Changes

==Structure==

<p>The lymphatic system can be divided into two anatomical and functional subsets:

*[[Lymphatic Vessels - Anatomy & Physiology|Lymphatic Vessels]]

==Introduction==

**Vessels that carry lymph around the body

 

*[[Lymphoreticular System - Anatomy & Physiology|Lymphoreticular System]]

The lymphatic system can be divided into two anatomical and functional subsets: [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessels]] that carry lymph around the body, and the [[Lymphoreticular System - Anatomy & Physiology|lymphoreticular system]] which describes the lymphoid tissues. The lymphatic system has three functions - immune defence, removal of interstitial fluid from tissues and the transport of fats.

**Consisting of the lymphoid tissues

 

***[[Primary Lymphoid Tissue - Anatomy & Physiology|Primary lymphoid tissues]]: [[Appendix - Anatomy & Physiology|Appendix]], [[Bone Marrow - Anatomy & Physiology|bone marrow]], [[Bursa of Fabricius - Anatomy & Physiology|bursa of Fabricius]], [[Haematopoiesis - Anatomy & Physiology#Hepatic Phase|foetal liver]], [[Peyer's Patches - Anatomy & Physiology|ileal Peyer's patch]] and [[Thymus - Anatomy & Physiology|thymus]]

***[[Secondary Lymphoid Tissue - Anatomy & Physiology|Secondary lymphoid tissues]]: [[Spleen - Anatomy & Physiology| Spleen]], [[Lymph Nodes - Anatomy & Physiology|lymph nodes]], [[Regional Lymphoid Tissue - Anatomy & Physiology|regional lymphoid tissue]] and [[Tonsils - Anatomy & Physiology|tonsils]]

Due to their structure lymphatic capillaries are more permeable than vascular capillaries which  means that not only can they remove fluid more effectively from tissues but they can also take up large molecules as well as chylomicrons. Chylomicrons transport fats and enter the [[Lymph - Anatomy & Physiology|lymph]] to eventually join the circulatory system via the thoracic duct; this enables the lipid soluble [[Small Intestine Overview - Anatomy & Physiology#Triacylglycerol Digestion and Absorption |triacylglycerols (TAGs)]] to be transported into the bloodstream. The interstitial fluid or lymph within the lymphatic vessels passes through lymph nodes where it is surveyed by [[Immunology|immune cells]] before returning to the circulation, ensuring that tissue pathogens are removed.

 

==[[:Category:Lymphoreticular System|Lymphoreticular system]]==

Primary (or central) lymphoid tissues can also be referred to as primary lymphoid organs. Maturation of [[Lymphocytes - Introduction|lymphocytes]] and [[Leukopoiesis#Lymphopoiesis|lymphopoiesis]] occurs in the primary lymphoid tissues, with different tissues responsible for maturing different types of lymphocyte. The primary lymphoid tissues are:

*[[Bone Marrow - Anatomy & Physiology|Bone marrow]]

*[[Bursa of Fabricius - Anatomy & Physiology|The Bursa of Fabricius]]

*[[Thymus - Anatomy & Physiology|The Thymus]]

*[[Haematopoiesis - Overview#Hepatic Phase|The Foetal Liver]]

 

Secondary (or peripheral) lymphoid tissues or secondary lymphoid organs provide a site for immune responses to occur and are populated by relatively mature [[Lymphocytes#T cells|T cells]] and [[Lymphocytes#B cells|B cells]], [[Macrophages|macrophages]] and dendritic cells; each tissue seems to be preferentially populated by lymphocyte types that specialise in the antigens that are most likely to be presented at that site. The secondary lymphoid tissues are:

*[[Lymph Nodes - Anatomy & Physiology|The Lymph nodes]]

*[[Spleen - Anatomy & Physiology|The Spleen]]

*[[Regional Lymphoid Tissue - Anatomy & Physiology|Mucosal Associated Lymphoid Tissue or MALT]]

*[[Tonsils - Anatomy & Physiology|The Tonsils]]

*[[Appendix - Anatomy & Physiology|The Appendix/caecal pouch]]

*[[Peyer's Patches - Anatomy & Physiology|The Ileal Peyer's Patch]]

*[[Regional Lymphoid Tissue - Anatomy & Physiology|Regional lymphoid tissue]]

==Functions==

==Functions==

<p>The lymphatic system has three functions:

<p>The lymphatic system has three functions:

#Immune defence

#'''Immune defence''': This is a broad topic area.</p><p>Immune functions are covered broadly under the [[:Category:Primary Lymphoid Tissue|primary]] and [[:Category:Secondary Lymphoid Tissue|secondary]] lymphoid tissues of the [[Lymphoreticular System - Anatomy & Physiology|lymphoreticular system]] with further information under the [[Immunology|immunology]] section.

#'''Removal of interstitial fluid from tissue''': Details can be found at [[Lymphatic Vessels - Anatomy & Physiology#Function|lymphatic vessel function]].

#'''Transport of fat''': Chylomicrons transport digested lipids, however these are too large to enter the blood stream directly and thus enter the lymphatic system before being released into the blood stream. Further details can be found at [[Small Intestine Overview - Anatomy & Physiology#Triacylglycerol Digestion and Absorption|Triacylglycerol Digestion and Absorption]].

 

<p>This is a broad topic area.</p><p>Immune functions are covered broadly under the [[Primary Lymphoid Tissue - Anatomy & Physiology|primary]] and [[Secondary Lymphoid Tissue - Anatomy & Physiology|secondary]] lymphoid tissues of the [[Lymphoreticular System - Anatomy & Physiology|lymphoreticular system]] with further information under the [[Immunology - Anatomy & Physiology|immunology]] section.</p>

===Removal of interstitial fluid===

Details can be found [[Lymphatic Vessels - Anatomy & Physiology#Function|here]].

 

 

 

[[Category:Lymphoreticular System]]

Chylomicrons transport digested lipids, however these are too large to enter the blood stream directly and thus enter the lymphatic system before being released into the blood stream. Further details can be found [[Small Intestine - Anatomy & Physiology#Triacylglycerol Digestion and Absorption |here]].