Embryology Flashcards
Q* What is incorrect regarding the primitive steak?
It gives origin to the neural tube
It appears on epiblast
gives origen to endoderm
gives origin to mesoderm
What type of connection is between mother and fetus?
Indirect-no direct blood contact
The germ layer that gives rise to the organs and structures that maintain contact with outside world
Ectoderm
What are the layerts of the ectoderm
CNS, PNS, Sensory-eyes,nose,eye
skin, hair and nails
pituitary, mammary and sweatglands and teeth enamel
Neurolation
formation of neural tube and neural crest
gives orgin to all nervous tissues
CNS(spinal cord and brain)comes from neural tube
Ganglia and peripheral nerves from neural crest
CNS(spinal cord and brain)
comes from neural tube
Ganglia and peripheral nerves from
neural crest
The primitive streak makes what germ layers
Mesoderm and Endoderm
The ectoderm originates from what tissue
epiblasts
Urinary system, what germ layer
mesoderm
Reproductive system, what germ layer
Mesoderm
cardiovascular system
mesoderm
digestive system
endoderm
skeletal system
mesoderm
Tissue of the Adrenal Medulla
*ectoderm, (neural crest)
it is an exception
adrenal cortex is epithelial tissue and is mesoderm, but the medulla is from the neural crest
what are neural crest derivitives
some bones of face
c-cells in thyroid
conotruncal septum in heart(conduction system)
ondontoblasts-teeth
Dermis of face and neck
part of meninges(forebrain only)
malanocyts
smooth muscle cells of blood vessels to face
**neural crest comes from Ectoderm
caudal end of fetus
tail end
somites on embryo forms
bones and muscles of back
Anencephaly
neural tube fails to close in the cranial region
what is failure of closure from the cervical region caudally on embyo
spina bifida
notochord is derived from what germ layer
mesoderm and becomes the intervertebral disks (only place where we still have reminants)
What is rapid division of zygote
cleavage
The derivitives of the somites (what the somites evolve into)
myotome(muscles), sclerotome(bones&cartilage), dermatome (dermis of skin)
*somites came from the mesoderm
urinary bladder is derived from what germ layer
endoderm
*small area trigon? is mesoderm
what germ layer makes up the thyroid gland
endoderm
what germ layer makes up the trachea, lungs, pancreas, liver
endoderm
of course the digestive tract also
what germ layer makes the typmanic cavity and auditory tube
endoderm
tympanic cavity(middle ear cavity)
once sperm enters oocyte, what occurs
meosis II
Sperm survives how long
72 hrs
Ovum survives how long
24 hrs
When is the zygote called a blastocyst
when a cavity forms
day 5 implants on uterine wall, vascularization occurs now
what marks the end of embryonic period
trilaminar embryonic discs form (3 germ layers)
what are the 4 extraembryonic membranes
amnion-innermost layer, bag of water
Yolk sac-from hypoblasts-
allantois-forms unbilical cord
chorion-outermost-forms fetal portion of placenta and produces HCG
what forms the ectoderm
epiblasts
The epiblasts form the ectoderm and the primitive streak
(the prim streak forms the mesoderm and endoderm)
(the hypoblasts dissappear)
tropoblasts-responsible for nutrients(placenta)
what is joining of the gametes called
fertilization
Sperm and oocyte have how many chromosomes
haploid so 23
zygote has how many chromosomes
diploid, so 46
