Gametogenesis Flashcards
The process by which the male gamete, the sperm, and the female gamete, the oocyte, unite to give rise to a 💡zygote.
Fertilization
These are the cells were 💡gametes are derived.
They are formed in the 💡epiblast during the 💡second week, move through the 💡primitive streak during 💡gastrulation, and migrate to the wall of the 💡yolk sac
Primordial Germ Cells (PGCs)
During the(1)__, these cells begin to migrate from the yolk sac toward the developing gonads, where they arrive by the end of the (2)__.
(1) fourth week
(2) fifth week
It is a process of of 💡producing gametes
Gametogenesis
Gametogenesis includes:
Meiosis
Cytodifferentiation
Humans have approximately __ genes on 46 chromosomes.
23,000
Genes on the 💡same chromosome tend to be 💡inherited together and so are known as __.
Linked genes
In somatic cells, chromosomes appear as __ to form the diploid number of 46.
23 homologous pairs
22 pairs of matching chromosomes
Autosomes
One pair of matching chromosomes
Sex chromosomes
One chromosome of each pair is derived from the maternal gamete, the (1)__, and one from the paternal gamete, the (2)__.
(1) oocyte
(2) sperm
Each gamete contains a (1)__, and the unión of the gametes at fertilization restores the (2)__.
(1) Haploid number of 23 chromosomes
(2) Diploid number of 46
It is the process whereby one cell divides, giving rise to 💡two daughter cells that are 💡genetically identical to the parent cell
MITOSIS
Before a cell enters mitosis, each chromosome __ its DNA.
replicates
It is a stage in mitosis where the chromosomes begin to 💡coil, 💡contract, and 💡condense.
PROPHASE
Two parallel 💡subunits of chromosome.
Chromatids
It 💡joins the two chromatids into a narrow region forming the chromosome.
Centromere
At what phase of mitosis where the 💡chromatids become distinguishable?
PROMETAPHASE
It is a phase of mitosis where the 💡chromosomes line up in the equatorial plañe, and their 💡doubled structure is clearly visible.
METAPHASE
It is an 💡extension of microtubles that 💡attaches chromosomes from the centromere to the centriole.
Mitotic Spindle
It marks the beginning of anaphase.
Division of centromere of each chromosome
It is a phase of mitosis where the 💡chromatids migrates to opposite poles of the spindle.
Anaphase
What happens during telophase?
Chromosomes uncoil and lengthen
The nuclear envelope reforms
The cytoplasm divides
It is the cell división that takes place in the germ cells to 💡generate male and female gametes, sperm and egg cells, respectively.
MEIOSIS
Why does meiosis requires two cell divisions, meiosis I and meiosis II.
To reduce the number of chromosomes to the haploid number of 23
It is a process seen in meiosis where 💡homologous chromosomes align themselves in pairs
Synapsis
It is the 💡interchange of chromatid segments between paired homologous chromosomes which is a 💡critical events in meiosis I.
These events 💡enhances genetic variability by 💡random distribution of homologous chromosomes to the daughter cells
CROSSOVERS
It is an 💡X-like structure that is formed from the points of interchange that temporarily united as separation occurs.
CHIASMA
Results of meiotic divisions:
- Genetic variability
2. Each germ cell contains a haploid number of chromosomes
The primitive female germ cell (primary oocyte) produces only __, the mature oocyte.
one mature gamete
The primitive male germ cell (primary spermatocyte) produces __, all of which develop into spermatozoa.
four spermatids
What will happen to the 3 daughter cells that did not mature into oocyte?
They degenerate during subsequent development because they receive little cytoplasm.
These are the 💡three daughter cells that 💡did not mature.
Polar Bodies
It is the process whereby 💡oogonia differentiate into mature oocytes.
Oogénesis
Maturation of Oocytes Begins Before __.
Birth
These are cells that formed once PGCs have arrived in the gonad of a genetic female.
Oogonia
It is a layer of single 💡flat epithelial cells where all of the 💡oogonia in one cluster are probably derived.
Follicular Cells
These are formed when the oogonia arrest their cell división in 💡prophase of meiosis I.
Primary Oocytes
By the __ of development, some oogonia give rise to primary oocytes that enter prophase of the first meiotic división.
third month
A 💡primary oocyte, together with its surrounding 💡flat epithelial cells, is known as a __
Primordial Follicles
Oocytes have entered the __ of prophase, in which they remain until just before ovulation
diplotene stage
It is a 💡resting stage during prophase that is characterized by a 💡lacy network of chromatin.
Diplotene Stage
It is a small peptide 💡secreted by follicular cells that causes the 💡primary oocyte to remain arrested in prophase and do not finish their first meiotic división before puberty is reached.
Oocyte Maturation Inhibitor (OMI)
It is a 💡space seen in primary follicles where 💡fluid accumulates as they mature.
Antrum
It is formed when the the small cavities of the primary follicle is 💡💡filled until these cavities fuse together to form a large cavity—the antral cavity/antrum.
Vesicular (Antral) Follicle
It is formed when primordial follicle begin to grow, surrounding follicular cells change from flat to 💡cuboidal and proliferate to produce a 💡stratified epithelium of 💡granulosa cells and presence of a well-defined 💡zona pellucida.
Mature Primary (Preantral) Follicle
By the __, the majority of oogonia have degenerated except for a few near the surface.
seventh month
It is a stage where mature primary (preantral) follicle 💡accumulates fluid in a space called antrum.
💡Longest stage
Antral/ Vesicular Stage
These are 💡stratified cuboidal cells that rest on a basement membrane separating them from surrounding ovarían connective tissue (stromal cells) that form the theca folliculi.
Granulosa Cells
These are 💡ovarian connective tissue (stromal cells)
Theca Folliculi
It is a layer of 💡visible in irregular patches glycoproteins on the surface of the oocyte which is 💡secreted by granulosa cells
Zona Pellucida
It is the 💡cells of the theca folliculi 💡organize into an inner layer of 💡secretory cells.
It is composed of cells having characteristics of 💡steroid secretion, rich in blood vessels
Theca interna