Gonadogenesis

Question 1

shortly after Gastrulation, the presumptive sperm or eggs are called:

1. Primitive Germ Layer
2. Presumptive Germ Line
3. Primordial Germ Cells

Answer 1

3.

Question 2

The week future Germ line can be identified:

1. After 3 weeks near the mesoderm of the yolk sac
2. After 4 weeks near the primitive streak
3. After 5 weeks near the allantois

Answer 2

1

Question 3

What are the Special Features associate with the Germ Line?

Answer 3

Germ line characterized by:

1. Lengthy migration to the gonadal ridge
2. Erasure of epigenetic information from the previous generation
3. Reactivation of the X chromosome (inactive X - Barr body)

Question 4

During PGCs Migration to the genital ridge……………..

Answer 4

1. Appearance in the genital ridge about 8-9 weeks
2. Proliferation by mitosis
3. Chemotactic Secretion by the genital ridge

Question 5

True or false, After population of the genital ridges:

a. Orientation of germinal epithelium into columnar structures called primitive sex chords
b. The SRX gene on the X chromosome is required for female differentiation
c. Expression of the SRY gene on the Y chromosome regulates key gender morphological changes
d. SRY up-regulation promotes the development of the Wolffian Duct
e. SRY up-regulation promotes the development of the Mullerian Duct
f. SRY up-regulation promotes the expression of SOX9 transcription factor
g. SOX9 is required for the activation of AMH/MIS
h. AMH/MIS causes regression of the Mullerian Duct
i. WNT4 (Wills Tumor gene) inhibits mesonephric endothelial migration

Answer 5

After population of the genital ridges:

a. Orientation of germinal epithelium into columnar structures called primitive sex chords (true)
b. SRX gene on the X chromosome is required for female differentiation (false)
c. Expression of the SRY gene on the Y chromosome regulates key gender morphological changes (true)
d. SRY up-regulation promotes the development of the Wolffian Duct (true)

e. SRY up-regulation promotes the development of the Mullerian Duct (false)

f. SRY up-regulation promotes the expression of SOX9 transcription factor(true)
g. SOX9 is required for the activation of AMH/MIS (true)
h. AMH/MIS causes regression of the Mullerian Duct(true)
i. WNT4 (Wills Tumor gene) inhibits mesonephric endothelial migration (true)

Question 6

The default gender is female

Answer 6

true

Question 7

SDF-1 is the main chemotactic substance secreted by the genital ridges

1. Yes
2. No

Answer 7

1.

Question 8

The main aim of SDF-1 is to provide a target location for migrating primordial germ cells

1. Yes
2. No

Answer 8

1.

Question 9

in males, the PGCs (primordial germ cells) and Coelomic Epithelium developed faster and deeper into medullary mesenchyme to form the Testis Cords.

1. Yes
2. No

Answer 9

1.

Question 10

In females, the PGC (primordial germ cells) and Coelomic Epithelium developed slower and less deeply and form small clusters to become the primordial follicles located more towards the ovarian cortex.

1. Yes
2. No

Answer 10

1.

Question 11

SRY Initiates Differentiation of Sertoli Cells

1. Yes
2. No

Answer 11

1

Question 12

Sertoli Cells are the source of Fibroblast Growth Factor 9 (FGF-9)

1. Yes
2. No

Answer 12

1

Question 13

FGF-9 induces the formation of the Testicular Cords (Pre-Seminiferous Tubules) at week ……….?

Answer 13

FGF-9 induces the formation of the Testicular Cords (Pre-Seminiferous Tubules) at weeks 7-8

Question 14

1. Sertoli cells form clusters around the germ cells
2. Peritubular myoid cells surround the clusters and create the basal laminar
3. The Sertoli cells produce AMH/MIS to suppress Mullerian duct development
4. The wolffian duct is the default development option
5. The Leydig cells develop in the interstitial regions between the clusters
6. The blood and lymphatic systems develop inside the clusters
7. The Leydig cells start to produce testosterone

Answer 14

1. Sertoli cells form clusters around the germ cells (True)
2. Peritubular myoid cells surround the clusters and create the basal laminar (True)
3. The Sertoli cells produce AMH/MIS to suppress Mullerian duct development (True)
4. The wolffian duct is the default development option (Fales)
5. The Leydig cells develop in the interstitial regions between the clusters (True)
6. The blood and lymphatic systems develop inside the clusters(Fales)
7. The Leydig cells start to produce testosterone(True)

Question 15

the Leydig cells start to produce Testosterone from:

1. weeks 4-5
2. weeks 6-7
3. weeks 8-10
4. weeks 11-14

Answer 15

3.

Question 16

production of Testosterone from the embryonic testis results in……………….?

Answer 16

production of Testosterone from the embryonic testis results in:

1. establishment of the male phenotype
2. Growth and differentiation of the Wolffian duct structures
3. metabolism to dihydrotestosterone
4. virilization (characteristics of male) of the urogenital sinus and external genitalia by Dihydrotestosterone

Question 17

The basic format of the testis is laid down by

1. week 8-12
2. week 13-15
3. week 16-20
4. week 21-25

Answer 17

3.

Question 18

when complete, which of the following are true:

1. Sertoli cells lie on the basal membrane within the seminiferous tubules
2. Prospermatogonial cells lie on the basal membrane within the seminiferous tubules
3. Prospermatogonial cells start to undergo spermatocytogenesis
4. The seminiferous tubules lie within a highly vascular stroma
5. The vascular stroma contain the leydig cells
6. All the tubules lie within a fibrous capsule, the tunicia albungine
7. Development of the testicular size continues slowly until puberty

Answer 18

all true except (3)

1. Sertoli cells lie on the basal membrane within the seminiferous tubules
2. Prospermatogonial cells lie on the basal membrane within the seminiferous tubules
3. Prospermatogonial cells start to undergo spermatocytogenesis (false)
4. The seminiferous tubules lie within a highly vascular stroma
5. The vascular stroma contain the leydig cells
6. All the tubules lie within a fibrous capsule, the tunicia albungine
7. Development of the testicular size continues slowly until puberty

Question 19

Main testicular events at Puberty………………….

Answer 19

Main testicular events at Puberty.

• the cords canalise an develop into tubules that connect to form the rete testis
• The ducts connect to the vasa efferentia and the epididymis
• Leydig cells increase their endocrine secretions
• The prospermatogonial cells develop into the spermatogeneic epithelium lining
• The prospermatogonial cells commence mitosis

Question 20

Testicular descent is controlled by hormones secreted by :

a. Leydig cells
b. Sertoli cells
c. primordial germ celss
d. genital chord

Answer 20

1.

Question 21

Descent is controlled by two ligaments: the suspensory and the gubernaculum. what happens during descent:

1. Both the suspensory and the gubernaculum elongate
2. The suspensory elongates and the gubernaculum does not
3. The gubernaculum elongates and the suspensory does not

Answer 21

2.

Question 22

Regarding the timetable for descent, which is true

1. The testes have migrated over the pubic bone by weeks 22-26
2. The testes have migrated over the pubic bone by weeks 24-26
3. The testes have migrated over the pubic bone by weeks 25-28
4. The testes have migrated over the pubic bone by weeks 25-32
5. The testes have migrated into the scrotum by weeks 35-40
6. The testes have migrated into the scrotum by weeks 35-38
7. The testes have migrated into the scrotum by weeks 32-36

Answer 22

3 and 5

Timetable for descent

• The testes have migrated over the pubic bone by weeks 25-28
• Migration into the scrotum by weeks 35-40

Question 23

The temperature difference between the testes and body temperature is approximately

1. 0.5ºC
2. 1ºC
3. 1.5ºC
4. 2ºC

Answer 23

4.

Question 24

the total length of seminiferous tubules in an adult testis is approximately:

1. 200m
2. 300m
3. 400m
4. 500m
5. 1000km

Answer 24

1.

Question 25

Morphology and properties of the **Seminiferous tubules\>\>\>\>\>**

Answer 25

Regarding the morphology of the **Seminiferous tubules**: \* The tubules are lined with a spermatogenic epithelium \* 4-5 generations of germs exist in the tubules \* The least differentiated are found in the periphery \* The most differentiated are found in the lumen \* Development is wavelike in cross section & in along the tubule

Question 26

Development from spermatogonia to spermatozoon takes approximately 1. 50 days 2. 55 days 3. 60 days 4. 65 days

Answer 26

4.

Question 27

The tubules lie on a delicate a nuclear basement membrane that lies on layer of connective tissue called the 1. tunica basali 2. tunica tubularis 3. tunica propria

Answer 27

3.

Question 28

Sertoli cells extend from the periphery to the lumen 1. Yes 2. No

Answer 28

1.

Question 29

The **Sertoli** cells are thought to nourish the germ cells via 1. gap junctions 2. passive diffusion 3. exocytosis 4. gap junctions and passive diffusion 5. gap junctions and exocytosis

Answer 29

1.

Question 30

Mature spermatozoa traverse the epididymis over a period of 1. 2-12 days 2. 2-14 days 3. 2-16 days 4. 2-18 days 5. 2-20 days

Answer 30

2.

Question 31

**Cryptorchidism**

Answer 31

**Undescended Testes**

Question 32

**hypoplastic**

Answer 32

**Underdeveloped Testes**

Question 33

one or both testicles are absent or underdeveloped. ## Footnote **Anorchia**

Answer 33

**Vanished Testes** ## Footnote Vanishing testis syndrome or Testicular regression syndrome (TRS) is defined as the absence **or** an incomplete development of the testis

Question 34

one absent or undeveloped tisticle. ## Footnote **Monorchism**

Answer 34

**A Single Testes**

Question 35

**the testes normally enter the scrotom via the**

Answer 35

**inguinal canal** the testes normally enter the scrotom via the inguinal canal at 30-34 weeks of pregnancy

Question 36

**The incidence at birth for undescended testes is**

Answer 36

5%

Question 37

**Retractile testes**

Answer 37

The term to describe the event if the cremasteric muscle attached to the testis pulls the testis up into the **groin** so that it cannot be felt or seen

Question 38

**Acquired undescended testes**

Answer 38

when a boy is born with his testes in the scrotum, they can occasionally move back out of the scrotum and into the **groin**

Question 39

Undescended testes are usually identified in the age group.....

Answer 39

18-39 years

Question 40

Regarding the risk of cancer: 1. Men with undescended tests have a higher risk of cancer 2. Men with undescended tests have a higher risk of cancer even after intervention 3. When one testes has not descended, the contralateral normal tests also has an elevated cancer risk

Answer 40

all true

Question 41

**A Hernia** almost always happens with an undescended testis

Answer 41

true

Question 42

The name of the operation to lower Undescended Testes is

Answer 42

**orchidopexy** **this operation performed in adults mainly to prevent cancer development by undescended testes NOT for Fertility results.** **so** the best time for Orchidpexy is **\>6 months**

Question 43

FGF-9 induces the formation of the testicular cords (pre-seminiferous tubules) about: a. weeks 5-6 b. weeks 7-8 c. weeks 9-10

Answer 43

c.)

Question 44

*derived from the surface celomic epithelium of the gonadal ridge: ## Footnote **surface celomic epithelium of the gonadal ridge?**

Answer 44

- sustentacular cells of Sertoli - follicular cells of the ovary - interstitial cells of Leydig - cells of kidney - cells of adrenal cortex

Question 45

Sertoli cells are the source of Fibroblast Growth Factor 9 (FGF-9). a. Yes b. No

Answer 45

a)

Question 46

The Leydig cells start to produce testosterone from: a. weeks 6-7 b. weeks 8-10 c. weeks 11-14 d. weeks 4-5

Answer 46

b)

Question 47

The **tubules** lie on► a delicate a nuclear **basement membrane** that lies on► layer of **connective tissue** called the: a. tunica basalis b. tunica propria c. tunica tubularis

Answer 47

b)

Question 48

Answer 48

Question 49

Regarding the timetable for the testicular descent the major events by weeks

Answer 49

Testes migrated over the **pubic bone** by weeks ***25-28*** ⇒ migrated into the scrotum by weeks ***35-40***

Question 50

7 *_FACTS_* ►**After population of the genital ridges:**

Answer 50

1. expression of the **SRY** gene on the Y chromosome regulates key gender morphological changes 2. **SOX9** is required for the activation of AMH/MIS 3. SRY up-regulation promotes the expression of **SOX9** transcription factor 4. AMH/MIS causes regression of the **Mullerian Duct** 5. **WNT4** (Wills Tumor gene) inhibits mesonephric endothelial migration 6. SRY up-regulation promotes the development of the **Wolffian Duct** 7. orientation of germinal epithelium into columnar structures called **primitive sex chords**

Question 51

Which of the following are derived from the surface celomic epithelium of the gonadal ridge? a. interstitial cells of Leydig b. epithelial lining of the ductus deferens c. oogonia d. follicular cells of the ovary e. spermatogonia

Answer 51

d) ## Footnote follicular cells of the ovary ►derived from the surface of celomic epithelium of the gonadal ridge بينما sustentacular (supporting) cells of Sertoli derived from the ►celomic epithelial cells that formed the primitive sex cords بصفه عامه all listed derived from the surface celomic epithelium of the gonadal ridge - sustentacular cells of Sertoli - follicular cells of the ovary - interstitial cells of Leydig - cells of kidney - cells of adrenal cortex

Question 52

SDF-1 is ..........

Answer 52

SDF-1 is the main **chemotactic** substance secreted by the genital ridges.

Question 53

Leydig cells start to produce testosterone from: a. weeks 6-7 b. weeks 8-10 c. weeks 11-14 d. weeks 4-5

Answer 53

b) review the included timetable diagram

Question 54

DEFECT of spermatocytogenesis may be caused by: Mutation of **SYCP 3** gene, ............ * *AURKC** gene............ * *SPATA16** gene...........

Answer 54

* Point mutation of the ***S*YC*P* 3** gene, chromosome 12 ♦► - arresting meiosis. * Mutations of the gen ***SP*ATA16**, chromosome 3 – globozoospermia. * Mutations of the gen ***A*URKC**, chromosome 19 - large, Abnormal heads.

Question 55

It is know, that there are at least 1,000 “spermatogenesis genes” on Y chromosome and autosomes and X chromosome. Is there anything false? * - chromosomal anomalies and microdeletions of regions of the azoospermia factor (AZF) of the Y chromosome -⇒ azoospermia * - Y chromosome microdeletions - idiopathic azoospermia and severe oligozoospermia * - SPATA 16 mutation, chromosome 3– ⇒ globozoospermia * - AURKC mutation, 19th chromosome – large, ⇒Abnormal heads * - USP9Y mutation (Yq11.2) – azoospermia by ⇒hypospermatogenesis * - RBMY mutations (Yq11.223) – azoospermia by arresting meiosis * - SYCP 3 mutation, 12th chromosome – azoospermia by ⇒arresting meiosis * - DAZ mutations (Yq11.23) - various forms of infertility, ranging from ⇒oligozoospermia to azoospermia * - androgen receptor gene mutations (AR, X-linked, defect in the AR gene (Xq11-12)) – androgen insensitivity syndrome and ⇒spermatogenesis damage * - CF mutations on the long arm of chromosome 7th at locus 7q31.2 – CFTR ⇒ OA

Answer 55

ALL TRUE IN GENERAL Spermatogenesis can disrupt by: chromosomal abnormalities and microdeletions of azoospermia factor (AZF) regions of the Y chromosome androgen receptor gene mutations (X-linked) mutations on the long arm of chromosome 7 at locus 7q31.2 (CFTR)