fecondazione Flashcards

1
Q

Fertilization definition

A

FERTILIZATION AND PLANT
FERTILIZATION
Set of phenomena related to
recognition and the union of two gametes and obtaining embryo

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2
Q

Fertilization steps

A
  • Formation of mature gametes (sperm and egg)
  • Presence in the contemporary site of fertilization
  • Recognition of the two gametes
  • Merger of the two gametes
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3
Q

Spermatogenesis definition.

A

Set of phenomena which transform the cell gamete
primitive (spermatogonium type A) in cell gamete
couple (sperm)

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4
Q

three phases of spermatogenesis

A

There are three phases:
1. multiplication of spermatogonia
2. meiosis (No of
chromosomes goes from 46 23)
3. spermiogenesis

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5
Q

Spermatogenesis hormonal niuances

A
  • Spermatogenesis is controlled by FSH and testosterone.
  • FSH binds to receptors expressed on the Sertoli cells and stimulates the production of ABP (Androgen Binding Protein)
  • LH binds to receptors expressed on Leydig cells and stimulates production of testosterone (T)
  • T ABP binds and stimulates the seminiferous tubule maturation spermatids and sperm
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6
Q

Spermatogenesis the process

A

Spermatogonia type A is
multiply by mitosis and form the
Spermatogonium type B.
Each spermatogonium type B gives
rise to two primary spermatocytes.

In the primary spermatocyte begins
meiosis, which halves of the num
chromosomes 46 to 23 and leads to
formation of two secondary spermatocytes (I div. meiotic).

By secondary spermatocyte
form 2 Spermatids (second
meiotic Div.)
The spermatid evolves in (spermatogenesis).
The spermatogenic cycle lasts 74

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7
Q

oogenesis steps

A

Mitosis (embrionic life):

Oogonio -> Oogonio (46 cr)

Meiosis I (puberty):

Primary oocyte (46 cr) -\> primary oocyte arrest division
Meiosis repression

**Meiosis II: **Secondary oocyte (23 cr) is made

Burst follicle

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8
Q

Fertilisation steps

A

Woman: ovarian cycle -> ovulation-> passage in uterina tuba ->

**Men: **ejaculation -> progression in female genital -> capacitation ->

Common:

ampularry portion of the tuba ->

-> acrosome reaction and penetration ->

fertilization

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9
Q

path of sperm

A

The migration process starts inside the genitals
male. From the lumen of the seminiferous tubules, which are released at the end of
spermatogenico process, migrate to the efferent ducts, hence
are pushed in the epididymis and then reach the corner of ‘epididymis where they acquire the ability to move straight.
The ability to move is due to the activity of the tail or flagellum
At the moment of ejaculation, immersed in the semen, are released into the vagina (vaginal fornix posterior), through
the cervix (cervical mucus), the uterine cavity, and reach ampullary portion of the tube.
Of 200-300 million
of sperm released into the vagina,

only about 200 come close to the oocyte.

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10
Q

CAPACITATION OF SPerm

A

Takes place in the passage through the cervical mucus and
consists in alterations of the plasma membrane
(Activation of enzymes
acrosomal and dell’adenil cyclase) that enables them to
undergo the acrosome reaction and thereby be able to cross the casings of oocyte
Also acquires the ability to sense stimuli chemotactic from oocyte

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11
Q

where does fertilisation occur?

A

Fertilization takes place in the ampullary portion of the tube
uterine, where the ‘secondary oocyte arrives, surrounded by
membrane pellucida, carried by ciliary movement
tubal epithelium and tubal muscle contractions

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12
Q

Oocyte parameters during fertilisation

A

The secondary oocyte is at
metaphase stage of
second meiotic division,
process that is completed only
if fertilization occurs

It is believed that the oocyte
maintains the capacity of
be fertilized for about
12-24 hours, after which it degenerates

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13
Q

INteraction of spermatozoid and oocyte

A

Overcoming of the cumulus-corona
 exceeded z. pellucida
 fusion of gametes
 Fusion of pronuclei
 cleavage embryo

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14
Q

Acrosome reaction

A

Acrosome reaction
Fusion of the plasma membrane of the oocyte with the membrane
outer acrosome of the sperm and subsequent lysis with
leakage of the contents enzyme (hyaluronidase, acid phosphatase,
collagenase, etc.) acrosome vesicle that digests the matrix
that holds the cells of the zona pellucida

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15
Q

Penetration of spz to oocyte

A

PENETRATION
After the zona pellucida sperm finds himself in
perivitelline space, where it engages with the plasma membrane
oocyte; the membranes of the two gametes begin to merge
(Gamete fusion) and the sperm enters the oocyte.

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16
Q

MODIFICATIONS of ovocite

A
  • Lock polispermia
  • Completion of meiosis: unlocking
    from the state of metaphase and herein after the second meiotic division with
    formation of a mature egg and expulsion of the second polar body
17
Q

Zygote

A

Coupling ooplasm, the structural components of the sperm
undergo degeneration, the nuclear membrane breaks
and the material contained in it goes to constitute the pronucleus of the male Zygote
Contemporary development female pronucleus

The two pronuclei after duplicate their DNA to undergo
prophase of the first division of segmentation. Disappeared
nucleoli and the nuclear envelope the two groups of chromosomes feature (anfimixi) equator in a single mitotic spindle.

18
Q

fertilisation

A

A: oocyte metaphase
B: the sperm entered the oocyte who completed
the second meiotic division
C: forming the pronucleus female and male

D: DNA replication occurs
and have highlighted the chromosomes
E: the maternal and paternal chromosomes are come together (anfimixi) on the equatorial plane of the first
zone segmentation

Before cell division ->Two-cell embryo

19
Q

FIRST WEEK OF DEVELOPMENT

A
  • Segmentation
  • Migration through the tube to the uterine cavity
  • Plant of the fertilized egg
20
Q

SEGMENTATION

A

Consists in the succession of mitotic divisions that
lead to the formation of more and smaller cells,
called blastomeres (totipotent cells).
(p)
The cleavage of the embryo is a phenomenon quite slow
, Requiring 16-24 h. for each cell duplication.
The first cleavage avviene16-18 h. After fertilization
The embryo reaches the morula stage (12-36 blastomeres)

21
Q

how
Morula -> Blastocyst happens

A

Inside the morula to forms
a cavity, the blastocele, stuffed
liquid: the embryo assumes a
cystic appearance and is called
blastocyst

Blastocyst
hollow sphere whose wall is formed by a single
layer of blastomeres flattened, the trophoblast, which are
grouped at one end (embryonic pole) blastomeres more
interior to form the embryonic node.

22
Q

Further blastocyst formations

A

The blastocyst remains free
into the uterine cavity to
contact with its
secretions for about 72 hours
then gets rid of the area
pellucida to start
plant

23
Q

Plant

A

Process through which the blastocyst begins to
penetrate the stratum decidual uterus

  • 18th - 19th day of the cycle
  • 3-7 days after ovulation
  • 5-9 days after fertilization

????along the midline of the uterus on the rear wall
a point equidistant between the hosts tubal-uterine and orifice
uterine internal??? somewhere in the middle I guess

24
Q

Phases of the plant and best time to plant

A

Phases:
Apposition
adhesion
invasion

The “window” is about four days in the woman, on days 20-24 of the cycle, or 7-11 days after the peak of LH

25
Q

implantation. apposition.

A

the blastocyst begins to approach the decidua, orienting the embryo at dell ‘endometrium

26
Q

plant. adhesion.

A

the blastocyst in its layer external shape of microvilli that
adhere to the decidua where occurred Vascular changes

27
Q

Invasion. (implantation phase).

A

the embryo penetrates through
the superficial uterine epithelium
to catch up there membrane
epithelial, basal stroma and
maternal vessels that are being eroded

28
Q

following steps after implantation:

A
  • differentiation of trophoblast
  • formation of the embryonic disk (hypoblast and epiblast)
  • formation of the embryonic disk (hypoblast and epiblast)
  • formation of corium and dell’amnios
  • placentation
29
Q

Embryogenesis

A

When the seventh day of fertilization the blastocyst
adheres to the endometrium, the phenomena of diversification
both parties charged that the trophoblast cell mass
uterine become multiple

30
Q

following DETAILED steps after implantation.

A

Just implantation has taken place there is a modification at the level of
node embryonic cells deeper watching the blastocele differ cubic becoming low and giving rise to a layer epithelial character;

*entoderma or hypoblast, the first package embryo germination *
At the beginning of the second week the cells located between the
cytotrophoblast polar and entoderma undergo a rearrangement in their relationship and are arranged to form a layer of cells cylindrical juxtaposed to the flat cells dell’ipoblasto;
second package germination, epiblast, which is the common matrix the ectoderm and mesoderm

31
Q

Ectoderma

A

Ectoderm
: Central and peripheral nervous system,
sensory epithelium of the ears, nose and eyes, skin,
hair, nails, ghandola pituitary,
breast tenderness,
sebaceous and smolto teeth

32
Q

Mesoderm

A

Mesoderm: somites (which give rise to the fabric
muscle, cartilage and bone, subcutaneous system
vascular, reproductive and urinary set apart except
bladder, spleen and adrenal

33
Q

Endoderma

A

Entoderma
:
epithelium
apparatus
tract,
respiratory, and bladder

34
Q

about Embryo genetically female

A

Embryo genetically female

 The sex cords are broken into irregular cell aggregates, which contain germ cells and are sites in the region medullary gonad
The surface epithelium of the gonad continues to proliferate and gives rise to a second generation of sex cord: strings cortical, That
penetrate the underlying mesenchyme and is segmented into isolated groups of penetrate the underlying mesenchyme and is segmented into isolated groups of cells each of which contains one or more primordial germ cells, in which will differentiate the ovogoni. Epithelium surface will form the follicular cells

35
Q

Genital ducts

A

The embryos of both sexes have initially two pairs of ducts
Genital:
 ducts mesonefridici or Wolff
 ducts paramesonefridici or Muller
 ducts paramesonefridici or Muller