Repro embryology Flashcards
1
Q
Sonic hedgehog gene
A
patterning along the anteroposterior axis and CNS development
2
Q
Mutation in the sonic hedgehog gene can result in
A
holoprosencephaly - failure of the prosencephalon (the embryonic forebrain) to sufficiently divide into the double lobes of the cerebral hemispheres. The result is a single-lobed brain structure and severe skull and facial defects.
3
Q
Wnt-7 gene
A
produced at apical ectodermal ridge
important for dorsal-ventral axis organization
4
Q
Fibroblast growth factor (FGF) gene
A
produced at apical ectodermal ridge
stimulates mitosis of underlying mesoderm –> lengthening of limb
5
Q
Homeobox (HOX) genes
A
involved in segmental organization of embryo in a craniocaudal direction
code for transcription factors
HOX mutations –> appendages in wrong locations
6
Q
ovulation secretes
A
secondary oocyte
7
Q
When does hCG secretion begin and implantation of blastocyst
A
hCG secretion begins and implantation of blastocyst
Within week 1 development
think blastoSIX –> day 6
8
Q
When does the fetus develop bilaminar disc of epiblast and hypoblast
A
Week 2 development ( weeks = 2 layers)
bilaminar disc of epiblast and hypoblast
9
Q
when does the epiblast invaginate to form the primitive streak and results in endoderm, mesoderm, ectoderm
A
Week 3 development
3 weeks= 3 layers
gastrulation forms trilaminar embryonic disc
epiblast invaginate to form the primitive streak and results in endoderm, mesoderm, ectoderm
notochord arises from midline mesoderm
overlying ectoderm becomes neural plate
10
Q
when is the fetus extremely susceptible to teratogens
A
weeks 3-8 (embryonic period) development
EXTREMELY susceptible to teratogens because this is when neural tube is formed by neuroectoderm and closes by week 4. Also have organogenesis
before week 3 its an all or none effect
after week 6 its a growth and function affect
11
Q
Heart beats and limb buds form
A
Week 4
4 weeks=4 limbs and 4 heart chambers
12
Q
fetal cardiac activity visible on tranvaginal ultrasound
A
Week 6
13
Q
Fetal movement starts at
A
week 8
8 is GAIT
14
Q
Genitalia develop male or female characterisitics
A
Tenitalia
week 10
15
Q
craniopharyngioma
A
benign rathke pouch tumor with cholesterol crystals, calcifications
16
Q
Embryonic derivatives of the surface ectoderm
A
epidermis adenohypophysis from Rathke pouch lens of eye epithelial linings of oral cavity sensory organ of ear olfactor epithelium anal canal below the pectinate line parotid sweat mammary glands
17
Q
Embryonic derivatives of the neural tube
A
Brain
Retina
Spinal cord
neuroectoderm –> think CNS
neural plate –> nucleus pulpulsos
18
Q
Embryonic derivatives of the Neural crest
A
Melanocytes Myenteric (Aurbach)plexus Odontoblasts Endocardial cushions Laryngeal cartilage Parafollicular cells of thyroid PNS Adrenal medlla and all ganglia Spiral membrane Schwann cells Pia and arachnoid bones of skull
“PNS and non neural structure nearby”
19
Q
Embryonic derivatives of the mesoderm
A
Muscle Bone CT Serous linings of body cavities spleen cardiovascular structures lymphatics blood wall of gut tube upper vagina kidneys adrenal cortex dermis testes ovaries
20
Q
Mesodermal defects
A
VACTERL
Vertebral defects Anal atresia Cardiac defects Tracheo esophageal fistula Renal defects Limb defects
21
Q
Embryonic derivatives of the endoderm
A
gut tube epithelium
anal canal above the pectinate line epithelium
most of urethra and lower vagina
luminal epithelia derivatives
22
Q
aplasia vs agenesis
A
agenesis is absent organ due to absent primordial tissue
aplasia is absent organ despite presence of primordial tissue
23
Q
deformation vs malformation
A
deformation is extrinsic disruption that occurs after embryonic period
malformation is intrinsic disruption that occurs during embryonic period (weeks 3-8)
24
Q
sequence error
A
abnormalities result from a single primary embryologic event
25
Teratogen medications: ACEi
renal damage
26
Teratogen medications: Alkylating agents
absence of digits, multiple anomalies
27
Teratogen medications: aminoglycosides
ototoxicity
"a mean ol' guy hit baby in the ear"
28
Teratogen medications: antiepileptic drugs
neural tube defects
cardiac defects
cleft palate
skeletal abnormalities
29
Teratogen medications: Diethylstilbestrol
vaginal clear cell adenocarcinoma
| congenital mullerian anomalies
30
Teratogen medications: folate antagonists
neural tube defects
trimethoprim
Methotrexate
31
Teratogen medications: Isotretinoin
multiple severe birth defects
contraception mandatory
think isoTERATinion
32
Teratogen medications: Lithium
ebstein anomaly (apical displacement of tricuspid valve)
33
Teratogen medications: Methimazole
aplasia cutis congenita
34
Teratogen medications:Tetracyclines
discolored teeth
inhibited bone growth
Teethracyclines
35
Teratogen medications: Thalidomide
limb defects
tha-limb-domide
36
Teratogen medications: warfarin
bone deformities, fetal hemorrhage, abortion, ophthalmologic abnormalities
do not wage war on the baby. Keep it heppy with herparin because it does not cross the placenta
37
Teratogen: maternal diabetes
caudal regression syndrome (anal atresia to sirenomelia)
```
congenital heart defects
Neral tube defects
macrosomia
neonatal hypoglycemia
Polycythemia
```
38
Teratogen: vitamin A excess
extremely high risk for spontaneous abortions and birth defects like cleft palate and cardiac
39
Baby has a smooth philtrum, thin vermillion border (upper lip), small palpebral fissures, limb dislocation, heart defects
Fetal alcohol syndrome
can also have microcephaly
if very severe: heart lung fistulas and holoprosencephaly in most severe form
mechanism? failure of cell migration
40
Neonatal abstinence syndrome
complex disorder involving CNS, ANS, GI systems
Secondary to maternal opiate use/abuse
41
dizygotic twins
arise from a separate egg and sperm
dichorionic
diamniotic
42
Monozygotic twins
1 egg and 1 sperm
43
Monozygotic twin's chorionicity and amnionicity depends on time of cleavage
0-4 days: dichorionic and diamniotic
4-8 days: monochorionic and diamniotic
8-12 days: monochorionic and monoamniotic
13+ days: shared body (conjoined) and monochorionic, monoamniotic
44
fetal component of the placenta
cytotrophoblast (inner) --> makes cells
| syncytiotrophoblast (outer) --> synthesizes hormones
45
lack of ____ expression in fetal placenta decreases the chance of attack by maternal immune system
MHC-I
46
hCG from the syncytiotrophoblast
stimulates the corpus luteum to secrete progesterone during first trimester
47
Maternal component of the placenta
decidua basalis which is derived from endometrium
maternal blood in lacunae
48
most common type of monozygotic twins? second most?
most common is monochorionic diamniotic
| second most common is dichorionic and diamniotic
49
components of the umbilical cord
2 umbilical arteries
| 1 umbilical vein
50
role of umbilical arteries and veins
arteries return deoxy blood from fetal internal iliac arteries to placenta
veins supply oxygenated blood from placenta to fetus and drains into IVC via liver or via ductus venosus
51
umbilical arteries and veins are derived from
allantois
52
Yolk sac forms the _____ in the 3rd week
allantois
which extends into urogenital sinus
53
The allantois becomes the ______, a duct between fetal bladder and umbilicus
urachus
54
obliterated urachus is the
median umbilical ligament
55
patent urachus
urine discharge from umbilicus
56
urachal cyst
partial failure in obliteration of urachus
fluid filled cavity lined with uroepithelium between umbilicus and bladder
can become infected and present as painful mass below umbilicus
57
Vesicourachal diverticulum
slight failure of urachus to obliterate
outpouching of bladder
58
vitelline duct connects the ____ to the ____. It is obliterated in the ____ week
yolk sac to the midgut lumen
7th
59
vitelline fistula
vitelline duct fails to close and meconium discharge from ubilicus
60
Meckel diverticulum
partial closure of vitelline duct
patent portion attached to ileum (true diverticulum)
can get melena, hematochezia, abdominal pain
61
aortic arch derivatives : 1st
maxillary artery
#1 is maximal
62
aortic arch derivatives : 2nd
stapedial artery
hyoid artery
2 arteries
63
aortic arch derivatives : 3rd
common carotid artery
internal carotid artery
C is the 3rd letter of alphabet
64
aortic arch derivatives : 4th
left: aortic arch
Right: proximal R. subclavian artery
65
aortic arch derivatives : 5th
```
proximal part of pulm arteries
ductus arteriosus (left)
```
66
____ nerve loops around the R. subclavian artery
right recurrent laryngeal nerve
67
_____ nerve loops around aortic arch distal to the ductus arteriousus
left recurrent laryngeal nerve
68
Branchial apparatus
CAP
Branchial cleft --> ectoderm
Branchial arches --> mesoderm and neural crest
Branchial Pouches --> endoderm
69
Branchial cleft derivatives
1st cleft: EAM
| 2nd-4th: temporal cervical sinuses
70
persistent cervical sinuses
normally obliterated by proliferation of 2nd arch mesenchyme
branchial cleft cyst within lateral neck, anterior to sternocleidomastoid muscle
71
Branchial arch derivatives: 1st branchial arch
Cartilage: maxilla, zygomatic, meckel cartilage, mandible, malleus, incus, sphenomandibular ligament
mm: muscles of mastication(temporalis, masseter, lateral and medial pterygoids), mylohyoid, anterior belly of digastric, tensor tympani, anterior 2/3 of tongue, tensor veli palatini
CN V3
"chewing"
72
Branchial arch derivatives: 2nd branchial arch
cartilage: reichert cartilage, stapes, styloid process, lesser horn of hyoid, stylohyoid ligament
mm: muscles of facial expression, stapedius, stylohyoid, platysma, posterior belly of digastric
CN7
"smile"
73
Pierre robin sequence
micrognathia, glossoptosis, cleft palate, airway obstruction
Branchial arches 1 and 2
74
Treacher collins syndrome
neural crest dysfunction causing mandibular hypoplasia and facial abnormalities
branchial arches 1 and 2
75
Branchial arch derivatives: 3rd
cartilage: greater horn of hyoid
mm: stylopharyngeus
```
CN 9 (glossopharyngeal)
"swallow"
```
76
Branchial arch derivatives: 4th-6th
Cartilage: arytenoids, cricoid, corniculate, cuneiform, thyroid
Muscles: 4th arch is most pharyngeal constrictors, cricothyroid, levator veli palatini
6th arch: all intrinsic muscles of larynx except cricothyroid
arch 3 and 4 make the posterior 1/3 of tongue
arch 5 makes no major developmental contributions
CN X (superior laryngeal branch) for 4th arch
"swallow"
CN X (recurrent/inferior laryngeal branch) for 6th arch
"speak"
77
CNs for branchial arches mnemonic
children tend to first CHEW, then SMILE, then SWALLOW STYLishly, or simply SWALLOW, and then SPEAK
78
Branchial pouch derivatives: 1st
middle ear cavity
eustachian tube
mastoid air cells
endoderm lined structures of the ear
79
Branchial pouch derivatives 2nd
epithelial lining of palatine tonsil
80
Branchial pouch derivatives 3rd
dorsal wings --> inferior parathyroids
ventral wings --> thymus
ends up below 4th pouch structures
81
Branchial pouch derivatives 4th
Dorsal wings --> superior parathyroids
| Ventral wings --> ultimobranchial body and parafollicular (C) cells of thyroid
82
mnemonic for Branchial pouch derivatives
Ear, tonsils, bottom to top
```
1 ear
2 tonsils
3 bottom for inf parathyroids (dorsal)
3 to =thymus (ventral)
4 top (superior parathyroids)
```
83
what pouches are problematic in digeorge
3rd and 4th puches
3rd ventral = thymus
3rd dorsal and 4 = parathyroids
t cell deficiency due to thymic aplasia and hypocalcemia due to failure of parathyroid development
84
What is the developmental defect in cleft lip
failure of fusion of the maxillary and merged medial nasal processes
85
What is the developmental defect in cleft palate
failure of fusion of the two lateral palatine shelves or failure of fusion of lateral palatine shelves with the nasal septum and/or median palatine shelf (formation of secondary palate)
86
female genital embryology: the mesonephric duct ____ and the ___ duct develops
degenerates
paramesonephric duct
87
the SRY gene on Y chromosome produces
testis determining factor
88
sertoli cells secrete ____ that suppresses the development of the ___ ducts
mullerian inhibitory factor (MIF)
paramesonephric duct
male development
89
leydig cells secrete androgens that stimualte the development of _____ ducts
mesonephric ducts
male development
90
Paramesonephric (mullerian) duct
develops into female internal structures : fallopian tubes, uterus, upper portion of vagina (lower portion is from the urogenital sinus)
male remnant: appendix testes
91
Mesonephric (wolffian) duct
develops into male internal structures except the prostate : seminal vesicles, epididymis, ejaculatory duct, ductus deferens
female remnant is gartner duct
92
Mullerian agenesis (MAyer Rokitansky Kuster Hauser syndrome)
primary amenorrhea (due to lack of uterine development in females) with fully developed secondary sexual characteristics (functional ovaries)
93
What if after the undifferentiated gonads have been exposed to the testis determining factor (due to SRY gene) , they lack sertoli cells and mor mullerian inhibitory factor?
develop male and female internal genitalia
male external genitalia
SRY gene has already made the testes but without sertoli cells/MIF we cannot inhibit paramesonephric mullerian duct development into internal female genitalia
94
What if after external genitalia has been differentiated into testes, there is a 5alpha reductase deficiency
inability to convert testosterone into DHT
male internal genitalia
but ambiguous external genitalia until puberty when the testosterone levels cause masculinization
95
leydig cells
leydig cells LEAD to male internal and external sexual differentiation
96
Sertoli cells
sertoli cells SHUT down female (internal) sexual differentiation
97
incomplete fusion of the mullerian ducts
bicornuate uterus
98
incomplete resorption of septum
septate uterus
99
complete failure of mullerian duct fusion
uterus didelphys
double uterus, cervix, vagina
pregnancy possible
100
Genital tubercle male and female homolog
male: via dihydrotestosterone form the glans penis, corpus cavernosum and spongiosum
female: via estrogen form glans clitoris and vestibular bulbs
101
Urogenital sinus male and female homolog
male: via dihydrotestosterone forms bulbourethral glands of cowper and the prostate gland
female: via estrogen forms the greater vestibular glands of bartholin and the urethral and paraurethral glands of skene
102
Urogenital folds male and female homolog
male: via dihydrotestosterone forms ventral shaft of penis (penile urethra)
female: via estrogen forms labia minora
103
Labioscrotal swelling male and female homolog
male: via dihydrotestosterone forms scrotum
female: via estrogen forms labia majora
104
Penile abnormality due to failure of urethral folds to fuse
hypospadias - abnormal opening of penile urethra on ventral surface
associated with inguinal hernia and cryptorchidism
more common than epispadias
105
penile abnormalities due to faulty positioning of genital tubercle
epispadias- abnormal opening of penile urethra on dorsal surface of penis
associated with exstrophy of bladder
106
Gubernaculum
male remnant: anchors tests within scrotum
female remnant: ovarian ligament + round ligament of uterus
107
Processus vainalis
male remnant: forms tunica vaginalis
| female remnant: obliterated
