Changes

==Introduction==

==Introduction==

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

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

<p>It is a [[Primary Lymphoid Tissue - Anatomy & Physiology|primary lymphoid organ]] found in birds. The bursa was the first place that a certain subset of [[Lymphocytes - WikiBlood|lymphocytes]] was observed and consequently they were named [[Lymphocytes - WikiBlood#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 - WikiBlood#B cells|B lymphocytes]].</p>

<p>It is a [[Primary Lymphoid Tissue - Anatomy & Physiology|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>

==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 - WikiBlood|lymphocytes]] are supported by epithelial cells. [[Lymphocytes - Anatomy & Physiology#B 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|lymphocytes]] are supported by epithelial cells. [[Lymphocytes - Anatomy & Physiology#B 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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==Functions==

==Functions==

<p>The bursa’s primary function is maturating and causing the differentiation of [[Lymphocytes - WikiBlood#B cells|B lymphocytes]], it also produces the hormone bursin which activates [[Lymphocytes - WikiBlood#B cells|B lymphocytes]]. </p>

<p>The bursa’s primary function is maturating and causing the differentiation of [[Lymphocytes#B cells|B lymphocytes]], it also produces the hormone bursin which activates [[Lymphocytes#B cells|B lymphocytes]]. </p>

<p>The bursa has some [[Lymphocytes - WikiBlood#T cells|T lymphocytes]] present near to its opening into the proctodeum where they survey antigens.</p>

<p>The bursa has some [[Lymphocytes#T cells|T lymphocytes]] present near to its opening into the proctodeum where they survey antigens.</p>