Embryogenesis and Fetal Period Flashcards
neurulation
ectoderm thickens and becomes known as the neural place
what happens on day 22 in reference to the neural plate
it begins to fold inward and makes contact with four occpital somites and the first cervical somites
what day does the cranial neuropore close
24 or 25
what day does the caudal neuropore close
26 or 27
the fusion of the neural folds results in the formation of what ?
neural tube
neural crest cells
really important, lose attachment to neural tube and form a lot of things
what are some examples of neural crest derivatives
parasympathetic ganglia of 3,7, 9 and 10, sensory ganglia of central nervous sytem of 5, 7, 9 and 10 and the autonomic doral root ganglia
surface ectoderm gives rise to what ?
epidermis, hair, nails, cutaneous, mamary glands, anterior pituitary gland, enamel of teeth, internal ear, and lens of eye
mesoderm immediately laterally to the notochord form cylindrical bodies called ___________
paraxial mesoderm
mesoderm just laterally to the notochord forms_________
intermediate mesoderm
futherest lateral to the notochord forms _____-
lateral plate mesoderm
paraxial mesoder
axial skeleton, volutary musclulatur and part of the dermis
intermediate mesoderm
form the urinary system and parts of the genital system
lateral plate mesoderm
will split into two layers splachnic mesoderm (associated with endoderm) and somatopleuric mesoderm (associated with the ectoderm)
the paraxial mesoderm helps form the first ________-
somite on day 20
how many pairs of somites are there ?
37 pairs
the endoderm of the embryo contributes to what structure ______________
yolk sac
endoderm derivatives
epithelial lining of GI tract, allantois, epithelium of repiratory tract, bladder, urethra, tympanic cavity and auditory tube, parenchyma of thyroid, parathyroid, liver and pancreas, stroma cells of the tonsils and the thymus
when is the fetal period
9th week til birth
characteristics of weeks 9-12
liver is major site of erythropoeisis, and the external genitals can be distinguished male or female
weeks 13-16
sites of ossification are evident, eye movements and the eyes are facing forward
weeks 17-20
primary ovarian follicles are formed and testes are descending
weeks 21-25
period of weight gain, blink and startle reflexes, surfactant is beginning to be secreted into the lungs
weeks 26-29
lungs are capable of breathig, CNS is capable of breathing and body temperature, spleen is still making blood cells but by 28 weeks blood formation shifts to the bone marrow
weeks 30-34
pupillary light reflex is present, fat is still accumulating
weeks 35-38
finish period involves final preparations of tissues important to the outside world
for the first 12 weeks of developent what is the major blood producing organ
yolk sac
for weeks 12-30 what organ is the major blood producing organ and weeks 12-24
liver, spleen
by week 30 what is the major hemopoietic organ
bone marrow
what is amniocentesis ?
sampling of the amnioc fluid to test for genetic disorders (must pass through chorion and amnion to get the sample)
by the 4th week the somites begin to differentiate into ______________ and ___________-
sclerotome and dermomyotome
hemangioblast
give rise to blood vessels
vasculogenesis
formation of blood islands, denovo vessels
angiogenesis
sprouting from existing vessels
hemangiomas
tumor like collections of blood vessels typically on the face
epithlium derived from the mesoderm is
vascular endothelium
epithelium derived from the endoderm is
epithelium of structures derived from yolk sac (gut and airway)
epithlium derived from the ectoderm
epidermis and ependyma
benign tumors of mesoderm epithelium are
angiomas
malignant tumors of mesoderm epithelium are
sarcomas
benign tumors of endoderm epithelium are
pailoma or adenomas
malignant tumors of endoderm epithelium are
carcinomas
benign tumors of ectoderm epithelium are
papiloma and ademoas
malignant tumors of ectoderm epithelium are
carcinomas
connective tissue is derived from ?
mesoderm for torso and limps and neuroectoderm (head)
benign tumors of connective tissue mesoderm
fibroma, lipoma, chondroma, osteoma
malignanty tumors of connective tissue medoderm
sarcomas
benign tumors of muscle mesoderm
myomas
malignant tumors of muscle mesoderm
myosarcomas
what are the two types of paraxial mesoderm
sclerotome and dermomyotome
what does the sclerotome give rise to
skeleton and cartilage
what does the dermomyotome give rise to
skeletal muscles, dermis and connective tissues
expected date of confinement ( EDC)
measures corwn rump length, head measurements and femur length to determine age
gestation age
age from last menstruation!
last nomrla menstrual period
with this gestation takes 40 week
actual date of fertilization
with this measure it takes 38 weeks
what is the first trimester
all major systems are developed
second trimester
external anatomy, many birth defects can be detected
third trimester
fetus becomes viable
if alpha fetoprotein is elevated what happens
detects of embryonic body wall
if alpha fetoprotein is depressed what can result
downs syndrome and trisomy 18
surface ectoderm gives rise to
epidermis, hair,cutaneous and mammary glands, anterior pituitary gland, enamel of teeth, internal ear, and lens of the eye
what does paraxial mesoderm give rise to
sclerotome which gives rise to skeleton and cartilage
dermomyotome which gives rise to skeletal muscles, dermis and connective tissue
what does intermediate mesoderm give rise to
urogenital system and contributions to the reproductive system
what does the lateral plate mesoderm give rise to
somatic(parietal) layer gives rise to connective tissue of limbs and serious membranes
splanchnic (visceral) layer gives rise to connective tissue, smooth muscle of vercera, serious membranes, primordial heart, blood, spleen, and suprarenal cortex
what does the endoderm give rise to
epithelium of the GI tract, liver, pancrease, liver, urachus, trachea, bronchi, longs, pharynyx, and thyroid
what does the neural ectoderm give rise to
neural tube (CNS, retina, pineal gland, and posterior pituitary) neural crest (all ganglia)
the myotome splits into what
epaxial (intrinsic back muscleS) and hypomeres (hypaxial)
epithelium is derived from what layers
all three
connective tissue is derived from what
neuroectoderm and mesoderm
muscle is derived from
mesoderm
nerve is derived from
neuroectoderm
