Embryology Year 1

8/10/2019 Embryology Year 1

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EMBRYOLOGYEMBRYOLOGY

SpermatogenesisSpermatogenesisDefinition: formation of the sperm at the testis .Definition: formation of the sperm at the testis .

Duration : from puberty till death ..Duration : from puberty till death ..

StepsSteps: 1: 1))proliferationproliferation:: the spermatogonium divides bythe spermatogonium divides bymitosis to increase and form daughter cell .mitosis to increase and form daughter cell .

22)) growthgrowth: daughter spermatogonium enlarge and form: daughter spermatogonium enlarge and form

primary spermatocyte contain 46 44 !"y chromosome ) diploid no..primary spermatocyte contain 46 44 !"y chromosome ) diploid no..

#)#)maturationmaturation: a) first maturation division meiosis ) of the primary: a) first maturation division meiosis ) of the primary

spermatocyte to form two secondary spermatocyte 2# 22" or 22y)spermatocyte to form two secondary spermatocyte 2# 22" or 22y)

chromosome which is the haploid number .chromosome which is the haploid number .

b) second maturation division : is the division of the secondary sparmato$b) second maturation division : is the division of the secondary sparmato$

cyte by mitosis into two spermatids each contain haploid number 2#cyte by mitosis into two spermatids each contain haploid number 2#

4)4) transformation of the spermatid into sperm spermiogenisis ) .transformation of the spermatid into sperm spermiogenisis ) .

%he sperm maturate at the epididymis and stored at ampulla of vas deferens .%he sperm maturate at the epididymis and stored at ampulla of vas deferens .

..
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lecture noteslecture notes

general embryologygeneral embryology

Prof. Ezz EldinProf. Ezz Eldin

year 1year 1

USIMUSIM


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SPERMSPERMSperm : 4&$&' um in length.Sperm : 4&$&' um in length.

1)(ead: formed by covered1)(ead: formed by covered nucleusnucleusof spermatidof spermatid

2) crosomal cap : formed by2) crosomal cap : formed by *olgi comple"*olgi comple" ..

#) +ec, : -ormed by two#) +ec, : -ormed by two centriolescentriolesthat gives a"ialthat gives a"ial

filament .filament .

#)iddle piece body) :#)iddle piece body) : mitochondrial sheathmitochondrial sheatharoundaround

the a"ial filament .the a"ial filament .

4)taila"ial filament). /s responsible for motility of sperm4)taila"ial filament). /s responsible for motility of sperm

+.0: %( S3 S%3D % 5S D-3+S+.0: %( S3 S%3D % 5S D-3+S

%( S3 7+% :%( S3 7+% : #''$6'' /88/+ 3 978%#''$6'' /88/+ 3 978%

THE SPERM CONTAINS HABLOIDTHE SPERM CONTAINS HABLOID

NUMBER OF CHROMOSOME 22XNUMBER OF CHROMOSOME 22XOR 22OR 22
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ogenesis: 4644"").ogenesis: 4644"").

Definition :Definition : is formation of ovum inside ovaryis formation of ovum inside ovaryDuration : from puberty till menopause 4&$&' yearDuration : from puberty till menopause 4&$&' year

Steps :Steps :

11) ogonium : by) ogonium : by proliferateproliferate by mitosisby mitosis and thenand then growgrowto form daughterto form daughter

cells give rimary oocyte 46 chromosome 44"") diploid number .cells give rimary oocyte 46 chromosome 44"") diploid number .

2)rimary oocyte by2)rimary oocyte by firstfirstmaturationmaturationmeiotic)meiotic) divisiondivisionat the pubertyat the puberty

gives secondary oocyte 2#chromosome) ontains 22 autosome and onegives secondary oocyte 2#chromosome) ontains 22 autosome and one

; se" chromosome). and first polar body smaller cells also2# 22!") .; se" chromosome). and first polar body smaller cells also2# 22!") .

#) Secondary oocyte by#) Secondary oocyte by secondsecond maturationmaturation mitoticmitotic) division gives one) division gives one

vum and three second polar bodies that e"truded into vitelline spacevum and three second polar bodies that e"truded into vitelline space

%his second maturation division occurs after fertili


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Development of Graan follicleDevelopment of Graan follicle1)%he primary oocyte inside the ovary surrounded by1)%he primary oocyte inside the ovary surrounded by

follicular cells from the ovarian tissue formingfollicular cells from the ovarian tissue forming

!"#$%"'( )%((#*(+!"#$%"'( )%((#*(+at birth there are = million .at birth there are = million .

2) ultiple small cavities develops between2) ultiple small cavities develops between

the follicular cells then these cavities fuse to formthe follicular cells then these cavities fuse to form

one single cavityone single cavity )%((#*,('" '-.",$)%((#*,('" '-.",$contains fluid.contains fluid.

#) %he secondary oocyte pushed to one side#) %he secondary oocyte pushed to one side

and surrounded by follicular cells form theand surrounded by follicular cells form the

*,$,(,/ %%!0%"%,/*,$,(,/ %%!0%"%,/ . .

4) %he rest of the cells surround the large cavity4) %he rest of the cells surround the large cavity

as one or two layers calledas one or two layers called /."'.,$ 1"'-,(%/,$/."'.,$ 1"'-,(%/,$..

&) %he follicle surrounded by connective tissue from the ovary&) %he follicle surrounded by connective tissue from the ovary

that form a capsule ,nownthat form a capsule ,nown .0+*' )%((%#*,(# .0+*' )%((%#*,(#


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*raffian follicle*raffian follicle


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OvulationOvulation

D+)#-#.#%-D+)#-#.#%-: is rupture of the *raffian follicle and liberation of the ovum .: is rupture of the *raffian follicle and liberation of the ovum .

C',/+/C',/+/: 1)the pituitary hormones: 1)the pituitary hormones FSHFSHandand LHLHcauses growth of the follicle andcauses growth of the follicle and

the fluid pressure inside it increases .the fluid pressure inside it increases .

2) at 14$1&2) at 14$1&ththday of the menstrual cycle the *raffian follicle ruptureday of the menstrual cycle the *raffian follicle rupture

and the ovum escape into the peritoneal cavity to reach the fallopian tube .and the ovum escape into the peritoneal cavity to reach the fallopian tube .

#) at the fallopian tube the ovum live only for 24 $#6 hour and become ready for#) at the fallopian tube the ovum live only for 24 $#6 hour and become ready for

fertili


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OVUMOVUM

57:57:

1)orona radiata1)orona radiata: outer cellular layer: outer cellular layer

2) >ona pellucid a2) >ona pellucid a: non cellular layer that llow: non cellular layer that llow

only one sperm to enter


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!ertilization!ertilization

DefinitionDefinition:: meeting of the ovum and spermmeeting of the ovum and spermTo form the zygote.To form the zygote.

SiteSite: at the lateral part of fallopian tue: at the lateral part of fallopian tue

METHODMETHOD:1)enetration of the head of sperm:1)enetration of the head of sperm

that form the male pronucleusthat form the male pronucleus

2)%he nucleus of ovum form female ronucleus .2)%he nucleus of ovum form female ronucleus .

#) ale and female pronuclear#) ale and female pronuclearfuse to form the


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mitosismitosis

C+(( *(+'4'1+C+(( *(+'4'1+
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ell divisionell divisionell division and segmentationell division and segmentation

ccurs at fallopian tube :ccurs at fallopian tube :

1)16 cell stage ,nown as1)16 cell stage ,nown as $%",('$%",('

2) %hen 6' cell stage of division2) %hen 6' cell stage of division

#) %hen a cavity develop called#) %hen a cavity develop called

B('/.%*+(+B('/.%*+(+ and the cell are dividedand the cell are divided/nto & form/nto & form #--+" *+((#--+" *+((mass and themass and the

8ining && form8ining && form trophoblast .trophoblast .

Such vesicle calledSuch vesicle called 3('/.%*5/.3('/.%*5/. thatthat

Descend into the uterine cavity at &Descend into the uterine cavity at & thth

Day for implantation .Day for implantation .
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ImplantationImplantation

Definition:Definition:is the process of embedding of the fertili


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-ormation of the germ layers-ormation of the germ layers
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Differentiation of endoderm and ectodermDifferentiation of endoderm and ectoderm

nd appearance of the amniotic cavitynd appearance of the amniotic cavity


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0ilaminar germ disc0ilaminar germ disc


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%rilaminar germ disc%rilaminar germ disc


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/ntraembryonic mesoderm/ntraembryonic mesoderm

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Embryology Year 1