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119 Cards in this Set

  • Front
  • Back
What develops into the midline
what induces the overlying ecotoderm to form the neural tube
what does the paraxial mesoderm give rise to
skeletal muscle, vertebrae, dermis of the back
where does paraxial mesoderm form
lateral to the spinal cord
where does intermediate mesoderm form
lateral to the paraxil mesoderm
what does the intermediate mesoderm give rise to
Urogenital system
where does lateral plate mesoderm form
most lateral
What two mesoderms does lateral plate mesoderm give rise to
somatic mesoderm and splnchic mesoderm
What forms somtatic mesoderm, what does somatic mesoderm form
somatic formed from lateal plate mesosderm; it gives rise to dermis, connective tissue and cartilage and bone of the skeleton
what forms splanchic mesoderm, what does splanchic form from
lateral plate mesoderm; it gives rise to smooth muslce and cardiac muscle
name the three types of mesoderm
paraxial, intermediate, lateral
What gives rise to somites
paraxial mesoderm
how manyt pairs of somites exist
42-44 pairs
What are the subdivisions of somites
dermatome, myotome, sclerotome
Formation of the neural tune and what does the NT give rise to
Neurulation, neural tube gives rise to CNS - spinal cord and the brain
Neural crest cells give rise to
sensory neurons, autonomic neurons, supportive cells of the PNS, esp schwann cells. also give rise to pigment in the skin, head mesenchyme
formation of the back muscles
WNT from the dorsal spinal cord induces Myf5 in the myotome
formation of the anterior body wall nad limb musculature (intercostal muscle, ab muscle, limb) muscle
WNT from the body wall ectoderm induces myotome to express myoD
Formation of bone
1) mesenchymal cells migrate to region of presumptive vertbrae nad ribs
2) mesenchymal cells form pre-cartilage mass
3) cartilage is formed
4) cartilage is replaced with bone
what hormones act to form vertebra
SHH induces PAX1 int eh sclerotome
formation of vertebra
1) sclerotome surrounds notochord nad neural tube
2) notochord and neural tube produce substanes that direct development
3) cartilage model begins to develop
what do limb buds form from
apical ectoderm ridge- AER
w/o AER, the limb will not develop
what genes help determine where the limb buds develop
HOX genes
involved in determining forelimb and hindlimb
TBX5(upper limb) TBX4 (lower limb)
what is the pattern of digit formation dependent upon
posterior limb bud mesoderm (ZPA)
ZPA - zone of polarizing activity - influences hte overlying AER to produce what
AER priduces retinoic acid, which initiates SHH that regualtes the AP axis
What reglates the types and shapes of bones
HOX expression (mainly HOXD and HOXA)
What is the end of hte limb, intially
a paddle
HOw does hte limb paddle form into fingers
Cell death (apoptosis) occurs along the AER, dividing the ridge into 5 regions
When does development of the CV system start
3rd week of gestation or 5th week LMP
How long does it take for the heart to develop
5 weeks
when the heart begins to beat
21 days of gestation
septation of the heart, what and when
4 chambers of the heart form, at 37 days of gestation
what does the heart first begin as
horshoe shaped pericardial cavity
what occurs when the heart starts to beat at 21 days of gestation
the two endocaridal heart tubes fuse into a sigle heart
when does the respiratory system develop
4th week of gestation
two portions of the respiratory portion
conducting portion and respiratory portion
parts of the conducting portion of hte respiratory portion
nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles
parts of the respiratory portion of the resp system
respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli
what occurs in the alveoli
gaseous exchange
when is the indiffernet stage
first 6 weeks of development (cant tell the sex)
when the cell divides into 2
how does blastocyst form
compaction of morula as it moves down the uterine tube
parts of the blastocyst
a cavity surrounded by an outer trophoblast layer nad an inner cell mass
center of the blastocyst
blastocyst cavity, primary yolk sac
what occurs during gastrulation
establishes the three germs layers of the trilaminar embryo
how is the trilaminar disc formed
the top epiblast layer of the blastocyst migrates down to the space in between it and hte hypoblast.
the three layers formed when the epiblast migrates downward (tri laminar)
epiblast becomes the ectoderm, the migrated cells become the middle mesoderm, and hte hyoderm is replaced by epiblast cells to become the endoderm
what composes the bilaminar disc
epiblast and hypoblast
which end of the neural tube become the spinal cord and brain
the caudal end becomes the spinal cord and the fat cephalic end becomes the brain
what does formation of the vertebrate body plan include
ecto, endo and mesoderm
what happens during lateral body folding
the lateral edges of the ecto, meso and endoderm begin to fold under the embryo
which layer that forms develops into a cavity
lateral mesoderm (forms a somatic mesoderm and splanchic mesoderm)
what starts forming when HOXB8 is expressed
the upper limb
3 layers of mesoderm and their order
lateral, intermediate, paraxial LIPO
when does fertilization occur
14 days after LMP, first day of gestation
when does implantation occur
beginning of the third week of menstrual cycle
when does gastrulation begin
the time when next menstrual cycle would begin
things occuring in the first 15 days of gestation
ovulation (0),
fertilization (1), blastocyst (20-21), bilaminar disc (28), gastrulation (29)
gives rise to pluripotent stem cells
inner cell mass (can dvlp into anything with help of endo, meso and ecto)
Best chances for conception, worst chances?
early 20's - 25% in one month
early 30's - 15% in one month
late 40's - 10% in one month
what is hCG produced by
syncytiotrophoblast cells
what maintains hte corpus luteum for productionof pregesterone
what can detect pregnancy at 14 days of gestation
when can hCG be detected
as soon as lucunae are formed and communicate with maternal blood
compacted blastomeres form a (how many celled)?
16 celled morula
what does the outer cell mass of the blastocyst become
trophoblast layer
what does the trophoblast differentiate into
inner layer, cytotrophoblast
outer lyaer, syncytiotrophoblast
what develop in the synctiotrophoblast
what does the inner cell mass differentiate into
epiblast, hypoblast
what forms the bilaminar disc
the inner cell mass forms the epiblast and hypoblast
which germ layer that gives rise to organs and structures that maintain contact with the outside world
stuff arising from ectoderm
sensory epithelium of ear, nose, and eye
- skin, hair and nails
-pituitary, mammary and sweat glands
induction of the neural plate is regulated by INACTIVATION of what
growth factor BMP4
what causes widening of the neural tube
what causes elongating of neural tube
what forms on either side of the neural tube
what forms when the cranial neuropore closes
the brain
what forms when the causal neuropore closes
spinal cord
which germ layer gives rise to paraxial, intermediate nad lateral plate mesoderm
mesodermal layer
paraxial mesoderm forms somites, what do they give rise to
supporting tissues of the body (muscle, cartilage, bone and subcutaneous layer)
intermediate mesoderm forms what
urogenital system (kidneys, gonds, ducts and accessory glands)
what does lateral mesoderm form
connective tissue of the viscera and limbs, pericardium, peritoneum, blood and lympg cells, CV and lymphatic systems
what happens when the endodermal germ layer folds
head, tail and lateral body folding leaves the foregut, midgut and hindgut
what does the endodermal germ layer give rise to
epithelial lings of pharynx, gi tract, resp tract nad urinary bladder.
parenchyma of hte thyroid, parathyroid, liver and pancreas.
the epithelial lining of hte tympanic cacity nad audiotry tube
from what portion of hte somites do vertebra form
sclerotome portions
where are the sclerotome portions of the somites derived
paraxial mesoderm
what layer does the cardiovascular ssytem originate from
what do blood islands form
pair of heart tubes that fuse into one
Development of the Heart
1)Horse shoe shaped pericardial cavity
2) formation of single heart tube
3) convolution of heart tube
4) primitive 4 chamber heart
5) atrial and ventricular septation
6) aorticopulmonary septation
What forms the pair of heart tubes
blood islands that fuse together
Bulges that appear when the heart tube fuses
Top to bottom: aortic arches, bulbus cordis, primitive ventricle, primitive atrium, sinous venosus
Parts of bulbous cordus
aortic sac, truncus art., conus cordis.
ADult structure of truncus arteriosis
aorta and pulmonary aretery
Adult structure of conus arteriosus
right ventricle
adult structure of primitive ventricle
left ventricle
adult structure of Primitive atrium
trabeculated portion of left adn right atrium
adult structure of sinus venosus
smooth portion of atrium
adult structure of pulmonary vein
smooth portion of left atrium
allows blood to be shunted right atrium to left atrium
septum primium
4th aortic arch gives rise to..
arch of aorta on the left and subclavina artery on the right
6th proximal aortic arch gives rise to...
right and left pulmonary artery
distal 6th aortic arch gives rise to...
ductus arteriosis on the left, dissappears on the right
Prior to birth how is blood passage through the lungs diminished
open foramen ovale and dusctus arteriosus
At birth what changes occur in the heart
ductus arteriosus closes
oval foramen closes
how does the foramen ovale close
increased venous return from teh lungs raises pressure in the atrium, closing it
Stages of lung development
1)bronchi divide into bronchioles
2) bronchioles give rise to alveolar ducts
3) terminal sacs form that permit gas excahnge, surfactant forms
4) alveoli continue to be formed with increase SA where caps and alveolar cells are in contact
Subdivisions of the gut tube
foregut, midgut, hinggut
foregut forms
esophogus to the stomach and lower end of duodenum (also liver, pancreas)
midgut forms
primary intestinal loop, duodenum before the bile duct, 2/3 of large intestine
hindgut forms
remaining large intestine through the rectum and part of the anal canal
Rotation of hte gut tube
-stomach rotates 90 degrees around along axis
- then the stomach and duodenum rotate upwards
- this creates a C shape
- small intestine (mid gut) rotates
where do the connective tissue and muscular components of the digestive system originate
in the mesoderm
what does the epithelial lining of the digestive system and the parenchyma (fxn parts) originate
name three embryonic kidneys
pronephros, mesonephros, metaneprohs
First kidnet, never fully dvlps, degenerates
first set of fxn kidneys, later used in male repro ductive system
becomes adult kidney
where do the urinary and genital systems develop from
mesodermal tissue