Week 1 Flashcards
what is mesenchyme?
- mesenchyme is embryonic connective tissue.
- it has the same properties as a connective tissue and develops into bone, cartilage, blood vessels etc.
what is the embryological origin of the neck?
branchial/pharyngeal arches
what is the embryological origin of the face?
develops from 5 mesenchymal processes/prominences.
what is the embryological origin of the skull?
develops from the mesenchyme in the head region of developing embryo.
how is the neural tube formed and what does it give rise to?
- some of the ectoderm in the midline of an embryo folds down o form neural tube > brain + spinal cord.
what is the role of somites in the future head region of an embryo?
they help in cranial skeleton development.
what are pharyngeal/branchial arches?
series of arches which develop around the future mouth and pharynx.
how many branchial arches develop in humans?
5
- 6 arches start to develop but number 5 disappears so we are left with 1,2,3,4 and 6.
when do branchial arches begin developing?
late week 4 of gestation
what embryological tissues make up branchial arches? give detail
- ectoderm lines the outside > also forms clefts in between the arches.
- mesoderm in the middle (+ neural crest cells) > cartilage, muscles.
- endoderm on the inside > also forms pouches between arches.
which nerve is derived from the 1st branchial arch?
mandibular branch of trigeminal nerve (V).
what nerve is derived from the 2nd branchial arch?
facial nerve (VII).
which nerve is derived from the 3rd branchial arch?
glossopharyngeal nerve (IX).
which nerve is derived from the 4th branchial arch?
superior laryngeal branch of vagus (X).
which nerve is derived from the 6th branchial arch (no 5th arch)?
recurrent laryngeal branch of vagus (X).
which nerve innervates the muscles of the face?
facial nerve (VII).
which branchial arch are the facial muscles derived from?
2nd branchial arch
- remember because facial nerve is derived from this arch and this nerve innervated the facial muscles.
the anterior belly of the digastric muscle is innervated by which nerve?
- mandibular division of trigeminar nerve (V3).
the posterior belly of the digastric muscle is innervated by which nerve?
- facial nerve (VII).
the anterior belly of the digastric muscle is derived from which branchial arch?
1st
the posterior belly of the digastric muscle is derived from which branchial arch?
2nd
label this
The Meckel’s cartilage, Malleus and Incus are derived from which branchial arch?
1st
The Stapes, Styloid process, Stylohyoid ligament and Lesser horn of hyoid bone are derived from which branchial arch?
2nd