Embryo Memorization

lanimule's version from 2017-10-23 05:34

Tissue Derivatives

Question Answer
Surface Ectodermanterior pituitary, lens, mouth lining, nose and ear senses, skin, external anus, partoid, sweat, and mammary glands
NeuroectodermCNS - brain, retina/optic nerve, spinal cord
Neural crest (ectodermal)Cell line that harbors MEN2 mutations; PNS incl cranial nerves EXCEPT optic, melanocytes, parafollicular C cells of thyroid, chromaffin cells of adrenal medulla, Schwann cells, pia and arachnoid, SKULL BONES, odontoblasts, aorticopulmonary septum
MesodermMuscle, bone, connective tissue, peritoneum + mesentery, spleen (unlike rest of GI!), CV structures except aorticopulmonary septum, lymphatics, blood, GU system incl vagina
EndodermGut tube epithelium, lungs, liver, gallbladder, pancreas, eustachian tube, thymus, parathyroid, thyroid follicular cells
Abdominal organs not from endoderm?Spleen, peritoneum, mesentery, GU system

Aortic Arch Derivatives

Question Answer
1st1st = maximal; Maxillary artery (i.e. branch of external carotid that gives rise to middle meningeal artery of epidural hematoma fame)
2ndStapedial artery and hyoid; second = stapedial
3rdC=3rd letter; Common carotid and proximal internal Carotid
4th4th arch = 4 limbs i.e. perfuses systemically; left side = aortic arch, right = proximal subclavian
6thProximal pulmonary arteries, ductus arteriosus on left


Branchial Arch Derivatives (i.e. mesoderm) :

Question Answer
1stMs - Mandibular and Maxillary divisions of trigeminal = innervation; Mandible, malleus, muscles of mastication, masseter, medial/lateral pteryoid, mylohyoid, also tensor tympani and tensor tympani veli palatini; failure → Treacher Collins
2ndSs - Stapes, Styloid process, stylohyoid ligament; "smile" muscles i.e. CN VII muscles, stapedius, stylohyoid
3rdSwallow stylishly - CN IX innervation; stylophargengeus and posterior thrid of tongue; persistence → pharyngocutaneous fistula between tonsillar area, cleft in lateral neck
4thSimply swallow - CN X (superior laryngeal branch) = pharyngeal constrictors; shares posterior third of tongue with arch 3
6thSpeak - all instrinsic muscles of larynx except cricothyroid (CN X, recurrent laryngeal branch)
MnemonicWhen at the restaurant with the golden ARCHES, children tend to first CHEW (1), then SMILE (2), then SWALLOW STYLISHLY (3) or SIMPLY SWALLOW (4), then SPEAK (6).

Branchial Pouch Derivatives (i.e. endoderm) :

Question Answer
1stMiddle ear, mastoid air cells
2ndPalatine tonsils
3rdDorsal wings = inferior parathyroids (note pouches flip places), ventral wings = thymus
4thDorsal wings = superior parathyroids (note pouches 3 and 4 switch places)
Associated disordersDiGeorge aberrant 3rd or 4th (usually 3rd) pouch → thymic aplasia and T-cell deficiency + hypocalcemia due to no parathyroids; MEN 2A = germline neural crest cell mutation → pheo + parathyroid tumor + parafollicular cell tumor