^ Chapter 2 - Gametogenesis: Conversion of Germ Cells into Male and Female Gameters Flashcards Preview

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Flashcards in ^ Chapter 2 - Gametogenesis: Conversion of Germ Cells into Male and Female Gameters Deck (48):
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Male gamete

Sperm

1

Female gamete

Oocyte

2

Zygote=

Sperm + Oocyte

3

Where are the gameters derived from?

Primordial germ cells (PGCs) that are formed in the epiblast during the 2nd week and that move to the wall of the yolk sac

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When does the gameters move to the yolk sac toward the developing gonads?

During the 4th week

5

When does the gametes arrive the developing gonads?

By the 5th week

6

Synapsis

The process of homologous chromosomes aligning themselves with each other

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Can the chromosomes be recognized with light microscope before the cell enters mitosis?

Nope

8

Male germ cells

Spermatocyte

9

Female germ cells

Primary oocyte

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When does the cross overs happen?

Meiosis I

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What happens in the cross overs?

Interchange of chromatid segments between paired homologous chromosomes

12

Chiasma

X-like structure

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How many crossovers?

30-40 (1 or 2 per chromosome)

14

How many daughter cells does the primary oocyte give rise to?

4 daughter cells, each with 22 plus 1X chromosome

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How many of the oocyte daughter cells develops into a mature gamete?

1/4 develops into a mature gamete (secondary oocyte)

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How many of the oocyte daughter cells are called polar bodies?

3 of the 4 oocyte daughter cells are called polar bodies(first polar bodies?).
They recieve a little cytoplasm and degenerate during subsequent development

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How many daughter cells does one spermatocyte give rise to?

4 daughter cells:
- two with 22 plus 1X chromosome
- two with 22 plus 1Y chromosome

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How many of the spermatocyte daughter cells develops into mature gameters?

All 4 develop into mature gameter

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Oogenesis

The process whereby oogonia differentiate into mature oocytes

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What happens with the PGCs when they arrive the gonad?

They differentiate into mature oogonia

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Follicular cells

single, flat, epithelial cells that originate from the surface epithelium covering the ovary

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Primordial follicle =

Primary oocyte + flat epithelial cells

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Diplotene stage

A resting stage during prophase that is characterized by a lacy network of chromatin

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Oocyte maturation inhibitor (OMI)

- Small peptide secreted by follicular cells
- Produce the diplotene stage
- Prevents the primary oocyte to finish their meiotic division before puberty

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Follicular cells secret

Oocyte maturation inhibitor (OMI)

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Which stage is the longest?

The Vesicular (antral) stage

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What forms the theca folliculi?

The stromal cells

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Wah secrets the glycoproteins on the surface of oocyte, forming the zona pellucida?

Granulos cells and the oocyte secret glycoproteins

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Theca interna

Inner secretory cells

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Theca externa

Outer fibrous capsule

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What induces the preovulatory growth face?

- Lutenizing hormone (LH)

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When does the spermatogenesis begin?

It begins at puberty

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Spermatogenesis

Includes all the events by which spermatogonian are transformed into spermatoza

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Type B spermatogonia divide to form...

Primary spermatocytes

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What marks the initiation of spermatogenesis?

Type A spermatogonia

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What happens when the follicle stimulating hormone (FSH) binds to the Sertoli cells?

They stimulate testicular production and synthesis of intracellular androgen receptor proteins

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Spermiogenesis, including:

- Formation of the acrosome
- Condensation of the nucleus
- Formation of neck, middle piece, and tail
- Shedding of most of the cytoplasm

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How many days does the spermatogonium require in order to become a mature spermatozoon?

74 days

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Type B spermatogonia

- Derive from primordial germ cells
- Gives rise to primary spermatocytes

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What gives rise to secondary spermatocytes?

Primary spermatocytes

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Secondary spermatocytes undergo meiosis II and forms?

Spermatids

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When does the oogenesis begin?

Before birth

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Trisomies

An extra chromosome

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Monosomies

Loss of chromosomes

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Nondisjunction

Homologous chromosomes spearation fails, resulting in one cell recieving too many chromosomes and 1 recieves too few

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Primordial germ cells differentiate into:

When they arrive the gonads they differentiate into gonads

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Where does the first polar body lie?

The first polar body lies between the zona pellucida and the cell membrane of the secondary oocyte in the perivitelline space?