Embryology Flashcards
What pharyngeal pouches is the thymus derived from?
3rd and 4th pharyngeal pouch
What are hassall’s corpuscle’s associated with ?
Medulla of thymus
Which muscles are associated with the first pharyngeal arch?
Muscles of chewing - masseter, temporalis, pterygoid, tensor tympani
Muscles of swallowing - tensor veli palatini, digastric, mylohyoid
Which cranial nerve is associated with the first pharyngeal arch?
Mandibular branch of the trigeminal nerve (CN V3)
What is meckel’s cartilage the precursor for?
Malleus
Which pharyngeal arch is the stapes bone associated with?
Second
Which cranial nerve is associated with the second pharyngeal arch?
Facial nerve (CN VII)
What muscles are associated with the second pharyngeal arch?
Muscles of facial expression (think of the terminal branches of the facial nerve and the muscles they supply)
Stapedius
Digastric
Stylohyoid
Which pharyngeal arch is the cricopharyngeus muscle derived from?
Third
Which bony structures are derived from the third pharyngeal arch?
Greater horn and lower part of the hyoid bone
Which pharyngeal arch is the common carotid artery associated with ?
Third
What are the vascular derivatives of the fourth pharyngeal arch?
Left - Aortic arch
Right - proximal subclavian artery
What nerve is associated with the fourth pharyngeal arch?
Superior laryngeal branch of the vagus nerve (CN X)
What muscles are associated with the fourth pharyngeal arch?
levator palatini
pharyngeal constrictors
cricothyroid
What muscles are associated with the sixth pharyngeal arch?
intrinsic laryngeal muscles
transverse and oblique arytenoids
Thyroarytenoid
Lateral cricoarytenoid
Posterior cricoarytenoid
Which nerve is associated with the sixth pharyngeal arch?
Recurrent laryngeal branch of the vagus nerve
What structures are associated with the the pharyngeal pouches?
1st - cleft is external auditory meatus and tympanic membrane, pouch is internal auditory meatus, middle ear and eustachian tube
2nd - lining of the palatine tonsils
3rd - inferior parathyroid glands, thymus
4th - superior parathyroid glands, thyroid
What do the ventral and dorsal outgrowths of the duodenum derive into?
Ventral - uncinate process and adjacent part of head, pancreatic duct
Dorsal - anterior head, body and tail of pancreas
From which structure is the central tendon of the diaphragm derived
septum transversum - a thick ridge of mesodermal tissue
What is the main structure that determines the descent path of the testicle
gubernaculum
What is an adrenal rest?
Accessory adrenal tissue - appears small round and yellow
Often found in spermatic cord or broad ligament.
Can be found in abdomen or even intracranially
What pharyngeal arch is the pulmonary artery derived from?
Sixth
Where are branchial cysts most likely to develop from?
2nd branchial (pharyngeal) cleft
What other congenital malformations are associated with intestinal malrotation?
Exomphalos and diaphragmatic hernia
What is the embryological origin of the main pancreatic duct?
The duct of the ventral outgrowth of the duodenum
Which cranial nerves are associated with the pharyngeal arches?
1st - Trigeminal
2nd - Facial
3rd - Glossopharyngeal
4th and 6th - Vagus
What is the blood supply associated with each of the pharyngeal arches?
1 - Maxillary artery
2 - Stapedial and hyoid artery
3 - common carotid
4 - L is Aortic arch and R is proximal subclavian artery
6 - L is ductus arteriosus and R is pulmonary artery
What are the cranial nerves associated with each of the pharyngeal arches?
1 - Trigeminal
2 - Facial
3 - Glossopharyngeal
4 - Superior laryngeal branch of vagus
6 - Recurrent laryngeal branch of vagus
