Flashcards in Session 2 - Part II Deck (54):
What forms the embryonic head and neck?
The pharyngeal arches
What drives the development of the face?
What are pharyngeal arches?
System mesenchymal proliferations in the neck region of the embryo
Have a mesenchyme core, ectoderm covering (pharyngeal arch), endoderm inner side (pharyngeal cleft)
How many pharyngeal arches are there?
1 --> 6, but 5 regresses in humans
What is the largest pharyngeal arch?
What is the smallest pharyngeal arch?
Which section of the neural tube forms the brain?
The anterior end
What are 3 stages of neural tube making the brain?
Prosencephalon --> Forebrain
Mesencephalon --> Midbrain
Rhambencephalon --> Hindbrain
How many cranial nerves develop?
Which cranial nerves are derived from the mid/hind brain?
All except for nerve I & II
Which cranial nerves supply the pharyngeal arches and the derivatives of them?
V, VII, IX, X
What nerve does CN XI become?
Cranial accessory nerve
What nerve does CN XII become?
What is the facial skeleton derived from?
Frontonasal prominence and 1st pharyngeal arch
What are the muscles of mastication derived from?
Pharyngeal arch I
What are the muscles of facial expression derived from?
Pharyngeal arch II
What does the 3rd pharyngeal arch become?
What does the 4th pharyngeal arch become?
What does the 6th pharyngeal arch become?
Intrinsic muscles of the larynx
What is the nerve of the first pharyngeal arch?
What does CN V become?
What is the function of the Trigeminal nerve?
Sensory nerve of the head, skin of the face and lining of the mouth & nose
Motor nerve of the muscles of mastication and muscles derived from the mandibular process
What is the nerve of the 2nd pharyngeal arch?
What does CN VII become?
What is the function of the Facial nerve?
Sensory of taste buds in the anterior 2/3rd of tongue
Motor of muscles facial expression and those derived from 2nd pharyngeal arch
What does the Facial nerve pass through?
What is the nerve of the 3rd pharyngeal arch?
What does CN IX become?
What is the function of the Glossopharyngeal nerve?
Innervates stylopharyngeus muscle
General & specific sensory innervation to posterior 1/3 of tongue
What is the nerve of the 4th & 6th pharyngeal arch?
What does CN X become?
What is the branch of the Vagus nerve for the 4th pharyngeal arch?
Superior laryngeal nerve
What is the function of the Superior laryngeal nerve?
Innervates the Cricothyroid which constricts the pharynx
What is the branch of the Vagus nerve for the 6th pharyngeal arch?
Recurrent laryngeal nerve
What is the function of the Recurrent laryngeal nerve?
Intrinsic muscles of the larynx
What is unique about the Recurrent laryngeal nerve?
It wraps around the arch of the Aorta
What does each pharyngeal arch develop?
A neural crest derived cartilage bar (Contributes to basic skeletal parts)
What does the 1st cartilage bar do? (Meckel's cartilage)
Divides into Maxillary and Mandibular prominences
What does the Mandicular prominence of the 1st cartilage bar do?
Provides a template for the mandible which forms via membranous ossification leaving outline for the bone to form (Cartilage doesn't go to bone)
What does the 2nd cartilage bar do? (Reichert's cartilage)
Contributes to middle ear development (Stapes)
Contributes to styloid process, Hyoid bone (remainder from 3rd arch)
What does the 4th & 6th arch mesenchyme become?
The pharyngeal floor (Aortic sac lies in floor of pharynx)
Thyroid, Arytenoid, Cricoid (Derived from their cartilage bar)
What does the 1st & 2nd Aortic arch become?
What does the 3rd Aortic arch become?
Internal carotid artery
What does the 4th Aortic arch become?
Arch of the Aorta (Left)
Brachiocephalic artery (Right)
What does the 6th Aortic arch become?
What do the pharyngeal pouches mainly become?
How is the Parathyroid gland formed?
From the dorsal portion of the 3rd & 4th pharyngeal pouches
How is the Thymus gland formed?
From the ventral portion of the 3rd & 4th pharyngeal pouches
It is formed as 2 lobes that join in the middle
Which pharyngeal pouch forms the middle ear?
Ossicles = cartiage bar derivative
Tympanic cavity & auditory tube = pouch derivative
What can cause a middle ear infection in children?
What happens to the pharyngeal clefts?
The 2nd grows down and covers all leaving only the 1st remaining
What can occur if the cervical sinus is not obliterated by the 2nd cleft?
Cysts/Fistulae can occur anywhere along the anterior border of the SCM
What is a difference between a cyst and fistulae?
A fistulae is a cyst with an opening to the surface