VIDEO
HIGHLIGHT
Log InSign up
✅ EMBRIOLOGÍA de la CABEZA y el CUELLO (Parte 2°) 🦷🙇🏻
SummaryTranscriptChat

✅ EMBRIOLOGÍA de la CABEZA y el CUELLO (Parte 2°) 🦷🙇🏻

Introduction

The video introduces the topic of Head and Neck Embryology and mentions the reference book used for the information.

Welcome and Topic Introduction

  • The video starts with a greeting and welcomes viewers to the channel.
  • The topic of discussion is introduced as "Head and Neck Embryology."
  • The presenter mentions that they have tried to be as updated as possible, basing their information on the 14th edition of Langman Embryology book.
  • Viewers are encouraged to watch the video for helpful information.

Pharyngeal Bags

This section focuses on the development of pharyngeal bags in human embryos.

Development of Pharyngeal Bags

  • Human embryos have four pairs of pharyngeal bags, with the fifth pair being rudimentary.
  • The first pharyngeal pouch forms a diverticulum called recess tube-tympanic, which comes into contact with the epithelial lining of the first pharyngeal cleft.
  • The distal portion of this diverticulum widens to create a sack-like structure known as Primitive Tympanic Cavity or Middle Ear. Its proximal segment remains narrow and forms the Eustachian Tube (or Pharyngotympanic).
  • The Tympanic Cavity Coating later participates in Tympanic Membrane or Eardrum formation.
  • In the second pharyngeal bag, its epithelial lining proliferates and forms buds that penetrate into the surrounding mesenchyme. These buds undergo secondary invasion by mesodermal tissue, forming the primordium of Palatine Tonsils.
  • The third and fourth bags are characterized by dorsal and ventral wings at their distal ends.
  • In week five, the epithelium of the dorsal region of the third pouch differentiates into the Lower Parathyroid Gland, while in the ventral region, it forms the Thymus.
  • The thymus migrates caudally and medially, taking with it the Lower Parathyroid.
  • The dorsal region of the fourth pharyngeal pouch forms the Superior Parathyroid Glands, which attach to the dorsal surface of the Thyroid Gland during its caudal migration.
  • The ventral region of the fourth bag gives rise to Ultimobranchial Body, later incorporated into the Thyroid Gland.

Pharyngeal Clefts

This section discusses pharyngeal clefts and their development.

Development of Pharyngeal Clefts

  • In a five-week embryo, there are four pharyngeal clefts present.
  • The External Auditory Canal (CAE) was previously thought to be formed from the first pharyngeal cleft but is now known to develop from invagination of superficial ectoderm of the first Pharyngeal Arch.
  • Overgrowth of the second arch leads to disappearance of the first cleft.
  • Active proliferation of mesenchymal tissue from the second arch causes overlapping and fusion with third and fourth clefts.
  • Eventually, fusion occurs with epicardial border in lower neck region, causing loss of contact between second, third, and fourth clefts with outside environment.
  • The clefts form a cavity covered by ectodermal epithelium called Cervical Sinus, which disappears at a later stage of development.

Language Development

This section focuses on language development during embryonic stages.

Language Development

  • Around the fourth week, two lateral lingual bumps and a medial bulge called Odd Tuber appear as language development.
  • These bumps originate from the first Pharyngeal Arch.
  • A second medial bulge called the Dome or Hypobranchial Eminence is formed by mesoderm of the second, third, and part of the fourth arch.
  • The Epiglottis develops behind this bulge, and the Laryngeal Orifice is located flanked by arytenoid bumps.
  • The lateral lingual bumps merge with the odd tubercle to form the body of the tongue.

Terminal Groove

This section discusses the separation of the body of the tongue from its posterior third by a V-shaped groove called Terminal Groove.

Separation of Body of Tongue

  • The body of the tongue is separated from its posterior third by a V-shaped groove known as Terminal Groove.

New Section

This section discusses the development of the epiglottis, posterior end of the tongue, and thyroid gland.

Development of Epiglottis and Posterior End of Tongue

  • The epiglottis and posterior end of the tongue develop from the 4th arc.
  • Some tongue muscles are derived from myoblasts originating in the occipital somites.

Development of Thyroid Gland

  • The thyroid gland appears as epithelial proliferation on the floor of the pharynx.
  • It initially remains connected to the tongue through the thyroglossal duct.
  • As development progresses, it descends in front of the hyoid bone and laryngeal cartilages.
  • The thyroid reaches its final position in front of the trachea by the 7th week.
  • It consists of a small midline isthmus and two lateral lobes.

Formation of Face

This section explains how facial prominences form during embryonic development.

Facial Prominences

  • Facial prominences appear at the end of the 4th week, derived from neural crest mesenchyme.
  • Maxillary prominences can be identified laterally, while mandibular prominences are observed caudally to them.
  • The frontonasal prominence constitutes the upper edge of stomodeus, with nasal or olfactory placodes forming on both sides.

Formation of Nose

  • Nasal placodes invaginate during the 5th week, giving rise to nostrils and nasal prominences.
  • Maxillary prominences compress the medial nasal prominences towards the midline, leading to the formation of the upper lip.
  • The lower lip and jaw are formed from the mandibular prominences merging into the middle line.

Nasolacrimal Groove

  • At first, maxillary and lateral nasal prominences are separated by a deep groove called the nasolacrimal groove.
  • The ectoderm of this groove forms a solid epithelial cord that gives rise to the nasolacrimal duct.
  • After fusion of maxillary and lateral nasal prominences, the nasolacrimal duct connects from the medial angle of the eye to the inferior meatus of the nasal cavity.

Formation of Upper Lip

This section describes how different facial prominences contribute to forming the upper lip.

Formation of Upper Lip

  • Medial growth of maxillary prominences leads to fusion with medial nasal prominences on both surface and deeper levels, forming an intermaxillary segment.
  • The intermaxillary segment consists of a lip component (forming filtrum) and a superior maxillary component (containing incisor teeth).

Nose Formation

  • The nose is formed from five facial processes: frontonasal prominence (bridge), medial nasal prominences (back and tip), and lateral nasal prominences (wings).

New Section

This section discusses the development of the intermaxillary segment, nasal septum, primary palate, and definitive palate.

Development of Intermaxillary Segment and Nasal Septum

  • The intermaxillary segment maintains continuity with the rostral portion of the nasal septum.
  • The frontal prominence contributes to the formation of the intermaxillary segment.
  • The primary palate derives from the intermaxillary segment.
  • The definitive palate integrates from two similar evaginations called palatine crests, which appear in the 6th week of development.
  • The palatine crests grow oblique and down on either side of the tongue.

Formation of Secondary Palate

  • During the 7th week, the palatine ridges rise to a horizontal position above the tongue and merge to form the secondary palate.
  • The palatine crests merge with the triangular primary palate in a region marked by the incisor foramen.
  • Simultaneously, the nasal septum grows down and joins with the cephalic face of the newly formed palate.

New Section

This section focuses on nostril development during embryonic growth.

Nostril Development

  • During the 6th week, nostrils deepen due to growth of surrounding nasal prominences and penetration towards underlying mesenchyme.
  • Initially, oronasal membrane separates pits from primitive oral cavity through newly formed holes called primitive coanas located behind the primary palate.
  • With formation of secondary palate and further development of the primitive nostrils, definitive coanas are located at the junction of nasal cavity and pharynx.

New Section

This section discusses the development of paranasal sinuses and their contribution to facial configuration.

Development of Paranasal Sinuses

  • Paranasal sinuses develop as diverticula of the lateral nasal wall and extend into maxillary bone, ethmoid, frontal, and sphenoid bones.
  • They reach their maximum dimension during puberty and contribute to the final configuration of the face.
  • The shape of the face depends not only on expansion of paranasal sinuses but also on growth of jaw and maxilla to house teeth.

New Section

This section focuses on tooth development during embryonic growth.

Tooth Development

  • Teeth originate from an interaction between oral epithelium and underlying mesenchyme derived from neural crest cells.
  • Around the 6th week, dental sheet forms a C-shaped structure throughout maxilla and mandible.
  • Dental buds arise from this sheet, with 10 in the maxilla and 10 in the jaw, forming ectodermal components of teeth.
  • The buds invaginate to form cap stage, consisting of external dental epithelium, internal dental epithelium, and dental papilla.
  • As tooth development progresses, bell stage is reached with differentiation of odontoblasts in papillary mesenchyme that produce dentin. Ameloblasts in internal dental epithelium produce enamel prisms.
  • Odontoblasts retract into dental papilla as dentin layer thickens, while the remaining cells of the dental papilla constitute the pulp of the tooth.
  • Ameloblasts in internal dental epithelium produce enamel prisms, and a group of these cells form the enamel knot that regulates early tooth development.

New Section

This section briefly mentions tooth root formation.

Tooth Root Formation

  • The transcript does not provide specific information about tooth root formation.

New Section

This section discusses the formation of the epithelial radicular sheath, dental papilla cells, and the deposition of dentin in the tooth.

Formation of Epithelial Radicular Sheath and Dentin Deposition

  • The dental papilla cells form the epithelial radicular sheath.
  • These cells deposit a layer of dentin, which continues with that of the crown.

New Section

This section explains how more dentin deposition leads to narrowing of the pulp chamber and the formation of a canal containing blood vessels and nerves.

Dentin Deposition and Pulp Chamber

  • As more dentin is deposited, the pulp chamber narrows.
  • Eventually, it forms a canal that contains blood vessels and nerves responsible for tooth sensation.

New Section

This section describes mesenchymal cells on the outside of the tooth and their differentiation into cementoblasts.

Mesenchymal Cells and Cementoblasts

  • Mesenchymal cells on the outside of the tooth are in contact with root dentin.
  • These cells differentiate into cementoblasts.
  • Cementoblasts produce a thin layer of specialized bone called cement.

New Section

This section discusses the mesenchyme outside the cement layer giving rise to periodontal ligament, which holds the tooth in position.

Periodontal Ligament

  • Outside the cement layer, mesenchyme gives rise to periodontal ligament.
  • The periodontal ligament firmly holds the tooth in position.
  • It also acts as a buffer between teeth during chewing.

New Section

This section explains how the elongation of the root pushes the crown through tissue layers until it emerges into the oral cavity.

Elongation of Root and Crown Emergence

  • With additional elongation of the root, the crown is gradually pushed through overlying tissue layers.
  • Eventually, it emerges into the oral cavity.

New Section

This section discusses deciduous or milk teeth eruption and the formation of permanent tooth buds.

Deciduous Teeth Eruption and Permanent Tooth Buds

  • Deciduous teeth eruption occurs between 6 and 24 months after birth.
  • Permanent tooth buds, located on the lingual side of decidual teeth, are formed during the 3rd month of development.
  • These buds remain dormant until about 6 years in postnatal life.

New Section

This section concludes the video with a call to action for viewers to like and subscribe for future videos.

Conclusion

  • The video ends with a request for viewers to like if they enjoyed it and subscribe for notifications on future videos.
Playlists: ✅ VIDEOS DE EMBRIOLOGÍA
Video description

Fácil, Práctico y Sencillo. ✅ Aprende los CONCEPTOS BÁSICOS DE LA EMBRIOLOGÍA DE LA CABEZA Y EL CUELLO de una manera fácil, rápida y concisa. #EmbriologíaLangman #Medicina #Odontología ⌚Marcas de tiempo: 0:00 Bienvenida 0:20 Bolsas Faríngeas 2:26 Hendiduras Faríngeas 3:29 Lengua 5:36 Glándula Tiroides 10:06 Fosas Nasales 11:19 Formación de los Dientes —————————————————————————————— 🚀Lista de reproducción "EMBRIOLOGÍA HUMANA 👶 ✅" ● https://bit.ly/EmbriologiaHumana —————————————————————————————— 🤩Suscribete en el link de abajo 👇 : ● https://bit.ly/VideosMedicina —————————————————————————————— 👨‍💼Contacto comercial ● francokellytb@gmail.com —————————————————————————————— 💰 Donaciones (Apoyo para mejorar mi contenido): ● https://bit.ly/YoApoyoTuCanal —————————————————————————————— 🙏GRACIAS POR VER MIS VÍDEOS🙏 Bibliografía: Langman Embriología 14°Edición Resumen Las hendiduras faríngeas son estructuras transitorias que desaparecen. La primera hendidura se oblitera por el crecimiento excesivo del segundo arco faríngeo una vez que constituye la mayor parte del oído externo. La segunda, tercera y cuarta hendiduras quedan ocluidas por el crecimiento del segundo arco en dirección caudal, que se superpone al tercer y cuarto arcos, y se fusiona con el borde epicárdico en la región inferior del cuello. En algunos casos los remanentes de las hendiduras constituyen quistes, fístula cervicales o ambos. La definición de patrones de los elementos esqueléticos de los arcos faríngeos está regulada por la expresión de genes en el endodermo de las bolsas faríngeas. El proceso implica una señalización epitelio-mesénquima en que el endodermo de las bolsas envía señales al tejido que responde, el mesénquima. La expresión de genes en el mesénquima es al inicio determinada por factores de transcripción que contienen homeosecuencias (codificados por los genes OTX2 y HOX), llevados a los arcos faríngeos por las células de la cresta neural que migran. Las células de la cresta se originan a partir de la región caudal del mesencéfalo y segmentos del rombencéfalo denominados rombómeras. Estos genes responden a señales del endodermo y determinan el tipo de elementos esqueléticos que constituyen. La glándula tiroides se origina a partir de una proliferación epitelial en el piso de la lengua y esciende hasta su nivel frente a los anillos traqueales durante el proceso de desarrollo. Las prominencias maxilares y mandibulares, que se presentan en pares, y la prominencia frontonasal, son las primeras en aparecer en la región de la cara. Más adelante se forman prominencias nasales mediales y laterales en torno a las placodas nasales, a partir de la prominencia frontonasal. Todas estas estructuras son importantes debido a que determinan, por medio de la fusión y el crecimiento especializado, la dimensión y la integridad de la mandíbula, el labio superior, el paladar y la nariz. La formación de labio superior ocurre por la fusión de las dos prominencias maxilares con las dos prominencias nasales mediales. El segmento intermaxilar se forma por la fusión de las dos prominencias nasales mediales en la línea media. Este segmento está compuesto por (1) el filtrum; (2) el componente maxilar, que incluye a los cuatro dientes incisivos, y (3) el componente palatino, que forma el paladar primario triangular. La nariz deriva de (1) la prominencia frontonasal, que forma el puente; (2) las prominencias nasales mediales, que constituyen el dorso y la punta; y (3) las prominencias nasales laterales, que forman las alas. La fusión de las crestas palatinas, que se forman a partir de las prominencias maxilares, crea el paladar duro (secundario) y el blando. Se puede generar una serie de deformidades por hendiduras como consecuencia de la fusión parcial o incompleta de estos tejidos mesenquimatosos, que pueden tener como causa factores hereditarios o fármacos (difenilhidantoína). —————————————————————————————— videos de embriologia, videos de embriologia humana en español , videos de embarazo, videos embriologia langman, embriologia videos explicativos, videos sobre embriologia video embriologia, videos de embriologia humana, videos aulas de embriologia, embriologia humana pdf, embriologia humana y biologia del desarrollo pdf, embriologia humana, embriologia y biologia del desarrollo, embriologia humana etapas, embriologia humana flores pdf, embriologia humana video, inicio vida humana embriologia, embrion video, embriologia del corazon video, embriologia del ojo, embriologia del desarrollo, embriologia humana facil