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
embryonic origin of epicardium
splanchnic mesoderm
how many somites can be found
we first see 42-44 pairs of somites byd cadal most somites desappear so finally we ssee 35 pairs of somites
paraxial mesoderm is thick plate of mesodierm on sides of midline. Its organized into somitomeres that from in craniocaudal sequence. somitomieres 1-7 do not form somites but contribute to pharyngeal arches. the rest condenst in a craniocaudal seq to from 42-44 pairs. the somites closest to the caudal exnd dispaapesar leaving 35 pairs of somites. they differetiate to sclereotme [cartilage and bone], myotome [ muscle], dermatome [dermis of skin]
True for ganglia:
basal plate gives the preganglionec symp neurons. The ncc gives give postgang symp neurons within the symp chain gang, prevertebral symp gang, and chromaffin cells of adrenal medulla.
Basal plate gives pregang para symp of 4, 7, 9-10 and s2-s4. ncc gives postgang prasymp neurons in ciliary, pterygo, submandib, otic, enteric and abdomminal cavity parasymp ganglia.
pharyngeal pouches
pouch 1 - epithl lining of auditory atube and middle ear cavity and mastoid air cells
pouch 2- epithl lining of platine tonsil crypts
pouch 3 gives rise to thymus and infrerior parathyorid gland.
Pouch 4 - sup parathyroid gland and ultimobranchial body [ncc will migrate into it and form c cells of thyroid]
what happens just before the acrosomal reaction
capacitation. After the acrosomal reaction there are 3 phases of fertilization.
1 - penetration of the corona radiata
2 - penetration of the zona pellucida - mediated by the zp3 protein
3 - fusion of the oocyte and sperm cell membranes
mesonephros, metanephros (3/4 questions)
mesonephros - developsby differenetiation of mesoderm within the nephrogenic cord to form mesonephroic tubuels and eht mesonephric duce/wolffian duct. Most the the mesonephric tubules regress, vut the mesonephric duct persists and opens into the urogenital sinus. its functional for a short period
metanephros - develpos from outgrowth of mesonephrice duct [called ureteric bud] and from a condesntaton of mesoderm in the ne[hrogenic corrd called metanephric mesoderm. forms at week 5 and funcitonal at 10. it fevelops into the definitive adult kidney.
gastrulation
process of establishing the three germ layers and forming the trilaminar disk by day 21.
starts with the primitive streak - proliferation of epiblast cells. The primitive streak consist of a primitive groove node and pit. During the 3rd week we have the intraembryonic mesodem formed, during the 2nd week the extraembryonic mesoderm is formed.
what is maternal part of placenta?
maternal part of placenta - decidua basalis which includes the portiion of endometrium locatd bw blastocyst and myometrium [site of implantation]. Maternal surface is covered by cotyledons.
derivatives of inner optic cup (mcq)
the optic cup has the inner neural layer and outer pigment layer
inner nerual layer - nerural layer of retina [rods and cones, bipolar cells ganglion cells and ect], epithelium of iris [also from outer pigment layer], epithelium of ciliary body [and from outer pigmented layer]
outer pigment epithelium - the pigment layer of the rtina, epithelium of the iris. dilator pupillae and sphincter pupillae. epithelium of ciliary body
endoderm
Hepatocytes Principal and oxyphil cells of parathyroid Thyroid follicular cells thymus Epithelial reticular cells of thymus Acinar and islet cells of pancreas Acinar cells of submandibular and sublingual glands Epithelial lining of: Gastrointestinal tract Trachea, bronchii, lungs Biliary apparatus Urinary bladder, female urethra, most of male urethra Inferior 2/3 of vagina Auditory tube, middle ear cavity Crypts of palatine tonsils
The decline of the internal female genitalia is due to?
anti mullerian hormone - AMH. Sox 9 helps block beta catenin
What are the derivatives of metanephric blastema?
gives rise to nephrons, kidney and pary of collecting duct system
What makes up the placenta?
maternal component an the fetal componetnt [villi]
What parts are from the maternal placenta?
maternal part - decidua basalis, cotyledons, placnetal septa
fetal part - tertiary chorionic villi [derrived from trophoblast and extreaembryonic mesoderm], collectivly called chorion.
laryngeal cartilage origin
the laryngel epithelium and glans from the endoderm. the muscles and cartilages from pharyngeal arches 4 and 6
what derives from the 3rd pharyngeal arch
arch 3 - glossopharyngeal nerve. Stylopharyngeus. Common carotid arteries, internal arotid arteris. Greater horn and lower body of hyoid bone.
Pouch 3 - inferior parathyroid gland
derivatives of ventral mesogastrium
lesser omentum [hepatoduodenal and heptogastric ligaments], flaciform and coronary ligaments, and triangular ligaments of the liver
True for gonads?
female-
1. intermediate mesodrm forms urogenital ridge.
2. coelomic epithel proliferat and forms -> gonadal ridge
3. primary sexd cords develop from the gonadal ridge
4. primary sex cords extend into medulla and develop into rete ovarii that will eventually degenerate. the secondary sex cords develop and incorporate primordial germ cells as tunica albuginea forms.
5. secondary sex cords break apart and form cell clusters - primordial follicles
6. primary oocyte derived from primordial germ cells where the simple squamous of the primordial follical and ovarian stroma derive from mesoderm
descend of ovaries
1. gubernaculum is involvved. forms the ovarian ligament and then continues into the labia majora forming the round ligament of the uterus.
2. peritoneum evaginates alongside the gubernaculu to form the processus vaginalis whish is obliteratied i the female
male
1. same
2. same
3. same
4. y chromose carries gene for TDF
5. primary sex cords extend into the medulla and surface epithel form tunica albuginea
6.primary sex cords -> sminirferous cords, tubuli recti and rete testes
7. semineferous cords consist of primordial germ cells and sertoli cells
8. mesoder -> leydig cells
9. primordial germ cells sertoli and lytdig and stroma of testes derive from mesoderm
10. seminiferous cords remin solid until punerty and then get lumn and are valled seminiferous tubules
descent
1. gubernavulun connects testes to scortum
2. peritoneum evaginates alongside gubernaculum to form theprocessus vaginalis
3. the processes vaginalis is pbliterated except at distal end that is called the runica vavinalis of the testes.
cause of epispadias?
urethral meatus found on dorsum of the penis. Associated with exstrophy of the bladder and abnormal closure of ventral body wall.
Problem with ectopic testicles
testicle does not descend properly and stays in the abdominal cavity. Not functional
What does the sinus venosus form?
the ledft horn -> oblique cein of marshall and coronary sinus
right horn -> sinus venarum cavarum
when is the sex determined
genotype is established at fertilization but phenotype starts at week 7
from what are the parathyroids glands developing
the inferior from 3rd pouch and the sup from the 4th
what is true for zona pellucida (mcq)
zona pellucida is later of glcoproteins. Surrounded by cells called corona radiata. Zona proteins help the acrosome reaction once sperm binds th zona pellucida. The binding of the sperm and the acrosome reaction are mediated by ZP3. acrosin is one of the enzymes.
pharyngeal arch derivatives
1 - cranial nerve 5. mesoderm -> muscles of mastication, mylohyoid, ant belly of digastric, tensor veli palatini, tensor tympani. NCC -> maxilla, mandibe, malleus, incus, zygomatic, squamous temporal bone, palatine bone, vomer, sphenomandibular lig, mecels cartilage
2- cranial nerve 7. mesoderm -> muscles of facial experession, post belly of digastric, stylohyoid, stapedius. NCC -> stapes, styloid process, stylohyodi lig, lesser horn and upper body of hyoid bone, reichret cartilage
3 - cranial nerve 9 - mesoderm -> stylopharyngeus, common carotid arteris, internal carotid arteries. NCC -> grater horn and lower body of hgyoid bone
4-6 - Cranial nerve 10 - mesoderm -> muscles of soft paltate [ except from tensor veli palatini], mucles of pharynx [except stylophayngeus], cricothyroid, cricophayngeus, lartyngeal cartilages and right subclavian artery and arch of aorta. intrinsic muslces of larynx and ypper muscles of esophagus, latryngeal cratilages, pulmonary arteris and ductus arteriosus
where does the otic placode form
found in rhombencephalon and formed from ectoderm. Will go on to from the otic vesicle which will diveide into:
utricular portion -> utricl, semiciruclar ducts, vestibular gang of CN 8, endolyphatic duct and sac
saccular portion -> saccule, cochlear uct and organ of corti, spiral gang of CN 8
What type of tissue does hepatocytes develop from?
endoerm
when does the oocyte finish 2nd meiosis
fertilization
what is true for cleavage (mcq)
cleavage is a series of mitotic divisions which increases the number of cells but their size decreases with each division. The cells are know as blastomeres. After third division the cells are helt by tivht junctins in process called compaction. The 16 cell stage is clalled murola with inner and outer cell masses. the inner mass gives rise to embyro proper and outer cells to the trophoblast which later contributes to the placenta
where do you find the acrosome
head of sperm
what gives the terminal part of the inferior vena cava
right supracardinal vein
true about ooropharyngeal membrane
ectoderm and endoderm cone into direct contanct. Fors a septum between the primitive mouth and pharynx. Primitive mouth
what are the cells in the morula called
blastomeres
mesoderm
Muscle (smooth, cardiac, skeletal) Extraocular muscles, ciliary muscle of eye, iris stroma, ciliary body stroma Substantia propria of cornea, corneal endothelium, sclera, choroid Muscles of tongue (occipital somites) Pharyngeal arch muscles Laryngeal cartilages Connective tissue Dermis and subcutaneous layer of skin Bone and cartilage Dura mater Endothelium of blood and lymph vessels Red blood cells, white blood cells, microglia, and Kupffer cells Spleen Kidney Adrenal cortex Testes, epididymis, ductus deferens, seminal vesicle, ejaculatory duct Ovary, uterus, uterine tubes, superior 1/3 of vagina
true about the closure of the neural folds
ant neuropore close on 25 and post on 27
What surrounds amniotic fluid?
it is contained in the amniotic sac and is generated from the maternal plasma. It passes through the fetal membranes. When fetal kidney begin to function at week 16 the fetal urine contributes to this fluit. The fluid is absorbed through the fetal tissue and skin. at week 15-25 its absorbed by the fetal gut.
they asked a lot of questions about neural crest derivatives!!!
cranial neural crest cells: pharyngeal arch and skeletal cand connective tissue components, bones of neurocranium [except for basilar part of occipital bone that develops from mesodrm], pia and aracchnoid, parafollicular [c] cells of thyroid, aortiocpulmonary septum, odontoblatsts, sensory ganglia of cranial nerves 5, 7, 9, 10, ciliary, pterygopalatine, submandiubular and otic parasympathetic gangilia
trunk NCC: melanocytes, schwann cells, chromaffin cells of adrenal medulla, DRG, sympathetic chain ganglia, prevertebral symp ganglia, enteric parasymp ganglia of gut [meissner and aurbach], abdominal and pelvic parasymp ganglia
true about neural tube closing
craniocaudal direction of closing. Day 25 for ant neuropore and day 27 post neuropore
what is a derivative of the gubernaculum
ovarian ligament, round ligament of the uterus. Peritoneum evaginates alongside it to from the processu vaginalis. In male remanants serve to anchor the testes within the scortum
what is not a derivative of the ureteric bud
ureteric bud is outgrowth of mesonephric duct. Gives ureters, renal pelvis, major and minor calyces and collecting ducts
what makes up the diaphragm embryonically (mcq)
formed by fusion of :
septum transversum [from mesodrm], primordium of central tendon
paired pleuroperitoneal membranes of somatic mesoderm
dorsal mesentrary of the esophagus - forms crura of diaphragm
boydy wall -> peripheral portions
what is giving the thyroid
the parafollicular cells of the thyroid are developed from the ncc. Andodermal lining of the foregut forms thyroid diverticulum that migrates caudally passing ventral to the hyoid bone and laryx. The remains of this migration is the thryoglossal duct and in adult is the foramen cecum.
true about the allantois
allanois if continous with the urogenital siunus. Will become the urachus [median umbilical lig] the allantois is found in the umblilical cord as well. Helps from cloaca. Allantois formed from endoderm
what is a derivative of the ureteric bud?
the ureteric bud is an outgrowth of the mesonephric duct and will initially penetrate the metanephrinc mesoderm and undergoies repeated branching to form: ureters, renal pelvis, major calyces, minor calyces and collecting ducts
what are the pharyngeal arches made of/ giving (mcq)
nerve, muscles, artery, catilage/bone, mesenchyme/connective tissue
uestion on otic vesicle
forms from ectoderm of the rhombencephalon and gives rise to
utricle semicifular ducts, vestibular gang of 8, saccule, cochlear duct, spiral gang of 8, vestibulocochlear nerve
day of implantation
day 6-7
