Gametogenesis ➡️ Fetus Flashcards by Vaishnavi Gupta

Germ cells are derived from

Epiblast

How well did you know this?

Not at all

Perfectly

When Germ cells migrate to yolk sac ?

At 6wks of pregnancy germ cells migrate to?

3 wks of preg

Gonadal ridge in 6 wks

How well did you know this?

Not at all

Perfectly

Germ cells are bipotential till?

Gene to determine sex of fetus

6wks

SRY gene on short arm of Y chromosome

How well did you know this?

Not at all

Perfectly

Difference between spermatogenesis and spermiogenesis

Spermatogonia ➡️ Sperm

Spermatid ➡️ Sperm

How well did you know this?

Not at all

Perfectly

Spermatogenesis begins at?

Oogenesis begins at

Puberty

Intrauterine life

How well did you know this?

Not at all

Perfectly

Parts of spermatid

Acrosomal cap ⬅️ Golgi body
Head⬅️ nucleus
Middle piece⬅️mitochondria
Tail⬅️ centriole

How well did you know this?

Not at all

Perfectly

Organalle lacked by sperm

Arrangement of centriole in tail

Rough ER

9+2 arrangement of filament

How well did you know this?

Not at all

Perfectly

Site of spermatogenesis

Time for spermatogenesis

Seminiferous tubule

Puberty

How well did you know this?

Not at all

Perfectly

Where does a sperm attains maturity and motility

Caudal end of epididymis

How well did you know this?

Not at all

Perfectly

Gene for motility of sperm

Ion for motility

CATSPER

Ca+2

How well did you know this?

Not at all

Perfectly

Time taken for sperm to reach ampulla of fallopian tube

Sperm remains motile in fgt for?

30 min

12hrs

How well did you know this?

Not at all

Perfectly

FSH acts on? During spermatogenesis

Negative feedback to decrease fsh is given by

Sertoli cells

Inhibin B released by sertoli cells
And indirect by testosterone by inhibiting GnRH

How well did you know this?

Not at all

Perfectly

Blood testis barrier is formed by

Sertoli cells

How well did you know this?

Not at all

Perfectly

1st stimulus for testis to produce testosterone

hcg

How well did you know this?

Not at all

Perfectly

Primary oocyte gets arrested in which stage

Diplotene stage of prophase 1 during meiosis 1

How well did you know this?

Not at all

Perfectly

What is primordial follicle

Primary oocyte surrounded by follicular cells ie granulosa and theca cells

How well did you know this?

Not at all

Perfectly

What is ovulation

It is release of secondary oocyte from primary oocyte

How well did you know this?

Not at all

Perfectly

Female pronucleus is formed by

Secondary oocyte undergoes meiosis 2 but arrested in metaphase till fertilization
When fertilization takes place secondary oocyte changes to female pronucleus

How well did you know this?

Not at all

Perfectly

Follicles present during 5 month of IUL
At birth
At puberty

7 million follicles (max)
1-2 million
4lakhs

How well did you know this?

Not at all

Perfectly

What is dictyate stage

Where is it absent

Arrested stage of of primary oocyte in first meiosis

It is absent in spermatogenesis

How well did you know this?

Not at all

Perfectly

Sequence of events before fertilization

Capacitation
Acrosomal reaction
Cortical reaction
Zona reaction

How well did you know this?

Not at all

Perfectly

Function of zona pellucida

It prevent polyspermy when one sperm reaches zona

How well did you know this?

Not at all

Perfectly

What is cortical reaction and zona reaction

Cortical reaction-When sperm reaches perivitelline space it touches ooplasm and cortical granules release enzyme
Zona reaction- the enzymes make zona pellucida impermeable to other sperms

How well did you know this?

Not at all

Perfectly

Capacitation is

Where does in occurs mainly

Ability of sperm to fertilize ova
Takes place in fgt
Mainly occurs at fallopian tube

How well did you know this?

Not at all

Perfectly

Fertilization occurs in

Ampulla of fallopian tube

Function of zona pellucida in a zygote

It will not allow zygote to implant in fallopian tube

Morula is

8-16 celled zygote surrounded by zona pellucida

Types of cell in fallopian tube

Ciliated columnar cell - push zygote to uterine cavity by peristalsis Secretory cells nutrition to early zygote Peg cells unknown

What happens during implantation if progesterone contraceptive failure occurs

progesterone is smooth muscle relaxant | Contraceptive failure leads to ectopic pregnancy

Implantation takes place on day?

Day 5 of fertilization

Process of implantation occurring on uterine cavity

Zona pellucida sheds (Zona Hatching) Morula ➡️ Blastocyst as fluid enters Blastocyst attaches to uterine cavity

Implantation occurring deep inside endometrium | What structure prevents implantation in myo or serosa

Interstitial implantation | Nitabuch layer

Phases of implantation. | Which of these is morphological marker of endometrial receptivity and implantation

Apposition Adhesion Invasion Apposition facilitated by pinopods

Piskacek sign Hartman sign Intradecidual sign

Assymetrical growth of uterus in early pregnancy Bleeding at the time of implantation Blastocyst implants deep into endometrium

Division of decidua

Decidua basalis Capsularis Parietalis

Site of formation of future maternal side of placenta

Decidua basalis

When does uterine cavity gets obliterated

By 14-16 wks

2 ova fertilized by 2 sperm in same cycle

Superfecundation

Double decidual sac/ring sign the blastocyst surrounded by

``` decidua capsularis (inner ring) Decidua parietalis (outer ring) ```

Trophoblast is divided into

8 days after fertilization Trophoblast is divided into | Cytotrophoblast(langhans cell layer) and syncytiotrophoblast (multinucleated syncytium)

Embryonic disc is formed by

5 cells from inner cell mass of blastocyst out of 58cells

Function of cytotrophoblast

Retains its cell boundaries and divides into villous and extravillous cytotrophoblast

What is chorion frondosum

It is fetal side of placenta | Villous cytotrophoblast forms villi like str near decidua basalis

Rest of villous CT forms?

It remains smooth and is ka chorion laeve

What is trophoblastic invasion?

Non villous CT divides into endovascular CT and interstitial CT Endovascular CT replace lining of maternal spiral artery which open in IVS to convert high resistance vessels to low resistance

When does trophoblastic invasion occurs | What happens if it doesn't happen?

Occurs in 2 steps First wave- 12 wks Second wave - 16 wks If trophoblastic invasion doesn't happen it leads to UPI PIH IUGR

What is known as hormone factory of placenta

Syncytiotrophoblast -it rises from CT but doesn't retains their cell boundaries

Embryonic disc divides blastocyst cavity into

Amniotic cavity and yolk sac

Amniotic cavity is lined by Yolk sac is lined by Primitive streak forms

Ectoderm ( third germ layer) Endoderm (first germ layer) Mesoderm (second germ layer)

Amniotic cavity and yolk sac is seen on usg as

Double bleb sign

Curving of caudal and cranial end of embryonic disc is seen as? ( on usg)

Embryonic poles on usg

Distance between two embryonic poles

Crown rump length

Hearts starts beating on

Day 21 after fertilization

When is this str seen on TVS Gestational sac Yolk sac Cardiac activity

4 wk1 day to 4 wk 3 day 4wk 5 day 5-6 wks

First fetal str seen on usg

Gestational sac

What is critical value of beta hcg in Tvs and tas

If beta hcg is more than or equal to 2000IU/L in intrauterine pregnancy gestational sac is visible on TVS In TAS -6500 IU/L

Case A pregnant female with beta hcg more than 2000Iu/L Gestational sac not visible on TVS Probable diagnosis

Ectopic pregnancy

A pregnant female with beta hcg less than 2000 IU/L NO gestational sac visible on TVS Next step?

Repeat beta hcg after 48 hrs If doubles ➡️ intrauterine If increases but not doubles ➡️Ectopic

If MSD > equal to 10 mm and no yolk sac is seen | What can be the cause

Pseudogestational sac of ectopic pregnancy

What is blighted ovum (anembryonic pregnancy)

``` MSD more than 25mm Yolk sac present No fetal tissue No CRL No cardiac activity ```

Characterstic of human placenta

Discoid - disc like Hemochoroidal -lies in contact with maternal blood Deciduate -sheds off after delivery

Weight of placenta at term Ratio of weight of placenta to fetus When is wt of placenta= wt of fetus

500g 1:6 At 17wkd of pregnancy

Cells of placenta | Which virus infects this cell

``` Hofbauer cells (macrophage) Zika virus can infect hofbauer cell to allow fetal transmission ```

Str separating maternal blood from fetal blood

Syncytiotrophoblast Cytotrophoblast Extraembryonic mesoderm Fetal capillary endothelium

Primary villi Secondary villi Tertiary villi

Primary- trophoblastic shell Secondary- + extraembryonic mesoderm (mesodermal core) Tertiary --- (vascular) fetal blood capillary in villi

Timeline for formation of villi after fertilization

Primary -day 13 after fertilization Secondary villi- day 16 after fertilization Tertiary - day 17 after fertilization

When does maternal spiral artery opening into IVS

Day 15 after fertilization

When does fetoplacental circulation is established

Day 17 after fertilization

Diff bw anchoring and stem villi

Anchoring- tertiary villi reaches upto decidua plate | Stem - main tertiary villi from which branch arise

Maternal blood in placenta fetal blood Volume of placenta at term

150 ml 350ml 500 ml

``` Number of spiral artery opening into intervillous space O2 saturation in intervillous space Partial pressure in ivs Uteroplacental blood flow at term Uterine blood flow at term ```

``` 120 65-75% 30-35 mm hg 500-750 ml/min 750ml/min ```

Fetoplacental flow at term Fetal blood flow at term Rate of O2 delivery to fetus

400ml/min 125ml/kg 8ml/kg/min

Fetoplacental circulation is via

Umbilical artery -deoxygenated blood Fetus to placenta Umbilical vein- oxygenated blood Placenta to fetus

Gametogenesis ➡️ Fetus Flashcards

(73 cards)