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Human Reproduction > First Aid: Reproductive Embryology > Flashcards

First Aid: Reproductive Embryology Flashcards

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1
Q

List of important genes of embryogenesis

A
  • Sonic Hedgehog gene
  • WNT-7 gene
  • Fibroblast growth factor (FGF) gene
  • Homeobox (Hox) genes
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2
Q

Description of the Sonic Hedgehog gene

A
  • Produced at the base of limbs in zone of polarizing activity
  • Involved in patterning along anteroposterior axis and CNS development
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3
Q

Where is Sonic Hedgehog produced?

A

Produced at the base of limbs in the Zone of Polarizing Actibity (ZPA)

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4
Q

What is the function of Sonic Hedgehog gene

A

Involved in patterning along the anteroposterior axis and CNS development

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5
Q

What happens with a mutation in Sonic Hedgehog

A

Mutation can cause holoprosencephaly

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6
Q

What is WNT-7 gene

A
  • Produced at the apical ectodermal ridge (thickened ectoderm at distal end of each developing limb).
  • Necessary for proper organization along the dorsal-ventral axis
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7
Q

Where is Wnt-7 produced?

A

Produced at apical ectodermal ridge (thickened ectoderm at distal end of each developing limb)

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8
Q

What is the function of Wnt-7?

A

Necessary for proper organization along the dorsal-ventral axis

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9
Q

FGF AKA

A

Fibroblast Growth Factor

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10
Q

Description of FGF

A
  • Produced at apical ectodermal ridge
  • Stimulates mitosis of underlying mesoderm, providing for the legnthening of limbs
  • “Look at that Fetus, Growing Fingers”
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11
Q

FGF is produced where?

A

Produced at the apical ectodermal ridge

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12
Q

FGF function

A

Stimulates mitosis of underlying mesoderm, providing for the lengthening of limbs

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13
Q

FGF Nmemonic

A

“Look at that Fetus, Growing Fingers”

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14
Q

Description of Homeobox (Hox) genes

A
  • Involved in segmental organization of embryo in a craniocaudal direction
  • Code for transcription factors
  • Hox mutations result in -> appendages in the wrong locations
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15
Q

Hox genes AKA

A

Homeobox genes

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16
Q

Hox genes gunction

A
  • Involved in segmental organization of embryo in craniocaudal direction
  • Code for transcription factors
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17
Q

Hox gene mutations result in

A

Appendages in wrong locations

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18
Q

Describe early embryonic development

A
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19
Q

Describe Early fetal development within the first week

A
  • hCG secretion begins around the time of implantation of blastocyst
  • Blastocyst“sticks” at day 6
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20
Q

Describe Early fetal development within week 2

A
  • Bilaminar disc (epiblast, hypoblast)
  • 2 weeks = 2 layers
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21
Q

Describe Early fetal development within week 3

A
  • Gastrulation forms trilaminar embryonic disc
  • Cells from epiblast invaginate -> primitive streak -> endoderm, mesoderm, ectoderm
  • Notochord arises from midline mesoderm; overlying ectoderm becomes neural plate
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22
Q

Describe Early fetal development weeks 3-8 (embryonic period)

A
  • Neural tube formed by neuroectoderm and closes by week 4
  • Organogenesis
  • During this time embryo is extremely susceptible to teratogens
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23
Q

Describe Early fetal development week 4

A
  • Heart begins to beat
  • Upper and lower limb buds begin to form
  • 4 weeks = 4 limbs and 4 heart chambers
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24
Q

When does the heart begin to beat?

A

4 weeks

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25
When do the upper and lower limb buds begin to form?
4 weeks
26
Describe Early fetal development week 6
Fetal cardiac activity visible by transvaginal ultrasound
27
Describe Early fetal development week 8
* Fetal movements start * **Gait** at week **8**
28
Describe Early fetal development week 10
* Genitalia have male/female characteristics * week **10** = **Ten**italia (genitalia)
29
When do genitalia have male/female characteristics?
Week 10
30
What are the main embryonic derivatives?
* Ectoderm * Mesoderm * Endoderm
31
Components of ectoderm
* Surface ectoderm * Neural tube * Neural crest
32
33
Surface ectoderm derivatives 10 listed
* Epidermis * Adenohypophysis AKA anterior pituitary (from Rathke pouch) * Lens of eye * Epithelial linings of oral cavity * Sensory organs of the ear * Olfactory epithelium * Anal canal below below the pectinate line * Parotid glands * Sweat glands * Mammary glands
34
Issues with surface ectoderm
Craniopharyngioma - benign Rathke pouch tumor with cholesterol crystals, calcifications
35
Neural tube derivatives
Neuroectoderm (think CNS) * Brain * Neurohypophysis * CNS neurons * Oligodendrocytes * Astrocytes * Ependymal cells * pineal glands * retina * Spinal cord
36
Craniopharyngioma embronic origin
Surface ectoderm
37
What is Craniopharyngioma?
Benign Rathke pouch tumor with cholesterol crystals and calcifications
38
Neural crest derivatives
* **M**elanocytes * **M**yenteric (Auerbach) plexus * **O**dontoblasts * **E**ndocardial cushions * **L**aryngeal cartilage * **P**arafollicular (C) cells of the thyroid * **P**NS (dorsal root ganglia, cranial nerves, autonomic ganglia) * **A**drenal medulla and all ganglia * **S**piral membrane (aorticopulmonary septum) * **S**chwann cells * Pia and arachnoid * bones of skull **MMO**t**EL PPASS** Neural crest - think PNS and Non-neural structures nearby
39
Mesoderm derivatives
* Muscle * Bone * Connective tissue * serous linings of body cavities (eg peritoneum, pericardium, pleura) * Spleen (derived from foregut mesentary) * cardiovascular structures * lymphatics * blood * wall of gut tube * upper vagina * kidneys * adrenal cortex * dermis * testis * ovaries * Notochord induces ectoderm to form neuroectoderm (neural plate); its only postnatal derivative is the nuclues pulposus of the intervertebral disc
40
Mesoderm derivatives Nmemonic
**M**iddle/"**m**eat" layer Mesodermal defects = **VACTERL** * **V**ertebral defects * **A**nal atresia * **C**ardiac defects * **T**racheo-**E**sophageal fistula * **R**enal defects * **L**imb defects (bone and muscle)
41
Endoderm derivatives
* Gut tube epithelium (including anal canal above the pectinate line) * Most of the urethra and lower vagina (Derived from urogenital sinus) * Luminal epithelial derivatives (eg lungs, liver, gallbladder, pancreas, eustachian tube, thymus, parathyroid, thyroid follicular cells) **En**doderm = "**En**ternal" layer
42
What are the types of errors in morphogenesis? 7 listed
* Agenesis * Aplasia * Hypoplasia * Disruption * Deformation * Malformation * Sequence
43
What is agenesis
Type of error in morphogenesis where: Absent organ due to absent primordial tissue
44
What is aplasia?
Type of error in morphogenesis: Absent organ despite presence of primordial tissue
45
What is hypoplasia?
Type of error in morphogenesis: Incomplete organ development where the primordial tissue is present
46
What is Disruption?
Type of error in morphogenesis: 2o breakdown of previously normal tissue or structure (eg amniotic band syndrome)
47
What is Deformation?
Type of error in morphogenesis: Extrinsic disruption; occurs **after** the embryonic period (weeks 3-8)
48
When is the embryonic period?
weeks 3-8
49
What is malformation?
Type of error in morphogenesis: Intrinsic disruption; occurs **during** the embryonic period (weeks 3-8)
50
What is sequence?
Type of error in morphogenesis: Abnormalities result from a single 1o embryolodic event (eg oligohydramnios -\> Potter sequence)
51
Example of Disruption error in morphogenesis
Amniotic Band Syndrome
52
Example of Sequence error in morphogenesis
Oligohydramnios -\> Potter sequence
53
When is the embryo most susceptible to teratogens?
Most susceptible 3-8 weeks (embryonic period - organogenesis) Before week 3, "all-or-none" effects After week 8, growth and function affected
54
Teratogen sensitivity before 3 weeks
Before week 3, "all-or-none" effects
55
Teratogen sensitivity after 8 weeks
After week 8, growth and function affected
56
Examples of classes of medications that are teratogenic
* ACE Inhibitors * Alkylating agents * Aminoglycosides * Antiepileptic drugs * Diethylstilbestrol * Folate antagonists * Isotretinoin * Lithium * Methimazole * Tetracyclines * Thalidomide * Warfarin
57
Examples of substances that can be teratogenic in the setting of substance abuse
* Alcohol * Cocaine * Smoking (nicotine, CO)
58
Other teratogenic exposures 5 listed
* Iodine (lack or excess) * Maternal diabetes * Methylmercury * Vitamin A excess * X-rays
59
Ace inhibitors effects on fetus
Renal damage
60
Alkylating agents effects on fetus
* Absence of digits * multiple anomalies
61
Aminoglycosides effects on fetus
**Oto**toxicity **Amin**o**gly**cosides = **A mean guy** hit the baby in the **ear**
62
Antiepileptic drugs effects on fetus
* Neural tube defects * Cardiac defects * cleft palate * skeletal abnormalities (eg, phalanx/nail hypoplasia, facial dysmorphism) ## Footnote **High dose folate supplementation is recommended**
63
Which antiepileptic drugs are most teratogenic?
Most commonly * Valproate * Carbamazapine * Phenytoin * Phenobarbital
64
Diethylstilbestrol effects on fetus
* Vaginal clear cell adenocarcinoma * Congenital Müllerian anomalies
65
Folate antagonists effects on fetus
* Neural tube defects * Includes Trimethoprim, methotrexate, antiepileptic drugs
66
Isotretinoin effects on fetus
* Multiple severe birth defects * Contraception **MANDATORY** * Iso**TERAT**inoin
67
Lithium effects on fetus
Ebstein anomaly (apical displacement of the tricuspid valve)
68
What drug causes Ebstein anomaly
Lithium
69
What is Ebstein Anomaly?
Ebstein anomaly = apical displacement of tricuspid valve
70
Methimazole effects on fetus
Aplasia cutis congenita
71
Tetracyclines effects on fetus
* Discolored teeth * Inhibited bone growth (teeth?) **Tet**racyclines = "**TEETH**racyclines"
72
Thalidomide effects on fetus
* Limb defects (phocomelia, micromelia -"flipper" limbs) **Limb** defects with " tha-**limb**-domide"
73
Warfarin effects on fetus
* Bone deformities * fetal hemorrhage * abortion * Ophthalmologic abnormalities Do not wage **Warfar**e on the baby; keep it **hep**py with **hep**arin (does not cross the placenta)
74
Alcohol effects on fetus
* Common cause of birth defects and intellectual disability * Fetal alcohol syndrome
75
Cocaine effects on fetus
* Low birth weight * preterm birth * IUGR * placental abruption Cocaine -\> vasoconstriction
76
Smoking (nicotine and CO) effects on fetus
* Low birth weight (leading cause in developed countries) * Preterm labor * Placental problems * IUGR * SIDS * ADHD Nicotine -\> vasoconstriction CO -\> impaired O2 delivery
77
What is the leading cause of low-brith-weight in developed countries?
Smoking
78
Iodine effects on fetus
Either from **excess** or **lack** of) Congenital goiter (**Excess**) hypothyroidism (Cretinism) (**Lack**)
79
Maternal Diabetes effects on fetus
* Caudal regression syndrome (anal atresia to sirenomelia) * Congenital heart defects (eg VSD, transposition of the great vessels) * Neural tube defects * Macrosomia * Neonatal hypoglycemia * Polycythemia
80
Methylmercury effects on fetus
* Neurotoxicity Highest in * Swordfish * Shark * Tilefish * King mackerel
81
Vitamin A excess effects on fetus
Extremely high risk for spontaneous abortions and birth defects (cleft palate, cardiac)
82
X-rays effects on fetus
* Microcephaly * Intellectual disability Minimized by lead shielding
83
What is Fetal Alcohol Syndrome?
Newborns of alcohol-consuming mothers have ↑ incidence of congenital abnormalities, including pre- and postnatal * developmental retardation * microcephaly * facial abnormalities (eg. smooth philtrum, thin-vermillion border [upper lip], small palpebral fissures) * Limb dislocation * Heart defects * Heart and lung fistulas and holoprosencephaly in its most severe form of FAS
84
What is the leading cause of intellectual disability in the US
Fetal Alcohol Syndrome
85
Clinical manifestations of the most severe form of FAS
* Heart-lung fistulas * Holoprosencephaly
86
FAS AKA
Fetal Alcohol Syndrome
87
FAS pathophysiology
Mechanism is failure of cell migration
88
NAS AKA
neonatal abstinence syndrome
89
What is neonatal abstinence syndrome?
A complex disorder involving CNS, ANS and GI systems which is 2o to maternal opiate use/abuse.
90
Risk factors of NAS
* Maternal substance abuse during pregnancy * poor mental health * poor prenatal care * low SES * Lack of family support * HCV
91
NAS prophylaxis
Universal screening for substance abuse is recommended in all pregnant patients
92
NAS clinical manifestations
Newborns may present with: * Uncoordinated sucking reflexes * irritability * high-pitched crying * tremors * tachypnea * sneezing * diarrhea * possibly seizures
93
Possible mechanisms of twinning
* Dizygotic ("fraternal") * Monozygotic ("identical")
94
Fraternal Twins AKA
Dizygotic twins
95
Identical twins AKA
Monozygotic twins
96
Monozygotic twins AKA
Identical twins
97
Dizygotic twins AKA
Fraternal twins
98
Explain Dizygotic twins
Fraternal twins arise from 2 eggs that are separately fertilized by 2 different sperm (always 2 zygotes) and will have 2 separate amniotic sacs and 2 separate placentas (chorions)
99
Explain Monozygotic twins
* Identical twins arise from 1 fertilized egg (1 egg + 1 sperm) that splits in early pregnancy * The timing of cleavage determines chorionicity (number of chorions) and amniocity (number of amnions) (**SCAB**)
100
How to determine the number of chorions in Monozygotic twins
**SCAB** **S**eparate chorion and amnion = Cleavage in 0-4 days Shared **C**horion = Cleavage in 4-8 days Shared **A**mnion = Cleavage in 8-12 days Shared **B**ody (conjoined) = Cleavage in 13+ days
101
**SCAB**
**SCAB** **S**eparate chorion and amnion = Cleavage in 0-4 days Shared **C**horion = Cleavage in 4-8 days Shared **A**mnion = Cleavage in 8-12 days Shared **B**ody (conjoined) = Cleavage in 13+ days
102
What is the Placenta?
1o site of nutrient and gas exchange between mother and fetus
103
Components of the placenta
* Fetal component * Maternal component
104
Fetal component of the placenta
* Cytotrophoblast * Syncytiotrophoblast
105
Maternal component of the placenta
Decidua basalis
106
Cytotrophoblast is derived from what component of the placenta?
Fetal Component
107
Syncytiotrophoblast is derived from what component of the placenta?
Fetal component
108
Decidua basalis is derived from what component of the placenta?
Maternal component
109
What is the Cytotrophoblast?
Part of the fetal component of the placenta that has: * inner laver of chorionic villi * **C**ytotrophoblast makes **C**ells
110
What is the Synctiotrophoblast?
Part of the fetal component of the placenta and has: * Outer layer of chorionic villi * synthesizes and secretes hormones (eg hCG which is structurally similar to LH) * Stimulates corpus luteum to secrete progesterone during the first trimester) **Syn**cytiotrophoblast **syn**thesizes hormones \*Lacks MHC-1 expression → ↓ chance of attack by the maternal immune system\*
111
What helps prevent attack of the fetal component placenta from the maternal immune system?
Syncytiotrophoblast lacks MHC-1 expression → ↓ chance of attack by the maternal immune system
112
What is the Decidua basalis?
The maternal component of the placenta that is: * Derived from endometrium * Maternal blood in lacunae
113
Decidua basalis is derived from
Maternal endometrium
114
Umbilical arteries function
Return deoxygenated blood from fetal internal iliac arteries to placenta
115
Umbilical vein function
Supplies oxygenated blood from placenta to fetus, drains into IVC via liver or via ductus venosus
116
How many umbilical arteries are there?
* 2 * However, a single umbilical artery (2 vessel cord) is associated with congenital and chromosomal anomalies
117
How many umbilical veins are there?
1
118
Umbilical veins are derived from?
Allantois
119
Umbilical arteries are derived from?
allantois
120
What is the Urachus?
In the 3rd week the yolk sac forms the allantois, which extends into urogenital sinus Allantois becomes the urachus, a duct between fetal bladder and umbilicus. Failure of urachus to involute can lead to anomalies that may increase risk of infection and/or malignancy (eg adenocarcinoma) if not treated. Obliterated urachus is represented by the median umbilical ligament after birth, which is covered by median umbilical fold of the peritoneum
121
Failure of the urachus to...
failure of urachus to involute can lead to anomalies that may increase risk of infection and/or malignancy (eg adenocarcinoma) if not treated
122
Describe patent urachus
Total failure of urachus to obliterate → **u**rine discharge from **u**mbilicus
123
Describe urachal cyst
* Partial failure of urachus to obliterate; fluid-filled cavity lined with uroepithelium, between umbilicus and bladder. * Cyst can become infected and present as painful mass below umbilicus
124
Describe vesicourachal diverticulum
Slight failure of urachus to obliterate → outpouching of bladder
125
What is the Vitelline duct?
7th week - obliteration of vitelline duct (omphalomesenteric duct), which connects yolk sac to midgut ligament
126
Vitelline duct AKA
Omphalomesenteric duct
127
Omphalomesenteric duct AKA
Vitelline duct
128
What is vitelline fistula?
Vitelline duct fails to close → meconium discharge from umbilicus
129
What is meckel diverticulum?
* Partial closure of vitelline duct, with patent portion attached to ileum (true diverticulum) * May have heterotopic gastric and/or pancreatic tissue → melena, hematochezia, abdominal pain
130
What is Hematochezia?
Hematochezia is the passage of fresh blood through the anus, usually in or with stools (contrast with melena).
131
Vitelline duct failures
* Vitelline fistula * Meckel diverticulum
132
Aortic arch derivatives
* **1**st - Part of the **max**illary artery (branch of external carotid) - **1**st arch is **max**imal * **2**nd - **S**tapedial artery and hyoid artery - **S**econd = **S**tapedial * **3**rd - **C**ommon **C**arotid artery and proximal part of internal **C**arotid artery - **C** is the **3**rd letter of the alphabet * **4**th - on left, aortic arch; on right, proximal part of right subclavian artery - **4**th arch (**4** limbs) = systemic * 6th - Proximal part of pulmonary arteries and (on left only) ductus arteriosus - 6th arch = pulmonary and the pulmonary-to-systemic shunt (ductus arteriosus).
133
What is Bronchial apparatus?
* Composed bronchial clefts, arches, pouches. * Bronchial **c**lefts - derived from ectoderm. Also called bronchial grooves. * Branchial arches - derived from mesoderm (muscles, arteries) and neural crest (bones, cartilage) * Branchial pouches - derived from endoderm **CAP** covers outside to inside: **C**lefts = ectoderm **A**rches = mesoderm + neural crest **P**ouches = endoderm
134
Branchial apparatus is composed of?
* Branchial clefts * Branchial arches * Branchial pouches
135
Branchial clefts AKA
Branchial grooves
136
Branchial **c**lefts derived from?
derived from e**c**toderm
137
Branchial arches derived from?
derived from mesoderm (muscles, arteries) and neural crest (bones, cartilage)
138
Branchial pouches derived from?
derived from endoderm
139
Branchial apparatus derivatives Mnemonic
**CAP** **C**lefts = ectoderm **A**rches = mesoderm + neural crest **P**ouches = endoderm
140
Branchial cleft derivatives
* 1st cleft develops into external auditory meatus * 2nd through 4th clefts form temporary cervical sinuses, whic are obliterated by proliferation of 2nd arch mesenchyme * Persistent cervical sinus → branchial cleft cyst within lateral neck, anterior to sternocleidomastoid muscle
141
1st branchial cleft derivative
1st branchial cleft develops into external auditory meatus
142
2nd-4th branchial cleft derivative
2nd-4th clefts form temporary cervical sinuses, which are obliterated by proliferation of 2nd arch mesenchyme
143
2nd branchial arch derivatives: Cartilage
Reichert cartilage: * **S**tapes * **S**tyloid process * lesser horn of hyoid * **S**tylohyoid ligament
144
Persistent cervical sinus derivative
Persistent cervical sinus → branchial cleft cyst within lateral neck, anterior to sternocleidomastoid muscle
145
1st branchial arch derivatives: Cartilage
* **M**axillary process → **M**axilla, zygo**M**atic bone * **M**andibular process * → **M**eckel cartilage * → **M**andible, **M**alleus and incus, Spheno**M**andibular ligament
146
3rd branchial arch derivatives: Cartilage
Greater horn of hyoid
147
4th-6th branchial arch derivatives: Cartilage
* **A**rytenoids * **C**ricoid * **C**orniculate * **C**uneiform * **T**hyroid * (Used to sing and **ACCCT)**
148
4th-6th branchial arch derivatives: Muscles
4th arch: most pharyngeal constrictors; cricothyroid, levator veli palatini 6th arch: all intrinsic muscles of larynx except cricothyroid
149
3rd branchial arch derivatives: Muscles
Stylopharyngeus (think of stylo**pharyngeus** innervated by glosso**pharyngeal** nerve)
150
2nd branchial arch derivatives: Muscles
Muscles of facial expression **S**tapedius **S**tylohyoid platy**S**ma Posterior belly of digastric
151
1st branchial arch derivatives: Muscles
* **M**uscles of **M**astication * te**M**poralis, * **M**asseter, * lateral and **M**edial pterygoids * **M**ylohyoid * anterior belly of digastric, tensor tympani, anterior 2/3 of tongue, tensor veli palatini
152
1st branchial arch derivatives: Nerves
CN V3 **chew**
153
2nd branchial arch derivatives: Nerves
CN VII (facial expression) **smile**
154
3rd branchial arch derivatives: Nerves
CN IX (**stylo**-pharyngeus) **Swallow styl**ishly
155
4th-6th branchial arch derivatives: Nerves
* 4th arch: CN X (superior laryngeal branch) * **simply swallow** * 6th arch: CN X (recurrent/inferior laryngeal branch) * **speak**
156
1st branchial arch derivatives: abnormalities
* Pierre Robin Sequence * Treacher Collins Sndrome
157
2nd branchial arch derivatives: abnormalities
* Pierre Robin Sequence * Treacher Collins Syndrome
158
What is Pierre Robin Sequence?
Abnormality in 1st and 2nd branchial arches * micrognathia * glossoptosis * cleft palate * airway obstruction
159
What is Treacher Collins Syndrome?
Abnormality in 1st and 2nd branchial arches * Neural crest dysfunction → mandibular hypoplasia, facial abnormalities
160
3rd-6th branchial arches: Comments
* Arches 3 and 4 form posterior 1/3 of tongue * Arch 5 makes no major developmental contributions
161
3rd and 4th branchial arches form
Arches 3 and 4 form the posterior 1/3 of the tongue
162
5th branchial arch developmental contributions
The 5th branchial arch makes no major developmental contributions
163
Cranial Nerve V2 type of function
Sensory only
164
Branchial Arch Mnemonic
When at the restaurant of the golden **arches**, children tennd to first **chew** (1st arch), then **smile** (2nd arch) and then **swallow** **styl**ishly (3rd arch) or **simply** **swallow** (4th arch), and then **speak** (6th arch)
165
Branchial pouches with derivatives
1, 2, 3 and 4
166
1st Branchial pouch derivatives
* Middle ear cavity * Eustachian tube * Mastoid air cells
167
1st Branchial pouch notes
1st pouch contributes to endoderm-lined structures of the ear
168
2nd Branchial pouch derivatives
* Epithelial lining of palatine tonsil
169
3rd Branchial pouch derivatives
* Dorsal wings → **inferior** parathyroids * Ventral wings → thymus
170
3rd Branchial pouch notes
* **3**rd pouch contributes to **3** structures (thymus, left and right inferior parathyroids) * 3rd-pouch structures end up **below** 4th-pouch structures
171
4th Branchial pouch derivatives
* Dorsal wings * → **superior** parathyroids * Ventral wings * → ultimobranchial body * → parafollicular (C) cells of thyroid
172
Branchial Pouch Derivatives Mnemonic
**Ear, tonsils, bottom-to-top**: 1 (**ear**) 2 (**tonsils**) 3 dorsal (**bottom** for inferior parathyroids) 3 ventral (**t**o = **t**hymus) 4 (**top** = superior parathyroids)
173
What is DiGeorge Syndrome?
* Chromosome 22q11 deletion * Aberrant development of 3rd and 4th pouches → T-cell deficiency (thymic aplasia) and hypocalcemia (failure of parathyroid development) * Associated with cardiac defects (conotruncal anomalies)
174
What is Cleft lip?
Failure of fusion of the maxillary and merged medial nasal processes (formation of 1o palate)
175
Pathophysiology of Cleft lip
Failure of fusion of the maxillary and merged medial nasal processes (formation of 1o​ palate)
176
Cleft palate pathophysiology
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 2o palate)
177
Cleft lip and cleft palate etiologies
cleft lip and cleft palate have distinct multifactorial etiologies, but often occur together
178
Female genital embryology
* Default development * Mesonephric duct degenerates and paramesonephric duct develops
179
Male genital embryology
* SRY gene on Y chromosome - produces testis-determining factor → testes development * Sertoli cells secrete Müllerian inhibitory factor (MIF) that suppresses development of paramesonephric ducts * Leydig cells secrete androgens that dtimulate development of mesonephric ducts
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Describe the role of the Paramesonephric (Müllerian) duct
* Develops into female internal structures - fallopian tubes, uterus, upper portion of vagina (lower portion from urogenital sinus) * Male remnant is appendix testis
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Müllerian agenesis AKA
Mayer-Rokitansky-Küster-Hauser Syndrome
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Mayer-Rokitansky-Küster-Hauser Syndrome AKA
Müllerian agenesis
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Describe Müllerian agenesis
may present as 1o amenorrhea (due to a lack of uterine development) in females with fully developed 2o characteristics (functional ovaries)
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Mesonephric duct AKA
Wolffian duct
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Wolffian duct AKA
Mesonephric duct
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Describe the role of the mesonephric duct in genital embryology
Develops into male internal structures (except the prostate) (**SEED**) * **S**eminal vesicles * **E**pididymis * **E**jaculatory duct * **D**uctus deferens
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Wolffian duct female remnant
Female remnant is Garter duct
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Paramesonephric duct male remnant
male remnant is appendix testis
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Describe the mechanism of sexual differentiation abnormalities
* No Sertoli cells or lack of Müllerian Inhibitory Factor (MIF) → develop both male and female internal genitalia and male external genitalia * 5α-reductase deficiency - inability to convert testosterone into DHT → male internal genitalia, ambiguous external genitalia until puberty (When ↑ testosterone levels cause masculinization)
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Sexual differentiation Mnemonic
In the testes: * **L**eydig **L**eads to male (internal and external) sexual differentiation * **S**ertoli **S**huts down female (internal) sexual differentiation
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Sexual differentiation diagram pg 604
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Uterine anomalies AKA
Müllerian duct abnormalities
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Types of Uterine anomalies 3 listed
* Septate uterus * Bicornuate uterus * Uterus didelphys
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What is septate uterus?
* A Uterine anomaly * A common anomaly vs normal uterus * Incomplete resorption of septum * ↓ fertility and early miscarriage/pregnancy loss
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septate uterus treatment
Treat with septoplasty
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What is Bicornuate uterus?
* Incomplete fusion of Müllerian ducts ↑ risk of complicated pregnancy, early pregnancy loss, malpresentation, prematurity
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What is Uterus didelphys?
* Complete failure of fusion → double uterus, cervix, vagina * Pregnancy possible
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Uterine anomalies pg 605
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Genital tubercle -estrogen→
* Glans clitoris * Vestibular bulbs
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Genital tubercle -testosterone→
* Glans penis * Corpus cavernosum and spongiosum
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Urogenital sinus -estrogen→
* greater vestibular glands (of Bartholin) * Urethral and paraurethral glands (of Skene)
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Urogenital sinus -testosterone→
* Bulbourethral glands (of Cowper) * Prostate gland
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Urogenital folds -estrogen→
Labia minora
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Urogenital folds -testosterone→
Ventral shaft of penis (penile urethra)
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Labioscrotal swelling -estrogen→
Labia majora
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Labioscrotal swelling -testosterone→
Scrotum

Human Reproduction (40 decks)

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