Embryology + Genetics Flashcards
Function of somites in embryo
Give rise to bones and muscles
What is a totipotent zygote
initial cell has the capacity to develop into any kind of cell in the body
What is cleavage
Growth of the zygote via cell division
What is gastrulation
When the embryo which begins as a bilaminar disc becomes a trilaminer disc
What does Arch 1 give rise to
Arch 1 gives rise to the maxillary and
mandibular process
What are the 5 embryonic prominence
1 x Frontonasal
2 x Maxillary
2 x Mandibular
What is the stomodaeum
Primitive mouth
Three layers that make up each arch
Ectoderm, endoderm, mesoderm
What is ossophocation
Cartilage becoming bone
Cranial nerve derived from PA1
V Trigeminal
Muscles derived from PA1
Muscles of mastication, including the mylohyoid & ant. belly of digastric, Tensor tympani
Tensor veli palatini
Muscles derived from PA2
Muscles of facial expression: Stapedius, stylohyoid, post. belly of diagastric
Cranial nerve derived from PA2
VII Facial nerve
Cranial nerve derived from PA3
IX Glosssopharyngeal
Muscles derived from PA3
Stylopharyngeus
Cranial nerve derived from PA4-6
X Vagus
Muscle derived from PA4-6
Cricothyroid, Levator veli palatine, Constrictors of pharynx, Intrinsic muscles of the larynx
larynx, palate and esophagus
Proliferation meaning
Cell division
What is the structure that will become the future eye of the baby
The optic vesicle
What does the maxillary prominence develop from
Pharyngeal arch I
What does the mandibular prominence develop from
PA1
Development of the middle nose, upper lip and primary palate
Localised ectodermal thickenings become nasal placodes, ectomesenchyme proliferates and produces a ridge converting to nasal pits and medial and lateral nasal prominences, gives rise to middle of nose, upper lip and primary palate
How do the lateral side of the nose and lips develop
At weeks 7-8 the lateral nasal processes fuses with the maxillary processes
What formation makes the middle portion of the nose, the philtrum, upper portion of the upper lip and primary palate
Medial nasal process + frontonasal process
How is the lower lip formed
Formation of the two mandibular processes
Four steps of the formation of the tongue
- formation of lateral (distal) & medial swellings 2. distal swellings enlarge to become anterior 2/3 (facial nerve, chorda tympani branch) 3. arch 3 & 4 overgrow arch 2 to form posterior 1/3 (glossopharyngeal nerve) 4. arch 4 gives rise to epiglottis & CN X
The developing tongue receives a contribution from branchial arches I to IV. Which arch contributes to the anterior 2/3 of the tongue?
I
The posterior 1/3 of the tongue is largely derived from which pharyngeal/ branchial arch?
III
which developmental week post-fertilisation can branchial arches be seen?
Week 4
Most of the mesenchyme is derived from which embryonic structure?
Neural crest cells
What is mesenchyme
Type of embryological tissue derived from neural crest cells
The epiglottis is derived from which branchial arch?
PA
Which of the branchial arches gives rise to the cartilages of the larynx?
PA4-6
which arch do CARTILAGES
Thyroid Cricoid Artenoid Corniculate Cuneform
PA4-6
Which arch does the inferior hyoid bone develop from
PA3
Where is the styloid process and what arch does it develop from
Pokey bit behind TMJ joint, develops from PA2
Where are the malleus and incus located and what arch do they develop from
Ossicles of the middle ear, develop from PA1
Where is the stapes located and what pharyngeal arch does it develop from
Middle ear, develops from PA2
Which arch does the superior part of the hyoid bone develop from
PA2
Where is the palatine bone and which arch does it develop from
Posterior section of the palate in the skull, develops from PA1
Where is the vomer bone located and which arch does it derive from
Bone above palate that is visible on skeleton as a thin line in the nose, derived from PA1
Development of the face (6 steps)
- Facial prominences appear
- Frontonasal prom. form upper margin of stomodeum
- Nasal placodes form nasal pits and prominence
- Maxillary prominence grows medially and nasal prominence merges to midline to form upper lip
- Mandible prom. merge to midline to form midline
- Face develops to adult form
What makes up the primary palate
Premaxillary segment of the maxilla, which contains the four incisor teeth and incisive canal
How does the primary palate form
Two medial nasal prominence in the midline fuse, driven through the growth of the maxillary prom which pushes nasal prominences towards the midline
What does the secondary palate form from
Via outgrowths of the maxillary prominence called the palatine shelves
How does the secondary palate from
Palatine shelves project on either side of the tongue, as the mandible expands and grows the tongue moves down allowing the palatine shelves to grow towards the midline and fuse to form the secondary palate (palatine bone and palatine segment)
