EXPLICATION TIME

!"#$%$"&'()*+*,-"$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$./01230$456157$#89#:#89;$
<2$<=-+-<$$$$$$$$$$$$$$$$$$$$$$$$RÉPONSES(AUX(QUESTIONS(PAR(LE(PROFESSEUR(PHILIP((
LORS(DE(LA(SÉANCE(RÉVISION(DU(JEUDI(25(OCTOBRE(2012(
!"#$%$&'($#")$#*'($%+$,#-&%$"#'".'&/%0$+&1#&%#2"1$"#")$#+1$"'/+$",#
3(*"#4#)%'#5#
$
>>$"?<[email protected]*4$.-&"$>>$$
#
9B$+C$703DC$E32FCG5C$H$7C$750/C$0I5J$D3F7$J3$K2CL5M2C$1/$J3$DC/N5MLC$7CL35FC$O$$
!"#)$(/"#0('1"*+"#6#")$#7#08"2(9#)%'#9(#:+1#/"#9(#.'";+<'"#)";(+1"#"$#9"#/=>%$#/"#/"%?+<;"#;(+)#9")#
@&%')A)";(+1")#)&1$#97#7#$+$'"#+1/+0($+:B#9"#.9%)#+;.&'$(1$#=$(1$#/"#'"$"1+'#9")#)$(/")#0('1"*+"#
#B$+3$EP12DC$C70$0QCJJC$R5CF$DQ125G5FC$SK5RJ3705T/C$O$U/CJ$C70$JC$DSVCJ1KKCLCF0$DC$J3$EP12DC$O$"0$JC$
E3F3J$FC/2CF0S25T/C$W5F50:5J$K32$7C$2CWC2LC2$O$
!#!(#08&'/"#")$#/C&'+*+1"#SK5RJ3705T/C#
#
!#D&+0+#9"#/=2"9&..";"1$#/"#9(#08&'/"#E#
" !"#.'&0"))%)#08&'/(9#2+"1$#/=>&%08"'#/(1)#9(#D=)+0%9"#D+$"99+1"#FF#1(+))(10"#/%#E3F3J$
FC/2CF0S25T/C$T/5$C70$023F750152C#G+9#."')+)$"#$";.&'(+'";"1$H#
#
# #
" !C"1/&/"';"#"1#/"))&%)#/%#0(1(9#1"%'"1$='+I%"#2(#/+).('(J$'"B#&1#(#(9&')#9(#.9(I%"#
08&'/(9",##
NB#:#A#ce#stade,#le#canal#neurentérique#est#très#long.#
#
# #
#
#

!"#$%$"&'()*+*,-"$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$./01230$456157$#89#:#89;$
<2$<=-+-<$$$$$$$$$$$$$$$$$$$$$$$$RÉPONSES(AUX(QUESTIONS(PAR(LE(PROFESSEUR(PHILIP((
LORS(DE(LA(SÉANCE(RÉVISION(DU(JEUDI(25(OCTOBRE(2012(
!"#$%$&'($#")$#*'($%+$,#-&%$"#'".'&/%0$+&1#&%#2"1$"#")$#+1$"'/+$",#
3(*"#K#)%'#5#
#
" !C"1/&/"';"#"1#/"))&%)#2(#'".&%))"'#;(+)#9"#0(1(9#1"%'"1$='+I%"#")$#$&%@&%')#.'=)"1$,#
#
" !(#08&'/"#.9"+1"#)"#:&';"#"$#)C+1/+2+/%(9+)"#repoussant#le#canal#neurentérique#vers#la#partie#
caudale,#L#0"#;&;"1$#97B#9"#0(1(9#")$#$&%@&%')#.'=)"1$#;(+)#$&%$#."$+$,#
#
#
" !"#0(1(9#1"%'"1$='+I%"#2(#)"#'":"';"'#."$+$#7#."$+$B#"1#"::"$#+9#2(#)C&>)$'%"'#.'&*'"))+2";"1$#
"$#)"#>&%08"',#
#
#
#
!#M9#:+1+$#.('#)"#'":"';"'#0&;.9<$";"1$,#

!"#$%$"&'()*+*,-"$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$./01230$456157$#89#:#89;$
<2$<=-+-<$$$$$$$$$$$$$$$$$$$$$$$$RÉPONSES(AUX(QUESTIONS(PAR(LE(PROFESSEUR(PHILIP((
LORS(DE(LA(SÉANCE(RÉVISION(DU(JEUDI(25(OCTOBRE(2012(
!"#$%$&'($#")$#*'($%+$,#-&%$"#'".'&/%0$+&1#&%#2"1$"#")$#+1$"'/+$",#
3(*"#N#)%'#5#
#
;B$@1FEC2F3F0$J3$DSJ5L503051F$DC$J3$XXYZ$V1/7$D50C7$D3F7$JC$E1/27$[$KJ/75C/27$2CK257C7$T/Q1F$3$/FC$
7CE1FDC$K1/77SC$DC$JQP\K1RJ370C$T/5$2CW1/JC$J3$LCLR23FC$DC$=C/7C2]$
&357$D3F7$JC$2SE3K50/J305W$DC7$E32FCG5CZ$5J$C70$F10S$3/$E32FCG5C$^$T/C$JQ1F$3$/FC$_$7CE1FDC$K1/77SC$
DC$J3$LCLR23FC$DC$=C/7C2$`]$4QC70$EC$D1FE$K37$KJ/0a0$/FC$#FDC$K1/77SC$P\K1RJ3705T/C$O$
#
!(#;";>'(1"#/"#O"%)"'#2(#P$'"#'";.9(0="#.('#%1"#K<;"#0&%08"#I%+#/='+2"#/"#9CP\K1RJ370C,##
!")#.&%))=")#8Q.&>9()$+I%")#E#
" !(#4<'"#.&%))="#8Q.&>9()$+I%"#:&';"#9(#LCLR23FC$DC$=C/7C2#I%+#"10"'09"#9(#DD3#(cf#image#1)#
" !(#K<;"#.&%))="#8Q.&>9()$+I%"#)C(''P$"#7#;+R08";+1#.&%'#'":"';"'#9(#DDSB#9(#;";>'(1"#/"#
8"%)"'#")$#(9&')#'":&%9="#2"')#9"#:&1/#(cf#image#2)#
" T1#'"$'&%2"'(#(9&')#9(#;";>'(1"#/"#O"%)"'#)&%)#:&';"#/"#b\70C7$I%+#:+1+'&1$#.('#/=*=1='"'#
(cf#image#3)#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#

!"#$%$"&'()*+*,-"$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$./01230$456157$#89#:#89;$
<2$<=-+-<$$$$$$$$$$$$$$$$$$$$$$$$RÉPONSES(AUX(QUESTIONS(PAR(LE(PROFESSEUR(PHILIP((
LORS(DE(LA(SÉANCE(RÉVISION(DU(JEUDI(25(OCTOBRE(2012(
!"#$%$&'($#")$#*'($%+$,#-&%$"#'".'&/%0$+&1#&%#2"1$"#")$#+1$"'/+$",#
3(*"#6#)%'#5#
#
HB$U/5$KC2LC0$J3$DS0C2L5F3051F$G3/EPCcD2150C$O$
M9#")$#$'<)#+;.&'$(1$#/"#)(2&+'#I%"#0C")$#9(#!MUVW#3XMYM-MDW#I%+#/=$"';+1"#9C&'+"1$($+&1#/'&+$"A*(%08"#
"$#0'(1+&R0(%/(9"#/"#9C";>'Q&1#"$#1&1#9(#08&'/"#I%+#1C")$#I%C%1"#0&1$+1%+$=#Gen#effet#avec#la#chorde#
on#peut#savoir#où#se#trouve#la#droite#et#la#gauche#mais#ce#n’est#pas#elle#l’élément#fondamental#qui#a#
permit#de#déterminer#l’orientation#de#l’embryon#mais#bien#la#ligne#primitive#au#stade#carnegie#7#!H#
#
#
#
#
#
^B$"NKJ5T/1F7$/F$KC/$EC7$7EPSL37$5FW12LC7$d$
#
!"#.'";+"'#)08=;(#")$#0"9%+#I%"#2&%)#(2"Z#"%#/(1)#9"#
[\Y#K#/"#2&)#$%$'+0")#7#9(#)=(10"#'=2+)+&1,#
M0+B#+9#Q#(2(+$#I%"9I%")#)&%0+)#I%(1/#7#9C+1$"'.'=$($+&1#/%#
1"%'&.&'"#.&)$='+"%',#M9#")$#"1#:(+$#0&;;"#@"#2&%)#9C(2(+)#
"?.9+I%=B#7#%1#=$($#$'<)#]#.'+;+$+:#^#/+'&1)R1&%),#
#
#
_"#)%+)#$&;>="#.('#8()('/#)%'#0"#)08=;(#I%+#;&1$'"#
9C=2&9%$+&1#/"#0"#:(;"%?#";>'Q&1,#_"#2&%)#9"#;"$)#.&%'#
I%"#2&%)#2+)%(9+)+"Z#9C=2&9%$+&1#/"#0"#1"%'&.&'"B#2&%)#
2&Q"Z#+0+#I%"#9")#>&'/)#)"#/"))+1"1$#."$+$#7#."$+$#@%)I%C7#
)"#'":"';"',#
#
#
#
#
#
#
#
eB$U/CJJC7$71F0$JC7$DSW5F5051F7$DC$J3$V37E/J1GSFM7C$C0$DC$JQ3FG51GCFM7C$OO$
X37E/J1GSFM7C##`F#).8<'"#"$#0&'/&1)#(1*+&>9()$+I%")##
AFG51GCFM7C######`F#"?.(1)+&1B#'(;+:+0($+&1)#/%#'=)"(%#0(.+99(+'"##
FF#!")#/"%?#)"#:&1$#/"#:(a&1#0&10&;+$(1$"#
#
W1$'"#9")#0"99%9")#"1/&$8=9+(9")#+9#Q#(#9")#.'=0%')"%')#G3FG51RJ370C7H#I%+#.&%''&1$#."';"$$'"#
9C"?0'&+))(10"#/")#2(+))"(%?#)(1*%+1)#`F#(1*+&*"1<)"#
#
#
#

!"#$%$"&'()*+*,-"$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$./01230$456157$#89#:#89;$
<2$<=-+-<$$$$$$$$$$$$$$$$$$$$$$$$RÉPONSES(AUX(QUESTIONS(PAR(LE(PROFESSEUR(PHILIP((
LORS(DE(LA(SÉANCE(RÉVISION(DU(JEUDI(25(OCTOBRE(2012(
!"#$%$&'($#")$#*'($%+$,#-&%$"#'".'&/%0$+&1#&%#2"1$"#")$#+1$"'/+$",#
3(*"#b#)%'#5#
fB$U/QC70$EC$T/C$JC$2S05E/J/L$""$C0$JC$LS71RJ370C$""$OO$gQ1/$K21V5CFFCF0:5J7$O$
c"#9d"<-RJ370C#2(#.('$+'#%1"#première#poussée#proliférative#de#cellules#mésenchymateuses#I%+#2&1$#
2"1+'#)d+1)+1%"'#"1$'"#9(#;";>'(1"#/"#O"%)"'#"$#9"#0Q$&$'&.8&>9()$"#G.%+)#"1$'"#9")#(;1+&>9()$")#"$#
9"#0Q$&$'&.8&>9()$"H,##
\")#0"99%9")#2&1$#:&';"'#%1#e:+9"$#7#;(+99"#9f08"e#"$#)"#$'(1):&';"'#"1#0"99%9")#'=$+0%9(+'")B#0d")$#%1#
$+))%#'=$+0%9(+'"#(.."9=#(S05E/J/L,#
3%+)B#$&%@&%')#9&')#/"#0"$$"#.&%))="#.'&9+:='($+2"#/"#0"99%9")#;=)"108Q;($"%)")#/d&'+*+1"#
=.+>9()$+I%"B#+9#2(#Q#(2&+'#une#grosse#vague#de#cellules#mésenchymateuses#qui#vont#investir#le#
réticulumB#9"#0&1)&9+/"'#0"#I%+#2(#/&11"'#9"#&S7CFEP\LC$CN023:CLR2\1FF352C,#
#
g#L+1)+#9"#'=$+0%9%;#"$#9"#YWW#.&))</"1$#>+"1#/")#0"99%9")#(Q(1$#9(#;P;"#&'+*+1"#=.+>9()$+I%"B#0"99")#
/%#(""#)"#/+::='"10+"1$#"1#cellules#réticulaires#"$#0"99")#I%+#(''+2"1$#"1#2(*%"#(.'<)#.&%'#:&';"'#9"#
&""#/";"%'"1$#mésenchymateuses,##
###
3%+)#/(1)#9"#YWW#h#'=$+0%9%;#G0('#(%#:+1(9#&1#(#/")#0"99%9")#;=)"108Q;($"%)")#>9&I%=")#/(1)#9")#
0"99%9")#'=$+0%9(+'")#7#e;(+99"#9('*")e#/%#'=$+0%9%;H#2&1$#)"#:&';"'#/")#J3E/FC7#I%+#2&1$#*'&))+'#"$#
:%)+&11"'#"1$'"#"99")#.&%'#:&';"'#9"#E1CJ1LC$CN0C2FC,#
#
!#L+1)+#&1#1"#.('9"#_LYLMS#/"#.&%))="#Oi3T>9()$+I%"B#;(+)#$&%@&%')#/"#.&%))=")#W3M>9()$+I%")#j#
c"%?#)08=;()#/%#XWWAYWW#E#
L#*(%08"#`#9(0%1")#)"#:&';(1$#/(1)#9"#XWW#h#YWW#
L#/'&+$"#`#0k9&;"#+1$"'1"#:&';=#/(1)#9"#YWW#.('#0&1:9%"10"#/")#9(0%1")#
#
#
#
#
#
#