, bronchi, bronchioles, alveoli

Basic Anatomy of the Respiratory Basic Anatomy of the Respiratory SystemSystem

Figure 22.1

Respiratory MucosaRespiratory Mucosa

mucous membrane lining the respiratory mucous membrane lining the respiratory tract from the nasal cavity (and sinuses) to tract from the nasal cavity (and sinuses) to the bronchiolesthe bronchioles

epithelial layer is comprised epithelial layer is comprised predominantlypredominantly of ciliated, simple columnar epithelial cells, of ciliated, simple columnar epithelial cells, with mucous-secreting goblet cells with mucous-secreting goblet cells interspersedinterspersed No cilia or goblet cells in smallest bronchioles No cilia or goblet cells in smallest bronchioles

or alveolior alveoli

Respiratory MucosaRespiratory Mucosa

Conducting Zone-Conducting Zone- structures from the structures from the nasal cavity up to and including the nasal cavity up to and including the terminal bronchiolesterminal bronchioles

Respiratory Zone-Respiratory Zone- respiratory bronchioles respiratory bronchioles (with attached alveoli) through the alveolar (with attached alveoli) through the alveolar sacssacs

Fig 22.7up to nasal cavity

AlveoliAlveoli

Microscopic sacs where gas (OMicroscopic sacs where gas (O22/Co/Co22) )

exchange occurs; lined with simple exchange occurs; lined with simple squamous epithelium squamous epithelium

(called type I cells or Type I pneumocytes)(called type I cells or Type I pneumocytes)

AlveoliAlveoli

Figure 22.9c (not required)

AlveoliAlveoli, together with the , together with the pulmonary capillary pulmonary capillary endotheliumendothelium→form the →form the respiratory membranerespiratory membrane

AlveoliAlveoli Microscopic sacs where gas (OMicroscopic sacs where gas (O22/Co/Co22) exchange ) exchange

occurs; lined with simple squamous epithelium occurs; lined with simple squamous epithelium (called Type I cells or Type 1 pneumocytes(called Type I cells or Type 1 pneumocytes) )

AlveoliAlveoli, together with the , together with the pulmonary capillary pulmonary capillary endotheliumendothelium→form the →form the respiratory membranerespiratory membrane

(also called the alveolar-capillary membrane). Site (also called the alveolar-capillary membrane). Site of external respiration.of external respiration.

The thinness of the squamous alveolar cells and the The thinness of the squamous alveolar cells and the pulmonary capillary endothelial cells makes the pulmonary capillary endothelial cells makes the respiratory membrane very thin to allow efficient respiratory membrane very thin to allow efficient OO22/CO/CO22 exchange exchange

PleuraePleurae- - serous membranes covering the serous membranes covering the lungs; contain pleural fluidlungs; contain pleural fluid

protect and lubricate the lungsprotect and lubricate the lungs

PleuraePleurae- - serous membranes covering the serous membranes covering the lungs; contain pleural fluidlungs; contain pleural fluid

protect and lubricate the lungsprotect and lubricate the lungs The two pleurae are separate sacs