Embryology

Question 1

what are the complications of therapeutic supplemental O2 during neonatal respiratory distress syndrome

Answer 1

Retinopathy
Intraventricular hemorrhage
Bronchopulmonary dysplasia

due to free radicals

Question 2

club cells in lung

Answer 2

nonciliated

secrete component to surfactant
degrade toxins
reserve

Question 3

bronchogenic cysts

Answer 3

abnormal budding of foregut and dilatation of terminal or large bronchi

discrete round air-filled densities on CXR

can cause infection

Question 4

5 stages to lung development

Answer 4

1) Embryonic (weeks 4-7)- trachea, bronchi
2) Pseudoglandular (5-16)- terminal bronchioles
3) Canalicular (16-26)- resp bronchioles and alveolar ducts
4) Saccular (26-birth)- alveolar terminal sacs, pneumocytes
5) Alveolar (32- 8 years)- adult alveoli (secondary septation)
mnemonic: Emily Pogrund Can’t Sex Anyone

Question 5

sonic hedgehog gene produced where

Answer 5

base of limbs in zone of polarizing activity

Question 6

sonic hedgehog mutation leads to…

Answer 6

holoprosencephaly

Question 7

Wnt 7 gene and FGF gene produced where

Answer 7

apical ectodermal ridge of each limb

Question 8

FGF gene function

Answer 8

stimulates mitosis of mesoderm– lengthens limbs

Question 9

Hox mutations

Answer 9

appendages in wrong locations

Question 10

when does hcg secretion begin

Answer 10

day 6- blastocyst implantation

Question 11

what happens week 2 and 3?

Answer 11

2- 2 layers- epiblast, hypoblast

3- 3 layers- endoderm, mesoderm, ectoderm

Question 12

what happens week 4

Answer 12

4 limbs- form

4 chambers- heart beats

Question 13

when is heartbeat detected by ultrasound

Answer 13

week 6

Question 14

when do fetal movements begin

Answer 14

week 8

Question 15

when can you decipher genitalia

Answer 15

week 10

Question 16

when are teratogens most suscpetible to causing injury

Answer 16

week 3-8 (embryonic period)- organogenesis

before week 3- all or none
after week 8- growth function affected

Question 17

at what stages for MZ twins can you get dichorionic, diamnionic; monochor, diamnio; mono, mono; conjoined

Answer 17

separating at…

di, di: 0-4 days

monochorionic, diamnionic: 4-8 days

mono, mono: 8-12 days

conjoined- after 13 days

Question 18

patent urachus

Answer 18

failure of urachus to obliterate–> urine leaks from umbilicus

Question 19

urachal cyst

Answer 19

partial failure of urachus to obliterate–> cyst

–> adenocarc, infection

Question 20

vesicourachal diverticulum

Answer 20

slight failure of urachus to obliterate –> bladder outpouching

Question 21

vitelline duct

Answer 21

connects yolk sac to midgut lumen

closes 7th week

Question 22

vitelline fistula

Answer 22

vitelline duct completely fails to close (unlike meckel which is partial)

–> meconium discharge from umbilicus

Question 23

aoritc arches

Answer 23

1- maxillary artery

2- stapedial and hyoid artery

3- common carotid, internal carotid

4- aortic arch (left), right subclavian

6- pulm arteries and ductus arteriosus

Question 24

branchial (pharyngeal) apparatus

Answer 24

composed of:

clefts- ectoderm

arches- mesoderm

pouches- endoderm

Question 25

branchial clefts

Answer 25

1- external auditory meatus 2-4 temporary cervical sinus If this persists--> branchial cleft cyst anterior to SCM (immobile during swallowing unlike thryglossal cyst)

Question 26

branchial arch 1

Answer 26

Maxilla, zygomatic bone, mandible, meckel cartilage, malleus, incus, sphenoManidibular ligament Muscles of Mastication, Mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini Cn V2 and V3

Question 27

branchial arch 2

Answer 27

Reichert cartilage- stapes, styloid, stylohyoid lig stapedius, stylohyoid, platySma, posterior belly of digastric CN VII

Question 28

pierre robin sequence

Answer 28

abnl branchial arch 1 and 2 micrognathia, glossoptosis, cleft palate, airway obstruction

Question 29

treacher collins syndrome

Answer 29

neural crest dysfunction -- abnl branchial arch 1 and 2 manidble hypoplasia facial abnl

Question 30

branchial arch 3

Answer 30

greater horn of hyoid stylopharnygeus CN IX

Question 31

branchial arch 4-6

Answer 31

arytenoids, cricoid, corniculate, cuneiform, thryoid 4: pharyngeal constrictors, cricothyroid, levator veli palatini, CN X (superior laryngeal) ``` 6: intrinsic muscles of larynx except cricothyroid CN X (recurrent laryngeal) ```

Question 32

what branchial arches make up anterior and posterior tongue

Answer 32

anterior: 1-2 posterior: 3-4

Question 33

branchial pouch 1

Answer 33

middle ear, eustachian, mastoid air

Question 34

branchial pouch 2

Answer 34

palatine tonsils

Question 35

branchial pouch 3

Answer 35

dorsal- inferior parathyroids ventral- thymus

Question 36

branchial 4th pouch

Answer 36

dorsal--> superior parathyroids ventral: C cells of thyroid, ultimobranchial body

Question 37

mneumonic for pouches

Answer 37

ear, tonsils, bottom to top

Question 38

septate uterus

Answer 38

incomplete resorption of septum decrease fertility

Question 39

bicorunate uterus

Answer 39

incomplete fusion of mullerian ducts risk of complicated pregnancy

Question 40

uterus didelphys

Answer 40

complete fusion failure double uterus, cervix, vagina pregnancy is possible!