2011 Lab 5 - Early Embryo - Revision history

Z8600021: /* Pseudoglandular Stage */

2012-06-03T22:31:06Z

Pseudoglandular Stage

← Older revision		Revision as of 09:31, 4 Haziran 2012
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	[[File:~~Stage14~~-~~22_lungs~~.jpg]]		[[File:Lung_development_stage13-22.jpg]]

	{{2011Lab5Footer}}		{{2011Lab5Footer}}

S8600021: /* Respiratory Development */

2011-08-25T00:59:31Z

Respiratory Development

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 == Respiratory Development==
 '''Historic drawings of embryonic lung development'''
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 | Human embryo (CRL 10.5 mm)
 |}
 ===Pseudoglandular Stage===

S8600021: /* Respiratory Development */

2011-08-25T00:58:26Z

Respiratory Development

← Older revision		Revision as of 11:58, 25 August 2011
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	\| [[File:Bailey287.jpg\|300px]]		\| [[File:Bailey287.jpg\|300px]]
	\| [[File:Bailey288.jpg\|300px]]		\| [[File:Bailey288.jpg\|300px]]
			\| [[File:Bailey289.jpg\|300px]]
	\|-		\|-
	\| ~~Lungs of a human~~ embryo (CRL 4.3 mm)		\| Human embryo (CRL 4.3 mm)
	\| ~~Lungs of a human~~ embryo (CRL 8.5 mm)		\| Human embryo (CRL 8.5 mm)
			\| Human embryo (CRL 10.5 mm)
	\|}		\|}

S8600021: /* Respiratory Development */

2011-08-25T00:56:38Z

Respiratory Development

← Older revision		Revision as of 11:56, 25 August 2011
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	'''Week 7''' - enlargement of liver stops descent of heart and lungs.		'''Week 7''' - enlargement of liver stops descent of heart and lungs.

			'''Historic drawings of embryonic lung development'''

			{\|
			\| [[File:Bailey287.jpg\|300px]]
			\| [[File:Bailey288.jpg\|300px]]
			\|-
			\| Lungs of a human embryo (CRL 4.3 mm)
			\| Lungs of a human embryo (CRL 8.5 mm)
			\|}

	===Pseudoglandular Stage===		===Pseudoglandular Stage===

S8600021: /* Respiratory Development */

2011-08-24T03:54:42Z

Respiratory Development

← Older revision		Revision as of 14:54, 24 August 2011
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	'''Week 7''' - enlargement of liver stops descent of heart and lungs.		'''Week 7''' - enlargement of liver stops descent of heart and lungs.

			===Pseudoglandular Stage===
			* week 5 - 17
			* tubular branching of the human lung airways continues
			* by 2 months all segmental bronchi are present.
			* lungs have appearance of a glandlike structure.
			* stage is critical for the formation of all conducting airways.
			* lined with tall columnar epithelium, the more distal structures are lined with cuboidal epithelium.

S8600021: /* Respiratory Development */

2011-08-24T03:53:51Z

Respiratory Development

← Older revision		Revision as of 14:53, 24 August 2011
Line 248:		Line 248:

	'''Week 7''' - enlargement of liver stops descent of heart and lungs.		'''Week 7''' - enlargement of liver stops descent of heart and lungs.


			[[File:Stage14-22_lungs.jpg]]

	{{2011Lab5Footer}}		{{2011Lab5Footer}}

S8600021: /* Respiratory Development */

2011-08-24T03:53:01Z

Respiratory Development

← Older revision		Revision as of 14:53, 24 August 2011
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	== Respiratory Development==		== Respiratory Development==
			[[File:Stage14_respiratory_tract.jpg\|thumb\|300px\|Respiratory system overview ([[Carnegie_stage_13\|stage 13]])]]
	'''Week 4''' - laryngotracheal groove forms on floor foregut.		'''Week 4''' - laryngotracheal groove forms on floor foregut.

S8600021: /* Lesser Sac Development */

2011-08-24T03:52:24Z

Lesser Sac Development

← Older revision		Revision as of 14:52, 24 August 2011
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			{{Template:GIT cartoons}}

			== Respiratory Development==

	~~{{Template:GIT cartoons}}~~		'''Week 4''' - laryngotracheal groove forms on floor foregut.

			'''Week 5''' - left and right lung buds push into the pericardioperitoneal canals (primordia of pleural cavity)

			'''Week 6''' - descent of heart and lungs into thorax. Pleuroperitoneal foramen closes.

			'''Week 7''' - enlargement of liver stops descent of heart and lungs.

	{{2011Lab5Footer}}		{{2011Lab5Footer}}

S8600021: /* Lesser Sac Development */

2011-08-24T03:26:03Z

Lesser Sac Development

← Older revision		Revision as of 14:26, 24 August 2011
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	{{Template:GIT cartoons}}		{{Template:GIT cartoons}}

			{{2011Lab5Footer}}

S8600021: Created page with "{{2011Lab5}} We have now reached the end of Week 4 and beginning of 5 of development. Start by looking briefly at the overview of the Carnegie stage 13 embryo GIT from one end t..."

2011-08-24T03:16:08Z

Created page with "{{2011Lab5}} We have now reached the end of Week 4 and beginning of 5 of development. Start by looking briefly at the overview of the Carnegie stage 13 embryo GIT from one end t..."

New page

{{2011Lab5}}

We have now reached the end of Week 4 and beginning of 5 of development. Start by looking briefly at the overview of the Carnegie stage 13 embryo GIT from one end to the other.

Then work through the listed specific serial sections of the embryo identifying the GIT features. Alternatively step through the serial sections yourself identifying the tract, its associated mesentries, organs and spaces.

==Tract Development==
{|
| [[File:Gray0982a.jpg|The early developing gastrointestinal tract]]
| [[File:Gray0982b.jpg|The later developing gastrointestinal tract]]
|-
| Early Embryo
| Later Embryo
|}
==Carnegie Stage 13 (Week 4-5)==
{|
| [[File:Stage13-GIT-icon.jpg|200px|link=Movie_-_Gastrointestinal_Tract_3D_stage_13]]
[[Movie_-_Gastrointestinal_Tract_3D_stage_13|Gastrointestinal]]
| [[File:Stage13_bf1.jpg|200px]]
| [[File:Stage13_sem1.jpg|200px]]
|-
| The individual serial slices have also been incorporated into a 3D model of this embryo.
|
|
|}

{| class="wikitable" border="1"
|+ [[Carnegie stage 13 - serial sections|Stage 13]] '''- Gastrointestinal Tract'''
! Section
! Name
! Description
|-
| width= 210px|[[File:Stage 13 image 057.jpg|200px]]
[[File:Stage 13 image 058.jpg|200px]]

| width= 30px|[[:File:Stage 13 image 057.jpg|B1L]]

[[:File:Stage 13 image 058.jpg|B2L]]
| '''[[P#pharynx|Pharynx]]'''

[[File:Head arches cartoon.jpg|200px]] Note how in this region it is arched over and cut twice in this section.

The righthand side towards the buccopharyngeal membrane, the lefthand side descending into the embryo body. [[File:Stage13 B2 excerpt.gif]]

Central region is the floor of [[P#pharynx|pharynx]] formed by fusion of 3rd pharyngeal arches = [[H#hypopharyngeal eminence|hypopharyngeal eminence]] (precursor of root of tongue).

Rathke's pouch forming the rudimentary [[A#adenohypophysis|adenohypophysis]] (anterior pituitary).
|-
| [[File:Stage 13 image 059.jpg|200px]]
| [[:File:Stage 13 image 059.jpg|B3L]]
| '''Laryngeal tracheal groove''' - beginning of ventral compression, at 90 degrees to the lateral plane of the pharynx above this point.

Rudimentary thyroid ventral to aortic sac (also seen in [[:File:Stage 13 image 058.jpg|B2]], ventral to the hypopharyngeal eminence).
|-
| [[File:Stage 13 image 060.jpg|200px]]
| [[:File:Stage 13 image 060.jpg|B4L]]
| '''Laryngeal tracheal groove''' - Caudal pharynx compressed dorsoventrally.

Note that it lies between the aortic sac (ventrally) directly above the heart and the paired vessels of arch artery 6 and the dorsal aortas. The pale staining region behind these blood vessels is where the vertebral column will form.
|-
| [[File:Stage 13 image 061.jpg|200px]]
| [[:File:Stage 13 image 061.jpg|B5L]]
| '''Laryngopharynx''' - now compressed dorsoventrally between the paired arch artery 6 vessels.

|-
| [[File:Stage 13 image 063.jpg|200px]]
| [[:File:Stage 13 image 063.jpg|B7L]]
| '''Glottis''' - initial separation of the oesophagus (dorsal) from the trachea (ventral).

Note that this is occurring at the level of the heart atria.

Nasal placodes. Pulmonary arteries.
|-
| [[File:Stage 13 image 064.jpg|200px]]
| [[:File:Stage 13 image 064.jpg|C1L]]
| Gastrointestinal tract oesophagus (dorsal) is now separate from the respiratory trachea (ventral).
|-
| [[File:Stage 13 image 065.jpg|200px]]
| [[:File:Stage 13 image 065.jpg|C2L]]
| Oesophagus and trachea both surrounded by dense mesenchyme.

Right nasal pit.

|-
| [[File:Stage 13 image 066.jpg|200px]]
[[File:Stage 13 image 067.jpg|200px]]
| [[:File:Stage 13 image 066.jpg|C3L]]

[[:File:Stage 13 image 067.jpg|C4L]]
| Oesophagus and trachea both surrounded by dense mesenchyme.

Common cardinal vein in the posterior wall of the [[I#intraembryonic coelom|intraembryonic coelom]].

The pleuropericardial folds which contribute later to the formation of the pleura and pericardium.

In [[:File:Stage 13 image 067.jpg|C4]], junction of right common cardinal vein with dorsal wall of sinus venosus.

Left nasal pit.
|-
| [[File:Stage 13 image 068.jpg|200px]]
| [[:File:Stage 13 image 068.jpg|C5L]]
| Smaller oesophagus and expanding trachea, this is also the upper region of the lung buds.

The ventral anchoring of attachment site is at the most cranial extension of the septum transversum. This attachment now divides the intraembryonic coelom around the trachea into two canals, the left and right pleuro (pericardio-peritoneal) canals.

Canals are lined by coelomic mesothelium and are continuous with whole intraembryonic coelom (they will be referred to hereafter simply as coelomic canals).

The pleuroperitoneal fold on the medial side of the right common cardinal vein will form part of the diaphragm.

|-
| [[File:Stage 13 image 069.jpg|200px]]
| [[:File:Stage 13 image 069.jpg|C6L]]
| Trachea expanded and beginning to bifurcate to the major bronchial branches for each lung.

Lateral extension of pulmonary mesenchyme is moulded to shape of coelomic canals. Oesophagus lumen obliterated (common site of oesophageal atresia and/or tracheo-oesophageal fistula). Prominent R pleuroperitoneal fold.

|-
| [[File:Stage 13 image 070.jpg|200px]]
| [[:File:Stage 13 image 070.jpg|C7L]]
| Trachea bifurcated to the major bronchial branches for each lung.

Note dorsal extent of coelomic canals.

Oesophagus lumen reappears caudal to bifurcation.

Distinct R (smaller on L) pleuroperitoneal fold below the common cardinal vein.
|-
| [[File:Stage 13 image 071.jpg|200px]]
| [[:File:Stage 13 image 071.jpg|D1L]]
| Oesophagus/stomach junction.

Right lung bud bronchus still visible, left bronchus ends above this section. Note the oesophagus now lies in the midline between the 2 bronchi.

Coelomic canals.
|-
| [[File:Stage 13 image 072.jpg|200px]]
| [[:File:Stage 13 image 072.jpg|D2L]]
| Ovoid stomach with developing space of the lesser sac on R.

Dorsal and ventral attachments of the mesenchyme are now known as dorsal and ventral mesogastria. Coelomic canals.
|-
| [[File:Stage 13 image 073.jpg|200px]]
| [[:File:Stage 13 image 073.jpg|D3L]]
| Rotation of stomach (seen from above) to right side.

Note change in outline of coelomic canals due to presence of liver.

Lesser sac. Note thick mesothelium lining the coelom along left edge of stomach, the primordium of the spleen and greater omentum along greater curvature.

Liver embedded in septum transversum (ventral border of septum transversum contributes to diaphragm).
|-
| [[File:Stage 13 image 074.jpg|200px]]
| [[:File:Stage 13 image 074.jpg|D4L]]
| Rotation of stomach (seen from above) to right side.

Ventral mesogastrium - Stomach is attached ventrally to the liver. (note the position of the ductus venosus)

Dorsal mesogastrium - within this structure the spleen will begin to form and later the greater omentum.

Peritoneal spaces - identify greater and lesser sac.
|-
| [[File:Stage 13 image 076.jpg|200px]]
| [[:File:Stage 13 image 076.jpg|D6L]]
| Pyloric region of stomach.

Ventral mesogastrium - Stomach is closely attached ventrally to the liver.

Dorsal mesogastrium - within this structure the spleen will begin to form and later the greater omentum.

Peritoneal spaces - identify greater and lesser sac.
|-
| [[File:Stage 13 image 081.jpg|200px]]
| [[:File:Stage 13 image 081.jpg|E4L]]
| Midgut.

Region close to the umbilicus. Note the close associated portal vein and the paired placental (umbilical) veins.
|-
| [[File:Stage 13 image 085.jpg|200px]]
| [[:File:Stage 13 image 085.jpg|F1L]]
| Midgut.

Looping out of body wall ventrally (cut tangentially).

Also note the righthand side hindgut region.

|-
| [[File:Stage 13 image 098.jpg|200px]]
| [[:File:Stage 13 image 098.jpg|G7L]]
| Caudal pharynx (extending laterally, ventral to dorsal aorta - cf B4). Stomach, mesentery
|-
| [[File:Stage 13 image 097.jpg|200px]]
| [[:File:Stage 13 image 097.jpg|G6L]]
| Narrow oesophagus. Tracheal bifurcation dorsal to sinus venosus.
|}

==Peritoneal Cavity==
* Fusion of the two separate intra-embryonic coelom spaces.
* Intestinal loss of ventral attachment, except at the level of the stomach, dorsal attachment becomes true mesentery.

==Stomach Development==
The stomach initially appears at this stage (5 weeks) as a dilatation of the GIT in the foregut, which over the next 2 weeks will continue to expand to a fusiform structure and differential growth will it rotate in both the longitudinal and the horizontal planes.
{|
| Differential growth of the ventral and dorsal stomach walls leads to establishing a lesser and greater curvature.

<wikiflv width="488" height="500" autostart="true" position="left">Stomach rotation 01.flv|File:Stomach rotation 01 icon.jpg</wikiflv>
|

Key:
* Yellow - endoderm and splanchnic mesoderm of stomach.
* Red - mesentry (ventral at front and dorsal at back). The dorsal mesogastrium will form the greater omentum and the ventral mesogastrium will form the lesser omentum.
* Blue - vagus nerve branches (left and right). A 90 degree rotation (during week 7) brings the left vagus anteriorly (to the front) and carries the right vagus posteriorly (to the back).

These combined rotations position the stomach in its adult orientation and movement of the mesenteries also moves the developing liver to the right and generates the greater omentum and lesser sac (see animations below).
|-
| [[Media:Stomach_rotation_01.mov|Quicktime movie]] | [[Quicktime_Development_Animation_-_Stomach_Rotation|Quicktime]] | [[Development_Animation_-_Stomach_Rotation|Flash]]
|

|}

==Lesser Sac Development==
{|
| Development of Lesser Sac
| Development of Greater Omentum
|-
| [[File:Lesser sac_01_icon.jpg|300px|link=Development_Animation_-_Lesser_Sac]]
| [[File:Greater_omentum_001_icon.jpg|300px|link=Development_Animation_-_Greater_Omentum]]
|-
| [[Quicktime Development_Animation_-_Lesser_Sac|Quicktime]] | [[Development_Animation_-_Lesser_Sac|Flash]]
| [[Quicktime Development_Animation_-_Greater_Omentum|Quicktime]] | [[Development_Animation_-_Greater_Omentum|Flash]]
|}
Key: Yellow - endoderm of stomach. Orange - liver developing in ventral mesogastrium. Red - spleen developing in dorsal mesogastrium.

Note the narrow tubular connection between the intestinal loop and the yolk sac.

{{Template:GIT cartoons}}