Anatomy- Head And Neck Development Flashcards
1
Q
Gastrulaation three layers
A
- ectoderm: epidermis, nervous system
- endoderm: respiratory, digestive
- mesoderm: MSK, dermis, ardiovascular
2
Q
Promitrive streak/node
A
- first sign of gastrulation, epiblast cell moveement inward -> becomes the three layers
- diminishes after 4 weeks and becomes sacrum and coccyx
3
Q
Notochord
A
- triggers neural plate
- goes underneath ectoderm and sends out signal to it to become neural tissue
4
Q
- neural plate
A
- thickening of ectoerm, CNS
- also signalled by notchord - becomes neural groove - will become brain + spinal chord
- neural crest cells: from ectoderm, nerves (cranials) and connective tissue, muscle, dermis
5
Q
Cranium: foetal stage
A
- base bones: complex, chunky cranium from cartilaginous origin
- cranium flat bones from mesenchyme origine. Joined by sutures called fontanelles - molding during childbirth
6
Q
Cranium: newborn
A
- cranium round and large (thin)
- face small because jaw and sinuses have not developped
7
Q
Cranium: postnatal
A
- growth of cranium continues to 16 yo and then thickens until early 20
8
Q
Clinical issues with cranium
A
- acrania: cranium absent - death
- craniosysnotosis: prenatal closure of sutures - in particular sagital suture
- holoprosencephaly: single feature, cerebrum (single frontal lobe, cyclopia, single nostril….)
9
Q
Pharyngeal arches
A
- four main ones
- 5/6 rudimentary
- arches support walls of pharync
- componentsL mesenchyme core, ectoderm, endoderm
- arch has artery, cartilage, muscle, nerves
10
Q
1st pharyngeal arch:
- skeleton
- muscle
- nerve
A
- skeleton: incus, malleus, maxilla, zygomatic, vomer, mandible, temporal
- muscle: mastication, mylohyoid, anterior digastric, tensor tympani, TVP
- nerve: trigeminal
11
Q
2nd pharyngeal arch
- skeleton
- muscle
- nerve
A
- skeleton: stapes, styloid process, hyoid
- muscle: facial expression, stylohyoid, posterior digastric, stapedius
- nerve: facial
12
Q
3rd pharyngeal arch
- skeleton
- muscle
- nerve
A
- skeleton: hyoid
- muscle: stylopharyngeus
- nerve: glossopharyngeal
13
Q
4th/6th pharyngeal arch
- skeleton
- muscle
- nerve
A
- skeleton: laryngeal cartilages
- muscle: LVP, palatoglossus, palatopharyngeus, pharyngeal constrictors, laryngeal
- nerve: X
14
Q
Pharyngeal pouches: four internal diverticula
A
- 1st: tympanic cavity, auditory tube
- 2nd: tonsillar fossa, palatine tonsil
- 3rd, 4th: parathyroid gland, thymus
15
Q
Pharyngeal grooves
A
- four external clefts
1st: external acoustic meatus
- all the others obliterate
