Flashcards in Embryogenesis and Fetal Period Deck (72)
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1
neurulation
ectoderm thickens and becomes known as the neural place
2
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
3
what day does the cranial neuropore close
24 or 25
4
what day does the caudal neuropore close
26 or 27
5
the fusion of the neural folds results in the formation of what ?
neural tube
6
neural crest cells
really important, lose attachment to neural tube and form a lot of things
7
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
8
surface ectoderm gives rise to what ?
epidermis, hair, nails, cutaneous, mamary glands, anterior pituitary gland, enamel of teeth, internal ear, and lens of eye
9
mesoderm immediately laterally to the notochord form cylindrical bodies called ___________
paraxial mesoderm
10
mesoderm just laterally to the notochord forms_________
intermediate mesoderm
11
futherest lateral to the notochord forms _____-
lateral plate mesoderm
12
paraxial mesoder
axial skeleton, volutary musclulatur and part of the dermis
13
intermediate mesoderm
form the urinary system and parts of the genital system
14
lateral plate mesoderm
will split into two layers splachnic mesoderm (associated with endoderm) and somatopleuric mesoderm (associated with the ectoderm)
15
the paraxial mesoderm helps form the first ________-
somite on day 20
16
how many pairs of somites are there ?
37 pairs
17
the endoderm of the embryo contributes to what structure ______________
yolk sac
18
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
19
when is the fetal period
9th week til birth
20
characteristics of weeks 9-12
liver is major site of erythropoeisis, and the external genitals can be distinguished male or female
21
weeks 13-16
sites of ossification are evident, eye movements and the eyes are facing forward
22
weeks 17-20
primary ovarian follicles are formed and testes are descending
23
weeks 21-25
period of weight gain, blink and startle reflexes, surfactant is beginning to be secreted into the lungs
24
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
25
weeks 30-34
pupillary light reflex is present, fat is still accumulating
26
weeks 35-38
finish period involves final preparations of tissues important to the outside world
27
for the first 12 weeks of developent what is the major blood producing organ
yolk sac
28
for weeks 12-30 what organ is the major blood producing organ and weeks 12-24
liver, spleen
29
by week 30 what is the major hemopoietic organ
bone marrow
30
