Embryo

Question 1

Which pharyngeal/aortic arch is associated with CN V, VII, and IX?

Answer 1

• 1st aortic arch –> Trigeminal (CN V)
• 2nd aortic arch –> Facial (CN VII)
• 3rd aortic arch –> Glossopharyngeal (CN IX)

Question 2

What is the associated CN and key aortic arch derivative of the 6th pharyngeal/aortic arch?

Answer 2

• Recurrent laryngeal branch of Vagus (CN X)
• Pulmonary arteries and Ductus arteriosus

Question 3

What is the associated CN and key aortic arch derivative arising from the 4th pharyngeal/aortic arch?

Answer 3

• Superior laryngeal branch of Vagus (CN X)
• True aortic arch and Subclavian arteries

Question 4

What does the notochord become?

Answer 4

Nucleus pulposus of the intervertebral disks in adults

Question 5

What is embryological origin of the anterior and posterior pituitary gland?

Answer 5

• Anterior derived from the Rathke pouch, an evagination of the surface ectoderm
• Posterior derived from the infundibulum, an extension of neuroectoderm from the diencephalon

Question 6

Which cells suppress female internal reproductive organ development by producing anti-Mullerian hormone causing Mullerian duct involution?

Answer 6

Sertoli Cells

Question 7

Which cells secrete testosterone, stimulating the Wolffian (mesonephric) ducts to develop into the male internal reproductive organs i.e., epididymides, vas deferens, ejaculatory ducts and seminal vesicles?

Answer 7

Leydig cells

Question 8

The hyoid bone at the base of the mandible is derived from which 2 pharyngeal arches?

Answer 8

• The lesser horn: derived from the 2nd arch
• The greater horn: derived from the 3rd arch

Question 9

The most highly oxygenated blood in the fetus is carried by what and where does it empty into?

Answer 9

Umbilical vein which empties into the IVC via the ductus venosus