Changes

==Introduction==

==Introduction==

<p>''Also called aggregated nodules''</p>

<p>''Also called aggregated nodules''</p>

<p>Peyer’s patches are lymphoid tissues found in the wall of the [[Small Intestine - Anatomy & Physiology|small intestine]]. They are part of the mucosal-associated lymphoid tissues (MALT) and more specifically the gut-associated lymphoid tissue (GALT). Although nodules of lymphatic tissue are found throughout the intestines in the [[Small Intestine - Anatomy & Physiology|small intestine]] larger collections of nodules exist and these are referred to as Peyer’s patches. In many species they act as a primary lymphoid tissue (cattle, sheep , pigs, horses, dogs and rabbits).</p>

<p>Peyer’s patches are lymphoid tissues found in the wall of the [[Small Intestine - Anatomy & Physiology|small intestine]]. They are part of the [[Regional Lymphoid Tissue - Anatomy & Physiology|mucosal-associated lymphoid tissues (MALT)]] and more specifically the gut-associated lymphoid tissue (GALT). Although nodules of lymphatic tissue are found throughout the intestines in the [[Small Intestine - Anatomy & Physiology|small intestine]] larger collections of nodules exist and these are referred to as Peyer’s patches. In many species they act as a [[Primary Lymphoid Tissue - Anatomy & Physiology|primary lymphoid tissue]] (cattle, sheep , pigs, horses, dogs and rabbits).</p>

==Development ==

==Development ==

<p>In cattle, sheep , pigs, horses and dogs over eighty percent of the patches are found in the [[Ileum - Anatomy & Physiology|ileum]] where they form a continuous structure which is most developed before birth and regresses to the point that in the adult they cannot be detected. The rest of the patches are found in the [[jejunum - Anatomy & Physiology|jejunum]] and are isolated from each other, however these patches last throughout adult life.</p><p> In rabbits and rodents the patches are randomly located along both the [[Ileum - Anatomy & Physiology|ileum]] and [[jejunum - Anatomy & Physiology|jejunum]] and persist throughout life.</p>

<p>In cattle, sheep , pigs, horses and dogs over eighty percent of the patches are found in the [[Ileum - Anatomy & Physiology|ileum]] where they form a continuous structure which is most developed before birth and regresses to the point that in the adult they cannot be detected. The rest of the patches are found in the [[jejunum - Anatomy & Physiology|jejunum]] and are isolated from each other, however these patches last throughout adult life.</p><p> In rabbits and rodents the patches are randomly located along both the [[Ileum - Anatomy & Physiology|ileum]] and [[jejunum - Anatomy & Physiology|jejunum]] and persist throughout life.</p>

==Function==

==Function==

Peyer’s patches have a similar role to that of the avian [[Bursa of Fabricius - Anatomy & Physiology|bursa of Fabricius]] in maturing and differentiation immature B lymphocytes. Antigens are presented to the [[Lymphocytes - WikiBlood#B cells|B lymphocytes]] in the follicle which causes the [[Lymphocytes - WikiBlood#B cells|B cells]] to become committed to IgA synthesis. In ruminants and pigs Peyer's patches in the [[Ileum - Anatomy & Physiology|ileum]] have a primary lympoid fuction while those in the [[Jejunum - Anatomy & Physiology|jejenum]] have a secondary lymphoid function.

Peyer’s patches have a similar role to that of the avian [[Bursa of Fabricius - Anatomy & Physiology|bursa of Fabricius]] in maturing and differentiation immature B lymphocytes. Antigens are presented to the [[Lymphocytes - WikiBlood#B cells|B lymphocytes]] in the follicle which causes the [[Lymphocytes - WikiBlood#B cells|B cells]] to become committed to [[Immunoglobulin A - WikiBlood|IgA]] synthesis. In ruminants and pigs Peyer's patches in the [[Ileum - Anatomy & Physiology|ileum]] have a primary lympoid fuction while those in the [[Jejunum - Anatomy & Physiology|jejenum]] have a secondary lymphoid function.

==In pathology==

==In pathology==