ANAT2341 Lab 8 - Fetal - Revision history

Z8600021 at 05:52, 22 September 2016

2016-09-22T05:52:39Z

← Older revision		Revision as of 16:52, 22 September 2016
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	==Renal==		==Renal==
	The following events occur during the fetal period. Note that the nephron loop of ~~hence~~ continues to develop after birth.		The following events occur during the fetal period. Note that the nephron loop of henle continues to develop after birth.
	{\|		{\|
	! Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>		! Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>

Z8600021 at 05:52, 22 September 2016

2016-09-22T05:52:25Z

← Older revision		Revision as of 16:52, 22 September 2016
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	==Renal==		==Renal==
			The following events occur during the fetal period. Note that the nephron loop of hence continues to develop after birth.
	{\|		{\|
	! Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>		! Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>

Z8600021 at 05:50, 22 September 2016

2016-09-22T05:50:38Z

← Older revision		Revision as of 16:50, 22 September 2016
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	{\|		{\|
			! Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>
			\|-
	\| [[File:Nephron development 01.jpg\|600px]]		\| [[File:Nephron development 01.jpg\|600px]]
	~~Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>~~
	\|		\|
	* '''a''' - condensed aggregate forms		* '''a''' - condensed aggregate forms

Z8600021 at 05:50, 22 September 2016

2016-09-22T05:50:07Z

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	\| [[File:Nephron development 01.jpg\|600px]]		\| [[File:Nephron development 01.jpg\|600px]]
	Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>		Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>
			\|
	* '''a''' - condensed aggregate forms		* '''a''' - condensed aggregate forms
	* '''b''' - renal vesicle forms		* '''b''' - renal vesicle forms

Z8600021 at 05:49, 22 September 2016

2016-09-22T05:49:55Z

← Older revision		Revision as of 16:49, 22 September 2016
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	{\|		{\|
	\|
	* disorganised mesenchymal cells become a highly organised epithelial tubule
	* Condensation - groups of about 100 cells condense tightly together to form a distinct mass
	* Epithelialisation - condensed cells lose their mesenchymal character and gain epithelial
	* At end of this period formed a small epithelial cyst complete with a basement membrane, cell-cell junctions and a defined cellular apico-basal polarity.
	\| [[File:Nephron development 01.jpg\|600px]]		\| [[File:Nephron development 01.jpg\|600px]]
	Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>		Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>

Z8600021 at 05:49, 22 September 2016

2016-09-22T05:49:38Z

← Older revision		Revision as of 16:49, 22 September 2016
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	In the previous section we observed late embryonic male genital development and now in fetal development we will observe early fetal female development. Then we will explore fetal development of the external genitalia and gonadal descent.		In the previous section we observed late embryonic male genital development and now in fetal development we will observe early fetal female development. Then we will explore fetal development of the external genitalia and gonadal descent.

			==Renal==

			{\|
			\|
			* disorganised mesenchymal cells become a highly organised epithelial tubule
			* Condensation - groups of about 100 cells condense tightly together to form a distinct mass
			* Epithelialisation - condensed cells lose their mesenchymal character and gain epithelial
			* At end of this period formed a small epithelial cyst complete with a basement membrane, cell-cell junctions and a defined cellular apico-basal polarity.
			\| [[File:Nephron development 01.jpg\|600px]]
			Nephron development<ref name=PMID23338209><pubmed>23338209</pubmed></ref>
			* '''a''' - condensed aggregate forms
			* '''b''' - renal vesicle forms
			* '''c''' - S-shaped body (red), renal progenitors are localised, at this stage podocyte-committed progenitors (red + blue) as well as tubular-committed progenitors (orange) can already be seen.
			* '''d''' - mature nephron, renal progenitors (red), podocyte-committed progenitors (red + blue), as well as tubular-committed progenitors (orange) are distributed along the nephron.
			* '''e''' - glomerulus, renal progenitors (red) are localized at the urinary pole of the Bowman capsule. Podocyte-committed progenitors (red + blue) localize along the Bowman capsule.
			\|}

	==Week 10 Female==		==Week 10 Female==

Z8600021 at 01:01, 24 September 2014

2014-09-24T01:01:15Z

← Older revision		Revision as of 12:01, 24 September 2014
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	===Female External Genitalia===		===Female External Genitalia===
	{\|		{\|
	\| [[File:Female_external_001 icon.jpg\|200px\|link=~~Development_Animation_-_Genital_Female_External~~]]		\| [[File:Female_external_001 icon.jpg\|200px\|link=External_Genital_Female_Development_Movie]]

	\| \| Linked animation showing the development of external female genitalia from the indifferent external structure (week 9 to 12 approximately).		\| \| Linked animation showing the development of external female genitalia from the indifferent external structure (week 9 to 12 approximately).
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	===Male External Genitalia===		===Male External Genitalia===
	{\|		{\|
	\| [[File:Male_external_001 icon.jpg\|200px\|link=~~Development_Animation_-_Genital_Male_External~~]]		\| [[File:Male_external_001 icon.jpg\|200px\|link=External_Genital_Male_Development_Movie]]
	\| Linked animation showing the development of external male genitalia from the indifferent external structure (week 9 to 12 approximately).		\| Linked animation showing the development of external male genitalia from the indifferent external structure (week 9 to 12 approximately).

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	==Testes Descent==		==Testes Descent==
	{\|		{\|
	\| \| [[File:Testis_001 icon.jpg\|200px\|link=~~Development_Animation_-_Testis_Descent~~]]		\| \| [[File:Testis_001 icon.jpg\|200px\|link=Testis_Descent_Movie]]
	\| The linked animation shows the descent of the testes (between week 7 to 38, birth).		\| The linked animation shows the descent of the testes (between week 7 to 38, birth).

Z8600021: /* External Genitalia */

2012-09-18T23:59:06Z

External Genitalia

← Older revision		Revision as of 10:59, 19 September 2012
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	==External Genitalia==		==External Genitalia==
			[[File:Spaulding01.jpg\|thumb\|Genital Tubercle]]
	[[File:Testosterone_metabolism.jpg\|thumb\|Testosterone metabolism]]		[[File:Testosterone_metabolism.jpg\|thumb\|Testosterone metabolism]]
	This next section will look at the development of the external genitalia using a series of animations and online resources.		This next section will look at the development of the external genitalia using a series of animations and online resources.

Z8600021: Created page with "{{ANAT2341Lab8}} ==Introduction== In the previous section we observed late embryonic male genital development and now in fetal development we will observe early fetal female..."

2012-09-14T03:58:54Z

Created page with "{{ANAT2341Lab8}} ==Introduction== In the previous section we observed late embryonic male genital development and now in fetal development we will observe early fetal female..."

New page

{{ANAT2341Lab8}}

==Introduction==

In the previous section we observed late embryonic male genital development and now in fetal development we will observe early fetal female development. Then we will explore fetal development of the external genitalia and gonadal descent.

==Week 10 Female==
{|
| [[File:Human-_fetal_week_10_planes_icon.jpg|left]]
|
* week 10 to 12 - female in absence of Sry expression, within the gonad cortical cords extend from the gonad surface epithelium. Primordial germ cells which have entered the gonad form oogonia primordia, surrounding mesenchyme forms the follicular primordia.
* The selected images below show the general anatomy of the pelvic region of the an early female fetus (10 week, 40mm).
* This first image shows the relative positions of the kidney (plane A most lateral) and developing ovary (plane A and B away from the midline) and internal genitalia (plane C and D in the midline).
* The selected images below show sections through the pelvic region showing anatomical relationships between the developing female gonad (ovary), internal genital tract and external genitalia.
* Note the relative immaturity of the external genitalia, which at this time would appear identical to the male.
|}
{|
| [[File:Fetal 10wk urogenital 1.jpg|400px]]
| [[File:Fetal 10wk urogenital 2.jpg|400px]]
|-
| '''Plane A (midline)'''
|''' Plane B (medial)'''
|-
| [[File:Fetal 10wk urogenital 3.jpg|400px]]
| [[File:Fetal 10wk urogenital 4.jpg|400px]]
|-
| '''Plane C (lateral)'''
| '''Plane D (most lateral)'''
|}

==Uterus and Vagina==

{|
| [[File:Paramesonephric_duct.jpg|300px]]

'''Mouse paramesonephric duct (Müllerian duct)'''<ref><pubmed>12297555</pubmed></ref>
| This mouse image shows the relationship between the mesonephric and paramesonephric ducts opening into the urogenital sinus.
* The paramesonephric duct began as an infold of surface epithelium lying along the surface of the genital ridge.
* Estrogens, both maternal and fetal, stimulate its development and that eventually of the external female fetal genital structures.
* In contrast, the mesonephric duct regresses, remnants of this duct may remain lying within the broad ligament.
|}

{|
| [[File:Uterus_001 icon.jpg|200px|link=Development_Animation_-_Uterus]]
| '''Female Uterus and Vagina (between week 9 and 20)'''

* The initially paired ducts fuse in the midline forming the single body of the '''uterus'''.
* The ducts remain separate laterally where they form the '''uterine tubes''' (Fallopian tubes, uterine horns).
* The ducts peripheral attachment site to the '''urogenital sinus wall''' (yellow) is is described as the Müllerian tubercle.
* The fused ducts also generate the '''vagina''', under the influence of BMP4.
* Estrogen will also later alter the vaginal epithelium.

The uterus and broad ligament will eventulaly divide the pelvic cavity into two separate pouches.
* posteriorly - uterorectal pouch (pouch of Douglas)
* anteriorly - uterovesical pouch
|}

{|
| [[File:Fetal uterus growth.jpg]]

| This graph shows the growth during the fetal period of the uterus between week 19 and 38.<ref><pubmed>10374123</pubmed></ref>
* During this time the uterine circumference increases from 20 mm to just under 60mm and the width increases from less than 10mm to just over 20 mm.
* Uterine horn fimbrial development begins after week 20 and continues after birth.
* Uterine growth continues postnatally, increasing outer muscle thickness and cyclic changes in the lining with puberty.
|}

==External Genitalia==
[[File:Testosterone_metabolism.jpg|thumb|Testosterone metabolism]]
This next section will look at the development of the external genitalia using a series of animations and online resources.

===Female External Genitalia===
{|
| [[File:Female_external_001 icon.jpg|200px|link=Development_Animation_-_Genital_Female_External]]

| | Linked animation showing the development of external female genitalia from the indifferent external structure (week 9 to 12 approximately).

* original cloacal membrane becomes separated into the urogenital membrane and anal membrane
* urogenital folds beneath the genital tubercle remain separate (unfused)
** forming the inner '''labia minora'''
* second outer skin folds form the larger '''labia majora'''
** either side of the developing vestibule of the vagina
* genital tubercle (top of the animation) forms the glans of the '''clitoris'''
|}

===Male External Genitalia===
{|
| [[File:Male_external_001 icon.jpg|200px|link=Development_Animation_-_Genital_Male_External]]
| Linked animation showing the development of external male genitalia from the indifferent external structure (week 9 to 12 approximately).

* original cloacal membrane becomes separated into the urogenital membrane and anal membrane (identical to female).
* urogenital folds beneath the genital tubercle begin to fuse in the midline
* skin folds either side for the '''scrotum'''
** which also has a midline fusion, the raphe
* scrotal sac is initially empty and is an attachment site for the '''gubernaculum'''
* descent of the testes begins generally during week 26 and may take several days.
|}

===External Genitalia Comparison===

==Gonad Descent==
{|
| [[File:Gonad blood 01 icon.jpg|200px|link=Development_Animation_-_Gonad Blood Supply]]
| Linked animation shows the descent of the gonads and their blood supply.
* both male and female gonads undergo this relative descent within the peritoneal cavity
** this descent carries the gonads away from the kidneys which are ascending
* during the fetal period, male testes will continue to descend out of the peritoneal cavity
|}
Internal Gonad Descent

==Testes Descent==
{|
| | [[File:Testis_001 icon.jpg|200px|link=Development_Animation_-_Testis_Descent]]
| The linked animation shows the descent of the testes (between week 7 to 38, birth).

Descent of the testes into the scrotal sac begins generally during week 26 and may take several days.
* testis (white) lies in the subserous fascia (spotted)
* a cavity processus vaginalis evaginates into the scrotum
* gubernaculum (green) attached to the testis shortens drawing it into the scotal sac
* as it descends it passes through the inguinal canal extends
** from the deep ring (transversalis fascia)
** to the superficial ring (external oblique muscle)

Incomplete or failed descent can occur unilaterally or bilaterally, is more common in premature births, and can be completed postnatally. (see also cryptorchidism).

|}

{|
| [[File:Testis-descent start.jpg|350px]]
| [[File:Testis-descent end.jpg|350px]]
|-
| Start of testis descent
| End of testis descent
|}

==Additional Information==

===Testes Descent Timeline===

Data from a study of male human fetal (between 10 and 35 weeks) gonad position.<ref><pubmed>9649288</pubmed></ref>
* '''10 to 23 weeks''' - (9.45%) had migrated from the abdomen and were situated in the inguinal canal
* '''24 to 26 weeks''' - (57.9%) had migrated from the abdomen
* '''27 to 29 weeks''' - (16.7%) had not descended to the scrotum

A second study looked at the position of the testes<ref><pubmed>10510117</pubmed></ref>
* 33 weeks fetal testes had descended to the scrotum
* between 33 to 40 weeks (term) both testes have normally descended to the scrotum

Failure of descent (cryptorchidism) either unilateral or bilateral testicular descent, occurring in up to 30% premature and 3-4% term males.

Cryptorchidism in common eutherian mammals.<ref><pubmed>17379650</pubmed></ref>- [http://www.reproduction-online.org/content/133/3/541/F8.large.jpg Species comparison of descent timeline]

==Historic Genital Images==

<gallery>
File:Gray1108.jpg|Broad ligament of adult showing Epoöphoron
File:Gray1109.jpg|Urogenital Sinus of Female Human Embryo of 8.5 to 9 weeks old
File:Gray1111.jpg|Transverse section of Human Embryo 8.5 to 9 Weeks Old
File:Gray1112.jpg|Longitudinal Section of Ovary of Cat Embryo of 9.4 cm long
File:Gray1113.jpg|Section of the Ovary of a Newly Born Child
File:Gray1114.jpg|Human Embryo (3.5 cm long) Testis Section of a Genital Cord
File:Gray1115.jpg|Tail end of Human Embryo 25 to 29 Days Old
File:Gray1116.jpg|
File:Gray1117.jpg|Tail end of human embryo eight and a half to nine weeks old
File:Gray1118.jpg|Primitive Kidney and Bladder
File:Gray1119.jpg|Stages in the development of the external sexual organs in the male and female
File:Gray1126.png|Retroperitoneal structures
</gallery>

==References==

<references/>

{{ANAT2341Lab8}}

{{Glossary}}

{{Footer}}