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Chap 47 Animal development

Preformation

homunculus

• Development is determined by the zygote’s genome and molecules in the egg called cytoplasmic determinants

• Cell differentiation is the specialization of cells in structure and function

• Morphogenesis is the process by which an animal takes shape

FertilizationCleavageGastrulationOrganogenesis

Fig. 47-3-1

Basal body(centriole)

Spermhead

Sperm-bindingreceptors

Acrosome

Jelly coat Vitelline layer

Egg plasmamembrane

Fig. 47-3-2


Spermhead


Acrosome


Egg plasmamembrane

Hydrolytic enzymes

Fig. 47-3-3


Spermhead


Acrosome


Egg plasmamembrane

Hydrolytic enzymes

Acrosomalprocess

Actinfilament

Spermnucleus

Acrosomal reaction

Fig. 47-3-4


Spermhead


Acrosome


Egg plasmamembrane

Hydrolytic enzymes

Acrosomalprocess

Actinfilament

Spermnucleus

Sperm plasmamembrane

Fusedplasmamembranes

Acrosomal reaction fast block to polyspermy

Fig. 47-3-5


Spermhead


Acrosome


Egg plasmamembrane

Hydrolytic enzymes

Acrosomalprocess

Actinfilament

Spermnucleus

Sperm plasmamembrane

Fusedplasmamembranes

Fertilizationenvelope

Corticalgranule

Perivitellinespace

EGG CYTOPLASM

Acrosomal reaction

A fast block to polyspermy

Cortical reaction:

a slow block to polyspermy

Fig. 47-4 EXPERIMENT

10 sec afterfertilization

1 sec beforefertilization

RESULTS

CONCLUSION

25 sec 35 sec 1 min500 µm


20 sec 30 sec500 µm

Point ofspermnucleusentry

Spreadingwave of Ca2+


Ca2+

the formation of the fertilization envelope？

Fig. 47-4a

EXPERIMENT


25 sec 35 sec 1 min500 µm

Fig. 47-4b

1 sec beforefertilization

RESULTS


20 sec 30 sec500 µm

Fig. 47-4c

CONCLUSION


Spreadingwave of Ca2+


Fig. 47-5

Follicle cell

Zona pellucida

Cortical granules

SpermnucleusSperm

basal body

Fertilization in mammals

Fig. 47-6

(a) Fertilized egg (b) Four-cell stage (c) Early blastula (d) Later blastula

Cleavage Holoblastic cleavage meroblastic cleavage

Fig. 47-7

(a) The three axes of the fully developed embryo

(b) Establishing the axes

Pigmentedcortex

Right

Firstcleavage

Dorsal

Left

Posterior

Ventral

Anterior

Graycrescent

Futuredorsalside

Vegetalhemisphere

Vegetal pole

Animal poleAnimalhemisphere


(anterior—posterior)(Dorsal– ventral ) (right—left)

Fig. 47-7b-1

(b) Establishing the axes

Vegetalhemisphere

Vegetal pole

Animal poleAnimalhemisphere

Fig. 47-8-6

Blastula(crosssection)

BlastocoelAnimal pole

4-cellstageforming

2-cellstageforming

Zygote 8-cellstage

Vegetalpole

0.25 mm 0.25 mm

Fig. 47-9-1

Animalpole

Blastocoel

Vegetalpole

Vegetalplate

Mesenchymecells

Future ectoderm

Future mesoderm

Future endoderm

Gastrulation I (sea urchin)

Invagination

Fig. 47-9-2

Future ectoderm

Future mesoderm

Future endoderm

Fig. 47-9-3

Archenteron

Filopodiapullingarchenterontip

Future ectoderm

Future mesoderm

Future endoderm

Fig. 47-9-4

Archenteron

Blastopore

Blastocoel

Future ectoderm

Future mesoderm

Future endoderm

Fig. 47-9-5

Digestive tube (endoderm)

Mouth

Ectoderm

Mesenchyme(mesodermforms futureskeleton)

Anus (from blastopore)

Future ectoderm

Future mesoderm

Future endoderm

Fig. 47-9-6

Future ectoderm

Key

Future endoderm

Digestive tube (endoderm)

Mouth

Ectoderm

Mesenchyme(mesodermforms futureskeleton)

Anus (from blastopore)

Future mesoderm

Blastocoel

Archenteron

Blastopore

Blastopore

Mesenchymecells

Blastocoel

Blastocoel

Mesenchymecells

Archenteron

Vegetalplate

Vegetalpole

Animalpole

Filopodiapullingarchenterontip

50 µm

Fig. 47-10-1

Future ectoderm

Key

Future endoderm

Future mesoderm

SURFACE VIEW

Animal pole

Vegetal poleEarlygastrula

Blastopore

Blastocoel

Dorsal lipof blasto-pore

CROSS SECTION

Dorsal lipof blastopore

Invagination and Involution

Gastrulation II (frog embryo)

Fig. 47-10-2

Future ectoderm

Key

Future endoderm

Future mesoderm

SURFACE VIEW

Blastocoelshrinking

CROSS SECTION

Archenteron

Fig. 47-10-3

SURFACE VIEW

BlastoporeLategastrula

Blastopore

Blastocoelremnant

Yolk plug

CROSS SECTION

Ectoderm

Mesoderm

Endoderm

Archenteron

Future ectoderm

Key

Future endoderm

Future mesoderm

Fig. 47-10-4

Future ectoderm

Key

Future endoderm

Future mesoderm

SURFACE VIEW

Animal pole

Vegetal poleEarlygastrula

Blastopore

Blastocoel

Dorsal lipof blasto-pore

CROSS SECTION

Dorsal lipof blastopore

Lategastrula

Blastocoelshrinking Archenteron

Blastocoelremnant

Archenteron

Blastopore

Blastopore Yolk plug

Ectoderm

Mesoderm

Endoderm

Gastrulation III (a chick embryo)

Fig. 47-11

Endoderm

Futureectoderm

Migratingcells(mesoderm)

Hypoblast

Dorsal Fertilized egg

Blastocoel

YOLK

Anterior

Right

Ventral

Posterior

Left

Epiblast

Primitive streak

Embryo

Yolk

Primitive streak

Fig. 47-12

Neural folds Tail bud

Neural tube

(b) Neural tube formation

Neuralfold

Neural plate

Neuralfold

Neural plate

Neural crestcells

Neural crestcells

Outer layerof ectoderm

Mesoderm

Notochord

Archenteron

Ectoderm

Endoderm

(a) Neural plate formation

(c) Somites

Neural tube

Coelom

Notochord

1 mm

1 mmSEM

Somite

Neural crestcells

Archenteron(digestivecavity)

SomitesEye

Fig. 47-12a

Neural foldsNeuralfold

Neural plate

Mesoderm

Notochord

Archenteron

Ectoderm

Endoderm

(a) Neural plate formation

1 mm

Fig. 47-12b-1


Neuralfold

Neural plate

Fig. 47-12b-2


Fig. 47-12b-3

Neural crestcells


Fig. 47-12b-4

Neural tube

Neural crestcells

Outer layerof ectoderm


Fig. 47-12c

Tail bud

(c) Somites

Neural tube

Coelom

Notochord

1 mmSEM

Somite

Neural crestcells

Archenteron(digestivecavity)

SomitesEye

Fig. 47-13

Endoderm

(a) Early organogenesis

Neural tube

Coelom

Notochord

These layersform extraembryonicmembranes YOLK

Heart

Eye

Neural tube

Somite

Archenteron

Mesoderm

Ectoderm

Lateral fold

Yolk stalk

Yolk sac

(b) Late organogenesis

Somites

Forebrain

Bloodvessels

Mesenchyme cellsNotochord (vertebrate)

Fig. 47-14

ECTODERM MESODERM ENDODERM

Epidermis of skin and itsderivatives (including sweatglands, hair follicles)Epithelial lining of mouthand anusCornea and lens of eyeNervous systemSensory receptors inepidermisAdrenal medullaTooth enamelEpithelium of pineal andpituitary glands

NotochordSkeletal systemMuscular systemMuscular layer ofstomach and intestineExcretory systemCirculatory and lymphaticsystemsReproductive system(except germ cells)Dermis of skinLining of body cavityAdrenal cortex

Epithelial lining ofdigestive tractEpithelial lining ofrespiratory systemLining of urethra, urinarybladder, and reproductivesystemLiverPancreasThymusThyroid and parathyroidglands

organogenesis

Fig. 47-15

Embryo

Amnion

Amnioticcavitywithamnioticfluid

Shell

Chorion

Yolk sac

Yolk (nutrients)

Allantois

Albumen

Extraembryonic membrane

Fig. 47-16-5

Yolk sac

Mesoderm

Amnion

Chorion

Ectoderm

Extraembryonicmesoderm

Trophoblast

Endoderm

Hypoblast

Expandingregion oftrophoblast

Epiblast

Maternalbloodvessel

Allantois

Trophoblast

Hypoblast

Endometrialepithelium(uterine lining)

Inner cell mass

Blastocoel

Uterus

Epiblast

Amnioticcavity

Expandingregion oftrophoblast

Yolk sac (fromhypoblast)

Chorion (fromtrophoblast)

Extraembryonicmesoderm cells(from epiblast)

Mammalian development

Fig. 47-17-6

Neural tube

Actin filaments

Microtubules

Ectoderm

Neuralplate

Morphogenesis:

Cell type, position, and adhesion

Fig. 47-18

ConvergenceExtension

Convergent extension

Fig. 47-19

Control embryo Embryo without EP cadherin

0.25 mm 0.25 mmRESULTS

CAMs(cell adhesion molecules): Cadherin

EP cadherin is required for proper cell organization in the blastula

Fig. 47-20

Experiment 1

Matrix blocked

RESULTS

Experiment 2

Control

Matrix blockedControl

An organized fibronectin matrix is required for convergent extension.

Injection the molecule to block the interaction of fibronectin and its receptor

Tightly packed in a column

Fig. 47-21

Epidermis

(b) Cell lineage analysis in a tunicate(a) Fate map of a frog embryo

Epidermis

Blastula Neural tube stage(transverse section)

Centralnervoussystem

Notochord

Mesoderm

Endoderm

64-cell embryos

Larvae

Blastomeresinjected with dye

The developmental fate of cells depends on their history and on inductive signals

Fate map

Fig. 47-22

Mouth

Zygote

Intestine

Nervoussystem,outer skin,muscula-ture

Intestine

Hatching

Eggs Vulva

Anus

1.2 mmANTERIOR POSTERIOR

Muscula-ture, gonads

10

0First cell division

Germ line(futuregametes)

Musculature

Outer skin,nervous system

Tim

e a

fter

fe

rtil

iza

tio

n (

ho

urs

)

Fig. 47-23a

Thread

Graycrescent

Experimental egg(side view)

Graycrescent

Control egg(dorsal view)

EXPERIMENT

Gray cresent affects the developmental potential of the first two daught cells

Fig. 47-23b

Thread

Graycrescent

Experimental egg(side view)

Graycrescent

Control egg(dorsal view)

EXPERIMENT

NormalBelly pieceNormal

RESULTS

Fig. 47-24

Primary structures:Neural tube

Dorsal lip ofblastopore

Secondary(induced) embryo

Notochord

Pigmented gastrula(donor embryo)

EXPERIMENT

Primary embryo

RESULTS

Nonpigmented gastrula(recipient embryo)

Secondary structures:Notochord (pigmented cells)

Neural tube (mostly nonpigmented cells)

The Organizer of Spemann and Mangold

Fig. 47-24a

Dorsal lip ofblastopore

Pigmented gastrula(donor embryo)

EXPERIMENT

Nonpigmented gastrula(recipient embryo)

Fig. 47-24b

Primary structures:Neural tube

Secondary(induced) embryo

Notochord

Primary embryo

RESULTS

Secondary structures:Notochord (pigmented cells)Neural tube (mostly nonpigmented cells)

Fig. 47-25

(a) Organizer regions

Apicalectodermalridge (AER)

Digits

Limb buds

(b) Wing of chick embryo

Posterior

AnteriorLimb bud

AER

ZPA

50 µm

Anterior

2

34

Posterior

Ventral

Distal

Dorsal

Proximal

Two critical organizer regions in a limb have profound effects on the limb’s development

1. AER (apical ectodermal ridge)---FGF ---FGF-secreting AER

2. Removing the AER blocks outgrowth of the limb along the proximal –distal axis

3. ZPA (zone of the polarizing activity)

Cells nearest the ZPA give rise to the posterior structures (three digit)

Pattern formation

Fig. 47-26

Host limb bud

Posterior

2

34

AnteriorNewZPA

EXPERIMENT

RESULTS

ZPA

Donor limb bud

2

34

Fig. 47-27

HOX gene--- HoxD13 mutation polysyndactyly

Fig. 47-UN1

Sperm-egg fusion and depolarizationof egg membrane (fast block topolyspermy)

Cortical granule release(cortical reaction)

Formation of fertilization envelope(slow block to polyspermy)

Fertilization

Fig. 47-UN2

Blastocoel

Animal pole

2-cellstageforming

8-cellstage

Blastula

Vegetal pole

Cleavage

Fig. 47-UN3

Gastrulation

Fig. 47-UN4

Neural tube

Coelom

Notochord

Coelom

Notochord

Neural tube

Organogenesis

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