Skull and Face

Question 1

Mesenchyme for the formation of the head region is derived from…..

Answer 1

• paraxial mesoderm
• lateral plate mesoderm
• ## neural crest cells

Question 2

What is formed from paraxial mesoderm?

Answer 2

large portion of the cartilaginous components of the neurocranium, all voluntary muscles of the crainiofacial region, the dermis, the connective tissues in the dorsal region of the head, and the meninges caudal to the prosencephalon

Question 3

What is formed from lateral plate mesoderm?

Answer 3

laryngeal cartilages and connective tissue

Question 4

How are neural crest cells involved in the head and neck region?

Answer 4

Neural crest cells originate in the neuroectoderm of forebrain, hindbrain and midbrain and migrate ventrally into the pharyngeal arches and rostrally around the forebrain and optic cup into the facial region. They form the face, and part of the membranous and cartilaginous regions of the skull.
They also form other tissues including cartilage, bone, dentin, tendon, dermis, pia, arachnoid, sensory neurons, glandular connective tissue

Question 5

When do the pharyngeal arches appear?

Answer 5

Week 5

Question 6

What nerve innervates each of the arches?

Answer 6

1 = trigeminal, maxillary and mandibular branches 
2 = facial 
3 = glossopharyngeal 
4 = vagus (superior laryngeal branch)
6 = vagus (recurrent branch)

Question 7

Which muscles are derived from each arch?

Answer 7

1 = mastication x4, mylohyoid, anterior belly of digastric, tensor palatine, tensor tympani 
2 = facial expression, posterior belly of digastric, stylohyoid, stapedius 
3 = stylopharyngeus 
4-6 = cricothyroid, levator palatine, constrictors of pharynx, intrinsic muscles of larynx