Gametogenesis
-
Upload
jessabeth-aluba -
Category
Health & Medicine
-
view
96 -
download
3
Transcript of Gametogenesis
![Page 1: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/1.jpg)
![Page 2: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/2.jpg)
SEX CELL DIFFERENTIATION
OOGENESIS – EGG DIFFERENTIATION
SPERMATOGENESIS – SPERM DIFF.
◦ SPERMIOGENESIS – TRANSFORMATION OF THE MALE GAMETE
![Page 3: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/3.jpg)
IN MAN/MAMMALS, PRIMORDIAL GERM CELL COMES FROM YOLK SAC ENTODERM NEAR CAUDAL END OF BODY
FROM THERE THEY MIGRATE FORWARD THROUGH THE MESENCHYME OF THE MESENTERY AND INTO THE GENITAL RIDGE WHICH SOON BECOMES THE SEX GLAND
THEN PROLIFERATION
![Page 4: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/4.jpg)
PROLIFERATION IS PERIODIC (MONTHLY IN FEMALES) URING THE POTENTIAL CHILD-BEARING YEARS
![Page 5: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/5.jpg)
CELL PROLIFERATION – PRIMITIVE CELL REPEATEDLY DIVIDES
PERIOD OF GROWTH – RAPID ENLARGEMENT OF THE CELLS PRODUCED
PERIOD OF MATURATION – NUCLEAR CHANGES LIMITED TO THE FINAL TWO DIVISIONS
![Page 6: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/6.jpg)
ORIGIN OF THE FOLLICLES
◦ PRIMORDIAL CELLS (OOGONIA) PROLIFERATE WITHIN THE CORTEX OF THE OVARY
◦ SMALLER EPITH. CELLS, OF GERMINAL-EPITH ORIGIN ENCASED THE OOGONIA AND PRODUCED PRIMARY FOLLICLE
◦ AFTER BIRTH, FORMATION OF HUMAN OOGONIA STOPS THEN CELLS ARE NOW CALLED OOCYTES
![Page 7: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/7.jpg)
370,000 – AT BIRTH
190,000 – AT PUBERTY
26,000 – AT AGE 30
AFTER 30 OR MORE YEARS (CHILD-BEARING SPAN), FOLLICLES WILL NO LONGER BE SEEN
![Page 8: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/8.jpg)
NO ADVANCE BEYOND THE STAGE OF THE PRIMARY FOLLICLE UNTIL PUBERTY (14TH YEAR)
FEW HUNDREDS OF OOCYTES ARE LIBERATED PERIODICALLY DURING OVULATION
![Page 9: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/9.jpg)
GROWTH OF FOLLICLE STARTS SLOWLY BUT GROWS RAPIDLY 1-3 DAYS PRIOR TO RUPTURE
MATURATION – ACHIEVED BY MEIOSIS WITH 4 CELLS HAVING EQUAL NUCLEI WHILE THE CYTOPLASM IS UNEQUALLY DIVIDED
![Page 10: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/10.jpg)
1 LARGE RIPE OVUM 3 RUDIMENTARY OVA (POLAR BODIES) OR
POLOCYTES CYTOPLASM – GRANULAR AND
CONTAINS FEW TO MANY INERT GRANULES
YOLK/DEUTOPLASM – MADE UP OF FATTY AND ALBUMINOUS SUBSTANCE; SERVES AS NOURISHMENT FOR THE EMBRYO
![Page 11: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/11.jpg)
YOLK – USEFUL IN CLASSIFYING EGGS.
I. BASED ON RELATIVE ABUNDANCE OF YOLK:
1. SMALL
2. MEDIUM
3. LARGE
![Page 12: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/12.jpg)
II. DISTRIBUTION OF YOLK IN CELLS:
1. ISOLECITHAL – EQUAL YOLK
MEIOLECITHAL – LITTLE YOLK
- INVERTEBRATES
- ALL MAMALS EXCEPT LOWEST FORMS
2. TELOLECITHAL EGGS – ABUNDANT YOLK AND CONCENTRATED IN ONE HEMISPHERE
![Page 13: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/13.jpg)
-INVERTEBRATES
-ALL VERTEBRATES LOWER THAN MARSUPIALS
- CHICK EGG
3. MEDIALECITHAL (MEDIUM YOLK) –MODERATE YOLK – AMPHIBIANS
4. MEGALECITHAL- LARGE, YOLK RICH EGGS OF BONY FISHES , REPTILES , BIRDS
![Page 14: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/14.jpg)
5. CENTROLECITHAL- DISTINCTIVE ARRANGEMENT OF YOLK, MASSED CENTRALLY BUT SORROUNDED BY A PERIPHERAL SHELL OF CLEAR CYTOPLASM.
EGG POLARITY:
ANIMAL POLE – SITE WHERE POLAR BODIES PINCH OFF
![Page 15: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/15.jpg)
- VIGOROUS PART IN DEVT. & WHERE HIGHEST CAPACITY FOR ACTIVITY RESTS
- VEGETAL POLE- SLUGGISH END OF CELL AND CONCERNED WITH THE DEVT. OF NUTRITIVE ORGANS
- YOLK LADEN
PROTECTIVE MEMBRANES:
1° MEMBRANE-CELL/PLASMA MEMBRANE
![Page 16: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/16.jpg)
2° MEMBRANE- ZONA PELLUCIDA
3° MEMBRANE –ADDED BY THE OVIDUCT
AS THE EGG PASSES THROUGH IT
- JELLY OF FROG’S EGGS
- ALBUMEN OF RABBIT’S EGG
- ALBUMEN AND SHELL OF HEN’S EGG
![Page 17: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/17.jpg)
CELLULAR CORDS ( GERMINAL EPITHELIUM)
TESTES TUBULES
SPERMATOGONIA (STEM CELLS)- LARGER
INDIFFERENT CELLS- SMALLER
PUBERTY – SOME SPERMATOGONIA REMAIN AS STEM CELLS WHILE OTHERS BECOME PRIMARY SPERMATOCYTE-2°SPERMATOCYTE-SPERMATID-SPERM
![Page 18: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/18.jpg)
DETACHED FROM SERTOLI CELLS AND ARE SET FREE INSIDE THE SEMINIFEROUS TUBULES
SPERM CELL- SMALLEST CELL IN MASS MADE UP OF HEAD, NECK & TAIL.
AT THE END OF MATURATION (MEIOSIS)
THE DEVT. OF EGG IS COMPLETE AND THE EGG BECOMES FUNCTIONAL WHILE THE MALE GAMETE UNDERGOES A SERIES OF TRANSFORMATIONS BEFORE A FUNCTIONAL SPERM CELL IS DERIVED
![Page 19: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/19.jpg)
CHROMOSOME NUMBERS
(2N) MAN=46 (DIPLOID CHROMOSOME#)
(N) MAN=23 (HAPLOID CHROMOSOME#)
FEMALE -22 ORDINARY CHROMOSOME PAIR
-23RD PAIR(SEX CHROMOSOME)
(XX) PAIR
MALE
22 ORDINARY CHROMOSOME PAIR
23RD PAIR (XY) PAIR
![Page 20: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/20.jpg)
24 DIFFERENT KINDS OF CHROMOSOMES
COMPARISON OF EGG & SPERM OF ANIMALS IN GENERAL
![Page 21: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/21.jpg)
FEATURES OVUM SPERMATO-ZOON
SIZE LARGE SMALL
SHAPE SPHEROIDAL ELONGATED
QUANTITY FEW (ONE) OFTEN IN MILLIONS
MOTILITY NON-MOTILE VIGOROUS(FLAGELLATE)
PROTECTION EGG ENVELOPES
NONE
![Page 22: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/22.jpg)
CYTOPLASM BULKY MINIMAL
YOLK LITTLE TO MUCH
NONE
CENTRO-SOME
DISAPPEARS RETAINED –CENTRIOLE &
AXIAL FILAMENT
MITOCHON-DRIA
DIFFUSED IN THE BODY ONLY
![Page 23: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/23.jpg)
GOLGI-APPARATUS
DIFFUSED IN ACROSOME
ONLY
NUCLEUS OPEN STRUCTURED
CONDENSED AS SPERM
HEAD
NUCLEOLUS TYPICAL INDISTINGUISHABLE
SEX DETERMININ
G ROLE
RARELY TWO KINDS(MOTH
S/BIRDS)
USUALLY TWO
KINDS(MALE&FEMALE)
![Page 24: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/24.jpg)
![Page 25: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/25.jpg)
![Page 26: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/26.jpg)
![Page 27: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/27.jpg)
![Page 28: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/28.jpg)
![Page 29: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/29.jpg)
INTERNAL FERTILIZATION
-SMALL NUMBER OF EGGS
EXTERNAL FERTILIZATION
-LARGE VOLUME OF EGGS
TYPES OF BREEDING:
• CONTINUOUS-ALL THOUGHOUT THE YEAR
• SEASONAL/ANNUAL SPAWNING PERIOD
• SPONTANEOUS- SEXUAL EXCITEMENT/PERIOD OF HEAT / ESTRUS
![Page 30: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/30.jpg)
• PROVOKED OVULATION- INDUCED BY THE ACT OF COPULATION.
• PERIODIC (INTERVALS OF 4 WEEKS) SPONTANEOUS
HUMAN FEMALE
-OVULATION (14 YRS.) + 30 YEARS OF SEXUAL ACTIVITY
FOLLICLE RUPTURE- SIMILAR TO THE RUPTURE OF A BOIL; TAKES PLACE AT THE STIGMA
![Page 31: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/31.jpg)
- HORMONAL FACTOR AND LOCAL WEAKENING OF FOLLICULAR WALL
EGG TRANSPORT- MADE POSSIBLE BY HORMONAL CONTROL AND OVARY ACTIVITY.
TIME OF OVULATION- MIDDLE OF THE CYCLE
28-DAY CYCLE
26-DAY CYCLE
30-DAY CYCLE
![Page 32: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/32.jpg)
EGG VIABILITY- FERTILIZABLE PERIOD IS LESS THAN ONE DAY – GENERATION TAKES PLACE
CORPUS LUTEUM- OVARIAN STRUCTURE (COLLAPSED & FOLDED) VESICULAR
FOLLICLE- MADE UP OF LUTEIN CELLS• CORPUS LUTEUM OF OVULATION• CORPUS LUTUEM OF PREGNANCY• CORPUS ALBICANS- WHITE SCAR LEFT
MADE UP OF FIBROUS TISSUE.
![Page 33: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/33.jpg)
• PSEUDOCOPULATION- INCREASES CERTAINTY OF UNION
• COPULATION- SEXUAL EMBRACESPERM STORAGE- ACCUMULATION AT
EPIDIDYMIS(TRAVERSED IN 12 DAYS)SPERM DISCHARGE- EJACULATION(MALE
CLIMAX DURING COITUS) SEMEN (SPERMATOZOA PLUS THE
SECRETIONS FROM 3 ACCESSORY GLANDS:
![Page 34: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/34.jpg)
• SEMINAL VESICLE
• BULBO-URETHRAL GLAND
• PROSTATE GLAND
3 ML EJACULATE-250,000,000 SPERMS
SPERM TRANSPORT-LASHING, FLAGELLATED MOVEMENT ; WILL TRAVERSE UTERUS IN 70 MIN.(7 INCHES)
SPERM VIABILITY= 1-2 DAYS
![Page 35: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/35.jpg)
IN VITRO- TWO WEEKS
HUMAN SEMEN(FROZEN IN GLYCEROL
AT - 70℃ (CAN SURVIVE FOR MANY MONTHS
![Page 36: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/36.jpg)
PROCESS WHEREBY 2 GAMETES FUSE TOGETHER TO CREATE A NEW INDIVIDUAL WITH A GENOME DERIVED FROM BOTH PARENTS
ACCOMPLISHES 2 SEPARATE ENDS; SEX (THE COMBINING OF GENES DERIVED FROM 2 PARENTS) AND REPRODUCTION (THE CREATION OF A NEW ORGANISM)
CONCEPTION CONSISTS OF 4 MAJOR EVENTS:
![Page 37: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/37.jpg)
1. CONTACT AND RECOGNITION BETWEEN SPERM AND EGG. THIS ENSURES THAT THE SPERM AND EGG ARE OF THE SAME SPECIES
2. REGULATION OF SPERM ENTRY INTO THE EGG. ONLY ONE SPERM CAN ULTIMATELY FERTILIZE THE EGG. THIS IS USUALLY ACCOMPLISHED BY ALLOWING ONLY ONE SPERM TO ENTER THE EGG AND INHIBITING ANY OTHERS FROM ENTERING
![Page 38: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/38.jpg)
3. FUSION OF THE GENETIC MATERIAL OF SPERM AND EGG
4. ACTIVATION OF EGG METABOLISM TO START DEVELOPMENT
![Page 39: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/39.jpg)
ANTON VAN LEEUWENHOEK – CO-DISCOVERER OF SPERM
NICOLAS HARTSOEKER – CO-DISCOVERER OF SPERM
DREW A PICTURE OF A PREFORMED HUMAN (HOMUNCULUS)
BELIEF THAT THE SPERM CONTAINED THE ENTIRE EMBRYONIC ORGANISM
![Page 40: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/40.jpg)
![Page 41: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/41.jpg)
POOLING TOGETHER OF SPERM AND EGG NUCLEI
• INVERTEBRATES ( ROTIFERS, CRUSTACEANS INSECTS) DEVELOP WITHOUT THE BENEFIT OF FERTILIZATION(PARTHENOGENESIS)
![Page 42: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/42.jpg)
![Page 43: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/43.jpg)
![Page 44: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/44.jpg)
RESULTS OF FERTILIZATON:
1. REASSOCIATION OF MALE AND FEMALE SETS OF CHROMOSOMES , RESTORING THEM TO THE FULL DIPLOID NUMBER.
2. SEX DETERMINATION
3. ACTIVATION OF OVUM INTO CELL DIVISION OR CLEAVAGE.
![Page 45: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/45.jpg)
SEX DETERMINATION – IS ESTABLISHED AT THE TIME OF FERTILIZATION
DURING MEIOSIS, CHROMOSOME NUMBER IS HALVED
22+X – FEMALE
22+X – MALE; 22+Y – MALE
22+X + 22+X = 44+2X
22+X + 22+Y = 44+X+Y
![Page 46: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/46.jpg)
PERIODS OF EARLY DEVELOPMENT:
1) GAMETOGENESIS
2) FERTILIZATION
3) CLEAVAGE
4) GASTRULATION
FERTILIZED EGG-MANY CELLED INDIVIDUAL(CLEAVAGE) - CELLS TYPICALLY ARRANGE THEMSELVES INTO A HOLLOW SPHERE, THE BLASTULA
![Page 47: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/47.jpg)
CELLS OF BLASTULA- REDISTRIBUTED AS THE PRIMARY GERM LAYERS(GASTULATION)
IT CONTAIN THE MATERIAL OUT OF WHICH THE EMBRYO AND ALL ITS PARTS WILL DIFFERENTIATE.
• ECTO
• MESO
• ENTO/ENDODERM
![Page 48: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/48.jpg)
THE VERTEBRATE GROUPS
I. ANAMNIOTA- WITHOUT AMNION
FISHES-LAMPREY , STURGEON,SHARK,BONY FISHES
AMPHIBIANS-FROGS,TOAD,SALAMANDERS
II. AMNIOTA- WITH AMNION
REPTILES
-LIZARD,CROCODILES,SNAKES,TURTLES
![Page 49: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/49.jpg)
MAMMALS – HAIR AND MAMMARY GLANDS
• MONOTREMES- DUCK-BILL /ECHIDNA• MARSUPIALS-OPOSSUM/ KANGAROO• PLACENTALS-YOUNG NOURISHED IN THE
UTERUS VIA PLACENTA • PRIMATES- WITH NAILS
(LEMUR,MONKEY,APE AND MAN) –SUBORDER ANTHROPOIDA
![Page 50: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/50.jpg)
-DOUBLING/FRACTIONATING PROCESS PRODUCING COHERING,STICKY, BLASTOMERES ARRANGED AROUND A CENTRAL,FREE SPACE(BLASTOCOELE)
EGG CLASSIFICATION ON THE BASIS OF ABUNDANCE AND YOLK DISTRIBUTION:
A. TOTAL- HOLOBLASTIC OVA; ENTIRE OVUM DIVIDES
![Page 51: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/51.jpg)
1. EQUAL-ISOLECITHAL OVA
-EQUAL SIZED BLASTOMERES
• AMPHIOXUS/MARSUPIAL/PLACENTAL MAMMALS
2. UNEQUAL- MODERATELY TELOLECITHAL OVA
• LOWER FISHES / AMPHIBIANS
![Page 52: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/52.jpg)
B. PARTIAL- MEROBLASTIC OVA; ONLY PROTOPLASMIC REGION DIVIDES.
1. DISCOIDAL-HIGHLY TELOLECITHAL OVA
-MITOSIS RESTRICTED TO THE ANIMAL POLE.
• HIGHER FISHES/REPTILES/BIRDS/
MONOTREME MAMMALS
![Page 53: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/53.jpg)
2. SUPERFICIAL – CENTROLECITHAL OVA; DIVISION RESTRICTED TO THE PERIPHERAL CYTOPLASMIC INVESTMENT
• ARTHROPODS
AMPHIOXUS-FISH-SHAPED; LOW CHORDATE
AMPHIBIANS REPTILES/ BIRDS MAMMALS
![Page 54: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/54.jpg)
- FISH SHAPED; LOW CHORDATE
- EARLY STAGES OF DEVT. IS SIMILAR TO SOME INVERTEBRATES
- ISOLECITHAL EGGS
- CLEAVAGE IS TOTAL AND NEARLY EQUAL
- SUBSEQUENT CELL DIVISIONS IN ALTERNATE PLANES PRODUCES 32,64 ANO 128 CELL STAGES
- SIZE OF CELLS ARE PROGRESSIVELY DIMINISHED WHILE THE CENTRAL CAVITY ENLARGES TO FORM THE BLASTOCOELE
![Page 55: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/55.jpg)
MODERATELY TELOLECITHAL (FAIR AMOUNT OF YOLK)
- CLEAVAGE IS TOTAL BUT UNEQUAL
- UPPER 4 MICROMERES ARE SMALLER THAN THE LOWER 4
- FORMS A CENTRAL BLASTOCOELE WHERE BLASTOMERES AT THE ANIMAL POLE ARE SMALLER; LARGER & FEWER AT VEGETAL POLE
![Page 56: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/56.jpg)
WALL IS MORE THAN 1 CELL THICK
BLASTOCOELE IS RELATIVELY SMALL; LOCATED ABOVE CENTER DUE TO THE THICK WALL OF THE VEGETAL POLE
![Page 57: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/57.jpg)
WITH LARGE EGGS
- CLEAVAGE IS PARTIAL & DISCOIDAL
- PRODUCES A DISCOIDAL PLATE OF CELLS PERCHED ON THE SURFACE OF THE YOLK AND SEPERATED FROM IT BY A CLEFT
- CLEAVAGE PRODUCES A MODIFIED BLASTULA( DISCOBLASTULA) WITH THE CELLULAR CAP CALLED A BLASTOCOELE
![Page 58: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/58.jpg)
MARSUPIAL & PLACENTAL MAMMALS HAVE EMBRYOS THAT ARE DEVELOPED WITH DEPENDENCE ON THE MOTHER.
- EGGS ARE ISOLECITHAL- CLEAVAGE TAKES PLACE IN THE ZONA
PELLUCIDA & THE BLASTOMERES ACCOMMODATE THEMSELVES TO THE SPHEROIDAL CAVITY.
- CLEAVAGE IS TOTAL AND NEARLY EQUAL/
![Page 59: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/59.jpg)
- DIVISION BEGINS IN THE UTERINE TUBE & COMPLETED IN THE UTERUS
- COMPLETED WITHIN A RANGE OF 70 HRS.(RABBIT) TO 190 HRS. FOR THE COW.
![Page 60: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/60.jpg)
INVOLUTION , ELONGATION & CONVERGENCE
- CHARACTERIZE GASTRULATION IN ALL CHORDATES
![Page 61: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/61.jpg)
![Page 62: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/62.jpg)
![Page 63: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/63.jpg)
ANIMAL TYPE
TYPE OF EGG
CLEA-VAGE
BLAS-TULA
BLASTU-LA CAVITY
METHODS OF GASTRULATION
COMMENT ON GASTRULATION
AMPHIOXUS
ISOLECITHAL (LITTLEYOLK)
TOTAL;EQUAL
SPHERE;WALL A SINGLE LAYER
SPHERI-CAL RELATIVELY LARGE
INVAGI-NATION; INVOLU-TION VIA BLASTO-PORE
EARLY INNER LAYER IS A COMPO-SITE
AMPHI-BIANS
TELOLE-CITHAL(MODE-RATE YOLK)
TOTAL;UNEQUAL
SPHERE; WALL LAYERED;THICK-NESS VARIES
SPHERI-CAL; RELATIVELY SMALL;ECCEN-TRIC
CHIEFLY IN VOLU-TION VIA BLASTO-PORE
INVOLU-TED LAYERS ARE SEPARA-TE FROM START
![Page 64: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/64.jpg)
BIRDS TELOLE-CITHAL(MASSIVE YOLK)
PARTIAL;DISCOI-DAL
CELL-DISC;BLASTO-DERM)LIES ON MASSIVE YOLK
SHA-LLOW;DELAYED UNTIL ENTO-DERM FORMS
DELAMI-NATION;INVOLU-TION VIA PRIMI-TIVE STREAK
OCCURS IN TWO STAGES;MODI-FIEDAMPHIBIAN STYLE
MAMALS(EXCEPTLOWEST)
ISOLECI-THAL(LITTLE YOLK)
TOTAL;EQUAL
BLASTO-CYST, WITH INNER CELL MASS
MERGEDWITH YOLK-FREE BLASTOCYST CAVITY
DELAMINATION;INVOLU-TION VIA PRIMI-TIVE STREAK
OCCURS IN TWO STAGES;BASICA-LLYSIMILAR TO BIRDS
![Page 65: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/65.jpg)
![Page 66: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/66.jpg)
ECTODERM MESODERM(INCLUDING
MESENCHYME)
ENTODERM
1. EPIDERMIS,INCLUDING: CUTANEOUS GLANDS HAIR, NAILS &LENS
2. EPITHELIUM OF: SENSE ORGANS. NASAL CAVITY;SINUSES.MOUTH , INCLUDING: ORAL GLANDS; ENAMEL,
1. MUSCLE(ALL TYPES)
2. CONNECTIVE TISSUE ; CARTILAGE;BONE;NOTOCHORD
3. BLOOD;BONEARROW
4. LYMPHOID TISSUE.
EPITHELIUM OF:5.BLOOD VESSELS;
LYMPHATICS.
EPITHELIUM OF:1. PHARYNX,INCLU
DING: ROOT OF TONGUE , AUDITORY TUBE, ETC. TONSILS; THYROID PARATHYROIDS ; THYMUS
2. LARYNX; TRACHEA; LUNGS
![Page 67: Gametogenesis](https://reader034.fdocuments.us/reader034/viewer/2022042500/55aba19d1a28ab87348b4683/html5/thumbnails/67.jpg)
3. NERVOUS TISSUE , INCLUDING; HYPOPHYSIS,CHROMAFFIN TISSUE
6. BODY CAVITIES
7.KIDNEY; URETER
8.GONADS; GENITAL DUCTS
9.SUPRARENAL10.JOINT
CAVITIES , ETC
3.DIGESTIVETUBE , INCLUDING : ASSOCIATED GLANDS4.BLADDER5.VAGINA(ALL?),VESTIBULE.6.URETHRA , INCLUDING: ASSOCIATED GLANDS.