Lymphatic organs & Tissue

Question 1

What are Primary Lymphatic Organs used for by the Lymphatic System?

Answer 1

These are the sites where Stem cells divide and become “Immunocompetent”.

Question 2

What does it mean for a cell to be Immunocompetent?

Answer 2

This means the cell is capable of mounting an immune response.

Question 3

What are the Primary lymphatic Organs?

Answer 3

Red bone marrow & Thymus.

Question 4

What does the Red bone marrow and Thymus do as the Primary Lymphatic Organs?

Answer 4

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”.

Question 5

What are the Secondary Lymphatic Organs and Tissues?

Answer 5

These are the sites where most immune responses occur, including lymph nodes, Spleen, and lymphatic nodules.

Question 6

What is the Thymus?

Answer 6

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.

Question 7

What do Dendritic cells do in the Thymus?

Answer 7

They help with the maturation process of Pre T-cells.

Question 8

What do the Specialized Epithelial cells do in the Thymus?

Answer 8

Each of the cells in the Cortex help educate Pre T-cells in a process called positive selection.

Question 9

Only about 2% of the maturing T-cells survive in the thymus cortex, what happens to the rest of the cells?

Answer 9

The remaining cells Die Via Apotosis, The surviving T-cells enter the Medulla.

Question 10

What are Lymph Nodes?

Answer 10

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”.

Question 11

What is the functioning part of the Lymph node?

Answer 11

Parenchyma is divided into Superficial Cortex (Inner and outer) and a Deep Medulla.

Question 12

What is within the Outer cortex of the Superficial cortex of the lymph node?

Answer 12

B-cells called Lymphatic Nodules.

Question 13

What is a Lymphatic Nodule consisting Primarily of B-cells?

Answer 13

This is called a Primary Lymphatic Nodule.

Question 14

What are the Most common Lymphatic Nodule in the Superficial Cortex?

Answer 14

The most common type is Secondary Lymphatic Nodule.

Question 15

What does the Medulla of a Lymph node consist of?

Answer 15

B-cells, Antibody producing plasma cells and macrophages.

Question 16

What is the Route of Lymph flow through a Lymph node?

Answer 16

Afferent Lymphatic Vessel, Subscapular Sinus, Trabecular Sinus, Medullary Sinus, Efferent Lymphatic Vessel.

Question 17

What is the Spleen?

Answer 17

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”.

Question 18

What does white pulp in the Spleen function as?

Answer 18

This is a Lymphatic Tish, Consisting mostly of Lymphocytes and Macrophages.

Question 19

What does Red pulp in the Spleen Function as?

Answer 19

Consisting of Blood filled venous sinuses and cords of the splenic tissue Called “Splenic Cords”.

Question 20

What occurs within the White pulp of the Spleen?

Answer 20

B & T cells carry out immune functions.

Spleen macrophages destroy blood-borne pathogens using phagocytosis.

Question 21

What occurs within the Red pulp of the Spleen?

Answer 21

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.

Question 22

What are Lymphatic Nodules?

Answer 22

Egg shaped masses of lymphatic Tish not surrounded by a capsule.

Question 23

Where are Lymphatic Nodules located?

Answer 23

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)

Question 24

What is “MLAT” in reference to the Lymphatic Nodules?

Answer 24

These are the Lymphatic Nodules tat are located in the “Lamina Propria” (CT) of mucus membrane of various structures of the body.

Question 25

What are the Large groups fo Lymphatic Nodules located around the body?

Answer 25

These are Tonsils, there are usually 5 tonsils.
This includes:
The single Pharyngeal Tonsil / Adenoid, 2 Palatine Tonsils & Paired Lingual Tonsils.