Lymphatic organs & Tissue Flashcards
What are Primary Lymphatic Organs used for by the Lymphatic System?
These are the sites where Stem cells divide and become “Immunocompetent”.
What does it mean for a cell to be Immunocompetent?
This means the cell is capable of mounting an immune response.
What are the Primary lymphatic Organs?
Red bone marrow & Thymus.
What does the Red bone marrow and Thymus do as the Primary Lymphatic Organs?
Stem cells in Red bone marrow gives rise to “B-Cells” and to “Pre T-cells”.
Pre T-cells migrate to the Thymus, where they become “T-cells”.
What are the Secondary Lymphatic Organs and Tissues?
These are the sites where most immune responses occur, including lymph nodes, Spleen, and lymphatic nodules.
What is the Thymus?
Bilobed organ, located in the mediastinum between the sternum and the aorta.
Cortex is composed of a large number of T-cells & Scattered dendritic cells and macrophages.
Pre T-cells migrate from the RBM to the cortex of the Thymus to mature.
What do Dendritic cells do in the Thymus?
They help with the maturation process of Pre T-cells.
What do the Specialized Epithelial cells do in the Thymus?
Each of the cells in the Cortex help educate Pre T-cells in a process called positive selection.
Only about 2% of the maturing T-cells survive in the thymus cortex, what happens to the rest of the cells?
The remaining cells Die Via Apotosis, The surviving T-cells enter the Medulla.
What are Lymph Nodes?
They are found along Lymphatic Vessels about 600 bean shaped nodes.
Covered in a dense capsule of CT that extends into the node. The extension are called “Trabeculae”.
What is the functioning part of the Lymph node?
Parenchyma is divided into Superficial Cortex (Inner and outer) and a Deep Medulla.
What is within the Outer cortex of the Superficial cortex of the lymph node?
B-cells called Lymphatic Nodules.
What is a Lymphatic Nodule consisting Primarily of B-cells?
This is called a Primary Lymphatic Nodule.
What are the Most common Lymphatic Nodule in the Superficial Cortex?
The most common type is Secondary Lymphatic Nodule.
What does the Medulla of a Lymph node consist of?
B-cells, Antibody producing plasma cells and macrophages.
What is the Route of Lymph flow through a Lymph node?
Afferent Lymphatic Vessel, Subscapular Sinus, Trabecular Sinus, Medullary Sinus, Efferent Lymphatic Vessel.
What is the Spleen?
Largest mass of Lymphatic Tish in the Body.
The functioning part of the spleen consist of 2 different kinds of Tish called “White Pulp and Red Pulp”.
What does white pulp in the Spleen function as?
This is a Lymphatic Tish, Consisting mostly of Lymphocytes and Macrophages.
What does Red pulp in the Spleen Function as?
Consisting of Blood filled venous sinuses and cords of the splenic tissue Called “Splenic Cords”.
What occurs within the White pulp of the Spleen?
B & T cells carry out immune functions.
Spleen macrophages destroy blood-borne pathogens using phagocytosis.
What occurs within the Red pulp of the Spleen?
Within Red pulp the Spleen performs 3 functions related to blood cells:
1, Removal by Macrophages of Ruptured, worn out or defective platelets and blood cells.
2, Storage of platelets, up to 1/3 of the body’s supply.
3, Production of Blood cells during fetal life.
What are Lymphatic Nodules?
Egg shaped masses of lymphatic Tish not surrounded by a capsule.
Where are Lymphatic Nodules located?
Scattered throughout the lamina propria (CT) of mucus membrane lining of the GI, Urinary & reproductive tracts , and the respiratory airways.
The lymphatic nodules in these areas are referred to as Mucosa-Associated Lymphatic Tish. (MLAT)
What is “MLAT” in reference to the Lymphatic Nodules?
These are the Lymphatic Nodules tat are located in the “Lamina Propria” (CT) of mucus membrane of various structures of the body.
What are the Large groups fo Lymphatic Nodules located around the body?
These are Tonsils, there are usually 5 tonsils.
This includes:
The single Pharyngeal Tonsil / Adenoid, 2 Palatine Tonsils & Paired Lingual Tonsils.
