M1 Embryology Final Exam Flashcards

Terms Definitions
Labia majora
Cowper’s glands
Bartholin’s glands
Blastocyst hatches when?
6-7 day
fetal circulation p. 121
Extraembryonic mesoderm
9-11 days postconception
Fetal period
last 30 weeks
what transcription factor promotes acinar cell production from primitive gut?
Week 3
Gastrulation, primitive streak, notocord, neural plate
Formation of ectoderm, mesoderm, endoderm
establishment of correct orientation and position of (progenitor) cells in relation to other tissues and cells for proper differentiation.
The syncytiotrophoblast is derived from the
primitive streak
first sign of gastrulation
meninges and CNS both protruding
function of the notocord?
induces neural tube
kidneys derive from what tissue?
Intermediate mesoderm
_____________________ name given to the middle 1/3 of the bulbus cordis
Conus cordis
the mediaN umbilical ligament arises from the urachus which arises from the
in drosophila, important in specifying the craniocaudal axis, contain the Antennapedia and Bithorax classes (which are organized on a single chromosome as a functional unit), genes specifying more cranial structures lie at the 3’ end of DNA and are expressed first with genes controlling posterior development expressed sequentially and lying INC toward the 5’ end
Urethral opening on inferior (ventral) side
From where do Melanocytes derive?
Neural crest
primary chorionic villi
11-13ed, contain: syncytiotrophoblast, cytotrophoblast
Abnormal (reduced) growth of the cerebrum and cerebellum, cranium still present. Growth of the calvaria due to response to pressure of the growing brain.
Embryologically, the stapedius is derived from branchial arch _____, and the tensor tympani is derived from branchial arch _____.
2; 1
• Neovascularization
at the retina, associated w/ diabetes
the mucous membrane lining the uterus.
no long bone ossification, only hand off chest
What large cavity surrounds the embryoblast and fills the trophoblast?
Chorionic cavity
what is the function of unterine glands?
umbilical arteris
Retunrs deoxygenated blood from the fetus to the placenta
most common site of ectopic thyroid tissue:
What fetal structure forms:
Cricoid cartilage
4th-6th Branchial arch
The cardiovascular system derives from:
Lateral plate mesoderm
neuroenteric canal
temporarily connects the amniotic and yolk sac cavities, found where primitive pit forms an indentation in the epiblast
umbilical cord
develops from the connecting stalk when infiltrated with blood vessels
smaller than the hypomere, dorsal to the transverse processes of the vertebrae. These cells do not migrate far. They become the epaxial muscles. Innervated by the dorsal branches of the spinal nerves.
Ear development: which arch are the following derived from:Stapes
* syncytial layer idea for penetration into the endometrium of the uterus

1) Multinucleate protoplasmic mass formed by the fusion of cells

2) 7th day starts to penetrate into the uterus
The tissue of origin for tracheal epithelium is:
Which branchial arch forms the anterior 2/3 of tongue?
Arch 1
formation of neural tube (via neural plate, folds, and closure of folds)
What does PGCs stimulate the growth of?
Embryologically, cranial nerve IX innervates the derivatives of which branchial arch?
Branchial arch 3
_______ is the number of chromosomes in sex cells (before fertilization).
Thoracic outlet syndrome
cervical rib compresses subclavian artery / inf. Trunk of brachial plexus… cervical rib is an embryological anomaly
any of several major female sex hormones produced primarily by the ovarian follicles of female mammals, capable of inducing estrus, developing and maintaining secondary female sex characteristics, and preparing the uterus for the reception of a fertilized
Splanchnic (Visceral) Mesoderm
Continous around yolk sac
 Cover the abdominal organs, lung and heart
Spermiogenesis (the conversion of spermatids into mature sperm) is characterized by:
Nuclear condensation
Loss of cytoplasm
Formation of an acrosome
Neck and tail formation
1. At 5 days: after formation of morula, but before implantation
2. Cluster of cells with a fluid filled cavity (blastocele)
3. Possesses embryoblast and trophoblast
Define acrosome reaction?
The release of enzymes (Hyaluronidase, Acrosin and Trypsin-like substances) from the acrosome of the spermatoza, INDUCED by 'Zona proteins' and mediated by 'ZP3 ligand' in order for the spermatoza to PENETRATE the Zona Pellucida of the Ovum.
A precursor to a portion of the urinary baldder is:
Surfactant and type I pneumocytes develop from what?
Type II pneumocytes
what does the ascending aorta and pulmonary trunk arise from embryologically
truncus arteriosus
What is the remnant of:
Umbilical arteries
Medial umbilical ligaments
TGF-beta superfamily (transforming growth factor)
includes the transforming growth factor betas, bone morphogenetic proteins, the activin family, the Mullerian inhibiting factor and others, important for extracellular matrix formation and epithelial branching that occurs in lung, kidney and salivary gland development, bone formation, regulating cell division, cell death and cell migration
two derivatives of the somite
dermomyotome -> muscle
sclerotome -> bone
Which CN is a derivative of BA#2
What is the role of Indomethacin?
closes the PDA.
Fetal head restraint usually occurs from what type of pregnancies?
Twin or tiplet
What else occurs?
Resistance in the pulmonary blood vessels decreases
What gives rise to the ureteric buds?
mesonephric ducts?
In female development, the _____ duct degenerates and the _____ duct develops.
Mesonephric; paramesonephric
What is the adult derivative of the mesencephalon in the developing brain?
What separates the stomodeum and the foregut?
Buccopharyngeal membrane
intermediate mesoderm forms what
urogenital system (kidneys, gonds, ducts and accessory glands)
o Coarctation of the Aorta
congenital thickening of aortic wall
the stage in mitosis or meiosis in which the duplicated chromosomes line up along the equatorial plate of the spindle.
Gut formation
forms as the cephalic and caudal ends are seperated ("pinched off") from the main yolk sack
the will be neural tissue forms what here ... it will eventualy cavitate to form the lumen of the neural tube
medullary cord
thyroid gland derives from what tissue?
Endoderm between Arch 1-3
Becomes the palatine tonsil and the tonsilar crypts:
Second pharyngeal pouch
Branchial cleft derivatives
1st - external auditory meatus2-4 - cervical sinuses that get obliterated
this sx in the umbilical cord removes nitrogenous waste from the fetal bladder (lika a urethra)
allantoic duct
intraembryonic mesoderm forms from what kind of cells? migrating between what layers?
epiblast cells migrate between epiblast and newly formed embryonic endoderm
yolk sac
is vestigial in humans, probably has a nutritive role only in early stages of development
What is an Extra-uterine implantation?
Implantation outside of the uterus
Head development results from molecular signals from what?
Anterior visceral endoderm, which establishes the cranial end
These are known as what?
The three primary germ layers
what does the notochord induces changes of
ectoderm --> neuroectoderm, mesoderm --> somites, endoderm --> segments
Where do the nasal placodes form?
Within the frontonasal prominence
At about what age do infants with congenital pyloric stenosis typically start projectile vomiting?
2 weeks
In an embryo, the neural tube forms from the neural plate how many days after fertilization
Days 18-21
where do the connective tissue and muscular components of the digestive system originate
in the mesoderm
Fertilization takes place where?
Distal part of the uterine tube
functional changes at birth
closure of umb aa
   prox portion remains as sup vesical aa
   med umbilical lig's
closure of umb v and ductus venosus
   lig teres hepatis
   lig venosum
closure of ductus art goes to lig arter
closure of for ovale to fossa ovale
What are the two layers of the trophoblast, and their defining features?
Cytotrophoblast (maintains cellularity) and Syncytiotrophoblast (lose individual cellularity, becomes a multinucleated cell)
what are the embryologic derivatives from neuroectoderm?
brain (neurohypophysis, CNS tumors, oligodentrocytes, astrocytes, ependymal cells, pineal glands), retina, spinal cord
Midgut derivatives?
Blood supply?
3rd part of duodenum --> proximal 2/3 of tranverse colon, with appendix
Superior mesenteric artery
Baby takes first breath -->
lower pulmonary vasculature R --> raise LA P --> close foramen ovale
raise in O2 --> drop in prostaglandins --> close ductus arteriosus
A child presents with a systolic heart murmur heard at the upper left sternal border and in the back to the left of the thoracic spine. Chest X-ray/electrocardiogram shows right ventricular enlargement and decreased density of the lung fields, suggesting
Pulmonary artery stenosis
physical characteristics during the second half of intrauterine life
weight INC considerably (esp during the last 2.5 months), skin is reddish and wrinkly during the 6th month, at 7 months 1100g,
How long is the sperm viable?
1-2 days (3 days max)
What is placenta previa?
Implantation of the zygote close to the internal os leading to bridging the opening of the uterus, which results in hemorrhaging late in pregnancy
For the following caridio embryonic structure state the neonatal structure to which is gives rise: Primitive atria
trabeculated L and R aorta
By 6 weeks the embryo has grown to how long?
Where does the nasal septum start and what does it separate?
intermaxillary segment
left/right sides of nasal cavity
Horseshoe kidneys remain low in the abdomen because, during fetal development, they get trapped under what artery?
The inferior mesenteric artery
What is an Chiari type II malformation?
Cerebellar tonsillar herniation through the foramen magnum resulting in aqueductal stenosis and hydrocephaly
parts of the respiratory portion of the resp system
respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli
what is the most important even that occurs during the 8th week?
bones begin to calcify
how does dorsal/ventral patterning occur?
signals from outside the neural plate begin to establish a d/v pattern.
what are the teratogenic effects of vit A excess?
spontaneous abortions, birth defects (cleft palate, cardiac abnormalities)
1. muscles2. most of skeleton3. circulatory system4. reproductive organs5. excretory organs6. dermis of skin (deeper layers)
What originates from the gastrula outer layer?
Give 2 bones/cartilage, muscles, and 1 nerve that arrises from branchial arch 2 derivitives
Reichert's cartilage: Stapes, Syloid process, lesser horn of hyoid, Stylohyoid ligament
Muscles: mm of facial expression, stapedius, stylohyoid, posterior belly of digastric
Nerve: CN VII
menstrual phase of the menstrual cycle
occurs if fertilization does not occur, shedding of the endometrium, if fertilization does occur then the endometrium assists in implantation and contributes to the placenta, bleed out the spongy and compact layer, keep basal layer
What are 4 results of fertilization?
1. Restoration of diploid chromosomal number (46 d)
2. Species variation
3. Determination of sex
4. Initiation of zygote division
What are the two layers of the germ disc?
Epiblast and hypoblast
prostaglandins in relation to early embryonic development is important because
stimulate uterine motility and assist in the movement of sperms
Trace the name of the fertilized egg through the first week embryogenesis.
Fertilization, Zygote, Morula, Blastocyst
What does this cause?
An increase in blood flow through the lungs
How are the branchial sinuses formed?
the 2nd and 6th
arches overgrow the
3rd and 4th
create the cervical sinus,
which is subsequently
What are 2 complications associated with a bicornuate uterus?
Bicornuate uterus is associated with urinary tract abnormalities and infertility
The swellings and positions of tooth buds correspond to what?
location of the primary teeth
Germ Cell Viability
-oocyte is viable up to 18 hours after ovulation
-capacity of the oocyte to fertilize decreases after 14 hours when it starts to loose its viability
-dies within 24 hours of ovulation
-sperm can stay alive in the female reproductive tract for about 24 hours - optimum conditions can be viable as long as 3 days after insemination
what are the 5 secondary vesicles from cranial to caudal?
Telencephalon and diencephalon (from the prosencephalon), the mesencephalon (hasnt subdivided and is therefore the same), the metencephalon and myelenchephalon (from the rhombenchephalon).
How do pregnancy tests work?
They detect hCG in the mother's blood beginning at day 10.
Define 'Gastrulation' and write the embryonic structures that develop from it?
Gastrulation is the process of forming the 3 primary germ layers (trilaminar germ disc) from the epiblast - involving the migration of the epiblast cells through the primitive streak to form the ectoderm, mesoderm and the endoderm.-Ectoderm-Mesoderm.-Endoderm.-Notochord.
what does the coronary sinus arise from embryologically
Left horn of sinus venosus (SV)
lacunar stage of the 9th day
vacuoles in the syncytium fuse and form large lacunae during this stage
What is the complication/treatment for an Ovarian Implantation?
Removal of the blastocyst and ovary due to scarring of the ovary
The neural folds are temporarily incomplete where
At the cranial and caudal neurotropes (close at day 25 and day 27)
What are the 3 embryologic structures of the kidney and when do they develop?
Pronephros (week 4), Mesonephros (1st trimester), Metanephros (permanent)
Why does aniridia form? What happens?
The Pax6 gene encodes a transcription factor required for normal eye development.
Aniridia (e.g., in heterozygous pax6 mutant individuals) is a rare condition in which the iris fails to form and there are lens cataracts and other eye problems, such as micropthalmia.
The notochord in the fetus becomes what structure in the adult?
The nucleus pulposus of the intervertebral disks
distal 6th aortic arch gives rise to...
ductus arteriosis on the left, dissappears on the right
What are the 3 "rod and sheet-like" mesodermal derivates and what systems will they form?
Paraxial mesoderm - axial skeleton, skeletal muscle, part of the dermis
Intermediate mesoderm - urinary and part of genital system
Lateral plate mesoderm - gives rise to splanchnic and somatic mesoderm
branchial cyst in the neck is due to:
persistent cervical sinus, which are 2nd - 4th branchial clefts
What give rise to: Right common cardinal vein and right anterior cardinal vein
Smooth part of right atrium and SVC
What are the two components of this system?
The placenta and the umbilical cord
Why is the tunica albuginea delayed in women?
the secondary sex cords can form
What two components make up the interventricular septum?
The muscular septum and the membranous septum
How sensitive to teratogenesis is the Embryo?
The embryonic period is the period of greatest sensitivity throughout the pregnancy
what is the bilaminar germ disk? when does it appear?
epiblast and hypoblast
end of week 1 beginning of week 2
What are the risk outcomes with pregnancies involving twins?
Death of twins, low birth weight and premature birth
What ectopic sites can ureters fuse with bladder?
neck of the bladder, genital duct or prostatic urethra in males or with the neck of the bladder or vestibule of the vagina in females
How can a thyroglossal duct cyst be differentiated from a branchial cleft cyst on physical exam?
A thyroglossal duct cyst will move with swallowing, unlike a branchial cleft cyst
A 7 year old boy develops a fever of 39 C while playing in his front yard a Dallas summer day. He becomes limp and lethargic, prompting his mother to rush hime to the emergency room. She stats that he never seems to sweat, and that he often feels very wa
A defect in gasturlation that produces undergrowth of the ectoderm.
Why does the brain inflate? Why is this pressure necessary?
By the sixth week of development the forebrain is inflated by increased internal pressure caused by the production of the cerebral spinal fluid (CSF), by the choroid plexus. This increased pressure is necessary for normal development of the brain, as evidenced by experiments performed in other vertebrates, including chicken embryos, in which a cannula was inserted to drain CSF.
what does it mean for a cell to be "born"?
they go through their final cell division...loose their ability to divide. later in cns developement proliferation exists in the ventricular zone.
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