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Vincent Van Gogh – Skull with Cigarette (1886)

ANATOMY OF THE RESPIRATORY SYSTEM

Kaan Yücel M.D., Ph.D.

19.10.2012

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Nose is divisible into :External nose Nasal cavity

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Extends the nasal cavities onto the front of the face

Pyramidal in shape

EXTERNAL NOSE

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External nose has bony & cartilaginous parts.

Bones Cartilages Nasal bones Lateral cartilages (paired)Frontal process of maxilla Alar cartilages (paired)Nasal part of frontal bone Septal cartilage (single)

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NASAL CAVITIES

separated from:each other by a midline nasal septumoral cavity below by the hard palatecranial cavity above by parts of the frontal, ethmoid, &sphenoid bones.

uppermost parts of the respiratory tract

olfactory receptors

Posteriorly, each nasal cavity communicates with the nasopharynx through two openings choana.

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Each nasal cavity consists of 3 regions.

1) nasal vestibule internal to the naris 2) respiratory region largest , rich neurovascular

supply 3) olfactory region @ apex of each nasal cavity,

olfactory receptors

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the most anterior part of the nasal cavity.

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Olfaction (sense of smell)RespirationFiltration of the dust in the inspired air Humidification and warming of the inspired air (cooling the internal carotid artery for brain)Reception of the secretions from the paranasal sinuses and nasolacrimal ducts

FUNCTIONS OF THE NOSE & NASAL CAVITIES

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2. PARANASAL SINUSES

lined by respiratory mucosa. open into the nasal cavitiesinnervated by branches of the trigeminal nerve [V].

air filled spaces lying within the bones around the nasal cavity

1) Frontal sinuses2) Ethmoid sinuses3) Sphenoid sinuses4) Maxillary sinuses

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3. LARYNXorgan of phonation

(vocalization)

CartilageMuscles Connective tissue

continuous below with the tracheaabove opens into the pharynx immediately posterior & slightly inferior to the tongue

between C3- C6

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Unpaired cartilages1) Thyroid cartilage (biggest)2) Cricoid cartilage3) Epiglottic cartilage

SKELETON OF LARYNX LARYNGEAL CARTILAGES

Paired cartilages1) Arytenoid2) Corniculate3) Cuneiform

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THYROID CARTILAGElargest cartilage of the

larynx2 laminae which fuse anteriorly at the thyroid angle & form laryngeal prominence (Adam’s apple)

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CRICOID CARTILAGE

Inferiorly attaches to 1st tracheal ring via cricotracheal ligament. Completely encircles the airway

Broad lamina of cricoid cartilage posteriorlyNarrower arch of cricoid cartilage anteriorly

a ring shaped cartilage, most inferior of the laryngeal cartilages

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ARYTENOID CARTILAGES

3 processesApex (superior) articulation w/corniculate cartilageVocal process (anterior) vocal ligament attaches hereMuscular process (lateral)

pyramidal in shape

posterior & lateral crico-arytenoid muscles

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EPIGLOTTIC CARTILAGE (EPIGLOTTIS)a leaf-shaped cartilage

attached by its stem to the posterior aspect of the thyroid cartilage

@ the angle

Most superior end is free.

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CORNICULATE & CUNEIFORM CARTILAGES

lie in the posterior part of the aryepiglottic fold.

corniculate cartilages two small conical cartilagesLocated on the arytenoid cartilagescuneiform cartilages small cartilages anterior to corniculate cartilages

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between lower border of cricoid cartilage & upper border of 1st tracheal cartilage

EXTRINSIC LIGAMENTS OF THE LARYNXThyrohyoid membraneBelow superior margin of the thyroid cartilage, above hyoid bonelateral thyrohyoid ligament (posterior thickening), triticeal cartilagemedian thyrohyoid ligament (midline thickening)

Hyo-epiglottic ligamentfrom the midline of the epiglottis to the body of hyoid bone

Cricotracheal ligament

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. INTRINSIC LIGAMENTS OF THE LARYNXFibroelastic membrane of the larynx

lies under the mucosa of the larynxlinks together the laryngeal cartilages completes the architectural framework of the laryngeal cavityforms some of the ligaments between the cartilages.

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2 parts1) lower conus elasticus 2) upper quadrangular membrane

INTRINSIC LIGAMENTS OF THE LARYNXFibroelastic membrane of the larynx

Conus elesticus cricothyroid ligament, cricovocal membrane, cricothyroid membrane

Free upper margin thickens & forms vocal ligament vocal foldopening between the 2 vocal folds

(rima) glottis

median cricothyroid ligament anterior midline thickening of conus elasticus

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Each vocal ligament free upper margin attaches to anterior part of inner surface of thyroid cartilage

@ thyroid angleposteriorly attach to vocal processes of the arytenoid cartilages.

Conus elasticus cricothyroid ligament, cricovocal membrane,

cricothyroid membrane

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InspirationWidens

PhonationNarrows- 2 vocal fold come together

Pitch increases with tensing, decreases by relaxation. Intensity of expiration determines the loudness of sound.

Rima glottis

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vestibular ligament attached posteriorly arytenoid cartilage anteriorly thyroid angle superior to the attachment of the vocal ligament.

Quadrangular membrane

lateral margin of epiglottis

anterolateral surface

free lower margin is thickened

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vestibular ligament attached posteriorly arytenoid cartilage anteriorly thyroid angle superior to the attachment of the vocal ligament.

Quadrangular membrane

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architectural support fibro-elastic membrane of the larynx laryngeal cartilages.

LARYNGEAL CAVITYtubular

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1) opens into anterior aspect of pharynx

just below and posterior to the tongue

continuous with the lumen of tracheacompletely encircled by cricoid cartilage

superior aperture (laryngeal inlet) V.S. inferior aperture

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2) oblique and points posterosuperiorly into the pharynx

horizontal in position

superior aperture (laryngeal inlet) V.S. inferior aperture

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superior aperture (laryngeal inlet) V.S. inferior aperture

3) can be closed by downward movement of the epiglottis.

continuously open

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LARYNGEAL CAVITYvestibular and vocal folds divide into three major regions

Vestibulebetween laryngeal inlet & vestibular folds

Middle partbetween vestibular folds & vocal folds Infraglottic space between the vocal folds & inferior opening of the larynx

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.Rima glottidis

between vocal foldsseparates middle chamber from infraglottic cavity.

base formed by interarytenoid fold @ bottom of interarytenoid notch.

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FUNCTIONAL ANATOMY OF THE LARYNXRespiration

Quiet: laryngeal inlet, rima glottidis open arytenoid cartilages abducted

Forced: rima glottidis widens arytenoid cartilages rotated laterally, vocal folds abducted

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Rima glottidis is completely closed.Completely and forcefully shut the airway

FUNCTIONAL ANATOMY OF THE LARYNXEffort closure

occurs when air is retained in the thoracic cavity to stabilize the trunk

increasing intra-abdominal pressure

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arytenoid cartilages & vocal folds adducted rima glottidis closed

FUNCTIONAL ANATOMY OF THE LARYNXPhonation

Air is forced through the closed rima glottidis Vocal folds vibrate against each other and produce sounds.

Tension in the vocal folds adjusted by vocalis & cricothyroid muscles

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Larynx moves up & forward – opens the esophagusattached to the posterior aspect of the lamina of cricoid cartilage

Epiglottis goes down toward the arytenoid cartilages laryngeal inlet narrowed or closed

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FUNCTIONAL ANATOMY OF THE LARYNXSwallowing

Rima glottidis closed.Laryngeal inlet narrowed

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from the inferior end of larynx to the level of T5-T6

Terminates by dividing into right & left main bronchi @ sternal angle. Main bronchi give branches inside the lungs & form bronchial tree.

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formed of tracheal rings which are incomplete posteriorlyPosterior parts of the tracheal rings closed by

smooth muscle trachealis muscle.

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5. PLEURA

visceral pleura invests all surfaces of the lungs parietal pleura lines the pulmonary cavities & thorax’s inner surface

covers the pulmonary cavities and external surfaces of the lungs in these cavities

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Visceral pleura insensitive to pain

Parietal pleura extremely sensitive to pain

Irritation causes local pain or referred pain projecting to the dermatomes supplied by the same spinal

nerve.

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contains a capillary layer of serous pleural fluid lubricates the pleural surfaces allows layers of pleura slide smoothly over each other during respiration.

lung surface in contact with thoracic walllung expands fills with air when thorax expands

pleural cavitypotential space between the layers of pleura

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5. LUNGSorgans of respiration

lie on either side of the mediastinum surrounded by right & left pleural cavities

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5. LUNGS

Air enters and leaves the lungs via main bronchi branches of trachea

Inspired air into close relation with venous bloodin pulmonary capillaries.

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5. LUNGSApex upper pole3 surfaces costal, mediastinal and diaphragmaticRoot of the lung 2 lobes in the left lung oblique fissure3 lobes in the right lung horizontal & oblique fissures

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TRACHEOBRONCHIAL TREEsublaryngeal airway

Trachea @ superior mediastinum TRUNK OF THE TREE Bifurcation @ sternal angle Main bronchi

Right main bronchus & Left main bronchus enter hilum of the lungBranches of the tracheobranchial tree

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TRACHEOBRONCHIAL TREEMain (primary) bronchus

Secondary (lobar) bronchi 2 on the left, 3 on the right

Tertiary (segmental) bronchi

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o Pyramidal-shaped segments of the lungapices facing the root of the lung.

o Separated from adjacent segments by connective tissue septa.

BRONCHOPULMONARY SEGMENTSlargest subdivisions of a lobe

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o Segmental bronchus & Tertiary branch of pulmonary artery

o Drained by intersegmental parts of the pulmonary veins

BRONCHOPULMONARY SEGMENTSlargest subdivisions of a lobe

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o Named according to the segmental bronchi supplying them.

o Usually 18-20 in number

o Surgically resectable.

BRONCHOPULMONARY SEGMENTSlargest subdivisions of a lobe

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tertiary segmental bronchi

conducting (lobular) bronchioles end as terminal bronchioles

respiratory bronchioles

pulmonary alveolus basic structural unit of gas exchange in the lung

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Branching of the bronchial tree • Trachea• Principal bronchus • Lobar bronchi (secondary bronchi)• Segmental bronchi (tertiary bronchi)• Terminal bronchiol• Respiratory bronchiol• Alveolar duct• Alveolar sac• Alveolus

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root of the lungT5 to TV7

mediastinal pleura reflects off mediastinum a sleeve-like covering forairway, vessels, nerves, lymphatics which pass between

the lung and mediastinum

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hilum of lung

The root of the lung joins medial surface of the lung here!mediastinal pleura continuous with visceral pleura @ hilum of the lung.

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VASCULATURE OF PLEAURA & LUNGS1 LUNG

1 pulmonary artery (venous blood)2 pulmonary veins (arterial blood)

Each lobe and segment its own arteryBranching of the arteries follow the bronchial tree Terminate as capillaries around the alveols.

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VASCULATURE OF PLEAURA & LUNGS

Veins of the parietal pleura drain into systemic veins mainly through the intercostal veins.

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BRONCHIAL ARTERIESfollow bronchial tree as far as respiratory bronchioles.Left bronchial arteries from thoracic aortapaired Right bronchial artery usually arises from 3rd posterior intercostal arterysingle artery.

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BRONCHIAL VEINSRight bronchial vein into azygos vein

Left bronchial vein into accessory hemiazygos vein.

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pulmonary plexuses

parasympathetic innervation vagus nerve bronchoconstrictor, vasodilator to the lung vessels, secretomotor to the glandssympathetic sympathetic trunk bronchodilator, vasoconstrictor to the lung vessels, inhibitor to glandsparietal pleura intercostal & phrenic nerves