Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Yr 2 - Reproductive System > Embryology - Gonads > Flashcards

Embryology - Gonads Flashcards

1
Q

When is genetic sex determined?

A

By sperm at fertilisation (oocyte is always X, sperm can be X or Y)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is SRY? How does this determine the sex of the baby?

A

SRY is the sex-determining region of the Y chromosome that determines the sex

SRY gene (only present in Y chromosome) initiates production of Testis-Determining Factor (TDF)

No Y chromosome –> no TDF –> female development develops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is TDF?

A

A protein made by SRY

Kicks off cascade that makes testes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What structure does the reproductive system develop from?

A

Intermediate mesoderm

Intermediate mesoderm –> urogenital ridge –> urinary system & reproductive system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the first stage of gonadal development?

A

Indifferent stage (impossible to distinguish between male and female gonads)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do the gonads initially develop?

A

Epithelium covering the urogenital ridge proliferates and thickens. Epithelium starts to penetrate the underlying mesenchyme to form the primitive sex cords

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When the gonads begin as genital ridges, do they contain any germ cells?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do germ cells reach the genital ridges?

A

In the fourth week, primordial germ cells begin to migrate from the endoderm lining of the yolk sac to the genital ridges, via the dorsal mesentery of the hindgut (is the dorsal mesentery that attaches the developing gut tube to the posterior wall). They reach the genital ridges in the sixth week.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is this migration of germ cells happening simultaneously with?

A

Proliferation and penetration of epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the primitive sex cords?

A

Proliferations of epithelium into the mesenchyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What weeks is the indifferent stage?

A

Weeks 5-6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 2 regions of the indifferent gonads?

A
  1. Outer cortex

2. Inner medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the outer cortex of the indifferent gonad?

A

Outer region with developing epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the inner medulla of the indifferent gonad?

A

Inner region where epithelium projects into (primitive sex cords project into the medulla)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the fate of the medullary and cortical regions dependent on?

A

TDF production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

If TDF is present, which area is developed?

A

Medulla region (forms testes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

If TDF is not present, which area is developed?

A

Cortical regions (forms ovaries)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What cells are found in the primitive sex cords?

A

Somatic support cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In males, what forms around the testis (medullary) cords?

A

The tunica albuginea, a fibrous connective tissue layer, forms around the cords.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens to the cortical cords in females/males?

A

Develops/regresses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens to the medullary cords in females/males?

A

Regresses/develops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens to the tunica albuginea in females/males?

A

No development/develops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What happens to the primitive sex cords in females?

A

No SRY/TDF present so primitive sex cords degenerate and do not form the testis cords.

Instead, the epithelium of the gonad continues to proliferate, producing cortical cords.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is job of somatic support cells?

A

Primitive sex cords (specifically the somatic support cells) invest primordial germ cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the rete testis?

A

Medullary cords continue to develop and eventually begin to break up as you get further into medulla –> called rete testis.

Found at hilum of gonad.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

During puberty, what happens to testis cords?

A

These cords acquire a lumen (canalisation) and become the seminiferous tubules – the site within which sperm will be formed.

Rete testis join up with the seminiferous tubules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the tunica albuginea?

A

Connective tissue that develops around the testes

28
Q

What is located behind the testis cords?

A

The Leydig cells (derived from the intermediate mesoderm).

29
Q

What is job of Leydig cells in foetus?

A

In the eighth week, they begin production of testosterone – which drives differentiation of the internal and external genitalia.

30
Q

In females, after the primitive sex cords/medullary cords have regressed, what develops?

A

Surface epithelium continues to proliferate and produces 2nd generation of cords –> cortical cords

31
Q

What then happens to these cortical cords? What does this form?

A

Cortical cords invest primordial germ cells and the somatic support cells comprising the cortical cords are then signalled to differentiate –> forms follicle cells

Follicle cells surround primordial germ cells

Primordial germ cells themselves differentiate to form oocyte

Oocyte surrounded by follicle cells –> primordial follicle

32
Q

What week do the gonads become distinguishable?

A

At 7 weeks

33
Q

What area of the body are the gonads developed?

A

Posterior abdominal wall in upper lumbar region

34
Q

How are the gonads tethered to the scrotum/labia?

A

By the gubernaculum

35
Q

What is the gubernaculum?

A

A ligamentous structure formed from mesenchyme.

36
Q

What is the adult remnant of the gubernaculum in males?

A

The scrotal ligament

37
Q

How do the testes descend?

A

Gubernaculum shortens and pulls testes towards the anterior abdominal wall.

Testes arrive at deep inguinal ring where it stays from 3rd to 7th month.

At 7 months, gubernaculum begins shortening again and pulls testes through inguinal canal to reach scrotum.

38
Q

What is descent of testes through inguinal canal aided by?

A

By pressure from growing abdominal organs

39
Q

When do testes reach scrotum?

A

By 9th month, just before birth

40
Q

What is the processus vaginalis?

A

A projection of peritoneum that forms the pathway of descent for the testes during embryonic development.

41
Q

What happens to the processes vaginalis after birth?

A

Within the 1st year, it obliterates leaving a remnant around the testes –> tunica vaginalis

42
Q

What happens if tunica vaginalis fails to fuse?

A

Abdominal contents can follow testes through processus vaginalis –> hernia

43
Q

What is the remnant of the processus vaginalis in males?

A

Tunica vaginalis

44
Q

How do the ovaries descend?

A

Migrate caudally in a similar fashion to the testes from their origin on the posterior abdominal wall. However they do not travel as far, reaching their final position just within the true pelvis.

45
Q

What is the remnant of the gubernaculum in females?

A

The ovarian ligament and round ligament of the uterus.

46
Q

Where is the deep ring of the inguinal canal located?

A

Entrance of inguinal canal located in transversalis fascia

47
Q

Where is the superficial inguinal ring located?

A

Exit of inguinal canal located in external oblique

48
Q

What are the testes accompanied by during their descent?

A

A part of the peritoneal lining (fascia) of the abdominal cavity –> processus vaginalis

49
Q

How is the inguinal canal formed?

A

Formed by the processus vaginalis that as the name suggest is an invagination of the parietal peritoneum

50
Q

What coverings from the abdominal wall do the testes acquire?

A
  1. Internal spermatic fascia (inner)
  2. Cremasteric fascia (middle)
  3. External spermatic fascia (outer)
51
Q

What is the internal spermatic fascia formed from?

A

Transversalis fascia

52
Q

What is the cremasteric fascia formed from?

A

From internal oblique muscle

53
Q

What is the external spermatic fascia formed from?

A

From external oblique muscle

54
Q

What happens if parts of processes vaginalis fail to fuse? What is this called?

A

Causes small fluid filled cysts –> hydrocele

55
Q

If the processus vaginalis remains open completely to the abdominal cavity, what can happen?

A

Intestines may protrude through the inguinal canal –> indirect inguinal hernia

56
Q

How can you distinguish a hydrocele from a tumour/hernia?

A

Hydrocele is formed by clear fluid therefore light passes through easily –> transillumination.

Solid tissue (e.g. tumour or hernia) would block light.

57
Q

Are hydroceles dangerous?

A

Benign but larger hydroceles may cause discomfort.

Can be removed surgically.

58
Q

What is cryptorchidism?

A

One or both of the testes fail to descend from the abdomen into the scrotum.

59
Q

How is cryptorchidism corrected?

A

Most spontaneously correct by 3 months of age.

Those that remain undescended are corrected surgically at 4-6 months.

60
Q

What is cryptorchidism associated with?

A

An increased risk of testicular cancer and infertility.

61
Q

Where do the ovaries descend to?

A

The pelvic brim

62
Q

What does the gubernaculum attach to in females?

A

Passes through inguinal ring and attaches onto labia majora

63
Q

Where does the round ligament of the uterus attach from/to?

A

From uterus to labia majora, passing through inguinal canal

64
Q

Where does the ovarian ligament proper attach from/to?

A

From the uterus to the inferior side of the ovary

65
Q

Describe the basic development pathway of male gonads

A
  1. Surface epithelium of genital ridge
  2. Medullary cords (somatic support cells)
  3. Sertoli cells
  4. Primordial germ cells invested –> testes cords
  5. Seminiferous tubules
66
Q

Describe the basic development pathway of female gonads

A
  1. Surface epithelium of genital ridge
  2. Medullary cords regress
  3. Cortical cords develop (somatic support cells)
  4. Follicle cells
  5. Primordial germ cells invested –> primordial follicles (1ary oocyte)

Yr 2 - Reproductive System (30 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions