67 Development of head and neck Flashcards
Where are the bones and autonomic ganglia derived from?
Neural crest of the surface ectoderm;
also contains the connective tissue of head and go pharyngeal arches
Where are the cranial sensory ganglia derived from?
Neural crest and places of the surface ectoderm
What will the neural tube develop into?
Brain and spinal cord;
parasympathetic preganglionic neurons;
optic cup with optic neurons
3 structures from the ectoderm? > form cranial nerves
- Neural crest
- Neural tube
- Placodes
Which of the following are derived from the placodes (ectodermal thickenings in the cranial region)?
Lens and CN1;
inner ear epithelium, CN8 ganglion;
olfactory epithelium
Mesoderm forms part of the cranio-cervical skeleton and _____________?
all muscles
Head muscles are from __________ paraxial mesoderm and prechordal mesoderm.
Unsegmented
_______________ are from segmented paraxial mesoderm.
Tongue and neck muscles
Which of the following are true?
A. Eyes are derived from the prechordal mesoderm
B. SCM and trapezius is derived from the lateral plate mesoderm
C. Pharyngeal arch muscles and tongue muscles are derived from the paraxial mesoderm
All of the above
Fronto-nasal and pharyngeal arches 1-3 skeleton - face bones, palate, smaller bones (ear ossicles, styloid process, hyoid) are from _________.
Neural crest
Pharyngeal arches 4-6 - laryngeal cartilages (thyroid, cricoid) are from?
Lateral plate mesoderm
Posterior part of the skull is from ____________.
Paraxial mesoderm
___________ forms part of the skeleton and all ANS ganglia.
Neural crest
Pharyngeal arches rows of thickened regions of the head and neck which are filled with mesenchyme (undifferentiated cells) migrating from _____________ and __________.
Mesoderm and neural crest
What are the narrow spaces between the pharyngeal arches inside and outside respectively?
Outside: Pharyngeal cleft, lined with ectoderm
Inside: Pharyngeal pouch, lined with endoderm
What does the first pair of pharyngeal arch do?
Surround a space to form stomodeum (primordial mouth) > maxillary x2 and mandibular x2 prominences.
Above the 1st arches, the mesenchyme forms an eminence above the stomodeum named?
Frontonasal prominence
> > total number of prominences = 5 (together with maxillary prominences + mandibular prominences)
Rupture of the _______________ between the primordial mouth and pharynx results in the mouth.
Oropharygeal membrane
Which of the followings are components of the pharyngeal arch? A. Cartilage bar B. Muscular tissue C. Artery D. Vein E. Cranial nerve (CN5,7,9,10) F. Mesenchyme
All except D
Pharyngeal arch 1 is the __________ arch that forms the skeleton of the mandible, maxilla, zygomatic. Will Meckel’s cartilage persist?
Mandibular;
no, except it forms the incus and malleus
Pharyngeal arch 2 gives rise to the _______ (skeleton)
Hyoid
Arch 4: thyroid
Arch 6: larynx
Which of the following about the pharyngeal arches matches with the muscles they give rise to?
A. Arch 1: Masticatory (CN5)
B. Arch2: Facial (CN7)
C. Arch 3 Stapedius
D. Arch 4-6: Pharyngeal and laryngeal
C is wrong
should be stylopharyngess (CN9)
(5,7,9,10)
What muscles are not from arch?
Tongue muscles, somite cells migrate to arches 1-3 of primordial tongue, CN12 grows along;
CN11 SCM and trapezius too
The 1st pharyngeal cleft forms the _________.
External acoustic meatus;
*2nd arch grows over the 3rd and 4th, forming a cavity (cervical sinus) between them, which later disappears
The auricle of the ear is formed from?
1st and 2nd arches form 6 tubercles
List 2 maldevelopment of the ear.
- Cervical sinus may persist as a branchial (lateral cervical) cyst or fistula in front of SCM
- Defect of the fusion of the auricular tubercles results in preauricular cyst (common in people that hole)
1st pharyngeal pouch gives rise to?
Tympanic cavity, auditory tube;
1st pharyngeal cleft: EAM
2nd pharyngeal pouch gives rise to?
Palatine tonsil, tonsillar fossa
3rd pharyngeal pouch gives rise to?
Inferior parathyroid gland; thymus
4th pharyngeal pouch gives rise to?
Superior parathyroid gland. Parafollicular cells of thyroid gland.
Apposing linings of the 1st pouch and 1st cleft form the?
Tympanic membrane
Which of the following about development of thyroid is false?
A. A diverticulum of the pharynx forms immediately caudal to the anterior 2/3 of tongue at the midline = at the foramen cecum (apex of sulcus terminalis)
B. The diverticulum extends downward in front of the larynx to form the thyroid gland
C. The diverticulum narrows down to a canal (thyroglossal duct) and persists.
C is wrong; it later disappears
if not > Ectopic thyroid tissue and cysts (remnants of the thyroglossal duct) along the midline
What is DiGeorge syndrome?
Hypoplasia of the parathyroid, thyroid and thymus, therefore reduced functions and immunological defects , face and heart detects
Which arch makes up anterior 2/3 of the tongue?
1st arch
2,3,4th arches: posterior 1/3 of the tongue
Which arch forms the epiglottis?
4th arch
Myoblast from somites migrate to the tongue primordial, dragging CN______ along with them
12 (dragged to the arch in front)
Which is true about development of the larynx?
A. Caudal to 4th arch, a laryngeoracheal groove appears in pharyngeal floor and expands as diverticulum
B. Cranial end of diverticulum: 4th-6th arches form the largyngeal cartilages
C. Laryngeal lumen is occluded by rapid thickening of wall, and is recanulized.
All of them
C: imcomplete recanulization results in laryngeal Arte
In the face, thickening of the ____________ invaginate to form the nasal pit.
frontonasal prominence
*then adjacent mescenchyme proliferates to form the medial and lateral prominences
Which prominences forms the upper lip?
- Maxillary prominence
2. Medial nasal prominences
Nasolacrimal duct and lacrimal sac is developed from?
The groove between the maxillary and lateral nasal prominences
The mandible and lower lip is formed from?
The mandibular prominences
NOT MAXILLARY!
The intermaxillary segment that formed by the 2 medial nasal prominences fusing together forms the __________ and part of the palate.
Philtrum
The __________ forms the nasal septum which grows downwards to meet the palate.
Frontonasal prominence
The _________ membrane separates the nasal from the oral cavity, which ruptured later to form the ______________ > nasal and oral cavities becomes continuous.
oronasal; primitive choana (is a space/hole)
The posterior end of the nasal cavity is the __________choana.
definitive
The nose is made up of which 3 types prominences?
Frontonasal, medial nasal and lateral nasal prominences.
Median cleft lip is due to?
Left and right medial prominences fail to fuse
Unilateral and bilateral cleft lip is due to? (from 鼻哥窿)
Maxillary and medial nasal prominences fails to use
Oblique cleft lip is due to?
Maxillary, Medial, lateral nasal prominences fail to fuse.
In the baby skull, ______ is underdeveloped and thus causes?
Mastoid;
unprotected CN7
Closure of fontanelles?
- Posterior fontanelle: 2-4 months (3 sutures)
2. Anterior fontanelle: 15-24 months (4 sutures)
The anterior fontanelle:
A. Allows ultrasound to penetrate (in contrast to bone): useful in diagnosis
B. In infants, allow aspiration of blood/fluid and administration of drugs
C. In labour, allows determination of head position by palpation
D.Tense/ persistent bulging of fontanelle indicates raised intracranial pressure
E. Sunken fontanelle indicates dehydration/ malnutrition
All of the above
