scholarly journals Correlation of external ear auricle formation with staging of human embryos

2016 ◽  
Vol 56 (2) ◽  
pp. 86-90 ◽  
Author(s):  
Maimi Ozeki-Sato ◽  
Shigehito Yamada ◽  
Chigako Uwabe ◽  
Koichi Ishizu ◽  
Tetsuya Takakuwa
Keyword(s):  
Human Embryos ◽  
External Ear ◽  
Ear Auricle

Three-Dimensional Development of the Facial Nerve Path through the Ear Region in Human Embryos

1994 ◽  
Vol 103 (5) ◽  
pp. 395-403 ◽  
Author(s):  
Raymond F. Gasser ◽  
Shuntaro Shigihara ◽  
Kazuyuki Shimada
Keyword(s):  
Facial Nerve ◽  
Three Dimensional ◽  
Human Embryos ◽  
Geniculate Ganglion ◽  
External Ear ◽  
Two Dimensional ◽  
Horizontal Segment ◽  
Ear Development ◽  
Definitive Arrangement

The goal was to determine how the facial nerve path forms normally through the ear region. Five three-dimensional computer reconstructions and eight wax plate—graphic, two-dimensional reconstructions were made from a group of 47 serially sectioned human embryos that were in the blastemal period of ear development, when most of the definitive arrangement is established. The size, shape, and positional changes of the facial nerve relative to the external ear and notochord were studied in both lateral and frontal views. The vertical (dorsoventral) position of the external ear region remains constant but shifts caudally. After formation, the geniculate ganglion assumes a position that gradually becomes rostrodorsal to the external ear. Facial nerve branches form and grow into regions expanding peripherally. The superficial petrosal branch appears to hold the ganglion in position as the horizontal segment of the facial nerve forms when the external ear shifts caudally. Possible growth movements explaining abnormal nerve paths are discussed.

Injuries of the External Ear

1990 ◽  
Vol 23 (5) ◽  
pp. 1003-1018 ◽  
Author(s):  
Jerry Templer ◽  
Gregory J. Renner
Keyword(s):  
External Ear

Cleavage of Human Embryos: Options and Diversity

Acta Naturae ◽  
2016 ◽  
Vol 8 (3) ◽  
pp. 88-96
Author(s):  
Yu. K. Doronin ◽  
I. V. Senechkin ◽  
L. V. Hilkevich ◽  
M. A. Kurcer
Keyword(s):  
Time Lapse ◽  
Reproductive Technologies ◽  
Human Embryos ◽  
Imaging Data ◽  
Noninvasive Methods ◽  
Topographic Features ◽  
Time Parameters ◽  
Embryo Cleavage ◽  
Time Lapse Imaging ◽  
Developmental Dynamics

In order to estimate the diversity of embryo cleavage relatives to embryo progress (blastocyst formation), time-lapse imaging data of preimplantation human embryo development were used. This retrospective study is focused on the topographic features and time parameters of the cleavages, with particular emphasis on the lengths of cleavage cycles and the genealogy of blastomeres in 2- to 8-cell human embryos. We have found that all 4-cell human embryos have four developmental variants that are based on the sequence of appearance and orientation of cleavage planes during embryo cleavage from 2 to 4 blastomeres. Each variant of cleavage shows a strong correlation with further developmental dynamics of the embryos (different cleavage cycle characteristics as well as lengths of blastomere cycles). An analysis of the sequence of human blastomere divisions allowed us to postulate that the effects of zygotic determinants are eliminated as a result of cleavage, and that, thereafter, blastomeres acquire the ability of own syntheses, regulation, polarization, formation of functional contacts, and, finally, of specific differentiation. This data on the early development of human embryos obtained using noninvasive methods complements and extend our understanding of the embryogenesis of eutherian mammals and may be applied in the practice of reproductive technologies.

Quantitative Study of the Heart in Staged Human Embryos in Stage 17

1987 ◽  
Vol 64 (5) ◽  
pp. 253-257
Author(s):  
Carlos A ◽  
MANDARIM-DE-LACERDA ◽  
Francisco Jose ◽  
B. SAMPAIO
Keyword(s):  
Quantitative Study ◽  
Human Embryos
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