Fa Embryology High-Yield Facts And Mnemonics

Front 1

Neural crest derivatives?

Back 1

DR DP ESCAPes in the AM to save Face

Dorsal Root ganglia
oDontoblasts (dentin)
Pigment (melanocytes)
Endocardial cushions
Schwann cells, Sympathetic ganglion
C cells (parafollicular) of thyroid
Arachnoid and Pia mater
Adrenal Medulla chromaffin cells
Facial bones

Front 2

Surface ectodermal derivatives?

Back 2

DEAd PEEL

Distal male urethra
Enamel
Adenohypophysis (rathke's pouch)
Parotid gland
Epidermis
Ear (external and inner, not middle)
Lens of eye

Front 3

Defects from lack of mesodermal derivatives?

Back 3

VATER

Vertebral defects
Anal atresia
Tracheo-Esophageal fistula
Renal defects

Front 4

Fetal Erythropoiesis?

Back 4

Young Liver Synthesizes Blood

Yolk sac (3-8 wk)
Liver (6-30 wk)
Spleen (9-28 wk)
Bone marrow (28 wk onward)

Front 5

Clefts, Arches, and Pouches

Back 5

CAP

Clefts~Ecto
Arches~Meso
Pouches~Endo

Front 6

Aortic Arches? Branchial Arches?

Back 6

1st--MAX ; maxillary a.; M's (meckel's cartilage, mm. of mastication) CN V2 and V3
2nd--Second~Stapedial a., Smile (CN VII)
3rd--3rd letter C; Carotid a.; CN IX
4th--4 limbs; systemic, aortic arch; superior laryngeal n
6th--pulmonary a. and ductus arteriosus; CN X recurrent laryngeal n

When at the restaurant of the golden ARCHES, children tend to CHEW, then SMILE, then SWALLOW STYLishly or SIMPLY SWALLOW, and the SPEAK.

Front 7

Fetal-postnatal derivatives~
Umbilical vein?
Umbilical arteries?
Ductus arteriosus?
Ductus venosus?
Foramen ovale?
Allantois?
Notochord?

Back 7

Umbilical vein: ligamentum teres; contained in falciform ligament
Umbilical arteries: medial umbilical ligaments
Ductus arteriosus: ligamentum arteriosum
Ductus venosus: ligamentum venosum
Foramen ovale: fossa ovalis
Allantois: urachus, median umbilical ligament
Notochord: nucleus pulposus

Front 8

Interatrial septum development?

Back 8

Septum primum grows toward endocardial cushions as foramen primum narrows. Foramen secundum forms in the middle of the septum primum as R-to-L shunt. Septum secundum begins to grow; it contains a permanent opening (foramen ovale). Foramen primum disappears and septum primum degenerates. Septum primum becomes valve for foramen ovale. Septum primum and septum secundum fuse to close the foramen ovale.

Front 9

The five main section of the developing heart and what do they give rise to?

Back 9

Truncus arteriosus: pulmonary trunk and aorta
Bulbus cordis: smooth parts of R/L ventricles
Primitive vesicle: trabeculated R/L ventricles
Primitive atria: trabeculated R/L atria
Sinus venosus: R horn becomes smooth part of right atrium, L horn becomes coronary sinus

Front 10

Twinning?

Back 10

2-cell stage split: yields dichorionic and diamnionic
Morula stage split: yields monochorionic and diamnionic
Blastocyst stage split: yields monochorionic and monoamnionic
Split of embryonic disc yields conjoined twins, monochorionic and monoamnionic

Front 11

Important genes of embryogenesis and their fxns?

Back 11

SHH: produced at the base of limbs in zone of polarizing activity. A/P axis.
Wnt-7: produced at distal end of developing limb in apical ectodermal ridge. D/V axis.
FGF: Produced in apical ectodermal ridge. Stimulates mitosis of underlying mesoderm in order to lengthen limb.
Homeobox (Hox): Responsible for segmental organization in craniocaudal axis. Mutations lead to appendages in wrong locations.

Front 12

Interventricular septum development?

Back 12

Muscular ventricular septum forms. Neural crest cells migrate to form AP septum which grows spirally to meet and fuse with muscular septum. This section becomes a membranous septum.

Front 13

Branchial pouches?

Back 13

Ear, tonsils, bottom-to-top

Ear: pouch 1; middle ear, eustachian tube
Tonsils: pouch 2; epithelial lining of palatine tonsils
Bottom-To: pouch 3; dorsal is inferior parathyroid, ventral is thymus
Top: pouch 4; superior parathyroid

Front 14

DiGeorge Syndrome?

Back 14

Aberrant 3rd and 4th pouch formation. Thymic aplasia and hypocalcemia (lack of parathyroid glands).

Front 15

Sensory and taste innervation of tongue?

Back 15

People makes Faces as they Taste.

Arches 1, 3, and 4 form innervation of the tongue.
CN VII (corda tympani) provides taste to anterior 2/3 and hitches a ride via CN V3 (sensation anterior 2/3). CN IX and X are the sensation and taste to the posterior 1/3 and extreme posterior portions of the tongue.

Front 16

Muscles of the tongue derive from where?

Back 16

Occipital myotomes.

Front 17

Typical thyroid development begins where? What is the process? If the remnant persists and a cyst forms, where will it be located and will it move with swallowing?

Back 17

Development begins at the foramen cecum down the thyroglossal duct to the normal site of the thyroid. Most common site for ectopic thyroids is the tongue. If a cyst develops in the thyroglossal duct, it will be seen midline and it will move when swallowing (its attached to the tongue) as opposed to the persisten cervical sinus/branchial cleft cyst which does not move when swallowing.

Front 18

What is the etiology of a cleft lip? cleft palate?

Back 18

Cleft lips are caused by failure of fusion between maxillary and medial nasal processes.

Cleft palates are caused by failure of fusion between the lateral palatine processes and the nasal septum and/or medial palatine process.

Front 19

Developing babies who can't urinate develop what syndrome?

Back 19

Potter's

Babies who can't Pee in utero develop Potter's.

Malformation of ureteric buds.

Front 20

SRY plays what role in genital embryology?

Back 20

SRY is a gene on the Y chromosome. It produces testis determining factor. The developing testes play a crucial role in complete development. Sertoli cells secrete mullerian inhibitory factor to inhibit paramesonephric/mullerian duct development. Leydig cells secrete androgens which maintain the mesonephric/wolfian duct.

Front 21

Why is DHT required? What does a 5a-reductase deficiency cause?

Back 21

DHT is required for male external genitalia to form.

5a-reductase deficiency causes male internal genitalia and ambiguous external genitalia until puberty...penis at 12.

Front 22

What is the fate of the metanephros, mesonephros, and pronephros in kidney embryology?

Back 22

The pronephros develops first during week 4 and degenerates. The mesonephros (wolfian duct) functions as an interim kidney during the first trimester. Genital differentiation can maintain (male genital system) or regress this duct. The metanephros becomes the permanent kidney.

Front 23

What are the clinical presentations of congenital pyloric stenosis? Tracheoesophageal fistula? Duodenal atresia?

Back 23

Palpable mass in epigastric region/right costal margin and nonbilious projectile vomiting.

Vomiting with feeding, air bubbles in stomach, polyhydramnios, and failure to pass NG tube into stomach.

Double bubble on x-ray, bilious vomit, and polyhydramnios.

Front 24

Which arteries supply the foregut? Midgut? and Hindgut? What parts of the GI tract do these terms contains?

Back 24

Foregut: Celiac a.; pharynx to duodenum
Midgut: SMA; duodenum to transverse colon
Hindgut: IMA; transverse colon to rectum

Front 25

When does the midgut herniate through the umbilical ring?

Back 25

This happens during the 6th week. Around week 10 it returns to the abdominal cavity and rotates around the SMA.

Front 26

Fetal Circulation?

Back 26

Oxygenated blood flows from the placenta to the fetus via the umbilical vein. This flows to but bypasses the liver via the ductus venosus. This oxygen rich blood enters the right atrium (IVC) and travels through the foramen ovale to hit systemic circulation, mainly the head. Systemic/oxygen depleted blood returns to the heart via SVC but travels through the right atrium to the pulmonary circulation. A large portion of this bypasses the lungs via the ductus arteriosus (enters aorta after left subclavian). This blood returns to the placenta via two umbilical arteries.

Front 27

Spina bifida occulta? Meningocele? Meningomyelocele?

Back 27

Spina bifida occulta: spine fails to close, dura intact, tuft of hair on skin overlying defect.
Meningocele: meninges herniate through the spinal column defect.
Meningomyelocele: meninges and spinal cord herniate through defect.

This defect is associated with decreased folic acid during pregnancy.