Pulmonary Anatomy and Pulmonary Anatomy and PhysiologyPhysiology

The Respiratory SystemThe Respiratory System Functions to supply the body with OFunctions to supply the body with O22 and and

remove COremove CO22

There are actually 4 distinct processes:There are actually 4 distinct processes:1.1. VentilationVentilation – Movement of air into & out of the lungs – Movement of air into & out of the lungs

2.2. External RespirationExternal Respiration – Gas exchange between blood – Gas exchange between blood and air-filled chambers of the lungsand air-filled chambers of the lungs

3.3. Transport of GasesTransport of Gases – Accomplished by Cardiovascular – Accomplished by Cardiovascular systemsystem

4.4. Internal RespirationInternal Respiration – Gas exchange between systemic – Gas exchange between systemic blood and the tissue cellsblood and the tissue cells

Functional Functional AnatomyAnatomy

Organs include: nose, Organs include: nose, nasal cavity, pharynx, nasal cavity, pharynx, trachea, bronchi, trachea, bronchi, bronchioles, and the bronchioles, and the alveoli.alveoli.

Divided into Divided into Respiratory Respiratory and and Conducting ZonesConducting Zones. .

Gas exchange with Gas exchange with the blood occurs in the blood occurs in the respiratory zones. the respiratory zones. It does NOT occur in It does NOT occur in the conducting zones.the conducting zones.

The conducting zones The conducting zones transport, cleanse, transport, cleanse, warm and humidify warm and humidify the incoming air.the incoming air.

The Upper AirwayThe Upper Airway

NoseNose Oral CavityOral Cavity PharynxPharynx LarynxLarynx

The NoseThe Nose

Only externally visible part of the Only externally visible part of the respiratory system.respiratory system.

Functions include: Functions include: – Providing an airway for respiration- Providing an airway for respiration- ConductConduct– Moistening and warming air- Moistening and warming air- Warm and Warm and

HumidifyHumidify– Filtering inspired air- Filtering inspired air- ProtectProtect– Serving as a resonating center for speechServing as a resonating center for speech– Housing the olfactory receptors.Housing the olfactory receptors.

Skeletal Framework of Skeletal Framework of External NoseExternal Nose

Fashioned by the:Fashioned by the:– Nasal and frontal Nasal and frontal

bones superiorlybones superiorly– Maxillary bones Maxillary bones

laterallylaterally– Plates of hyaline Plates of hyaline

cartilage (lateral, cartilage (lateral, septal, and alar septal, and alar cartilages) cartilages) inferiorly.inferiorly.

Nasal CavityNasal Cavity Lies in and posterior to the Lies in and posterior to the

external noseexternal nose Divided by a midline Divided by a midline nasal nasal

septumseptum – formed anteriorly – formed anteriorly by septal cartilage and by septal cartilage and posteriorly by the vomer posteriorly by the vomer bone and perpendicular bone and perpendicular plate of the ethmoid bone.plate of the ethmoid bone.

Continuous with the Continuous with the nasopharynx via the nasopharynx via the internal naresinternal nares..

Roof is formed by the Roof is formed by the sphenoid & ethmoid bones.sphenoid & ethmoid bones.

Nasal CavityNasal Cavity Floor is formed Floor is formed

by the palate. by the palate. – Hard palateHard palate

contains contains portions of the portions of the maxillary and maxillary and palatine bones. palatine bones.

– Soft palateSoft palate lacks bone, a lacks bone, a flexible mass of flexible mass of collagen fiberscollagen fibers

Nasal CavityNasal Cavity

Lined by 2 types of Lined by 2 types of epithelium. epithelium. – Slit-like superior Slit-like superior

region is lined by region is lined by olfactory epithelium.olfactory epithelium. What does it do? What does it do?

– The rest is line by The rest is line by respiratory epitheliumrespiratory epithelium (pseudostratified (pseudostratified ciliated columnar with ciliated columnar with goblet cells) goblet cells) It rests on a It rests on a

connective tissue connective tissue layer richly supplied layer richly supplied with mucous and with mucous and serous glands.serous glands.

Nasal CavityNasal Cavity

Produces 1 quart of mucus per day. Produces 1 quart of mucus per day.

Mucus vs SputumMucus vs Sputum

SputumSputum is matter that is coughed up is matter that is coughed up from the respiratory tract, such as from the respiratory tract, such as mucusmucus or or phlegmphlegm, mixed with , mixed with salivasaliva and then expectorated from the mouth.and then expectorated from the mouth.

MucusMucus is a slippery secretion of the is a slippery secretion of the lining of the lining of the mucous membranesmucous membranes in the in the body.. Mucus is produced by body.. Mucus is produced by goblet goblet cellscells in the mucous membranes that in the mucous membranes that cover the surfaces of the membranes. cover the surfaces of the membranes.

MucusMucus

Mucus is produced by goblet cells in Mucus is produced by goblet cells in the mucous membranes that cover the the mucous membranes that cover the surfaces of the membranes. It is made surfaces of the membranes. It is made up of up of mucinsmucins and inorganic salts and inorganic salts suspended in water. Contains suspended in water. Contains LysosomesLysosomes..

Phlegm Phlegm is a type of mucus that is is a type of mucus that is restricted to the respiratory tract, while restricted to the respiratory tract, while the term the term mucusmucus refers to secretions of refers to secretions of the nasal passages as well. the nasal passages as well.

MucusMucus

High HHigh H22O content of mucus humidifies O content of mucus humidifies inward airinward air

Ciliary current moves mucus to Ciliary current moves mucus to pharynx for swallowing. pharynx for swallowing. – Cold temps disable these cilia; runny Cold temps disable these cilia; runny

nosenose Rich plexuses of capillaries and veins Rich plexuses of capillaries and veins

underlie the nasal epithelium and underlie the nasal epithelium and warm incoming airwarm incoming air

Nasal CavityNasal Cavity Protruding medially from Protruding medially from each lateral wall of the each lateral wall of the nasal cavity are 3 scroll-nasal cavity are 3 scroll-like, mucosa-covered like, mucosa-covered projections: the projections: the superior, superior, middle, and inferior middle, and inferior conchae or turbinatesconchae or turbinates

They increase the They increase the mucosal surface area mucosal surface area exposed to airexposed to air

The groove inferior to The groove inferior to each concha is a each concha is a meatusmeatus..

Nasal cavity is Nasal cavity is surrounded by a ring of surrounded by a ring of paranasal sinusesparanasal sinuses located in the frontal, located in the frontal, sphenoid, ethmoid and sphenoid, ethmoid and maxillary bones.maxillary bones.

Anatomy and Physiology Anatomy and Physiology RevealedRevealed

CUT AWAY OF UPPER AIRWAYCUT AWAY OF UPPER AIRWAY

How Does this System How Does this System function..function..

Air first enters the Air first enters the naresnares into a slightly into a slightly dilated area called the dilated area called the vestibulevestibule. The . The vestibule is lined with hairs called vestibule is lined with hairs called vibrissae, vibrissae, a protective mechanism a protective mechanism against foreign particlesagainst foreign particles. . PROTECTPROTECT

The anterior 1/3The anterior 1/3rdrd of the nasal cavity is of the nasal cavity is lined with stratified squamous lined with stratified squamous epithelium, posterior 2/3epithelium, posterior 2/3rdrd lined with lined with pseudostratified ciliated columnar pseudostratified ciliated columnar epitheliumepithelium

How Does this System How Does this System function..function..

Air then travels through the turbinates Air then travels through the turbinates (conchae) where the function is to (conchae) where the function is to separate inspired air into separate separate inspired air into separate streams. streams.

This allows for an increase of surface area. This allows for an increase of surface area. This increased surface area increases the This increased surface area increases the

temperature of the air and adds moisture.temperature of the air and adds moisture.

WARM and HUMIDIFYWARM and HUMIDIFY

Oral CavityOral Cavity

Accessory Respiratory PassageAccessory Respiratory Passage– Lined with stratified squamous epitheliumLined with stratified squamous epithelium– Air enters the vestibule (small outer portion Air enters the vestibule (small outer portion

between gums and lips) and large opening between gums and lips) and large opening that extends to the back of the oropharynxthat extends to the back of the oropharynx

– Roof of the oral cavityRoof of the oral cavity Hard PalateHard Palate Soft PalateSoft Palate UvulaUvula

Oral CavityOral Cavity

Soft palate rises, shutting off the passage Soft palate rises, shutting off the passage between the nasal and oral cavitybetween the nasal and oral cavity– Levator veli palatinum muscle draws up and backLevator veli palatinum muscle draws up and back– Palatopharyngeal muscle draws down and Palatopharyngeal muscle draws down and

forwardforward Palantine ArchesPalantine Arches

– Palatopharyngeal ArchPalatopharyngeal Arch– Palatoglossal ArchPalatoglossal Arch

Contains the tonsils, adenoids and lymph Contains the tonsils, adenoids and lymph tissue; Front line protectiontissue; Front line protection

PharynxPharynx Funnel-shaped.Funnel-shaped. Connects the nasal Connects the nasal

cavity and mouth cavity and mouth superiorly to the superiorly to the larynx and larynx and esophagus esophagus inferiorlyinferiorly

3 regions. From 3 regions. From superior to inferior: superior to inferior: – NasopharynxNasopharynx– Oropharynx Oropharynx – LaryngopharynxLaryngopharynx

NasopharynxNasopharynx

Posterior portion of the Posterior portion of the nasal cavity, superior nasal cavity, superior portion of the soft palate, portion of the soft palate, contains adenoids.contains adenoids.

Only an air passage. Only an air passage. During swallowing, the soft During swallowing, the soft palate and its uvula move palate and its uvula move superiorly and close it off. superiorly and close it off.

Lined by pseudostratified Lined by pseudostratified ciliated columnar ciliated columnar epithelium.epithelium.

High on its posterior wall is High on its posterior wall is the pharyngeal tonsil the pharyngeal tonsil (adenoids) which traps (adenoids) which traps entering pathogens.entering pathogens.

The eustachian tubes open The eustachian tubes open into its lateral walls. They into its lateral walls. They connect the middle ear to connect the middle ear to the nasal cavity; pressure the nasal cavity; pressure release functionrelease function

OropharynxOropharynx Lies posterior to the Lies posterior to the

oral cavity oral cavity Extends from the soft Extends from the soft

palate to the base of palate to the base of the tongue – hyoid the tongue – hyoid bonebone

Lined by stratified Lined by stratified squamous epithelium squamous epithelium

Paired palatine tonsils Paired palatine tonsils lie in the lateral walls lie in the lateral walls while the lingual tonsil while the lingual tonsil covers the base of the covers the base of the tonguetongue

LaryngopharynLaryngopharynxx Also called Also called

“hypopharynx”“hypopharynx” Extends from the base Extends from the base

of the tongue to the of the tongue to the entrance of the entrance of the esophagus.esophagus.

Common passage for Common passage for both food and airboth food and air

Lined by stratified Lined by stratified squamous epitheliumsquamous epithelium

LarynxLarynx

Superiorly attached to the hyoid bone Superiorly attached to the hyoid bone and opens into the laryngopharynx. and opens into the laryngopharynx.

Inferiorly, it’s continuous with the Inferiorly, it’s continuous with the tracheatrachea

Main tasks are:Main tasks are:– Provision of a patent airway for air and food.Provision of a patent airway for air and food.– Routing of air and food to proper pathways. Routing of air and food to proper pathways. – Voice production.Voice production.

LarynxLarynx

Consists of an intricate arrangement of Consists of an intricate arrangement of 9 cartilages connected by membranes 9 cartilages connected by membranes and ligaments. and ligaments.

3 single cartilages3 single cartilages– Epiglottis, Cricoid, and ThyroidEpiglottis, Cricoid, and Thyroid

3 paired cartilages3 paired cartilages– Cuneiform, corniculate and arytenoidCuneiform, corniculate and arytenoid

The large, shield-shaped The large, shield-shaped thyroid thyroid cartilagecartilage is formed by the fusion is formed by the fusion of 2 cartilage plates. of 2 cartilage plates. – The fusion point is the The fusion point is the

laryngeal prominencelaryngeal prominence (adam’s apple). The ridge is (adam’s apple). The ridge is called the thyroid notch called the thyroid notch

Inferior to the thyroid cartilage Inferior to the thyroid cartilage is the is the cricoid cartilagecricoid cartilage. Signet . Signet ring shape with increased size to ring shape with increased size to the posterior. Cricoid the posterior. Cricoid membrane is the site for membrane is the site for emergent airways.emergent airways.– The first “C” shaped tracheal The first “C” shaped tracheal

ring lies below the cricoid ring lies below the cricoid cartilagecartilage

3 pairs of small cartilages, the 3 pairs of small cartilages, the arytenoid, cuneiform, & arytenoid, cuneiform, & corniculate cartilagescorniculate cartilages form part form part of the lateral & posterior walls of of the lateral & posterior walls of the larynxthe larynx

The important The important arytenoidsarytenoids anchor anchor the vocal cordsthe vocal cords

The 9The 9thth cartilage cartilage ((epiglottisepiglottis) is spoon-) is spoon-shaped & composed of shaped & composed of elastic cartilage.elastic cartilage.

Epiglottis is covered Epiglottis is covered almost entirely by a almost entirely by a taste-bud containing taste-bud containing mucosa. mucosa.

During swallowing, the During swallowing, the larynx is pulled superiorly larynx is pulled superiorly and the epiglottis tips to and the epiglottis tips to cover the laryngeal inlet.cover the laryngeal inlet.

If anything other than air If anything other than air enters the larynx – a enters the larynx – a cough/gag reflex is cough/gag reflex is initiated by the sensory initiated by the sensory nerve; glossopharyngeal nerve; glossopharyngeal and the motor nerve; and the motor nerve; vagus. vagus.

SwallowingSwallowing

Epiglottis and ValleculaEpiglottis and Vallecula

The space between the base of the The space between the base of the tongue and the epiglottis is called the tongue and the epiglottis is called the valleculavallecula

This is an important landmark in the This is an important landmark in the airwayairway– While intubating, if using a macintosh blade While intubating, if using a macintosh blade

the tip of the blade slides into the vallecula the tip of the blade slides into the vallecula causing the epiglottis to lift. If using a miller causing the epiglottis to lift. If using a miller blade, the epiglottis is directly lifted up to blade, the epiglottis is directly lifted up to allow access to the airway.allow access to the airway.

Lying under the laryngeal Lying under the laryngeal mucosa on each side are the mucosa on each side are the vocal ligamentsvocal ligaments These ligaments These ligaments (made mostly of elastic fibers) (made mostly of elastic fibers) form the core of mucosal folds form the core of mucosal folds called the called the vocal foldsvocal folds or or true true vocal cordsvocal cords

Vocal cords vibrate, producing Vocal cords vibrate, producing sounds as air rushes up from the sounds as air rushes up from the lungs.lungs.

Superior to the true vocal cords Superior to the true vocal cords is a similar pair of mucosal folds is a similar pair of mucosal folds called the called the vestibular foldsvestibular folds or or false false vocal cordsvocal cords..

The superior portion of the larynx The superior portion of the larynx is lined by stratified squamous is lined by stratified squamous epithelium, while below the vocal epithelium, while below the vocal cords, it’s a pseudostratifed cords, it’s a pseudostratifed ciliated columnar epithelium.ciliated columnar epithelium.

The medial opening The medial opening between them thru which between them thru which the air passes is the the air passes is the rima rima glottidis or GLOTTIS.glottidis or GLOTTIS.

In an adult, the glottis is In an adult, the glottis is the narrowest point of the the narrowest point of the adult larynx.adult larynx.

In an infant and small In an infant and small child, the cricoid cartilage child, the cricoid cartilage is the narrowest point.is the narrowest point.

Subglottic swelling in an Subglottic swelling in an infant or small child, due to infant or small child, due to infection or trauma can infection or trauma can cause cause stridor stridor during during inspirationinspiration

Epiglottitis vs Croup (LTB)Epiglottitis vs Croup (LTB)

Croup – Steeple SignCroup – Steeple Sign

Epiglottitis – Thumb SignEpiglottitis – Thumb Sign

The larynx is closed by the epiglottis during The larynx is closed by the epiglottis during swallowing.swallowing.

In addition to opening and closing the glottis for In addition to opening and closing the glottis for speech, the vocal folds can act as a sphincter during speech, the vocal folds can act as a sphincter during conditions such as coughing, sneezing or strainingconditions such as coughing, sneezing or straining

The Arytenoid cartilage is shaped like a pyramid which rests on the posterior portion of the cricoid cartilage

At the base of the arytenoid cartilage a projection called the vocal process, the vocal ligaments attach vocal process and the thyroid cartilage

The cuneiform and corniculate are accessory cartilages at the superior portion of the arytenoids

http://www.youtube.com/v/wjRsa77u6OU

Animated Airways..Animated Airways..

http://www.youtube.com/v/ejVQEFbIfmI

http://www.youtube.com/v/IhAEm9004TQ

Laryngeal MusculatureLaryngeal Musculature

ExtrinsicExtrinsic– InfrahyoidInfrahyoid (below the hyoid) (below the hyoid)– Pulls the larynx and hyoid down the neckPulls the larynx and hyoid down the neck

Sternohyoid, sternothyroid, throhyoid and Sternohyoid, sternothyroid, throhyoid and omohyoidomohyoid

– SuprahyoidSuprahyoid (above the hyoid) (above the hyoid)– Pulls the hyoid bone forwards, upwards Pulls the hyoid bone forwards, upwards

and backwardsand backwards Stylohyoid, mylohyoid, digastric, geniohyoid Stylohyoid, mylohyoid, digastric, geniohyoid

and stylopharyngeusand stylopharyngeus

Laryngeal MusculatureLaryngeal Musculature

IntrinsicIntrinsic– They all deal with the arytenoid They all deal with the arytenoid

cartilage and vocal cord movement.cartilage and vocal cord movement.– Posterior cricoarytenoid, lateral Posterior cricoarytenoid, lateral

cricoarytenoid, transverse, cricoarytenoid, transverse, thyroarytenoid and cricothyroid. thyroarytenoid and cricothyroid.

Ventilatory Function of the Ventilatory Function of the LarynxLarynx

Ensures a free flow of air to and from the lungsEnsures a free flow of air to and from the lungs During inspiration, vocal cords move apart; During inspiration, vocal cords move apart;

abduct, and widens glottis for improved airflowabduct, and widens glottis for improved airflow Forced expiration against a closed glottis, Forced expiration against a closed glottis,

““Valsalva’s maneuverValsalva’s maneuver” causes massive adduction ” causes massive adduction preventing air from escaping during cough, preventing air from escaping during cough, vomiting, urination, defecation and parturition.vomiting, urination, defecation and parturition.

Forced inspiration against a closed glottis, “Forced inspiration against a closed glottis, “Mueller Mueller maneuver” maneuver” --- missed sputum bowl question!--- missed sputum bowl question!

The Lower AirwaysThe Lower Airways

After passing through the larynx, After passing through the larynx, inspired air enters the inspired air enters the Tracheobronchial TreeTracheobronchial Tree

The traceobronchial tree consists of a The traceobronchial tree consists of a series of branching airways called series of branching airways called “orders” or “generations”“orders” or “generations”

It is believed that there are 28 It is believed that there are 28 generations or orders of the generations or orders of the tracheobroncial treetracheobroncial tree

Dichotomous BranchingDichotomous Branching

Tracheobronchial TreeTracheobronchial Tree

The tracheobronchial tree is divided into The tracheobronchial tree is divided into two general zonestwo general zones– Conducting Zone or Cartilaginous AirwaysConducting Zone or Cartilaginous Airways

No Gas Exchange occurs in this zoneNo Gas Exchange occurs in this zone

– Respiratory Zone or Non Cartilaginous Respiratory Zone or Non Cartilaginous AirwaysAirways The site of Gas ExchangeThe site of Gas Exchange

– There a transition zone where no There a transition zone where no cartilage surrounds the airway, yet no cartilage surrounds the airway, yet no gas exchange occursgas exchange occurs

Histology of the Histology of the Tracheobroncial TreeTracheobroncial Tree

Three layersThree layers– Epithelial LiningEpithelial Lining– Lamina propriaLamina propria– Cartilaginous LayerCartilaginous Layer

Epithelial LiningEpithelial Lining

Psuedostratified ciliated columnar Psuedostratified ciliated columnar epitheliumepithelium

Numerous Mucous glands interspersedNumerous Mucous glands interspersed Anchored to a basement membrane that Anchored to a basement membrane that

contains basal cells (reserve cells and contains basal cells (reserve cells and replenish mucus glands and ciliated cells)replenish mucus glands and ciliated cells)

200 cilia per cell200 cilia per cell Cells move from columnar to cuboidal and Cells move from columnar to cuboidal and

cilia disappear as you move down the treecilia disappear as you move down the tree

Epithelial LiningEpithelial Lining A mucus layer, or “mucous blanket” covers A mucus layer, or “mucous blanket” covers

the epithelial lining of the tracheobronchial the epithelial lining of the tracheobronchial tree.tree.

Produced by goblet cells and submucosal Produced by goblet cells and submucosal /bronchial glands /bronchial glands

Goblet cells are located between the epithelial Goblet cells are located between the epithelial cellscells

Submucosal glands extend into the lamina Submucosal glands extend into the lamina propria and are innervated by the propria and are innervated by the parasympathetic nervous system.parasympathetic nervous system.

Composed of 95% water and the remainder is Composed of 95% water and the remainder is carbohydrates, glyocproteins, lipids, DNA, carbohydrates, glyocproteins, lipids, DNA, cellular debris and foreign particles.cellular debris and foreign particles.

Mucous BlanketMucous Blanket

The body produces about 100ml of The body produces about 100ml of secretions per day.secretions per day.

The viscosity of the secretions increase The viscosity of the secretions increase as you move from the lining to the as you move from the lining to the lumen.lumen.

Two distinct layersTwo distinct layers– SOL LayerSOL Layer, adjacent to the epithelial lining, adjacent to the epithelial lining

Less viscousLess viscous

– GEL LayerGEL Layer, adjacent to the inner lumen, adjacent to the inner lumen More viscousMore viscous

Mucous BlanketMucous Blanket

Cilia move in a wavelike fashion, beating Cilia move in a wavelike fashion, beating 1500 times per minute through the less 1500 times per minute through the less viscous sol layer and strike the inner viscous sol layer and strike the inner layer of the more viscous gel layer.layer of the more viscous gel layer.

This action propels the mucus layer, This action propels the mucus layer, along with any foreign particles along with any foreign particles attached to the “sticky” gel layer attached to the “sticky” gel layer towards the larynx at 2cm per minutetowards the larynx at 2cm per minute

The cough mechanism moves the The cough mechanism moves the secretions above the larynx and into the secretions above the larynx and into the oropharynxoropharynx

Mucous BlanketMucous Blanket This cleansing process is called Mucociliary This cleansing process is called Mucociliary

Transport or the Mucociliary EscalatorTransport or the Mucociliary Escalator What slows the rate down:What slows the rate down:

– Cigarette smoke,Cigarette smoke,– DehydrationDehydration– Positive Pressure VentilationPositive Pressure Ventilation– Endotracheal SuctioningEndotracheal Suctioning– High FiO2High FiO2– HypoxiaHypoxia– Atmospheric pollutantsAtmospheric pollutants– General anestheticsGeneral anesthetics– ParasympatholyticsParasympatholytics

Lamina PropriaLamina Propria

This is a submucosal layer This is a submucosal layer Loose fibrous tissue containing blood Loose fibrous tissue containing blood

vessels, lymphatic vessels, vagus nerve vessels, lymphatic vessels, vagus nerve innervationinnervation

Two sets of smooth muscle that wrap in Two sets of smooth muscle that wrap in spirals both clockwise and counterclockwisespirals both clockwise and counterclockwise

The smooth muscle fibers extend to the The smooth muscle fibers extend to the alveolar ductsalveolar ducts

The lamina propria is surrounded by a thin The lamina propria is surrounded by a thin connective tissue layer called the connective tissue layer called the peribronchial sheathperibronchial sheath

Lamina PropriaLamina Propria Mast Cells are located in the lamina propriaMast Cells are located in the lamina propria Their cytoplasm is loaded with granules Their cytoplasm is loaded with granules

containing mediators of inflammation. containing mediators of inflammation. – Histamine, heparin, SRS-AHistamine, heparin, SRS-A (slow reacting substance of (slow reacting substance of

anaphylaxis), anaphylaxis), PAFPAF (platelet activating factor), (platelet activating factor), ECF-AECF-A (eosinophilic chemotaxic factor of anaphylaxis)(eosinophilic chemotaxic factor of anaphylaxis)

Their surface is coated with a variety of Their surface is coated with a variety of receptors which, when engaged by the receptors which, when engaged by the appropriate antigen trigger exocytosis of appropriate antigen trigger exocytosis of the granules. the granules.

Destablization of mast cells in the lungs canDestablization of mast cells in the lungs can be extremely dangerous, and is what we be extremely dangerous, and is what we

see in patients with an allergic asthmatic see in patients with an allergic asthmatic episodeepisode

Cartilaginous LayerCartilaginous Layer

Outermost layer of the Outermost layer of the tracheobronchial treetracheobronchial tree

This layer progressively diminishes in This layer progressively diminishes in size as the airway extend into the size as the airway extend into the lungs.lungs.

Cartilage is absent in bronchioles Cartilage is absent in bronchioles less than 1 mm in diameterless than 1 mm in diameter

Lower AirwayLower AirwayCartilaginous AirwaysCartilaginous Airways

TracheaTrachea Main stem BronchiMain stem Bronchi Lobar BronchiLobar Bronchi Segmental BronchiSegmental Bronchi Subsegmental BronchiSubsegmental Bronchi THE CONDUCTING ZONETHE CONDUCTING ZONE

TracheaTrachea In the adult, it is 11 to In the adult, it is 11 to

13 cm long, 1.5 – 2.5 13 cm long, 1.5 – 2.5 cm in diametercm in diameter

Descends from the Descends from the cricoid to the 2cricoid to the 2ndnd costal cartilage costal cartilage – ANGLE OF LOUISANGLE OF LOUIS

It bifurcates, divides It bifurcates, divides into the right and left into the right and left main stem bronchi, main stem bronchi, this division is called this division is called the the carinacarina

The open posterior The open posterior parts of the rings parts of the rings are adjacent to the are adjacent to the the esophagus the esophagus and are connected and are connected by fibers of the by fibers of the trachealis muscletrachealis muscle, , which is involved in which is involved in coughing.coughing.

There are 15-20 There are 15-20 C-shaped rings of C-shaped rings of cartilage that cartilage that support the support the trachea, keeping trachea, keeping the airway patent the airway patent and prevent its and prevent its collapse.collapse.

. .

Main Stem and Lobar Main Stem and Lobar BronchiBronchi

The Main Stem Bronchi are the 1The Main Stem Bronchi are the 1stst generation of the tracheobronchial treegeneration of the tracheobronchial tree

The right main stem bronchus branches The right main stem bronchus branches off the trachea at a 25 degree angle, the off the trachea at a 25 degree angle, the left bronchus forms a 40 – 60 degree left bronchus forms a 40 – 60 degree angleangle

The right bronchus is wider, more The right bronchus is wider, more vertical, and 5 cm shorter than the left.vertical, and 5 cm shorter than the left.

Main Stem and Lobar Main Stem and Lobar BronchiBronchi

Main Stem bronchi are supported by ‘C’ Main Stem bronchi are supported by ‘C’ shaped cartilageshaped cartilage

Each Each bronchusbronchus runs obliquely into the runs obliquely into the mediastinum before plunging into the mediastinum before plunging into the medial depression (medial depression (hilushilus) of the lung on its ) of the lung on its own side.own side.

Inside the lungs, the Inside the lungs, the main stemmain stem or or primary primary bronchibronchi divide into divide into lobar lobar or or secondary secondary bronchibronchi, 3 on the right and 2 on the left, , 3 on the right and 2 on the left, each of which supplies one lung lobe. each of which supplies one lung lobe.

3 lobes on the right, 2 lobes on the left 3 lobes on the right, 2 lobes on the left (room for heart)(room for heart)

Bronchi and Bronchi and SubdivisionsSubdivisions

The lobar bronchi become The lobar bronchi become segmentalsegmental; ; third generation.third generation.– 10 in the right lung and 8 in the left lung10 in the right lung and 8 in the left lung

Subsegmental bronchi range in diameter Subsegmental bronchi range in diameter from 1 – 4 mm. Peribronchial sheaths from 1 – 4 mm. Peribronchial sheaths containing nerves, vessels and lymphatic containing nerves, vessels and lymphatic tissue surround the subsegmental tissue surround the subsegmental bronchi down to the 1 mm bronchi down to the 1 mm – These are the 4These are the 4thth – 9 – 9thth generation. generation.

Non Cartilaginous AirwaysNon Cartilaginous Airways

BronchiolesBronchioles– When the diameter decreases to less When the diameter decreases to less

than 1mm,than 1mm, they are no longer surrounded by a they are no longer surrounded by a

connective sheath,connective sheath, cartilage is absent, rigidity is absent-airway cartilage is absent, rigidity is absent-airway

patency can be compromisedpatency can be compromised A muscle sheath surrounding the A muscle sheath surrounding the

bronchiolesbronchioles Columnar epithelial becomes cuboidal Columnar epithelial becomes cuboidal

– Generations 10 - 15Generations 10 - 15

Terminal BronchiolesTerminal Bronchioles– Diameter is about 0.5 mmDiameter is about 0.5 mm– Cilia and mucous glands progressively disappearCilia and mucous glands progressively disappear– Epithelium is cuboidal and thinEpithelium is cuboidal and thin– Channels called “Channels called “Canals of LambertCanals of Lambert” appear” appear

Connect the surface of terminal bronchioles to adjacent Connect the surface of terminal bronchioles to adjacent alveolialveoli

Thought to aid in collateral ventilation in individuals with Thought to aid in collateral ventilation in individuals with respiratory disorders such as COPDrespiratory disorders such as COPD

– Presence of Presence of Clara CellsClara Cells Function unknown, they have a thick protoplasmic Function unknown, they have a thick protoplasmic

extensions that bulge into the bronchial lumen - perhaps extensions that bulge into the bronchial lumen - perhaps they secrete an enzyme that detoxifies inhaled substancesthey secrete an enzyme that detoxifies inhaled substances

1616thth – 19 – 19thth Generation; Generation; TERMINAL- END: Structures beyond this point TERMINAL- END: Structures beyond this point

are not part of the Tracheobronchial tree. are not part of the Tracheobronchial tree. Structures distal to this point are the sites of Structures distal to this point are the sites of

gas exchange; referred to as the Respiratory gas exchange; referred to as the Respiratory ZoneZone

As conducting tubes As conducting tubes become smaller…become smaller…

The cartilage support changes. It goes from The cartilage support changes. It goes from rings in the trachea to irregular plates in the rings in the trachea to irregular plates in the bronchi to none in the bronchioles. bronchi to none in the bronchioles. – Why?Why?

The epithelium changes. It goes from respiratory The epithelium changes. It goes from respiratory to simple columnar to simple cuboidal. to simple columnar to simple cuboidal. – Why?Why?

The number of cilia and goblet cells present The number of cilia and goblet cells present decrease. decrease. – Why?Why?

The amount of smooth muscle increases. The amount of smooth muscle increases. – Why?Why?

Gas FlowGas Flow

Once in the Respiratory Zone, the Once in the Respiratory Zone, the cross sectional area of the lung cross sectional area of the lung increases exponentially.increases exponentially.

Forward motion of gas flow stops-no Forward motion of gas flow stops-no bulk flow, no laminar flowbulk flow, no laminar flow

The movement of gas becomes The movement of gas becomes molecular molecular

Bronchial Blood SupplyBronchial Blood Supply

Tracheobronchial tree requires blood Tracheobronchial tree requires blood flow flow

Arteries follow the tracheobronchial tree Arteries follow the tracheobronchial tree as far as the terminal bronchiolesas far as the terminal bronchioles

Beyond the terminal bronchioles, this Beyond the terminal bronchioles, this vascular system merges with the vascular system merges with the pulmonary vascular system.pulmonary vascular system.– RA – RV– PARA – RV– PA - - Lungs Lungs – – LA – LV –Aorta - LA – LV –Aorta -

SystemicSystemic

Bronchial Blood SupplyBronchial Blood Supply

Approximately 1% of Cardiac Output Approximately 1% of Cardiac Output serves the tracheobronchial tree.serves the tracheobronchial tree.

Of that 1%, 1/3Of that 1%, 1/3rdrd of it returns to the Right of it returns to the Right Atrium as unoxygenated venous blood. Atrium as unoxygenated venous blood.

The vessels responsible for this returnThe vessels responsible for this return– AzygosAzygos– HemiazygosHemiazygos– Intercostal veinsIntercostal veins– RA – RV – PARA – RV – PA - - Lungs Lungs – – LA – LV –Aorta - LA – LV –Aorta -

SystemicSystemic

The remaining 2/3The remaining 2/3rdrd of the bronchial venous of the bronchial venous blood drains into the pulmonary circulation, blood drains into the pulmonary circulation, into the pulmonary arteries and capillariesinto the pulmonary arteries and capillaries

via via bronchopulmonary anastomosesbronchopulmonary anastomoses This results in a mixture of low oxygenated This results in a mixture of low oxygenated

and high carbon dioxide blood from the and high carbon dioxide blood from the tracheobronchial tree with highly oxygenated tracheobronchial tree with highly oxygenated low carbon dioxide blood returning to the left low carbon dioxide blood returning to the left atrium for systemic circulation atrium for systemic circulation – RA – RV – PARA – RV – PA - - Lungs Lungs – – LA – LV –Aorta – SystemicLA – LV –Aorta – Systemic

2/32/3rdrd of blood returning from bronchical circulation of blood returning from bronchical circulation

This is an example of an anatomical shunt, and called This is an example of an anatomical shunt, and called venous venous admixtureadmixture

The Respiratory ZoneThe Respiratory Zone

Distal to the terminal bronchioles are the Distal to the terminal bronchioles are the functional units of gas exchangefunctional units of gas exchange

Consists of:Consists of:– 3 generations of Respiratory Bronchioles3 generations of Respiratory Bronchioles– 3 generations of Alveolar Ducts3 generations of Alveolar Ducts– Ending in 15-20 grapelike clusters called Ending in 15-20 grapelike clusters called

Alveolar SacsAlveolar Sacs These units, Respiratory Bronchioles, Ducts These units, Respiratory Bronchioles, Ducts

and Alveoli are called a and Alveoli are called a primary lobuleprimary lobule or or acinusacinus, or , or terminal respiratory unitterminal respiratory unit or or lung lung parenchymaparenchyma or or functional unitsfunctional units

AlveoliAlveoli

Composed of smooth muscle fiberComposed of smooth muscle fiber Approximately 300 million alveoli which Approximately 300 million alveoli which

are 90% covered with capillaries.are 90% covered with capillaries. The surface area of the alveoli is 70 The surface area of the alveoli is 70

square meter, the surface of a tennis square meter, the surface of a tennis courtcourt

Each primary lobule, 130,000 each Each primary lobule, 130,000 each stem from a single terminal bronchiole stem from a single terminal bronchiole and contains about 2000 alveoliand contains about 2000 alveoli

Alveolar EpitheliumAlveolar Epithelium Alveoli are consist of 3 cell types: Alveoli are consist of 3 cell types: Type I cells; Squamous EpitheliumType I cells; Squamous Epithelium

– Cover 95% of the alveolar surfaceCover 95% of the alveolar surface– 0.1 – 0.5 micrometers thick0.1 – 0.5 micrometers thick– Major site of gas exchangeMajor site of gas exchange

Type II cells; Granular pneumocytesType II cells; Granular pneumocytes– Have microvilli Have microvilli – Cuboidal in shapeCuboidal in shape– Produce pulmonary surfactantProduce pulmonary surfactant– Form the remaining 5% of the alveolar surfaceForm the remaining 5% of the alveolar surface

Type III cells; Alveolar macrophagesType III cells; Alveolar macrophages– Migrate through the blood stream and are Migrate through the blood stream and are

embedded in the extracellular lining of the embedded in the extracellular lining of the alveolialveoli

Pores of KohnPores of Kohn

Pores of KohnPores of Kohn– Small holes in the alveolar wall or Small holes in the alveolar wall or

interalveolar septainteralveolar septa– Allow gas to move between alveoliAllow gas to move between alveoli– Formed byFormed by

Shedding of cells – desquamationShedding of cells – desquamation Normal degeneration due to ageNormal degeneration due to age Movement/detachment of macrophagesMovement/detachment of macrophages

Scattered Scattered among the among the Type I’s are Type I’s are Type II cellsType II cells which secrete which secrete surfactantsurfactant..

Pores of Kohn Pores of Kohn connect connect adjacent adjacent alveoli.alveoli.

Alveolar Alveolar macrophages macrophages ((dust cellsdust cells) ) crawl along crawl along the internal the internal alveolar alveolar surfacessurfaces

InterstitiumInterstitium

Surrounds, supports and shapes the alveolar Surrounds, supports and shapes the alveolar capillary clusterscapillary clusters

Gel like substance of hyaluronic acid molecules Gel like substance of hyaluronic acid molecules bound together by a network of collagen fibersbound together by a network of collagen fibers

Two compartmentsTwo compartments– Tight Space; the area between the alveolar Tight Space; the area between the alveolar

epithelium and the endothelium of the pulmonary epithelium and the endothelium of the pulmonary capillaries-Site of gas exchangecapillaries-Site of gas exchange

– Loose Space: the area the surround the bronchioles, Loose Space: the area the surround the bronchioles, respiratory bronchioles, alveolar ducts and sacs. respiratory bronchioles, alveolar ducts and sacs. Lymphatic vessels and neural fibers are in this areaLymphatic vessels and neural fibers are in this area

The Pulmonary Vascular The Pulmonary Vascular SystemSystem

Function is to deliver blood to and Function is to deliver blood to and from the lungs for gas exchangefrom the lungs for gas exchange

It also supplies nutrition to portions It also supplies nutrition to portions of the lung distal to the terminal of the lung distal to the terminal airwaysairways

Pulmonary Vascular SystemPulmonary Vascular System

ArteriesArteries ArteriolesArterioles CapillariesCapillaries VenulesVenules VeinsVeins

Pulmonary ArteriesPulmonary Arteries

Three LayerThree Layer– Tunica Intima; inner layerTunica Intima; inner layer

Endothelium and a thin layer of connective tissueEndothelium and a thin layer of connective tissue

– Tunica Media; middle layerTunica Media; middle layer Thickest layer of the vesselThickest layer of the vessel Elastic connective tissue in large arteries, Elastic connective tissue in large arteries, smooth smooth

muscles in smaller and medium arteriesmuscles in smaller and medium arteries

– Tunica Adventitia: outer layerTunica Adventitia: outer layer Connective tissueConnective tissue Contains small vessels that nourish all layersContains small vessels that nourish all layers

Stiff vessels, capable of carrying blood Stiff vessels, capable of carrying blood under high pressures.under high pressures.

ArteriolesArterioles

Endothelial layerEndothelial layer Elastic layerElastic layer Smooth muscle fibersSmooth muscle fibers

Called “Called “resistance vesselsresistance vessels” due to ” due to the ability of the smooth muscles to the ability of the smooth muscles to regulate the blood flowregulate the blood flow

CapillariesCapillaries

Surround 90% of the alveoliSurround 90% of the alveoli Composed of endothelial layer; single Composed of endothelial layer; single

layer of squamous epithelial cellslayer of squamous epithelial cells Essentially an extension of the inner Essentially an extension of the inner

lining of the larger vesselslining of the larger vessels This is where gas exchange occursThis is where gas exchange occurs Some prostaglandins are produced Some prostaglandins are produced

here, some biological substances are here, some biological substances are destroyed heredestroyed here

Veins and VenulesVeins and Venules

3 Layers, same as arteries, 2 layers in the 3 Layers, same as arteries, 2 layers in the smaller veins-no tunica adventitiasmaller veins-no tunica adventitia

Middle layer is poorly developed and contain Middle layer is poorly developed and contain less smooth muscle and elastic tissuesless smooth muscle and elastic tissues

Due to less elastic and smooth muscle Due to less elastic and smooth muscle tissue, veins can hold a greater volume of tissue, veins can hold a greater volume of blood with little pressure changes. Because blood with little pressure changes. Because of this, veins are called “of this, veins are called “capacitance capacitance vessels”vessels”

Veins return to the heart in a more direct Veins return to the heart in a more direct route out of the lungsroute out of the lungs

The Lymphatic SystemThe Lymphatic System Function is to remove excess fluid and protein Function is to remove excess fluid and protein

that leak out of the capillariesthat leak out of the capillaries Located in a dense connective tissue sheath Located in a dense connective tissue sheath

around the bronchioles, also in the loose around the bronchioles, also in the loose space of the interstitiumspace of the interstitium

More lymphatic channels located on the left More lymphatic channels located on the left side, increased incidence of right sided side, increased incidence of right sided pleural effusions due to less drainagepleural effusions due to less drainage

Like veins, they have one way valves/flapsLike veins, they have one way valves/flaps Bronchopulmonary lymph nodes, end of the Bronchopulmonary lymph nodes, end of the

line, are located outside the lung parenchymaline, are located outside the lung parenchyma No lymph vessels in the alveoli, they are No lymph vessels in the alveoli, they are

located immediately adjacent to the alveoli located immediately adjacent to the alveoli called called juxta-alveolar lymphaticsjuxta-alveolar lymphatics

Neural Control of the LungsNeural Control of the Lungs

Controlled by the autonomic nervous Controlled by the autonomic nervous systemsystem– Regulates involuntary vital functionsRegulates involuntary vital functions

Cardiac musclesCardiac muscles Smooth musclesSmooth muscles GlandsGlands

– Two divisionsTwo divisions SympatheticSympathetic ParasympatheticParasympathetic

Neural Control of the LungsNeural Control of the Lungs

SympatheticSympathetic– Accelerates heart rateAccelerates heart rate– Constricts blood vesselsConstricts blood vessels– Relaxes bronchial smooth musclesRelaxes bronchial smooth muscles– Raises blood pressureRaises blood pressure

ParasympatheticParasympathetic– Slows heart rateSlows heart rate– Constricts bronchial smooth musclesConstricts bronchial smooth muscles– Increases intestinal peristalsis and gland Increases intestinal peristalsis and gland

activityactivity

Neural Control of the LungsNeural Control of the Lungs

Sympathetic neural transmittersSympathetic neural transmitters– EpinephrineEpinephrine– NorepinehrineNorepinehrine

These agents stimulate theThese agents stimulate the– Beta 2 receptors in the bronchial smooth Beta 2 receptors in the bronchial smooth

muscles; causing airway muscle relaxationmuscles; causing airway muscle relaxation– Alpha receptors in the arteriole smooth Alpha receptors in the arteriole smooth

muscles, causing the pulmonary vascular muscles, causing the pulmonary vascular system to contrictsystem to contrict

Neural Control of the LungsNeural Control of the Lungs Parasympathetic neural transmittersParasympathetic neural transmitters

– AcetylcholineAcetylcholine Causes constriction of the bronchial smooth musclesCauses constriction of the bronchial smooth muscles

Inactivity of either portion allows the other Inactivity of either portion allows the other one to dominate the bronchial smooth one to dominate the bronchial smooth musclesmuscles

There must be careful attention to the role There must be careful attention to the role of pharmacological agentsof pharmacological agents– Beta blockers- causes parasympathetic to Beta blockers- causes parasympathetic to

dominatedominate– Atropine-a parasympathetic blocker allows Atropine-a parasympathetic blocker allows

sympathetic to dominatesympathetic to dominate

Lung Gross AnatomyLung Gross Anatomy Occupies all of the thoracic cavity except the Occupies all of the thoracic cavity except the

mediastinum. mediastinum. Each lung is within its own pleural cavityEach lung is within its own pleural cavity Anterior, lateral, and posterior surfaces are costal, Anterior, lateral, and posterior surfaces are costal,

adjacent to ribsadjacent to ribs Rises above the clavicle to the level of the 1Rises above the clavicle to the level of the 1stst rib rib The concave bases sit on the diaphragm.The concave bases sit on the diaphragm. The mediastinal border is concave to heart and the The mediastinal border is concave to heart and the

other mediastinal structureother mediastinal structure The hilum is at the center of the mediastinal border, The hilum is at the center of the mediastinal border,

and is where the main stem bronchi, blood and and is where the main stem bronchi, blood and lymph vessels, and nerves enter and exit the lungslymph vessels, and nerves enter and exit the lungs

Lung Gross AnatomyLung Gross Anatomy The right lung is larger The right lung is larger

and heavier than the and heavier than the left. The Right lung has left. The Right lung has 3 lobes; upper, middle, 3 lobes; upper, middle, and lowerand lower

The lobes are divided The lobes are divided by the by the – oblique fissure which oblique fissure which

divides the upper divides the upper and middle lobe from and middle lobe from the lower lobethe lower lobe

– Horizontal fissure, Horizontal fissure, divides the upper divides the upper from the lower lobe.from the lower lobe.

..

Lung Gross AnatomyLung Gross Anatomy The left lung is The left lung is

smaller than the smaller than the right, contains 2 right, contains 2 lobes; upper and a lobes; upper and a lower lobe and has lower lobe and has an indentation an indentation ((cardiac notchcardiac notch) ) where the heart where the heart sits.sits.– The lobes are The lobes are

divided by the divided by the oblique fissureoblique fissure

Lung SegmentsLung Segments All Lobes are All Lobes are

further divided further divided into into bronchopulmonabronchopulmonary segmentsry segments

10 on the right10 on the right 8 on the left8 on the left Careful with the Careful with the

numbering numbering systems!systems!

MediastinumMediastinum

A cavity that contains the organs and A cavity that contains the organs and tissues in the center of the thoracic tissues in the center of the thoracic cage between the right and left lungcage between the right and left lung

Bordered anteriorly by the sternum, and Bordered anteriorly by the sternum, and posteriorly by the vertabraeposteriorly by the vertabrae

Contains the trachea, heart, the Contains the trachea, heart, the great great vessels vessels the major vessels that enter and the major vessels that enter and exit the heart, the esophagus, thymus exit the heart, the esophagus, thymus gland, lymph nodes, and nervesgland, lymph nodes, and nerves

The Pleural MembranesThe Pleural Membranes Two moist, slick surfaced membranes Two moist, slick surfaced membranes Parietal pleuraParietal pleura covers the thoracic wall, superior covers the thoracic wall, superior

diaphragm and lateral portion of the mediastinum diaphragm and lateral portion of the mediastinum Visceral pleuraVisceral pleura firmly attached and covers the external firmly attached and covers the external

lung surface, extends into the interlobar fissureslung surface, extends into the interlobar fissures The potential space between visceral and parietal The potential space between visceral and parietal

pleurae is called the pleurae is called the pleural cavitypleural cavity The two membranes are held together by a thin film of The two membranes are held together by a thin film of

serous fluid. The fluid allows the membranes to glide serous fluid. The fluid allows the membranes to glide over each other during inspiration and exhalationover each other during inspiration and exhalation

The pleural membranes hold the lung tissue to the The pleural membranes hold the lung tissue to the inner surface of the thorax and diaphragm, allowing for inner surface of the thorax and diaphragm, allowing for lung expansion during inspirationlung expansion during inspiration

Because the lungs have a natural tendency to collapse and the thorax has a natural tendency to expand, a negative pressure normally exists between these two layers. Should air enter this space, the pleural membranes would separate causing a condition known as a pneumothorax

The DiaphragmThe Diaphragm The diaphragm is the major muscle of The diaphragm is the major muscle of

inspirationinspiration Dome-shaped musculofibrous partition Dome-shaped musculofibrous partition

located between the thoracic cavity and the located between the thoracic cavity and the abdominal cavityabdominal cavity

Two separate muscles; the Two separate muscles; the right and left right and left hemidiaphragmhemidiaphragm, joined at midline by the , joined at midline by the central tendoncentral tendon

Pierced by the esophagus, aorta, nerves and Pierced by the esophagus, aorta, nerves and the inferior vena cavathe inferior vena cava

Innervated mainly by the phrenic nerve, the Innervated mainly by the phrenic nerve, the lower thoracic nerves contribute to some lower thoracic nerves contribute to some motor innervationmotor innervation

InspirationInspiration When the diaphragm is When the diaphragm is

stimulated to contract, it stimulated to contract, it moves downward and the moves downward and the lower ribs move upward and lower ribs move upward and outwardoutward

This increases the thoracic This increases the thoracic volume volume

Which causes the lung volume Which causes the lung volume to increaseto increase

The increased lung volume The increased lung volume causes lung pressure; causes lung pressure; intrapleural and intra alveolar intrapleural and intra alveolar to decreaseto decrease

As a result, gas from the As a result, gas from the atmosphere flows into the atmosphere flows into the lungslungs

ExpirationExpiration During expiration, the During expiration, the

diaphragm relaxes and diaphragm relaxes and moves upward into the moves upward into the thoracic cavitythoracic cavity

This increases the This increases the intrapleural and intra-intrapleural and intra-alveolar pressures and alveolar pressures and causes gas to flow out of causes gas to flow out of the lungsthe lungs

Quiet expiration is a passive Quiet expiration is a passive process that is due to the process that is due to the elasticity of the lungs. elasticity of the lungs.

Forced expiration is an Forced expiration is an active process due to active process due to contraction of oblique and contraction of oblique and transverse abdominus transverse abdominus muscles, internal muscles, internal intercostals, and the intercostals, and the latissimuslatissimus dorsi.dorsi.