Development of reproductive system

Question 1

Explain the formation of gametes within the fetus

Answer 1

Begins within the 6th week, the primordial cells arise from the endoderm of yolk sac and detach to migrate to dorsal mesentry and midgit on posterior abdo wall and then migrate to urogenital ridge
on reaching primordial germ cell epithelium, germ cells embed to make primordial germ cell epithelium and sex cords are formed from both

Question 2

What forms from the mesenchyme beneath the germinal epithelium?

Answer 2

Leydig and theca cells

Question 3

What forms from the germinal epithelium?

Answer 3

Granulosa and sertoli cells

Question 4

What is the property of gametes?

Answer 4

They are haploid

Question 5

How many ova does a woman produce per fertile year?

Answer 5

12-14

Question 6

Does the woman have all the gametes she will ever have at birth?

Answer 6

Yes

Question 7

Does the male have all the gametes she will ever have at birth?

Answer 7

No

Question 8

How many ova does a woman have over her reproductive cycle?

Answer 8

400

Question 9

What are the features that enable reproduction in the woman?

Answer 9

Birth canal
Vagina to recieve penis
Womb

Question 10

What are female secondary sexual characteristics?

Answer 10

Increased breast development
Hair and skin development
Rugae 
Subcutaneous fat 
CNS effects
Decreased body size

Question 11

What are the male secondary sexual characteristics?

Answer 11

Increased body size
Hair and Skin
Deepened voice 
Facial hair 
CNS effects
Development of smell

Question 12

What is the male internal genitalia composed of?

Answer 12

Ducts

• Epididymis
• VD
• Urethra
• Seminal vesicles
• Bulbourethral glands
• Prostate

Question 13

What is the female internal genitalia composed of?

Answer 13

Ovaries 
Fallopian tubes 
Uterus 
Cervix 
Vagina

Question 14

How much sperm will a young man produce a second?

Answer 14

7000

Question 15

When are sperm produced and why?

Answer 15

Continuoulsy after puberty

Always have to be ready to fertilise a female’s ova

Question 16

In which bodily parts are reproductive hormones produced?

Answer 16

Hypothalamus
Pituitary (mostly anterior) but oxytocin is produced in posterior
Gonads
Placenta

Question 17

Where is the SRY gene expressed from?

Answer 17

Sertoli cells

Question 18

What surrounds the germ cells in the female to become the primary follicle?

Answer 18

Mesenchymal cells

Question 19

What internal genitalia does the female develop and how?

Answer 19

Paramesonephric ducts
They fuse together as they grow toward one another
- form the uterus and Fallopian tubes, cervix and upper vagina
due to no MIH

The mesonephric ducts regress due to no testosterone

Question 20

What would develop internally if there were no gonads?

Answer 20

Paramesonephric ducts

Question 21

What cells secrete MIH in the male?

Answer 21

Sertoli

Question 22

What cells secrete Testosterone in the male?

Answer 22

Interstitial cells of Leydig

Question 23

What internal genitalia does the male develop?

Answer 23

Testosterone causes development of the mesonephric ducts and no regression and these form the vd, epididymis, seminal vesicles and rete testes

Question 24

What are the regions of the external genitalia before they differentiate?

Answer 24

Genital tubercle
Genital fold
Genital swelling

Question 25

What causes differentiation of male external genitalia?

Answer 25

Dihydrotestosterone

Question 26

What does each part of the external genitalia develop into in the male?

Answer 26

Genital tubercle - glans penis Genital fold - shaft of penis and spongy urethra Genital swelling - sctorum

Question 27

What does each part of the external genitalia develop into in the female?

Answer 27

Genital tubercle - glans clitoris Genital fold - labia minora Genital swelling - labia majora

Question 28

Explain the descent of the male gonads

Answer 28

``` They start at postero abdo wall Then gubernaculum drags it down Scrotum starts to develop (Attached to gubernaculum) and it is surrounded by processus vaginalis Migrates over pubic bone at 28 weeks Reaches scrotum by 34-40 weeks ```

Question 29

What lies within the inguinal canal in males?

Answer 29

spermatic cord

Question 30

What does the gubernaculum become in the female?

Answer 30

The ovarian ligament and round ligament of uterus

Question 31

What lies within the inguinal canal in females?

Answer 31

Round ligament

Question 32

How long is a female fertile for a month?

Answer 32

36 hours

Question 33

At what stage are female gametes arrested before birth?

Answer 33

Diplotene in prophase I so they're still diploid

Question 34

When does meoisis continue after birth?

Answer 34

Before ovulation

Question 35

What are the 3 stages of gamete maturation?

Answer 35

Pre antral Antral Pre-ovulatory

Question 36

What is the period of preparation?

Answer 36

This is when the female gets ready for fertilisation Body changes Preparation for conceptus Thin, alkaline discharge

Question 37

What is the waiting period?

Answer 37

Body cannot tell if it's pregnant for 2 weeks after fertilisation and until then it assumes that the ova is fertilised

Question 38

What are the phases of the menstrual cycle?

Answer 38

Proliferative/follicular | Luteal

Question 39

Explain the pre-antral ovum

Answer 39

There are layers surrounding the ovum | ZP, cells that become corona radiata after ovulation - granulosa, theca interna, theca externa

Question 40

What is the function of the corona radiata?

Answer 40

This provides the zp with protiens

Question 41

What is the pro nuclei?

Answer 41

This is halving of the DNA so sperm and egg can fuse

Question 42

What is the antral oocyte?

Answer 42

This is when a fluid layer lays within the granulosa cells forms, LH acts upon the theca cells to secrete androgens and FSH acts upon granulosa cells to convert androgens to oestrogens

Question 43

What is the pre-antral oocyte?

Answer 43

``` 37 hours before ovulation LH receptors appear on the granulosa cells LH surge Initiation of meiosis again Pronuclei formed by halving DNA Follicle rupture Picked up by fimbria ```

Question 44

What is the function of the corpus luteum?

Answer 44

To secrete oestrogen and progesterone under influence of LH

Question 45

Explain what happens to the Seminiferous region in puberty?

Answer 45

The seminiferous cords hollow out to become seminiferous tubeules (250-270)

Question 46

Explain the pathway of spermatogenesis

Answer 46

``` Spermatogonia Primary spermatocytes Secondary spermatocytes Spermatids Spermatozoa Sperm ```