Embryology Pastpapers Flashcards
wrong about gonadal development/ sex determination
by the answer suggested: before the arrival of primordial germ cells the epithelium of the genital ridge proliferates and the epithel cells penetrate the underlying mesenchyme forming the primitvie sex cords. It is impossible to differntiate between male and femal at this point - indifferent gonad
What forms the chorion?
extraembryonic somatic mesoderm, cytotrophoblast, syncytiotrophoblast.
name of the phases of spermiogenesis
in langman it says
1 - formation of acrosome
2 - condensation of nucleus
3 - formation of neck middle and tail parts
4 - shedding of most of cyto as residual bodies
What does not form from the neural crest?
a lot of stuff
derivative of prometanephrogenic area
I think they mean the metaneprhinc mesoderm, and veiscles –> connecting tubule, distal conv tubule, loop of henle, prox conv tubule, bowans capsule, renal glomerulus
The allantois
gives rise to the median umbilical ligament/urachus. continous with the urogenital sinus
Tooth development, what week? 6th week, oral epithelium invagination into underlying mesenchyme
starts at week 6.
teeth develop from ectoderm and underlying layer of ncc. Dental laminal develops from the oral epithel ]ectoderm] as downgrowth into the ncc layer. Dental lamina gives -> tooth buds -> enalmel organs withsh are derived from ectoder -> 20 deciduous teeth, then 32 permanent teeth.
enamel organ -> ameoblast -> enamel.
dental papillaer from ncc and -> oddontoblasts -> dental pulp and pretdentin -> dentin
dental sace give reise to -> cementoblast -> cementum and periodonatl lig
phryngeal grooves
groove 1 - epithel lining of external auditory meatus
all rest aare obliterated
what contains amniotic fluid?
amniotic sac. the contents of the fluid:
electrolytes, carbohydrates,amino acids, lipids, proteins (hormones, enzymes, a-fetoprotein), urea, creatinine, lactate, pyruvate,desquamated fetal cells, fetal urine, fetal feces (meconium), and fetal lung liquid (useful for lecithin/sphingomyelin [L/S] ratio measurement for lung maturity).
derivative of mesonephric duct/wolfian
in male - epididymis, vas deferens, seminal vesile. [ prostate froms from the urogenital sinus and the efferenct ducts from the mesonephric tubules]
in female - regresses, may leave cysts
true about post-lat fontanelle
- anterior fontanlle - at junction of 2 parietal and 2 frontal bones. closes after 2 years
- posterior fontanelle - occipital and 2 parietal closes after 2-3 months
- posterolateral fontanelle - temporal occipital and parietal closes 6-18 months
- anterolateral/sphnoidal fontanelle - frontal parietal sphenoid and temporal closes after 6 months
True for morula
morula is 16 cell [cells alled blastomeres]. Inner cells are inner cell mas and the outer are outer cell mas. The inner gives rise to embryo proper. Forms by cleavage
derivative of vitelline veins
the right and left vitelline veins give portion of the IVC [hepatic], hepatic veins and sinusoids, ductus venosus, portal vein, inf mesenteric vein, sup mesenteric vein and splenic vein
what does mullarian duct give?
the mullerian/paramesonephric dducts develop as mesodermal invginations of lateral surface of the urogenital ridge. The cranial part gives the uterine tubes. The caudal part fuses in the midline to form the uterovaginal primordium - bringing 2 peritonial folds called the broad ligament. the uterovaginal primordium gives the uterus cervix and superior one third of the vagina. the mullerian duct induces formation of sinovginal bulbs which fuse to from vaginal plate which canalizes and developesinto inferior 2 thirds of vagina. the epithelial lining of the vagina is form ed from endoderm.
Where does oocyte fertilization occur?
ampulla of the fallopian tube
what part of the neural tube makes the ventral horn
the basal plate will make the ventral horn and the alar plate the dorsal horn
which bones have an endochondral type of ossification (mcq)
endrochondral ossification - ethmoid, sphenoid, petroous and mastomid parts of temporal, basilar of occipita, incus, malleus, stapes, styloid process, hyoid, bones of limbs, limb girdles, bertebrae, sternum and ribs
intramembranuous - frontal, prietal, intraparietal part of occipital, maxilla, zygomatic, squouamous part of termopral bone, palatine, vomer, mandible.
what makes up the smooth wall of the right atrium
sinus venosus gives - smooth part of RA [sinus venarum], coronary sinus, oblique vein of marshall
neuroectoderm
All neurons within brain and spinal cord Retina, iris epithelium, ciliary body epithelium, optic nerve (CN II), optic chiasm, optic tract, dilator and sphincter pupillae muscles Astrocytes, oligodendrocytes, ependymocytes, tanycytes, choroid plexus cells Neurohypophysis Pineal gland
What is the blastocyst comprised of?
morula secrets fluid that forms cavity -> blstocyts. Inner cell mass of the blasotcyst is the embroblast aand the outer cells mass is the trophoblast.
ture about the secondary palate plate
forms from outgrowths of the maxillary prominences of the pharyngeal arch 1 called palatine shelves. The shelves fuse along the palatine raphe to from the secondary palate. The primary and secondary palate fuse at the incisive foramen to from the definitive palate. bone develops in the primary palate and ant part of secondary so thepost part becomes the soft palate and uvula.
development of the telenchephalon
neuroectoderm -> neural plate -> prosencephalon -> telencephalon -> crebral hemi, caudate, putamen, amygdala, claustrum, lamina terminalis, olfacotyr bulbs, hippocampus
proscnecephalon -> diencephalon -> epit sub hypo thalmus, thalamus, mammillary bodies, neurohypophisis, pineal gland, globus pallidus, optic vesicle
True about heart formation?
primitive ventricle ventral and to the right, atrial region dorsal and to left.
what makes up the last portion of the ivc
the right vitellin vein/hepatocardiac channel forms the heptocardiac portion of the IVC. The proximal part of the left vitelline vein disapperss the right subcardinal vein becomes the main drainage channel and develops into the renal segment of the Ivc
simply the vitelline veins [hepatic protion], and post cardinal subcardinal and supracardinal contribute
What’s true for neural tube - came up twice
a lot of stuff, in answers I see genes, the department said that no genes will be asked this year
What is the name of the vessel that bypasses pulmonary circulation?
shunts in fetal circulation
ductus venousus- blood from liver bypasses the hepatic sinusoids throght it to tenter ivc
foramen ovale
ductus arteriosus - blood in RV enters pumonary turnk but most of the blood bypsasses te lungs throtugh it
where does the sensory ganglia develop from
neural crest cells
what is true for cloacal membrane ?
cloacal membrane is future site of anus whre epiblast and hypoblast cells fuse. The cloaca is partitinoed by trorectal septum into rectum and urogenital sinus. The cloacal memb is partitioned by the urorectal septum into the anal membrane and urogenital membrane. the urorectal septum fuses witht the cloacal membrane at the futrure site of the gross anatomical perineal body.
Part of spermiogenesis
spermatids undergo postmeiotice changes to form sperm - formation of acrosome, condenstaion of the nuclus, formation of head neck and tail. Total sperm formation time is around 70 days.
true about the limbs development
limb buds appear in the 4 week. The upper limb appear first. They are well diffeentiatied in week 8. the limb tip contains an apical ectodermal ridge that helps the growth and develpoment. The upper limbs roatae 90 deg laterally compared to lower that rotate 90 deg medially
ectoderm
Epidermis, hair, nails, sweat and sebaceous glands, Utricle, semicircular ducts, vestibular ganglion of CN VIII Saccule, cochlear duct (organ of Corti), spiral ganglion of CN VIII Olfactory placode, CN I Ameloblasts (enamel of teeth) Adenohypophysis Lens of eye Anterior epithelium of cornea Acinar cells of parotid gland Acinar cells of mammary gland Epithelial lining of: Lower anal canal Distal part of male urethra External auditory meatus
