Embriology Q&a

[Anonymous]

Q: After arising from the floor of the primitive pharynx, where does the thryoid diverticulum go?
A: It descends down into the neck

Q: After the first breath at birth, what causes closure of the ductus arteriosus?
A: An increase in oxygen

Q: After the first breath at birth, what causes the closure of the foramen ovale?
A: A decrease resistance in pulmonary vasculature causes increased left atrial pressure vs. right atrial pressure

Q: Although the diaphragm descends during development, it maintains innervation from ____?
A: C3-C5

Q: An easy pneumonic to remember fetal erythropoiesis is?
A: Young Liver Synthesizes Blood

Q: At what time in the course of development is the fetus most susceptible to teratogens?
A: Weeks 3-8

Q: Deoxygenated blood from the SVC is expelled into the pulmonary artery and ____ ____ to the lower body of the fetus.
A: ductus arteriosus

Q: Do the cardiovascular structures arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Do the chromaffin cells of the adrenal medulla arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Do the enterochromaffin cells arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Do the lungs arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Endoderm

Q: Do the lymphatics arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Do the melanocytes arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Do the neural crest cells arise from mesoderm, ectoderm, or endoderm?
A: Ectoderm

Q: Do the odontoblasts arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Do the parafollicular (C) cells of the thyroid arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Do the Schwann cells arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Do the urogenital structures arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Does blood arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Does bone arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Does muscle arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Does the thyroid arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Endoderm

Q: Does the adrenal cortex arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Does the ANS arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Does the celiac ganglion arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Does the dorsal root ganglion arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Does the dura connective tissue arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Does the gut tube epithelium arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Endoderm

Q: Does the liver arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Endoderm

Q: Does the pancreas arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Endoderm

Q: Does the parathyroid arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Endoderm

Q: Does the pia arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Neural Crest (Ectoderm)

Q: Does the serous linings of body cavities arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Does the spleen arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Mesoderm

Q: Does the thymus arise from neural crest (ectoderm), mesoderm, or endoderm?
A: Endoderm

Q: From what does the ligamentum teres hepatis arise?
A: Umbilical vein

Q: How does a bicornate uterus form?
A: Results from incomplete fusion of the paramesonephric ducts

Q: How does a cleft lip form?
A: Failure of fusion of the maxillary and medial nasal processes

Q: How does a cleft palate form?
A: Failure of fusion of the lateral palatine processes, the nasal septum, and/or the median palatine process

Q: How does a horseshoe kidney form?
A: Inferior poles of both kidneys fuse, as they ascend from the pelvis during development they get trapped under the inferior mesenteric artery, and remain low in the abdomen

Q: How is meckel's diverticulum different than an omphalomesenteric cyst?
A: Omphalomesenteric cyst is a cystic dilatation of the vitelline duct

Q: How long does full development of spermatogenesis take?
A: 2 months

Q: How many arteries and veins does the umbilical cord contain?
A: - 2 umbilical arteries (carries deoxygenated blood away from fetus)
A: - 1 umbilical vein (oxygenated blood to fetus)

Q: Is a primary spermatocyte 2N or 4N?
A: 4N

Q: Is a primary spermatocyte haploid or diploid?
A: Diploid, 4N

Q: Is a secondary spermatocyte haploid or diploid?
A: Haploid, 2N

Q: Is a secondary spermatocyte N or 2N?
A: 2N

Q: Is a speratogonium haploid or diploid?
A: Diploid, 2N

Q: Is a spermatid haploid or diploid?
A: Haploid, N

Q: Meiosis I is arrested in which phase until ovulation?
A: Prophase

Q: Meiosis II is arrested in which phase until fertilization?
A: Metaphase (an egg MET a sperm)

Q: Most oxygenated blood reaching the heart via IVC is diverted through the ____ ____ and pumped out the aorta to the head.
A: foramen ovale

Q: The right common cardinal vein and right anterior cardinal vein give rise to what adult heart structure?
A: Superior vena cava

Q: The stapedius muscle of the ear is formed by which branchial arch?
A: 2nd

Q: This type of bone formation consists of ossification of cartilaginous molds and forms long bones at primary and secondary centers.
A: Endochondral

Q: True or False, blood in the umbilical vein is 100% saturated with oxygen?
A: False, it is 80% saturated

Q: True or False, there are two types of spermatogonia?
A: True, type A & type B

Q: What are the 1st branchial arch derivatives innervated by?
A: CN V2 and V3

Q: What are the 2nd branchial arch derivatives innervated by?
A: CN VII

Q: What are the 3rd branchial arch derivatives innervated by?
A: CN IX

Q: What are the 4th and 6th branchial arch derivatives innervated by?
A: CN X

Q: What are the cartilage derivatives (5) of the 4th and 6th branchial arches?
A: - Thyroid
A: - Cricoid
A: - Arytenoids
A: - Corniculate
A: - Cuneiform

Q: What are the five 2's associated with meckel's diverticulum?
A: - 2 inches long
A: - 2 feet from the ileocecal valve
A: - 2% of the population
A: - Commonly presents in the first 2 years of life
A: - May have 2 types of epithelia

Q: What are the rule of 2's for the 2nd week of development?
A: - 2 germ layers: epiblast & hypoblast
A: - 2 cavities: amniotic cavity & yolk sac
A: - 2 components to the placenta: cytotrophoblast & syncytiotrophoblast

Q: What are the rule of 3's for the 3rd week of development?
A: 3 germ layers (gastrula): ectoderm, mesoderm, endoderm

Q: What can a persistent cervical sinus lead to?
A: A branchial cyst in the neck

Q: What can be found in the cortex of the thymus?
A: It is dense with immature T cells

Q: What can be found in the medulla of the thymus?
A: It is pale with mature T cells, epithelial reticular cells, and Hassall's corpuscles

Q: What connects the thyroid diverticulum to the tongue?
A: The thyroglossal duct

Q: What devlopmental contributions does the 5th branchial arch make?
A: None

Q: What do the 2nd - 4th branchial clefts form, which are obliterated by proliferation of the 2nd arch mesenchyme?
A: Temporary cervical sinuses

Q: What does aberrant development of the 3rd and 4th pouches cause?
A: DiGeorge's syndrome

Q: What does the 1st aortic arch give rise to?
A: Part of the maxillary artery

Q: What does the 2nd pharyngeal pouch develop into?
A: Epithelial lining of the palantine tonsils

Q: What does the 3rd aortic arch give rise to?
A: Common carotid artery and proximal part of the internal carotid artery

Q: What does the 4th pharyngeal pouch develop into?
A: Superior parathyroids

Q: What does the 5th aortic arch give rise to?
A: Nothing

Q: What does the 5th pharyngeal pouch develop into?
A: C cells of the thyroid

Q: What does the 6th aortic arch give rise to?
A: The proximal part of the pulmonary arteries and (on left only) ductus arteriosus

Q: What does the ductus arteriosus give rise to?
A: Ligamentum arteriosum

Q: What does the ductus venosus shunt blood away from?
A: Liver

Q: What does the first branchial cleft develop into?
A: The external auditory meatus

Q: What does the foramen ovale give rise to?
A: Fossa ovalis

Q: What does the left 4th aortic arch give rise to?
A: Aortic arch

Q: What does the ligamentum venosum come from?
A: Ductus venosus

Q: What does the notochord give rise to?
A: Nucleus Pulposus

Q: What does the primitive atria give rise to?
A: Trabeculated left and right atrium

Q: What does the primitive ventricle give rise to?
A: Trabeculated parts of the left and right ventricle

Q: What does the right 4th aortic arch give rise to?
A: Proximal part of the right subclavian artery

Q: What does the right horn of the sinus venosus give rise to?
A: Smooth part of the right atrium

Q: What does the spleen arise from?
A: Dorsal mesentery, but is supplied by the artery of the foregut

Q: What does the thymus arise from?
A: Epithelium of the 3rd branchial pouch

Q: What does the thyroid diverticulum arise from?
A: The floor of the primitive pharynx

Q: What does the truncus arteriosus give rise to?
A: The ascending aorta and pulmonary trunk

Q: What does the umbilical arteries give rise to?
A: Medial umbilical ligaments

Q: What ear muscle does the 1st branchial arch form?
A: Tensor tympani

Q: What effect does 13-cis-retinoic acid have on the fetus?
A: Extremely high risk for birth defects

Q: What effect does ACE inhibitors have on the fetus?
A: Renal Damage

Q: What effect does iodide have on the fetus?
A: Congenital goiter or hypothyroidism

Q: What effect does warfarin and x-rays have on the fetus?
A: Multiple anomalies

Q: What effects does cocaine have on the fetus?
A: Abnormal fetal development and fetal addiction

Q: What embryonic structure are the smooth parts of the left and right ventricle derived from?
A: Bulbus cordis

Q: What embryonic structure does the coronary sinus come from?
A: Left horn of the sinus venosus

Q: What embryonic structure does the median umbilical ligament come from?
A: Allantois (urachus)

Q: What fetal landmark has developed within week 2 of fertilization?
A: Bilaminar disk

Q: What fetal landmark has occurred within week 1 of fertilization?
A: Implantation

Q: What fetal landmark has occurred within week 3 of fertilization?
A: Gastrulation

Q: What fetal landmarks (2) have developed within week 3 of fertilization?
A: Primitive streak and neural plate begin to form

Q: What five things arise from neuroectoderm?
A: - Neurohypophysis
A: - CNS neurons
A: - Oligodendrocytes
A: - Astrocytes
A: - Pineal gland

Q: What four structures make up the diaphragm?
A: - Septum transversum
A: - pleuroperitoneal folds
A: - body wall
A: - dorsal mesentery of esophagus

Q: What four things arise from surface ectoderm?
A: - Adenohypophysis
A: - Lens of eye
A: - Epithelial linings
A: - Epidermis

Q: What four things does Meckel's cartilage (from the 1st arch) develop into?
A: - Mandible
A: - Malleus
A: - Incus
A: - Sphenomandibular ligament

Q: What four things does Reichert's cartilage (from the 2nd arch) develop into?
A: - Stapes
A: - Styloid process
A: - Lesser horn of hyoid
A: - Stylohyoid ligament

Q: What four things does the dorsal pancreatic bud become?
A: Body, tail, isthmus, and accessory pancreatic duct

Q: What four things does the mesonephric (wolffian) duct develop into?
A: - Seminal vesicles
A: - Epididymis
A: - Ejaculatory duct
A: - Ductus deferens

Q: What induces the ectoderm to form the neuroectoderm (neural plate)?
A: Notochord

Q: What is a hiatal hernia?
A: Abdominal contents herniate into the thorax due to incomplete development of the diaphragm

Q: What is a hypospadias?
A: Abnormal opening of penile urethra on inferior side of penis due to failure of urethral folds to close

Q: What is a single umbilical artery associated with?
A: Congenital and chromosomal anomalies

Q: What is a urachal cyst or sinus a remnant of?
A: The allantois

Q: What is an abnormal opening of penile urethra on superior side of penis due to faulty positioning of the genital tubercle?
A: Epispadias

Q: What is associated with an epispadias?
A: Exstrophy of the bladder

Q: What is Meckel's diverticulum?
A: Persistence of the vitelline duct or yolk sac

Q: What is oligohydramnios associated with?
A: Bilateral renal agenesis or posterior urethral valves (in males)

Q: What is oligohydramnios?
A: < 0.5 L of amniotic fluid

Q: What is polyhydramnios associated with?
A: Esophageal/duodenal atresia, anencephaly

Q: What is polyhydramnios?
A: > 1.5-2 L of amniotic fluid

Q: What is Potter's syndrome?
A: Bilateral renal agenesis, that results in ologohydramnios causing limb and facial deformities and pulmonary hypoplasia
A: (Babies with Potter's can’t pee in utero)

Q: What is the acrosome of sperm derived from?
A: Golgi apparatus

Q: What is the female homologue to the corpus spongiosum in the male?
A: Vestibular bulbs

Q: What is the female homologue to the prostate gland in the male?
A: Urethral and paraurethral glands (of Skene)

Q: What is the female homologue to the scrotum in the male?
A: Labia majora

Q: What is the female homologue to the ventral shaft of the penis in the male?
A: Labia minora

Q: What is the flagellum (tail) derived from?
A: One of the centrioles

Q: What is the food supply of sperm?
A: Fructose

Q: What is the male homologue to the glans clitoris in the female?
A: Glans penis

Q: What is the male homologue to the greater vestibular glands (of Bartholin) in the female?
A: Bulbourethral glands (of Cowper)

Q: What is the most common congenital anomaly of the GI tract?
A: Meckel's diverticulum

Q: What is the most common ectopic thyroid tissue site?
A: The tongue

Q: What is the normal remnant of the thyroglossal duct?
A: Foramen cecum

Q: What is the postnatal derivative of the notochord?
A: The nucleus pulposus of the intervertebral disc

Q: What is the site of T-cell maturation?
A: Thymus

Q: What part of the gut is the pancreas derived?
A: Foregut

Q: What suppresses the development of the paramesonephric ducts in males?
A: Mullerian inhibiting substance (secreted by the testes)

Q: What teratogenic agent causes limb defects ('flipper' limbs)?
A: Thalidomide

Q: What three structures does the 3rd pharyngeal pouch develop into?
A: - Thymus
A: - Left inferior parathyroid
A: - Right inferior parathyroid

Q: What three things does the 1st pharyngeal pouch develop into?
A: - Middle ear cavity
A: - Eustachian tube
A: - Mastoid air cells

Q: What three things does the paramesonephric (mullerian) duct develop into?
A: - Fallopian tube
A: - Uterus
A: - Part of the vagina

Q: What three things does the ventral pancreatic bud become?
A: - Pancreatic head
A: - uncinate process
A: - main pancreatic duct

Q: What two things occur during week 4 of fetal development?
A: Heart begins to beat, upper and lower limb buds begin to form

Q: What type of bone formation is spontaneous without preexisting cartilage?
A: Intramembranous

Q: What type of twins would have 1 placenta, 2 amniotic sacs, and 1 chorion?
A: Monozygotic twins

Q: What type of twins would have 2 amniotic sacs and 2 placentas?
A: Monozygotic or dizygotic twins

Q: What will DiGeorge's syndrome lead to?
A: T cell deficiency & hypocalcemia

Q: When do primary oocytes begin meiosis I?
A: During fetal life

Q: When do primary oocytes complete meiosis I?
A: Just prior to ovulation

Q: When does fetal erythropoiesis occur in the bone marrow?
A: Week 28 and onward

Q: When does fetal erythropoiesis occur in the liver?
A: Weeks 6-30

Q: When does fetal erythropoiesis occur in the spleen?
A: Weeks 9-28

Q: When does organogenesis occur in the fetus?
A: Weeks 3-8

Q: Where does positive and negative selection occur in the thymus?
A: At the corticomedullary junction

Q: Where does spermatogenesis take place?
A: Seminferous tubules

Q: Where is the first place fetal erythropoiesis occurs and when does this take place?
A: Yolk sac (3-8 wk)

Q: Which aortic arch does the stapedial artery and the hyoid artery come from?
A: 2nd aortic arch

Q: Which branchial arch are the greater horn of hyoid and the stylopharyngeus muscle derived from?
A: 3rd branchial arch

Q: Which branchial arch does Meckel's cartilage develop from?
A: 1st arch

Q: Which branchial arch forms the anterior 2/3 of the tongue?
A: 1st arch

Q: Which branchial arch forms the incus and malleus of the ear?
A: 1st arch

Q: Which ear bone(s) does the 2nd branchial arch form?
A: Stapes

Q: Which embryonic tissue are branchial clefts derived from?
A: Ectoderm

Q: Which embryonic tissue are branchial pouches derived from?
A: Endoderm

Q: Which is more common a hypospadias or epispadias?
A: Hypospadias

Q: Which muscles (3) are derivatives of the 4th branchial arch?
A: - Most pharyngeal constrictors
A: - Cricothyroid
A: - Levator veli palatini

Q: Which muscles (4) are derivatives of the 2nd branchial arch?
A: - Muscles of facial expression
A: - Stapedius
A: - Stylohyoid
A: - Posterior belly of digastric

Q: Which muscles (8) are derivatives of the 1st branchial arch?
A: - Temporalis
A: - Masseter
A: - Lateral pterygoid
A: - Medial pterygoid
A: - Mylohyoid
A: - Anterior belly of digastric
A: - Tensor tympani
A: - Tensor veli palatini

Q: Which muscles are derivatives of the 6th branchial arch?
A: All intrinsic muscles of the larynx, except the cricothyroid

Q: Which pharyngeal arch does Reichert's cartilage develop from?
A: 2nd arch

Q: Which teratogenic agent causes vaginal clear cell adenocarcinoma?
A: DES

Q: Which two branchial arches form the posterior 1/3 of the tongue?
A: 3rd and 4th arches

Q: Which two embryonic tissues are branchial arches derived from?
A: Mesoderm and neural crests

Q: Which week of fetal development have the genitalia taken on male/female characteristics?
A: Week 10