Green Boxes

Suppression of limb bud development during the early part of the fourth week

Arrest or disturbance of the differentiation or growth of the limbs during the fifth week. Maternal thalidomide usage

results from failure of one or more digital rays to develop

-often associated with exstrophy of the bladder,
-may result from inadequate ectodermal-mesenchymal interactions during development of the genital tubercle.
-The urogenital sinus opens on the dorsal surface of the penis.
-Failure of the primitive streak mesoderm to migrate around the cloacal membrane, or
-failure of fusion of the spongy urethra

due to failure of the fusion of labioscrotal folds so that the external urethral orifice is between the unfused halves of the scrotum. Open on the ventral aspect of the penis

failure of fusion of the urethral folds. Open on the ventral aspect of the penis.

failure of fusion of the inferior parts of the paramesonephric ducts

Failure of fusion of the superior parts of the paramesonephric ducts

failure of the sinovaginal bulbs to form the vaginal plate

develops when one paramesonephric duct doesn’t develop

Failure of the inferior end of the vaginal plate to perforate leading to hematocopolos (blood filling the vaginal cavity upon menstruation)

46, XX. Results from an error in sex determination, phenotype may be male or female but the external genitalia are always ambiguous

results from exposure of a female fetus to excessive androgens, the principle effect of which is virilization of the external genitalia. Have chromatin-positive nuclei.

have chromatin-negative nuclei, variable external genitalia. Anomalies caused by androgen insensitivity (lack of receptors)
- Mullerian inhibiting subastance (MIS) is present (paramesonephric duct degenerates)
-external appearance of female

results when the ureter is carried caudally with the mesonephric duct and is incorporated into the caudal portion of the vesical part of the urogenital sinus.
-Often inserts into the urethra or vagina leading to "drip" incontinence since urine is not deposited in bladder

Remnants of the epithelial lining of the urachus

The patent inferior end of the urachus dilates forming an urachal sinus that opens into the bladder

The entire urachus remains patent and forms a urachal fistula that allows urine to escape from its umbilical orifice

total/partial absence of the brain due to defective closure of the rostral neuropore.

failure of cleavage of the forebrain, resulting in a single fused ventricle. Cyclops. Associated with Sonic Hedgehog Gene

failure of maxillary prominence to fuse with merged medial nasal prominences /intermaxillary segmen

failure of the lateral palatine processes to meet and fuse with the primary palate.

failure of the lateral palatine processes to meet and fuse with each other and the nasal septum.

failure of maxillary prominence to fuse with lateral nasal process

defect in formation of the cranium (usually occipital bone).

meninges and CSF

meninges, CSF, brain

meninges, CSF, brain, parts of the ventricular system

Inferior displacement of the vermis of the cerebellum and medulla through the foramen magnum
-difficulty swallowing, dizziness, nausea, impaired coordination, headaches

can lead to macrosomia (high birth weight) , CNS, heart and skeletal defects

Majority of cases are due to a point mutation in the FGFR3 gene, which results in magnification of the normal inhibiting effect of endochondral ossification. Epiphyses fuse early. Results in shortened bone, but does not affect periosteal bone growth
- short stature
-bowed limbs
-short trunk
-enlarged head

congenital cataracts, deafness, cardiac defects, mental retardation

-A parasitic disease which can be passed from mother to fetus (transplacental)
-From raw or undercooked meat, contaminated fruits and vegetables, cat feces
-intracranial calcifications, convuslsions, hydrocephalus, chorioretinitis

-infection obtained causing the following effects on fetus
-microcephaly, micropthalmia, hydrocephalus, hearing loss, mental retardation, intrauterine growth retardation

teratogenic at any stage of pregnancy
-hydrocephalus
-deafness
-retardation
-malformed teeth

-a sedative and anti nauseant
-inhibits FGF’s (fibroblast Growth Factors) at the AER (apical epidermal ridge) --> meromelia (complete absence of limbs due to suppression of limb buds)

primitive streak remnants, contains tissues from all three germ layers

– failure of closure of the retinal fissure

the inner and outer layers of the optic cup don’t fuse during the fetal period to form the retina and obliterate the intraretinal space. Separation between the neural and pigmented layers.

absence of iris, arrest of development at the rim of the optic cup

absence of lens, failure of lens placode to form

hidden eye occurs due to failure of development of the palpebral fissure

due to maternal abuse of alcohol

Indistinct Philtrum, thin upper lip, depressed nasal bridge, short nose, mental retardation

toxoplasma gonadii: an intracellular parasite which can move from the mother to the fetus. Causes chorioretinitis, hydrocephalus, intracranial calcifications, convulsions

Cystic remnants of the thyoglossal duct, may be open to the exterior making it a thyroglossal fistula. Will move when you swallow

failure of neural crest migration into the first arch.
-Cleft palate,
-micrognathia,
-conductive hearing loss,
-drooping part of lower eyelid

Catch 22
deletion in long arm of Chromosome 22. Faulty migration of neural crest cells. Exposure to retinoids, alcohol and maternal diabetes mellitus. Cardiac anomalies, abnormal face (fish mouth), Thymic hypoplasia,
cleft palate, hypocalcemia

Micrognathia leading to glossoptosis where tongue blocks airway and palatal shelf development leading to cleft palate

Persistance of part of the cervical cyst formed from the fusion of the 2-4 pharyngeal grooves. Cystic swelling along anterior of SCM. Painless, Seen in late childhood.

can be obstructive or communicating where
-obstructive involves a blockage of the circulation of CSF and
-communicating involves lack of reabsorption of CSF.

A family of paracrine factors that are used by the embryo to induce particular cell types and create cell boundaries. Important for

-limb patterning, neural tube induction, somite differentiation, gut regionalization
Spermatogenesis
Stem cell maintanence
Oncogenesis
implantation
Organogenesis

produced at the tip of a limb bud by the Apical Ectodermal Ridge structure which is responsible for regulating limb length. FGF affects the Progress Zone to determine limb length.

patterning of dorso-ventral axis

Limb development
Bone, kidney, heart development
Control of skin development