Evaluación del mantenimiento de la infraestructura

days after fertilization, i.e. copulation age minus 8 hours (corresponding ages o f mouse em bryos o f the same stage are in brackets), largest dim ension o f em bryo in natural position (largest and smallest dim ensions o f blastocysts and chorionic vesicles are in brackets). Standard

Stages (Witschi)

Age (E) Size (mm) Identification of Stages

Cleavage and Blastula

1 1 0.07 1 cell (in oviduct)

2 2 (1) 0.08 X 0.06 2 cells (in oviduct)

3 3 4 cells (in oviduct)

4 3.25 (2) 0.08 X 0.05 8-12 cells (in oviduct)

5 3.5 0.08 X 0.04 Morula (in uterus)

6 4 (0.08 X 0.03) Early blastocyst (in uterus)

7 5 (4 ) (0.12 X 0.05) Free blastocyst (in uterus)

Gastruia

8 6 (4.5) (0.28 X 0.07) Implanting blastocyst, with trophoblastic cone and inner cell mass; outgrowth of endoderm (hypoblast)

9 6.75 (5) Diplotrophoblast; inner cell mass (pendant), covered with endoderm

10 7.25 (5.5) (0.3 X 0.1) Near complete implantation; pendant begins differentiation into embryonic and extra-embryonic parts

Neurula 13 9(7.5) 1.0 (1.4 X

0.45)

Presomite neurula; fusion of chorio-amniotic folds; chorio-amniotic stalk; neural plate; embryo bent dorsally; bud of allantoic stalk

14 9.5 (7.75) 1.5 (1.8 X 1.1) Somites 1-4 (occipital); pendant with 3 cavities: ectochorionic cyst, exocoelom, and amniotic cavity; embryo bent dorsally

15 10 (8.0-8.5) 2 Somites 5-12 (cervical); 1st visceral arch; ectochorionic cyst fused with ectoplacenta and with allantoic stalk; regression of peripheral (distal) yolk sac and trophectoderm (diplotrophoblast); Reichert’s membrane; gonia in endoderm; embryo bent dorsally

16 10.5 (8.5- 9.0)

2.4 (2.2-3.4) Somites 13-20 (upper thoracic); 2 visceral arches; disc and yolk sac placentas; appendicular folds; embryo reverses, curves ventrally

17 11 (9.5) 3.3 Somites 21-25 (lower thoracic); yolk sac closes at level of 15th somite; primary gonia in mesentery; primitive streak disappears; tail bud becomes organized; fore and hind limb buds recognisable

Tail Bud Embryo

18 11.5(10) 3.8 Somites 26-28 (upper lumber); 3 visceral arches

| l 9 11.75 (10.25) 4.2 Somites 29-31 (lower lumber); visceral arches I-IV; cervical folds; appendicular folds;#d bJus

1

11.875 5 (4.7 X 5.2) Somites 32-33 (upper sacral)

1

1 2 5.1 Somites 34-35 (lower sacral); deep cervical sinuses

2 2 12.125(10.5) 5.2 Somite 36 (1st caudal); olfactory pits

23 12.25 5.6 (4.5 X 5.8) Somites 37-38 (caudal); start of umbilical herniation 24 12.375 6 Somites 39-40 (caudal)

Complete Embryo

25 12.5(11) 6.2 Somites 41-42 (caudal); occipital somites dispersing; 4 visceral arches; deep cervical sinuses, fore limb buds at somite levels 8-14; hind limb buds at somite levels 28-31; body forms a spiral of about 1 '/2 turns, the left face and trunk applied to yolk sac, the right side turned toward placenta; tail and allantoic stalk rise to placenta

Metamorphosing Embryo

26 12.75 7 Somites 43-45 (caudal); mandibular, maxillary, and frontonasal processes; cervical sinuses closing; mammary welts; differentiation of handplates; fore limb buds vascularised, brachial nerves entering; beginning of umbilical hernia

27 13 (12) 8 Somites 46-48 (caudal); prominent facial processes and clefts; nose-snout projecting; cervical sinuses closed; primordia of mammary glands; round handplates and footplates; larger umbilical hernia

28 13.5(12.5) 8.5 Somites 49-51 (caudal); 1st visceral cleft transforms into external ear duct; precartilaginous condensations in handplates

29 14 9.5 Somites 52-55 (caudal); auricular hillocks on visceral arches 1 and II

14.5 (13) 10.5 Somites 56-60 (caudal); body uncoils; mandibular precartilage; nearly round openings of external ear duct; pleuroperitoneal narrows

31 15 12 _{Somites 61-63 (caudal); facial clefts closed; pleuroperitoneal canal closed; complete diaphragm} 32 15.5 (14.5) 14.2 (14.3 X

8.0)

Somite 64 (caudal); pinna turns forward; maximal size of umbilical hernia 33 16(15) 15.5 Somite 65 (caudal); snout lifts off chest; last stage of metamorphosis

Foetus 34 17-18(16-

16.5)

T A B L E A 2

D E V E L O P M E N T O F T H E S E N S E O R G A N S

(B a se d la r g e ly u p o n W itsc h i, 1962)

A g e = d a y s a f te r fe rtiliz a tio n , i.e . c o p u la tio n a g e m in u s 8 h o u rs. S iz e — la rg e s t d im e n sio n o f e m b ry o in n a tu ra l p o sitio n S ta n d a rd

S ta g e s (W itsc h i)

A g e (d ay s) S iz e (m m ) S tru c tu ra l D e v e lo p m e n t

15 10 2 O p tic su lc i. O tic p la c o d e s

16 10.5 2 .4 O lfa c to ry p a d s. O p tic b u lb s. O tic c u p s

17 11 3 .3 O lfa c to ry p la c o d e s . O p tic b u lb s an d sta lk s. C lo s in g o tic c u p s

18 1 1.5 3 .8 O lfa c to ry p la c o d e s . L e n s p la c o d e s; o p tic b u lb s c o n ta c t e p id e rm is; sta lk s s h o rt. O tic v e s ic le s c lo se d

19 1 1.75 4 .2 O lfa c to ry sa u c e rs. B e g in n in g in v a g in a tio n o f o p tic b u lb s an d le n s p la c o d e s . O tic v e s ic le s w ith sh o rt e n d o ly m p h a tic d u ct

22 1 2 .1 2 5 5 .2 S im p le o lfa c to ry c u p s . L e n s c u p s b e g in to c lo se ; o p tic b u lb s w ith c h o ro id fissu re ; n e rv o u s la y e r o f re tin a th ic k e r th an p ig m e n t la y e r. O tic v e sic le s w ith e n d o ly m p h a tic d u c t

2 3 1 2 .2 5 5 .6 O lfa c to ry p its. L e n s sa cs w ith fa irly la rg e p o re . E n d o ly m p h a tic d u c t tu rn s d o rsa lly 2 4 1 2 .3 7 5 6 D e e p o lfa c to ry p its fla tte n in g . L e n s sa cs w ith c lo s in g p o re ; o p tic sta lk s e lo n g a te 2 5 1 2 .5 6 .2 D e e p o lfa c to ry p o u c h e s w ith m e d ia n é v a g in a tio n s (v o m e ro n a s a l o rg a n ); n e rv e fib re s

g ro w in g o u t fro m o lfa c to ry e p ith e lia . L e n s sacs c lo s e d , d e ta c h fro m e p id e rm is; len ses d iffe re n tia te in to e p ith e lia l an d fib ro u s p a rts; o p tic c u p s an d sta lk s w ith d e e p c h o ro id fissu re ; h y a lo id v e sse ls an d p le x u s; v itre o u s m e se n c h y m e ; n e rv o u s la y e r o f re tin a 4 tim e s as th ic k as p ig m e n t la y e r. O tic v e s ic le s la te ra lly c o m p re ss e d , u tric u la r and sa c c u la r p a rts re c o g n isa b le .

2 6 1 2 .7 5 7 N a rro w o lfa c to ry p o u c h e s ; e lo n g a tin g tu b e -sh a p e d v o m e ro n a sa l o rg a n s. L e n se s w ith sm all ro u n d c a v ity . C o c h le a r ru d im e n t p ro je c ts fro m sa c c u le

2 7 13 8 B u c c o n a sa l m e m b ra n e s; o lfa c to ry n e rv e s a p p ro a c h b ra in ; p rim o rd ia l w e lts o f 2 c o n c h a e . L e n s c a v ity s lit-lik e ; v itre o u s b o d y . S e m ic irc u la r p rim o rd ia l p o u c h e s o f u tric le

2 8 13 .5 8 .5 O lfa c to ry n e rv e s re a c h b ra in ; p rim o rd ia l w e lts o f 3 c o n c h a e . L e n s c a v ity d isa p p e a rs , fib re p a rt 8 tim e s as h ig h as e p ith e lia l c e lls ; in v a sio n o f m e s e n c h y m e b e tw e e n le n s an d e p id e rm is ; c h o ro id f is s u re c lo se d ; h y a lo id c a n a l. E n d o ly m p h a tic d u c t p ro je c ts d o rsa lly fa r b e y o n d o tic v e s ic le ; s e m ic irc u la r p o u c h e s p ro je c t f u rth e r

2 9 14 9 .5 B u c c o n a sa l m e m b ra n e s o f c h o a n a e ru p tu re ; p re c a rtila g in o u s c o n d e n s a tio n s o f nasal c a p s u le a n d se p tu m . V e rtic a l d ia m e te r o f le n s g r e a te r th an h o riz o n ta l; n e rv o u s la y e r o f re tin a 8 tim e s a s th ic k as p ig m e n t la y e r; o p tic n e rv e fib re s g ro w in to sta lk ; e y e lid s; c o n d e n s a tio n s o f o c u la r m u sc le s. A n te rio r se m ic irc u la r c a n a ls j u s t fo rm in g ; a m p u lla ry b r a n c h e s o f v e s tib u la r n e rv e s; o p e n in g o f e x te rn a l e a r d u c ts b y c h a n g e s fro m irre g u la r v isc e ra l g ro o v e to ro u n d p o re ; p r e c a rtila g in o u s c o n d e n s a tio n o f o tic c a p s u le s.

31 15 12 P a rtly c a r tila g in o u s n a sa l se p tu m a n d c a p s u le . A n te rio r e y e c h a m b e r; iris fo ld s a t fre e b o r d e r o f re tin a ; lu m e n o f e y e sta lk s d isa p p e a rin g ; fib re s o f o p tic n e r v e re a c h b ra in ; o c u la r m u sc le s in n e rv a te d . A ll s e m ic irc u la r d u c ts w e ll d iffe re n tia te d , s le n d e r, w ith a m p u lla e ; c o c h le a r p r o c e ss h as a c c o m p lis h e d 1st sp ira l tu rn ; ty m p a n ic c a v ity fro m d ista l re c e s s o f 1st p h a ry n g e a l p o u c h ; c a rtila g in o u s d e v e lo p m e n t o f o tic c a p s u le an d o f a u d ito r y o ss ic le s ; e x te rn a l a c o u s tic m e a tu s p a rtly c o v e re d b y fo ld in g p in n a

32 15 .5 14 S lit-s h a p e d c h o a n a e (1 m m lo n g ); 3 c o n c h a e as h ig h as th ic k ; v o m e ro n a sa l o rg a n s lo n g (0 .8 m m ), th ic k -w a lle d tu b e s in se p tu m ; so m e p e rid e rm g ro w th in n a re s; n a s o la c rim a l d u c t. C o r n e a a n d s c le ra a tta in c o n d itio n o f m e s e n c h y m e la y e r a ro u n d e y e b a ll.

C h o n d r if ic a tio n o f o tic c a p s u le p ro g re s s in g ; u tric u lo s a c c u la r d u c t c o n s tric tio n ; c o c h le a r d u c t 1 Va tu rn s; sta rtin g c o n d e n s a tio n o f sp ira l g a n g lio n ; p in n a b e n t o v e r o u te r o p e n in g

o f a c o u s tic m e a tu s.

33 16 15.5 P a la tin e p r o c e ss e s m e e t m e d ia lly , d iv id in g e ach p rim a ry c h o a n a in to an a n te r io r p o re (n a s o p a la tin e d u c t) a n d a lo n g e r p o s te rio r (se c o n d a ry ) c h o a n a . E y e lid s slo w ly g ro w in g . P e r ily m p h a tic m e s e n c h y m e w ith in c a r tila g in o u s o tic c a p s u le s; e x te rn a l a c o u s tic m e a tu s c lo s in g , p e rid e rm fills d e e p e s t re c e ss

34 1 7-18 16-20 C o m p le tio n o f p a la te (e x c e p t in c isiv e fo ra m e n ) a d d s a lo n g n a s o p h a ry n g e a l m e a tu s to o lf a c to ry c a v ity o f n o se ; se c o n d a ry c h o a n a e o p e n in to th is d u c t; n a re s p lu g g e d w ith p e r id e rm . E y e lid s g r o w in g , ra p id ly c lo s in g ; c o rn e a a n d sc le ra a re s tra tifie d e p ith e lia ; sin g le , n u c le a te d n e u ro b la s t la y e r; fib ro u s la y e r m e a s u re s up to Ve th ic k n e s s o f n e rv o u s re tin a . E n d o ly m p h a tic sac e x p a n d in g ; c o c h le a , 1 % tu rn s; v e s tib u la r n e rv e , sp iral g a n g lio n ; p ro x im a l 1st p h a ry n g e a l p o u c h re d u c e d to sh o rt a u d itiv e tu b e ; o tic c a p s u le e x te n s iv e ly c h o n d rifie d ; e x te rn a l a c o u s tic m e a tu s fille d w ith p e r id e rm , o p e n in g c o v e re d b y p a rtly a tta c h e d p in n a

3 5 a a n te n a ta l 19 2 0 -4 0 P ro g r e s s iv e d e v e lo p m e n t o f c o n c h a e ; la te ra l n asal m u c u s g la n d s ; n a re s p lu g g e d . E y e lid s c lo s e d w ith p e rid e rm se al; re tin a w ith o u te r an d in n e r n u c le a r la y e rs an d

In document Evaluación ex post a nivel de culminación del proyecto de riego tecnificado San José, Provincia Azángaro – Puno (página 74-84)