Resp Anatomy-2.1 Development of Respiratory system
| Text | TracheaIt is made up of fibro-elastic {{c1::wall supported by C-shaped cartilaginous skeleton}}The rings are about {{c1::16-20}} in number, the last tracheal ring is called {{c1::carina}}Mucous membrane is lined by {{c4::pseudo stratified ciliated columnar}} epithelium with {{c1::goblet cells resting on a basement membrane.}}Deep to the basement membrane is the {{c2::lamina propria made up of areolar tissue with elastic fibres and lymphocytes.}}only Submucosa is composed of a {{c2::loose meshwork of connective tissue, containing large blood vessels, nerves, mucous, serous and mixed types ofglands. }}The ducts open on the free surface of the {{c2::epithelium}}.{{c2::Hyaline}} cartilage is present outside the submucosa. Cartilage is covered by {{c2::perichondrium on all sides, which separates it from theneighbouring structures.}}The gap of the C shaped ring is closed by {{c2::fibro-elastic membrane and trachealis muscle}}Posterior wall of trachea is {{c3::devoid of cartilage}}. Here outer {{c3::longitudinal and inner circular layers of smooth muscles (trachealis muscle)}} arepresent within the {{c3::fibrous membrane.}}Adventitia is the {{c3::outermost layer with connective tissue, blood vessels and nerves.}} |
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| Text | Development of nasal cavities:Develop from {{c1::ectodermal nasal pits}}Nasal pits deepen dorsally during {{c1::6th}} week of intrauterine life to form the {{c1::nasal sacs}}Each nasal sac grows dorsoventrally to the {{c1::developing forebrain to form the primitive nasal cavity}}Dorsal end of the primitive nasal cavity is separated from the oral cavity by {{c1::oronasal membrane}}At the end of 6th week the oronasal membrane ruptures to form {{c1::primitive choanae,}} and as a result the nasal cavitycommunicates with the {{c1::primitive oral cavity.}} |
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| Text | Development of paranasal air sinusesThe paranasal air sinuses develop as {{c1::diverticulae from the wall of the nasal cavities}}They grow into surrounding bones ({{c1::maxilla, ethmoid, frontal and sphenoid) and become air filled.}} They are named after the name of the bone that they invade ({{c1::maxillary air sinus, ethmoidal air sinuses, frontal air sinus and sphenoidal air sinus)}}The primitive opening of the diverticulae persists as {{c1::orifices}} of the adult sinusesThe lining of paranasal air sinuses is {{c1::ectodermal}} as that of the nasal cavityAll the air sinuses begin to develop before birth except {{c1::frontal air sinus,}} which begins to develop after birth{{c1::Maxillary}} air sinus are the first to develop during 3rd – 4th month of intrauterine lifeThe {{c1::frontal}} air sinus develop by 2nd to 5th or 6th postnatal yearThe paranasal air sinuses reach their maximum size at puberty and subserve following functions:{{c1::Contribute to definitive shape of faceReduce the weight of the skullAdd resonance to the voiceAct as air conditioning chamber by adding humidity and temperature to the inspired air}} |
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