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• 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
Basal body(centriole)
Spermhead
Sperm-bindingreceptors
Acrosome
Jelly coat Vitelline layer
Egg plasmamembrane
Hydrolytic enzymes
Fig. 47-3-3
Basal body(centriole)
Spermhead
Sperm-bindingreceptors
Acrosome
Jelly coat Vitelline layer
Egg plasmamembrane
Hydrolytic enzymes
Acrosomalprocess
Actinfilament
Spermnucleus
Acrosomal reaction
Fig. 47-3-4
Basal body(centriole)
Spermhead
Sperm-bindingreceptors
Acrosome
Jelly coat Vitelline layer
Egg plasmamembrane
Hydrolytic enzymes
Acrosomalprocess
Actinfilament
Spermnucleus
Sperm plasmamembrane
Fusedplasmamembranes
Acrosomal reaction fast block to polyspermy
Fig. 47-3-5
Basal body(centriole)
Spermhead
Sperm-bindingreceptors
Acrosome
Jelly coat Vitelline layer
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
10 sec afterfertilization
20 sec 30 sec500 µm
Point ofspermnucleusentry
Spreadingwave of Ca2+
Fertilizationenvelope
Ca2+
the formation of the fertilization envelope?
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
Point ofspermnucleusentry
(anterior—posterior)(Dorsal– ventral ) (right—left)
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. 47-9-3
Archenteron
Filopodiapullingarchenterontip
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
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. 47-12c
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. 47-19
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-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