Question

Anatomy Tutorial: Lymphatic Tissues & Organs

Answer 1

\({\bf{Lymphatic~Tissues:}}\)
> diffuse lymphatic tissues: lymphocytes are loosely embedded in CT, ex: mucous membranes

> lymphatic nodules: lymphocytes within reticular framework, oval shaped and located inside digestive tract. .no cpasule; germinal center = contains dividing lymphocytes

> MALT (mucosa-associated lymphoid tissue): lymphatic tissues in the digestive respiratory urinary and reproductive systems

> tonsils: nodules in the pharynx
- pharyngeal tonsil (adenoid): posterior+superior nasopharynx
- palatine tonsils: posterior inferior oral cavity
- lingual tonsils: under the base of tongue
> aggregated lymphatic nodules: nodules in the small intestine

> clinical note: tonsillitis, inflammation caused by repeated infection of the tonsils. if infection is frequent, the tonsils can form abscess and become infected, allowing bacteria to enter the bloodstream. swelling of tonsils can also interfere w/ normal breathing/sleeping patterns. if infection is frequent, tonsillectomy (removal of the tonsils) is considered esp. in children.

Answer 2

\({\bf{Lymphatic~Organs:}}\) lymph nodes, thymus, spleen. surrounded by fibrous CT capsule.

\({\bf{Lymph~Nodes:}}\)

*** removes antigens by phagocytosis, filters lymph before the venous system ***

- small, oval-shaped, distributed all over the body
_ outer cortex, inner medulla, and intermediary region (paracortex)
> cortex: B-cells, germinal centers
> paracortex: T-cells, site where lymphocytes enter lymph node
> medulla: B cells, macrophages, medullary cords
- subcapsular space: contains reticular fibers, macrophages, dendritic cells (cells that start immune response)
- trabeculae extend into the node
- vessels + nerves enter/exit at hilum
- afferent lymphatic vessels: bring lymph to the node
- efferent lymphatic vessels

> cervical lymph nodes: head, neck, meninges
> axillary lymph nodes: upper limbs, mammary glands
> popliteal lymph node: thigh
> inguinal lymph node: lower limbs
> thoracic lymph node: respiratory system, mediastinal structures
> abdominal lymph node: urinary + reproductive systems
> intestinal lymph node + mesenteric lymph node: digestive tract

Answer 3

\({\bf{Thymus:}}\) T cells, reticular cells, thymic corpuscles
> two thymic lobes
> septa, divide lobe into lobules
> lobule has cortex + medulla
- cortex: contains lymphatic stem cells --> mature, move to medulla
> capillaries make blood-thymus barrier
> epithelial reticular cells: produce thymic hormones that differentiate T cells. form thymic corpuscles

Answer 4

\({\bf{Spleen:}}\) RBC removal, iron storage, starts immune responses via B and T cells. can live without your spleen, although not ideal.
> diaphragmatic surface (surface that contacts the diaphragm)
> visceral surface: contacts the stomach and kidney
> splenic artery, vein, lymphatic vessels, enter/exit at hilum --> trabecular arteries that spread out towards cpasule
> capsule w/ collagen + elastic fibers

> red pulp: splenic cords, RBC-dominated, macrophages
> white pulp: lymphatic nodules
> sinusoids: lined w/ macrophages, empty into veins

Answer 5

Adapted from Human Anatomy, Martini, et. al. 9th edition