Explain the microscopic Explain the microscopic and gross anatomy of the and gross anatomy of the

respiratory system.respiratory system.

Identify the pleural Identify the pleural cavities, its membranes cavities, its membranes

and the muscles of and the muscles of ventilation.ventilation.

Ch. 21: The Respiratory Ch. 21: The Respiratory SystemSystem

RespiratoryRespiratory system tasks system tasks

1° Functions:1° Functions: Gas TransportGas Transport Gas ExchangeGas Exchange

OO22 and CO and CO2 2 via diffusionvia diffusion

Acid-Base BalanceAcid-Base BalanceCOCO22 + H + H22O ⇌ HO ⇌ H22COCO3 3 ⇌ H⇌ H++ + HCO + HCO33

--

2 ° Functions:2 ° Functions: Moistening and warming/coolingMoistening and warming/cooling Particulate/pathogen removalParticulate/pathogen removal

Understand this formula!

Respiratory System starts at Respiratory System starts at

the naresthe nares

Major FunctionsMajor Functions

Upper respiratory system:Upper respiratory system:1.1. Air conditioning (warming)Air conditioning (warming)2.2. Defense against pathogensDefense against pathogens3.3. Gas TransportGas Transport

Lower respiratory system:Lower respiratory system:1.1. Speech & other respiratory soundsSpeech & other respiratory sounds 2.2. Gas exchange (ventilation)Gas exchange (ventilation)3.3. Maintenance of homeostasis, e.g. pHMaintenance of homeostasis, e.g. pH

Respiratory EpitheliumRespiratory Epithelium

Histology? Histology? Pseudo…Pseudo…

Mucus produced Mucus produced by numerous by numerous goblet cellsgoblet cells

Defense by means of Defense by means of •filtering hairsfiltering hairs•turbinatesturbinates•ciliary escalator ciliary escalator (mucociliary blanket)(mucociliary blanket)•sticky mucussticky mucus

Upper Respiratory Upper Respiratory SystemSystem

1.1. NoseNose

2.2. Nasal CavityNasal Cavity

3.3. Paranasal sinusesParanasal sinuses

4.4. PharynxPharynx

Upper Respiratory Upper Respiratory SystemSystem

1)1) NoseNose external and internal external and internal

nares = Nostrilsnares = Nostrils Nose Hairs = vibrissaeNose Hairs = vibrissae Alar cartilages on the Alar cartilages on the

nosenose Paranasal SinusesParanasal Sinuses

Fig 7.11 p 165Fig 7.11 p 165

Upper Respiratory Upper Respiratory SystemSystem

• 2. Nasal Cavity2. Nasal Cavity

• Nasal Conchae:Nasal Conchae:

Superior, middle and inferiorSuperior, middle and inferior

Other name: “Turbinate bones” Other name: “Turbinate bones” because they create ______because they create ______

Advantage ?Advantage ?

• nasal septumnasal septum• hard palate, soft palatehard palate, soft palate

Upper Respiratory Upper Respiratory SystemSystem

3. Paranasal Sinuses3. Paranasal Sinuses

Named after their bonesNamed after their bones FrontalFrontal EthmoidEthmoid SphenoidSphenoid MaxillaryMaxillary

Fig. 7.11, p 165

Upper Respiratory Upper Respiratory SystemSystem

4)4) PharynxPharynx

SShared passageway for respiratory and hared passageway for respiratory and digestive systemsdigestive systems nasopharynxnasopharynx - part above uvula and - part above uvula and

posterior to internal naresposterior to internal nares oropharynx oropharynx – portion visible in mirror – portion visible in mirror

when mouth is wide openwhen mouth is wide openfauces = the openingfauces = the openinguvula - posterior edge of soft palateuvula - posterior edge of soft palate

laryngopharynxlaryngopharynx – between the hyoid – between the hyoid bone & the esophagusbone & the esophagus

Laryngopharynx

Oropharynx

Nasopharynx

Larynx:Larynx: Cartilaginous Cartilaginous cylinder (from Ccylinder (from C44- C- C77)  ) 

Made up of 9 cartilagesMade up of 9 cartilages– – 3 large unpaired (know these!) Thyroid, Cricoid, 3 large unpaired (know these!) Thyroid, Cricoid,

and Epiglottisand Epiglottis– – 3 small paired (involved in construction of voice box)3 small paired (involved in construction of voice box)

C3

C4C5

C6C7

Lower Respiratory Lower Respiratory System System = = Anything Anything inferior to the Pharynxinferior to the Pharynx

Larynx Larynx (AKA voice box)(AKA voice box)

Hyoid BoneHyoid BoneEpiglottisEpiglottisThyroid CartilageThyroid Cartilage Adam’s AppleAdam’s Apple

Cricoid CartilageCricoid CartilageVocal FoldsVocal Folds

Hyoid BoneHyoid BoneEpiglottisEpiglottisThyroid CartilageThyroid Cartilage Adam’s AppleAdam’s Apple

Cricoid CartilageCricoid CartilageVocal FoldsVocal Folds

Larynx, cont’dLarynx, cont’d

The pitch of sound is from tension of the elastic fibers of The pitch of sound is from tension of the elastic fibers of the vocal foldsthe vocal folds

Resonance from shape of pharynx and mouthResonance from shape of pharynx and mouth

The glottis is the opening between the vocal foldsThe glottis is the opening between the vocal foldsInnervation via laryngeal nervesInnervation via laryngeal nerves

Branches of CN XBranches of CN X Left recurrent laryngeal nerve loops around aortaLeft recurrent laryngeal nerve loops around aorta

Trachea Trachea (AKA windpipe)(AKA windpipe)

Passageway to lungsPassageway to lungs

Epithelial Lining ?Epithelial Lining ?

16 -20 incomplete hyaline cartilage 16 -20 incomplete hyaline cartilage rings (C-shaped) - completed by rings (C-shaped) - completed by trachealis muscle.trachealis muscle.

CarinaCarina is the site of branching to left is the site of branching to left and right primary bronchi AKA and right primary bronchi AKA tracheal bifurcationtracheal bifurcation

TrachealTracheal BlockageBlockage

oorr

Heimlich Maneuver Heimlich Maneuver or abdominal thrustor abdominal thrust

TracheostomyTracheostomy

From Bronchi to Lungs: The From Bronchi to Lungs: The Bronchial TreeBronchial Tree

11 bronchi ( bronchi (enter lungs at hilus, complete cartilage rings)enter lungs at hilus, complete cartilage rings)

22 bronchi bronchi (from now on cartilage plates)(from now on cartilage plates)

33 bronchi bronchi

BronchiolesBronchioles

Terminal bronchiolesTerminal bronchioles

Respiratory bronchiolesRespiratory bronchioles

Alveolar ductsAlveolar ducts

Alveolar sacsAlveolar sacs

Conducting portion

Respiratory portion

Fig 24.11

Note: Sympathetic stimulation (epinephrine) causes bronchodilation

Alveolar Organization Alveolar Organization p 624p 624

Alveoli are site of gas exchange Alveoli are site of gas exchange

Close association with capillariesClose association with capillaries

Lots of elastic fibers in alveolar wallLots of elastic fibers in alveolar wall

Alveoli, cont’dAlveoli, cont’d

Alveolar cells Alveolar cells 1.1. Type I cells – Type I cells – respiratory epitheliocytesrespiratory epitheliocytes2.2. Type II cells Type II cells – septal cells – produce surfactant, – septal cells – produce surfactant,

which prevents collapse of alveoliwhich prevents collapse of alveoli3.3. Alveolar Macrophages – Alveolar Macrophages – dust cells – phagocyticdust cells – phagocytic

SEM of alveoliSEM of alveoli

Respiratory MembraneRespiratory Membrane

Different from respiratory Different from respiratory epitheliumepithelium

Super thin. Made up of 4 Super thin. Made up of 4 layers:layers:

1.1. endothelium of capillaryendothelium of capillary2.2. basement membrane of basement membrane of

capillary endotheliumcapillary endothelium3.3. basement membrane of basement membrane of

epithelium of alveolusepithelium of alveolus

4.4. epithelium of alveolusepithelium of alveolus

Chronic progressive enlargement of alveoli accompanied by destruction of their wall and decrease in surface area for exchange

Due to prolonged exposure to respiratory irritants (??)

Emphysema

LungsLungs

Situated in Pleural (thoracic, chest) Situated in Pleural (thoracic, chest) CavityCavity

Subdivided into lobes (each supplied bySubdivided into lobes (each supplied by 22 bronchus) bronchus)

Right lung: 3 lobes (rel. broad and short)Right lung: 3 lobes (rel. broad and short)

Left lung: 2 lobes (long and narrow)Left lung: 2 lobes (long and narrow)

Right and left lung separated by the Right and left lung separated by the mediastinummediastinum

Lung hilusLung hilus

Left

Pleural Cavities and MembranesPleural Cavities and Membranes

Two cavities separated by Two cavities separated by mediastinummediastinum

Lining of cavitiesLining of cavities

Parietal PleuraParietal Pleura

Visceral PleuraVisceral Pleura

Pleural CavityPleural Cavity

pleurisy

Pneumothorax, (hemothorax, Pneumothorax, (hemothorax, pyothorax, pleural effusion)pyothorax, pleural effusion)

Pleural Membranes, Pleural Membranes, cont’dcont’d

Fig 21.13

PneumothoraxPneumothorax

Respiratory MusclesRespiratory Muscles

Diaphragm: Diaphragm: depresses on contraction depresses on contraction inhalation inhalation

External intercostals: External intercostals: elevate ribs elevate ribs inhalation inhalation

Internal intercostals: Internal intercostals: depress ribs depress ribs active exhalation active exhalation

(Accessory muscles - serratus anterior, scalenes, pectoralis minor, (Accessory muscles - serratus anterior, scalenes, pectoralis minor, sternocleidomastoid, internal and external obliques, transverse sternocleidomastoid, internal and external obliques, transverse abdominus, rectus abdominus)abdominus, rectus abdominus)

Pulmonary EmbolismPulmonary Embolism

Causes for development of emboli in veins of legs:

Immobilization

Trauma

Long surgeries

Oral contraceptives

Obesity

Cigarette smoking

Hypertension