Embryology Flashcards
Pharyngeal arch 1 derivatives (Ms and Ts)
Cartilage: Meckel's cartilage Mandible Mandibular ligament Malleus and Incus
Muscle:
M. of mastication: master, medial pterygoid, lateral pterygoid, temporals
myohyoid
Tensor tympani
Tensor veli palatini
Ant 2/3 tongue
Nerve: V2, V3
Defect in Arch 1 –> Treacher Collins Sn
Pharyngeal arch 2 derivatives (Ss)
Cartilage: Stapes Styloid process Stylohyoid ligament Lesser horn of hyoid
Muscle:
M. of facial expression
Stapedius
Stylohyoid
defects - pharyngocutaneous fistula
Nerve: CN 7
Pharyngeal arch 3 derivatives
Muscle:
StyloPHARYNGEUS
Nerve:
GlossoPHARYNGEAL n.
Pharyngeal arch 4 and 6 derivatives
Cartilage:
Cricoid
Thyroid
Larynx
Muscle:
4: Cricothyroid, pharyngeal m. (swallow)
6: Rest of laryngeal m. (speech)
Nerves: 4+6 = 10
CN 10: superior laryngeal to swallow; recurrent laryngeal for speech
Aortic arch derivatives
1: part of maxillary a.
2: stapedial and hyoid a.
3: Common carotid and proximal internal carotid a.
4: L- adult aorta; R-proximal part of R subclavian a.
6: proximal part of pulmonary a. and ductus arteriosis
Truncus arteriosis
proximal aorta and proximal pulmonary trunk
Primitive ventricle
muscular (trabeculated) L and R ventricles
Bulbus cordis
R/L ventricular outflow tracts (smooth parts)
Primitive atrium
muscular (trabeculated) L and R atria
Sinus venosis left horn
coronary sinus
Sinus venosis right horn
smooth portion of right atria
Right common cardinal v. and right anterior cardinal v
superior vena cava
Foregut
Esophagus stomach 1st and 2nd parts of duodenum Liver Gallbladder Pancreas
Blood supply: celiac trunk
Nerve: parasym: vagus n.
Sympath: splanchnic n.
Midgut
3rd and 4th parts duodenum jejunum ileum appendix colon to splenic flexure
Blood supply: SMA
Nerve: parasym: vagus n.
Sympath: splanchnic n.
Hind gut
distal 1/3 colon
rectum to pectinate line
Blood: IMA
Nerve: parasym: pelvic splanchnic n.
Sympath: lumbar splanchnic n.
Thymus origin
3rd branchial arch
Adult derivatives of hepatic diverticulum and where it develops from
Endodermal
develops on ventral surface of foregut
becomes liver, gallbladder, biliary tree
ventral pancreatic bud –> head of pancreas
embryologic origin of body and tail of pancreas
endodermal
dorsal pancreatic bud develops on foregut
Formation of pancreas
ventral bud rotates around as duodenum formed, fuses w/ dorsal bud around 8 weeks
Spleen origin
mesodermal
arises from dorsal mesentery of stomach
blood supply from foregut (celiac trunk)
Liver development
Endoderm
Hepatic diverticulum
weeks 3-4 grows off anterior part of distal foregut
–> liver, biliary system, head of pancreas
Major site of hematopoiesis in fetus weeks 3-28
Mesodermal hematopoietic stem cell migrate from mesonephrosis to the liver at 3 weeks
Liver becomes the major site of hematopoiesis until week 28
Diaphragm development
Septum transversum: thick mass of cranial mesenchyme
- part of diaphragm and anterior mesentery of foregut
Merges with:
Pleuroperitoneal membrane
Dorsal mesentery of esophagus
Muscles of abdominal wall
Kidney embryology
Pronephros – week 4 -> disappears
Mesonephros – fetal kidney first trimester -> male genital system
Metanephros -> adult kidney, appears week 5
Ureteric bud
Caudal end of mesophros -> collecting system
Induces metanephros to differentiate into renal tubular epithelial structures -> nephrons
Fetal erythropoiesis
3 wks – 1st primitive blood cell progenitors in yolk sac
true hematopoietic from mesoderm near mesonephros region
-migrate to liver
“Young Liver Synthesizes Blood” Yolk sac 3-8 wks Liver – most important site in fetal development Spleen Bone marrow 28 wks
