2014 Group Project 4

From Embryology
2014 Student Projects
2014 Student Projects: Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | Group 6 | Group 7 | Group 8
The Group assessment for 2014 will be an online project on Fetal Development of a specific System.

This page is an undergraduate science embryology student and may contain inaccuracies in either description or acknowledgements.

Genital

--Mark Hill (talk) 15:13, 26 August 2014 (EST) No sub-headings yet and I even had to add your project title! Get moving.

--Mark Hill (talk) 11:53, 6 September 2014 (EST) Just references not much else here yet.

System Development

Weeks M A L E F E M A L E
FERTILIZATION both male and female are same at this point- only difference is presence of XY or XX chromosome
WEEKS 1-7 GENITAL DEVELOPMENT IS UNDIFFERENTIATED. gonads derived from:
* mesothelium lining posterior abdominal wall
* underlying mesenchyme
* primordial germ cells.
WEEK 5 development of indifferent gonads
  • thickened area of mesothelium develops on medial side of mesonephros [primitive kidney]
  • this + proliferation of underlying mesenchyme = gonadal ridge
  • fingerlike epithelial chords = gonadal chords
  • gonad = cortex + medulla
WEEK 8 seminiferous tubules begin to release androgens
WEEK 10 rudimental rete ovarii forms from indifferent gonads
WEEK 12
  • testosterone determining factor induces seminiferous chords from indifferent gonads --> branch to rete testis
  • tunica albiguinea develops
WEEK 16 primordial follicles begin to develop

Genital system development is an extremely interesting area of embryology as it is not until the later stages of embryogenesis (around week 4-6) that sexual differentiation occurs in the fetus, and the sexual organs actually look very similar up until this point, and the formation of the correct sex organs depend really on whether the genital ridge releases Testosterone or oestrogen

<pubmed>24240231</pubmed> <pubmed>24928207</pubmed> <pubmed>24741072</pubmed> --Z3416697 (talk) 20:06, 26 August 2014 (EST)

Current Research Models and Findings

--Z3417753 (talk) 22:43, 26 August 2014 (EST)

<pubmed>18367374</pubmed> <pubmed>15086026</pubmed> <pubmed>14641326</pubmed> <pubmed>11684660</pubmed> <pubmed>22127979</pubmed>

Historic Finding

Female Genital Development

The mullerian (paramesonephric) ducts, found laterally to the wolffian ducts, are the original structures of the female reproductive system. Female sexual organs (the fallopian tubes, uterus and vagina) originate from the mullerian ducts, which differentiates within the foetal developmental phase. Initially the foetus contains two mullerian ducts, however by the ninth week, fusion of the lower portion of the ducts is complete, creating the fundamental structure of the uterus and the vagina, however the these two organs are not continuous with the vagina being solid. The non-fused upper part of the ducts emerge into the fallopian tubes. It is not until the fourth and fifth month of development that the uterus becomes continuous with the vagina, with both organs developing a hollow lumen. The muscular layers of the uterus is also present by this stage. The cervix begins to form within the fifth month in between the continuous vagina and uterus. Also within the same month, the formation of the hymen occurs. The hymen is described as a pouting vertical slit and represents the remains of the mullerian eminence. [1] [2]

References

  1. <pubmed>17232227</pubmed>
  2. <pubmed>13230915</pubmed>

Male Genital Development

--Z3415716 (talk) 01:10, 27 August 2014 (EST)

<pubmed>18462432</pubmed> <pubmed>17232227</pubmed> Martyn P. L. Williams, John M. Huston The history of ideas about testicular descent. Pediatric Surgery International: 1991, 6(3):180-184 The history of ideas about testicular descent

Abnormalities

Female

Male

Cryptorchidism

Hypospadias

In males the most common congenital malformation of the external genitalia is hypospadias, it’s also the second most common developmental disorder. It occurs due to the midline fusion of the male urethra, as a result the urethral meatus is misplaced. There are several sites where this abnormality may occur: granular, penile, penoscrotal, scrotal and perineal. [1] Its believed that genetic factors contribute to the presence of the disorder, however endocrine and environmental factors are also of significance. [2] Treatment The surgical methods currently used to treat distal hypospadias, include tabularized incised plate and meatal advancement and glansplasty intergrated repair. For proximal forms two staged procedures are employed. [3]

References

  1. <pubmed>16006950</pubmed>
  2. <pubmed>24936573</pubmed>
  3. <pubmed>25023236</pubmed>

--Z3417458 (talk) 21:01, 26 August 2014 (EST)

<<pubmed>24290348</pubmed>>

<<pubmed>25064170</pubmed>>

<<pubmed>23168057</pubmed>>

A review on spermatogenesis and cyptorchidism a common in males, results in an absence of testes either one or both.

<<pubmed>24829558</pubmed>>


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