8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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Paranasal Air Sinuses
• Diverticula grow from nasal cavity walls into
surrounding bones
•Openings of outgrowths persist as orifices ofadult sinuses
• At Birth- no frontal or sphenoidal sinuses
• Maillary-!-" mm• Ant # post $thmoidal- %ew cells
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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Paranasal Air Sinuses
• $thmoidal- small uptil & yrs grows rapidly
'-( yrs
•Maillary- grows slowly till puberty) fullydeveloped in adulthood
• %rontal grows from ant ethmoidal-&yrs
rapid dev* +yrs
• Sphenidal-grows from post* $th* & yrs
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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Pharyngeal arches # primordial
Pharyn
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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,aryngotracheal groove
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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rachea # Oesophagus
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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,aryn" w.s / w.s
'w.s 01 w.s
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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Bronchi
• "th w.-lung bud
• /th w.-bronchial buds
• 'th
w.-angiogenetic mesenchyme aroundprim* Br*
• +th w.- tertiary br*) bronchopul* Seg*
%ormed• &" w.s-0+ orders of bronchi formed
• After birth- + orders
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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Stages of ,ung Development
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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2istogenesis•Splanchnic Mesoderm
3onnective tissue
3artilage
Muscle
3apillaries4isceral pleura
•Somatic Mesoderm
Parietal pleura•$ndoderm
epithelium
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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2istogenesis
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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Stages of ,ung DevelopmentPseudoglandular phase
• +-0+ w.s
• Development of lower conducting airway # acini
• ,ung resembles eocrine gland
• $pithelium-mesenchyme interactions
• Airway epithelium differentiates
• Mucous glands-0&w.s enlarge) 0" w.s-secretion
• Sm* M # 3 differentiate
• 5o gaseous echange
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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Stages of ,ung Development3analicular phase
• 0+-&' w.s
• Overlaps with pseudoglandular phase
• ,umina of bronchi enlarge
• ! generations of branching
• 6esp* br* # alveolar ducts formed
• Saw7toothed margins of distal regions 7acini
• ype 8 # 88 pneumocytes• Surfactant - ' months
• 9aseous echange possible
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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Stages of ,ung Development
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Stages of ,ung DevelopmentSacular : terminal sac phase
• &" w.s 7 birth
• More terminal sacs with thin epithelium
• ype 8 # 88 alveolar cells 7 surfactant increases
• 8nterstitial tissue decreases
• 3ap*pleus7double cap* layer between alveoli
• $lastin deposited beneath ep*
• ,ymphatics develop
• %etus can survive if born
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Stages of ,ung Development
Alveolar phase• ,ate fetal period 7 childhood• hinning of alveolar lining cells) thin
alveolocapillary membrane- gaseous
echange is easy
• 8ncrease in no* of alveoli /1 million at full
term;0:' adult no*<
• %usion of cap* nets of ad=acent alveoli
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Stages of ,ung Development
8/17/2019 Embryo Lect by Prof Rafeea Tafwwez
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racheo-Oesophageal %istula
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3ongenital anomalies of lungs
• ,obe of A>ygous 4
• 3ongenital Pul* 3ysts
• ,ung Agenesis• ,ung 2ypoplasia
• Accessory ,ung
• Abnormal fissures
• Abnormal lobes
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