Cardiovascular System - Spleen Development - Revision history

Z8600021 at 02:08, 26 July 2019

2019-07-26T02:08:12Z

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	[[File:Stage_22_image_085.jpg\|thumb\|300px\|Developing Human Spleen ([[Carnegie stage 22\|stage 22]])]]		[[File:Stage_22_image_085.jpg\|thumb\|300px\|Developing Human Spleen ([[Carnegie stage 22\|stage 22]])]]

	The {{spleen}} is located on the left side of the abdomen and has an initial embryonic role in blood formation, and later in immune function and red blood cell recycling. The spleen's haematopoietic function (blood cell formation) is lost with embryo development and lymphoid precursor cells migrate into the developing organ. The {{mesoderm}} (mesenchymal progenitors) within the dorsal mesogastrium forms the precursors of nearly all mature spleen stromal cells. This mesoderm form a long strip of cells adjacent to the forming stomach above the developing pancreas. Vascularization of the spleen arises initially branches from the dorsal aorta, then the celiac trunk's largest branch.		The {{spleen}} is located on the left side of the abdomen and has an initial embryonic role in blood formation, and later in immune function and red blood cell recycling. The spleen's haematopoietic function (blood cell formation) is lost with embryo development and lymphoid precursor cells migrate into the developing organ. The {{mesoderm}} (mesenchymal progenitors) within the dorsal mesogastrium forms the precursors of nearly all mature spleen stromal cells. This mesoderm form a long strip of cells adjacent to the forming stomach above the developing pancreas. Vascularization of the spleen arises initially branches from the dorsal aorta, then the celiac trunk's largest branch. During the fetal period the spleen appears lobulated but these lobules normally disappear before birth.

Z8600021 at 02:21, 19 July 2019

2019-07-19T02:21:09Z

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	* Human splenic secondary follicles three zones - germinal centre, mantle zone and superficial zone.		* Human splenic secondary follicles three zones - germinal centre, mantle zone and superficial zone.

			The spleen in fetal life is a site for blood formation (hematopoiesis). The adult spleen has 2 main functions: immune, as a major site of antigen presentation for the circulation system and removal of aged erythrocytes from the circulation. The spleen has a dense connective tissue capsule, which contains trabeculae running into the interior of the spleen forming incomplete compartments (as in the thymus). The stroma is mainly composed of reticular connective tissue and cells. There is a hilum, which contains arteries and veins, but unlike a lymph node, there are no lymphatics. It should also be noted that the spleen cannot be divided into a medulla and cortex, which helps differentiate it from the thymus or a lymph node.

			<br>
	<gallery>		<gallery>
	File:Spleen_histology_01.jpg\|Overview Red and White Pulp		File:Spleen_histology_01.jpg\|Overview Red and White Pulp

Z8600021 at 22:52, 18 July 2019

2019-07-18T22:52:58Z

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 {{Spleen Vignette}}
 <br>
 For all website content related to the spleen see the [[:Category:Spleen|Category:Spleen]]
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 {{Immune Links}}
 == Some Recent Findings ==
 [[File:Spleen structure cartoon 01.jpg|thumb|Adult spleen structure{{#pmid:16056254|PMID16056254}}]]
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 * '''Neural Crest Cells Contribute an Astrocyte-like Glial Population to the Spleen'''{{#pmid:28349968|PMID28349968}} "{{Neural crest}} cells (NCC) are multi-potent cells of ectodermal origin that colonize diverse organs, including the gastrointestinal tract to form the enteric nervous system (ENS) and hematopoietic organs (bone marrow, thymus) where they participate in lymphocyte trafficking. ...Here, we demonstrate that NCC colonize the spleen during embryogenesis and persist into adulthood. Splenic NCC display markers indicating a glial lineage and are arranged anatomically adjacent to blood vessels, pericytes and nerves, suggesting an astrocyte-like phenotype." {{neural crest}}
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 | {{Older papers}}
 * '''Spleen versus pancreas'''{{#pmid:16912273|PMID16912273}} "During early stages of pancreatic development, the mesenchyme that contributes to the spleen overlies the dorsal pancreatic endoderm. Here, we show that interactions between splenic mesenchyme and pancreas proceed via a highly orchestrated morphogenetic program. ...Similar transformations occur in organ cultures employing wild-type pancreatic endoderm and spleen mesenchyme, revealing the developmental plasticity of the pancreas and that precise spatial and temporal control of tissue interactions are required for development of both organs."

Z8600021 at 22:51, 18 July 2019

2019-07-18T22:51:38Z

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	Mouse models have though shown that as the splenic white pulp ages it looses its structural organization, perhaps contributing to the impaired immune system function seen with age.{{#pmid:30706058\|PMID30706058}}		Mouse models have though shown that as the splenic white pulp ages it looses its structural organization, perhaps contributing to the impaired immune system function seen with age.{{#pmid:30706058\|PMID30706058}}
			<br>
			{{Spleen Vignette}}
	<br>		<br>
	For all website content related to the spleen see the [[:Category:Spleen\|Category:Spleen]]		For all website content related to the spleen see the [[:Category:Spleen\|Category:Spleen]]

Z8600021 at 11:05, 11 March 2019

2019-03-11T11:05:33Z

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	Note there are significant differences between human spleen structure and the usual {{mouse}} and {{rat}} models. White pulp components, marginal zone is absent, and red pulp sinusoid circulation differs:{{#pmid:21525186\|PMID21525186}}		Note there are significant differences between human spleen structure and the usual {{mouse}} and {{rat}} models. White pulp components, marginal zone is absent, and red pulp sinusoid circulation differs:{{#pmid:21525186\|PMID21525186}}
	* mouse - circulation is closed, afferent arterial blood to the red pulp sinusoids, and to the marginal zone sinus.		* {{mouse}} - circulation is closed, afferent arterial blood to the red pulp sinusoids, and to the marginal zone sinus.
	* humans - circulation is open, no connection from capillaries to sinuses in the red pulp.		* humans - circulation is open, no connection from capillaries to sinuses in the red pulp.

Z8600021 at 10:56, 11 March 2019

2019-03-11T10:56:53Z

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	Congenital absence of the spleen is usually accompanied by complex cardiac malformations, malposition and maldevelopment of the abdominal organs, and abnormal lobation of the lungs. There are a range of other spleen anatomical development abnormalities, some of which have no effect and others are very rare, including asplenia, polysplenia, hyposplenia, lobulation of spleen, accessory spleens, accessory splenic nodules, wandering spleen, splenogonadal and splenopancreatic fusion, splenic cysts, and cavernous haemangioma of the spleen.		Congenital absence of the spleen is usually accompanied by complex cardiac malformations, malposition and maldevelopment of the abdominal organs, and abnormal lobation of the lungs. There are a range of other spleen anatomical development abnormalities, some of which have no effect and others are very rare, including asplenia, polysplenia, hyposplenia, lobulation of spleen, accessory spleens, accessory splenic nodules, wandering spleen, splenogonadal and splenopancreatic fusion, splenic cysts, and cavernous haemangioma of the spleen.

	===Congenital ~~Asplenia~~===		===LB22 Structural developmental anomalies of spleen===
			{{ICD-11}} {{ICD11weblink}}703933743 '''LB22''' Structural developmental anomalies of spleen]

			===LB22.0 Congenital asplenia===

			{{ICD11weblink}}605819742 LB22.0 Congenital asplenia] - A condition caused by failure of the spleen to develop during the antenatal period. This condition may present with pneumococcal sepsis. Confirmation is through verification of no spleen by imaging.

	Can be due to left/right patterning abnormality or failure of early spleen differentiation.		Can be due to left/right patterning abnormality or failure of early spleen differentiation.

	===~~Splenic Lobulation~~===		===LB22.1 Polysplenia===
			{{ICD11weblink}}765928537 LB22.1 Polysplenia] - A condition caused by the development of supernumerary spleens during the antenatal period. This condition may present with cardiac defects, anomalies in abdominal organs, or may be asymptomatic.

	~~===Accessory Spleen===~~
	Clinically no significant efects in most patients, occur as single or multiple and generally found in autopsy or as an an incidental finding, occurs in approximately 10% to 15% of individuals.{{#pmid:7207579\|PMID7207579}} Thought to occur due to a failure of primordia fusion within the dorsal mesogastrium.		Clinically no significant efects in most patients, occur as single or multiple and generally found in autopsy or as an an incidental finding, occurs in approximately 10% to 15% of individuals.{{#pmid:7207579\|PMID7207579}} Thought to occur due to a failure of primordia fusion within the dorsal mesogastrium.

	===~~Polysplenia~~===		===LB22.2 Ectopic spleen===
			{{ICD11weblink}}1822281676 LB22.2 Ectopic spleen]]

			A very rare abnormality where the spleen can be found anatomically located in a range of places in the abdominal or thoracic cavity.

	===Splenogonadal Fusion===		===Splenogonadal Fusion===
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	(More? {{testis}})		(More? {{testis}})

	~~===Ectopic Spleen===~~

	~~A very rare abnormality where the spleen can be found anatomically located in a range of places in the abdominal or thoracic cavity.~~


	===Wandering Spleen===		===Wandering Spleen===

			Connexin-43 involved with abnormal spleen development (cardiac and lung also).



	~~Connexin-43 involved with abnormal spleen development (cardiac and lung also).~~

	== References ==		== References ==
	<references/>		<references/>

	===Reviews===		===Reviews===
	{{#pmid:29367882}}		{{#pmid:29367882}}

Z8600021 at 11:05, 17 February 2019

2019-02-17T11:05:40Z

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	\| {{GIT cartoons}}		\| {{GIT cartoons}}
	\|}		\|}
			==Childhood Spleen==

			The graph below compares normal and abnormal growth of the spleen in childhood with similar changes in the adult.{{#pmid:30138410\|PMID30138410}}


			[[File:Spleen size in children and adults.jpg\|600px]]


	==Adult Spleen==		==Adult Spleen==

Z8600021 at 04:09, 12 February 2019

2019-02-12T04:09:03Z

← Older revision		Revision as of 14:09, 12 February 2019
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	* mouse - circulation is closed, afferent arterial blood to the red pulp sinusoids, and to the marginal zone sinus.		* mouse - circulation is closed, afferent arterial blood to the red pulp sinusoids, and to the marginal zone sinus.
	* humans - circulation is open, no connection from capillaries to sinuses in the red pulp.		* humans - circulation is open, no connection from capillaries to sinuses in the red pulp.


			Mouse models have though shown that as the splenic white pulp ages it looses its structural organization, perhaps contributing to the impaired immune system function seen with age.{{#pmid:30706058\|PMID30706058}}


	<br>		<br>

Z8600021 at 03:33, 12 February 2019

2019-02-12T03:33:14Z

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			* '''Locating human splenic capillary sheaths in virtual reality'''{{#pmid:30356180\|PMID30356180}} "Stromal capillary sheath cells in human spleens strongly express CD271, the low affinity nerve growth factor receptor p75. Serial sections of a representative adult human spleen were double-stained for CD271 versus smooth muscle alpha actin (SMA) plus CD34 to visualise capillary sheaths, the arterial tree and endothelial cells by transmitted light. Preliminary three-dimensional (3D) reconstructions of single regions were inspected in virtual reality (VR). This method showed that a large number of CD271+ sheaths occur in a post-arteriolar position often surrounding capillaries located close to divisions of arterioles. The length and diameter of capillary sheaths are rather heterogeneous. Long sheaths were observed to accompany one or two generations of capillary branches. We hypothesise that human splenic capillary sheaths may attract recirculating B-lymphocytes from the open circulation of the red pulp to start their migration into white pulp follicles along branches of the arterial tree. In addition, they may provide sites of interaction among sheath macrophages and B-lymphocytes."

	* '''Review - Origin and Immunological Functions of Spleen Stromal Cells'''{{#pmid:29567327\|PMID29567327}} "The mammalian spleen is a peripheral lymphoid organ that plays a central role in host defence. Consequently, the lack of spleen is often associated with immunodeficiency and increased risk of overwhelming infections. Growing evidence suggests that non-hematopoietic stromal cells are central players in spleen development, organization, and immune functions. In addition to its immunological role, the spleen also provides a site for extramedullary hematopoiesis (EMH) in response to injuries. A deeper understanding of the biology of stromal cells is therefore essential to fully comprehend how these cells modulate the immune system during normal and pathological conditions."		* '''Review - Origin and Immunological Functions of Spleen Stromal Cells'''{{#pmid:29567327\|PMID29567327}} "The mammalian spleen is a peripheral lymphoid organ that plays a central role in host defence. Consequently, the lack of spleen is often associated with immunodeficiency and increased risk of overwhelming infections. Growing evidence suggests that non-hematopoietic stromal cells are central players in spleen development, organization, and immune functions. In addition to its immunological role, the spleen also provides a site for extramedullary hematopoiesis (EMH) in response to injuries. A deeper understanding of the biology of stromal cells is therefore essential to fully comprehend how these cells modulate the immune system during normal and pathological conditions."

Z8600021 at 03:28, 12 February 2019

2019-02-12T03:28:54Z

← Older revision		Revision as of 13:28, 12 February 2019
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	The human spleen arises in week 5 within the dorsal mesentery as proliferating mesenchyme overlying the dorsal pancreatic {{endoderm}}. Cells required for its hemopoietic function arise from the yolk sac wall and near dorsal aorta. The spleen generates both red and white cells in the {{second trimester}}.		The human spleen arises in week 5 within the dorsal mesentery as proliferating mesenchyme overlying the dorsal pancreatic {{endoderm}}. Cells required for its hemopoietic function arise from the yolk sac wall and near dorsal aorta. The spleen generates both red and white cells in the {{second trimester}}.

	~~<br>~~		Note there are significant differences between human spleen structure and the usual {{mouse}} and {{rat}} models. White pulp components, marginal zone is absent, and red pulp sinusoid circulation differs:{{#pmid:21525186\|PMID21525186}}
	~~Mouse~~ and ~~human~~ red pulp sinusoid circulation differs:{{#pmid:21525186\|PMID21525186}}
	* mouse - circulation is closed, afferent arterial blood to the red pulp sinusoids, and to the marginal zone sinus.		* mouse - circulation is closed, afferent arterial blood to the red pulp sinusoids, and to the marginal zone sinus.
	* humans - circulation is open, no connection from capillaries to sinuses in the red pulp.		* humans - circulation is open, no connection from capillaries to sinuses in the red pulp.