Gametogenesis I Flashcards
Diakiesis Phase
- Crossing over complete
- Spindle apparatus in place
Prophase II
- Chromosomes begin to condense again
- Spindle reforms
Stages of Meiosis
PMAT I —> PMAT II
T/F: Most mammals have an EMPTY yolk sac.
True
Morphogenesis
Generation of form
Or
Assumption of new shape
Determination
Cells become RESTRICTED to a given developmental pathway
Where are the FIRST Germ cells found?
In the ENDO-dermal layer of the Yolk sac
The 4 phases of Gametogenesis
- Germ cells Migrate to gonads
- Increase in # of germ cells by MITOSIS
- Reduction in Chromosomal # by MEIOSIS
- Structural and Functional maturation of Eggs and Sperm
Leptotene phase
- Chromosomes are threadlike
- They begin to COIL
What is the End result of Meiosis?
4 genetically Unique HAPLOID Daughter cells
What is a Teratoma?
- Growth from Misdirected migrating primordial germ cells.
- Contains mixtures of Highly differentiated tissues
Metaphase I
- Tetrads line up
- Centromeres do NOT divide
Pachytene Phase
- Max Coiling
- Tetrads (crossing over begins)
Anaphase I
- Homologous chromosomes move to OPPOSITE side
(Consist of 2 chromatids) - Chromatids are NOT genetically identical
- Establishment of HAPLOID
What is Embryology?
The study of the Embryo
Integration
Different Tissues are brought together and combined to form organs an tissues
Prophase I vs Prophase II
PI: 2n, 4c
PII: 1n, 2c
Induction
The effect that one tissue (Inductor) has upon another (responder)
Telophase I
- Nuclear membranes reform
- Spindle disassembles
- Chromosomes uncoil
What are the 6 Component Processes
- Determination
- Differentiation
- Growth
- Morphogenesis
- Induction
- Integration
Sub-parts of Prophase I
- Leptotene
- Zygotene
- Pachytene
- Diplotene
- Diakinesis
Zygotene phase
Homologous chromosomes PAIR
- complex forms
3 sections of Human ontogeny
- Prenatal
- Postnatal
- Adult
Aneuploidy
- Def
- Examples
- Abnormal # of Chromosomes
2. Monosomy and Trisomy
T/F: Genes may be Activated or Inactivated throughout development
True
Changes that can occur in part of the Chromosome
- Translocations
- Deletions
- Inversions
- Duplications
What are Atretic Follicles?
Spontaneous Degenerated follicles
Component Processes Mnemonic
DErrick DIssed GReg
&
MOlly INDUCed INTEractions
Diplotene Phase
- Crossing over continues
- Chiasmata well defined
When do the primordial germ cells first appear?
24 days AFTER Fertilization
T/F: Intrinsic factors (genes) do NOT limit Extrinsic factor (envrnmt) fxns.
False
Intrinsic factors DO limits Extrinsic factors.
Prior to Ovulation the Secondary Oocytes are arrested at what phase?
Metaphase II
Differentiation often results in what?
Luxury Molecules
- Stuff that the cell itself does not need BUT the BODY as a whole needs.
Telophase II
- Chromosomes uncoil
- Cytokinesis complete
Migration Route of primordial germ cells
Start in the YOLK sac
—> Hindgut Epithelium
——> Through Dorsal MESENTERY
———> End developing GONADS
Hyperplasia vs Hypertrophy
- Inc in Cell #
2. Inc in Cell SIZE
RESULTS of Meiosis
- Inc in cell # (male)
- Daughter cells are NOT genetically identical
- Daughter cells are Haploid
All development ultimately rests on ____?
Genes
What is Meiosis
2 NON-Identical, consecutive cell division
T/F: All Oogonia develop into Primary oocytes in the Early EMBRYO.
True
Metaphase II
Chromosomes line up on metaphase plate
Major events in Meiosis
- Pairing of the homologous chromosomes
- CROSSING over
- 2 cycles of Division, but ONE cycle of DNA Replication
After birth, there are approx ____ Primary oocytes. Only ______ will survive to Puberty and only _____ eggs will actually be ovulated
- 400K
- 40K
- 400
What is Embryogeny?
The part of ONTOGENY from
Conception ———> Birth/Hatching
T/F: The Properties of the Embryo are diff from the adult.
True
What kind of cells develop FSH and LH receptors
Granulosa Cells
Anaphase II
- CENTROMERES divide
- Each chromosome consists of ONE Chromatid
What is Ontogeny?
Includes ALL developmental processes from
Conception ———> Death
Differentiation
Complex Changes of structure and function
Factors leading to the Meiotic arrest at the Diplotene stage
- High [cAMP]
- cGMP from follicular cells inactivate the PDEA 3A in oocyte
- prevents conversion of cAMP to 5’AMP
- maintains high [cAMP]