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==Introduction==

==Introduction==

<p>''Also called the cloacal bursa''</p>

<p>''Also called the cloacal bursa''</p>

<p>It is a [[:Category:Primary Lymphoid Tissue|primary lymphoid organ]] found in birds. The bursa was the first place that a certain subset of [[Lymphocytes|lymphocytes]] was observed and consequently they were named [[Lymphocytes#B cells|B lymphocytes]] (<u>b</u>ursa of Fabricius or <u>b</u>ursa equivalent organs). The bursa is involved in the differentiation of [[Lymphocytes#B cells|B lymphocytes]].</p>

<p>It is a [[:Category:Primary Lymphoid Tissue|primary lymphoid organ]] found in birds. The bursa was the first place that a certain subset of [[Lymphocytes - Introduction|lymphocytes]] was observed and consequently they were named [[Lymphocytes#B cells|B lymphocytes]] (<u>b</u>ursa of Fabricius or <u>b</u>ursa equivalent organs). The bursa is involved in the differentiation of [[Lymphocytes#B cells|B lymphocytes]].</p>

==Development==

==Development==

[[Image:LH_Bursa_Cloaca_Photo.jpg|thumb|150px|right|<p>'''Bursa of Fabricius'''</p>^{©Nottingham Uni 2008}]]

[[Image:LH_Bursa_Cloaca_Photo.jpg|thumb|150px|right|<p>'''Bursa of Fabricius'''</p>^{©Nottingham Uni 2008}]]

==Structure==

==Structure==

<p>The bursa is a round out-pouching of the [[The Avian Vent and Cloaca - Anatomy & Physiology|cloaca]]. It is found on the caudodorsal surface of the [[The Avian Vent and Cloaca - Anatomy & Physiology|cloaca]] (in the proctodeum) cranial to the dorsal proctodeal gland. The bursa consists of a number of lymphoid lobules and crypt-like folds surrounding a lumen, which is enclosed in a thin layer of stratified squamous epithelium. The lumen opens into the proctodeum.</p>

<p>The bursa is a round out-pouching of the [[The Avian Vent and Cloaca - Anatomy & Physiology|cloaca]]. It is found on the caudodorsal surface of the [[The Avian Vent and Cloaca - Anatomy & Physiology|cloaca]] (in the proctodeum) cranial to the dorsal proctodeal gland. The bursa consists of a number of lymphoid lobules and crypt-like folds surrounding a lumen, which is enclosed in a thin layer of stratified squamous epithelium. The lumen opens into the proctodeum.</p>

<p>Like the [[Thymus - Anatomy & Physiology|thymus]] the lobules have a cortex and medulla and the [[Lymphocytes|lymphocytes]] are supported by epithelial cells. B lymphocytes developing from the lymphoid precursors gather in the cortex, hence the cortex stains stronger than the medulla.</p>

<p>Like the [[Thymus - Anatomy & Physiology|thymus]] the lobules have a cortex and medulla and the [[Lymphocytes - Introduction|lymphocytes]] are supported by epithelial cells. B lymphocytes developing from the lymphoid precursors gather in the cortex, hence the cortex stains stronger than the medulla.</p>

===Histology===

===Histology===

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