[MT] Immune System pt.5 - Secondary Lymphoid Organs

Organs that provide the environment for the proliferation and maturation of cells in the adaptive immune response

SECONDARY LYMPHOID ORGANS

What antigens are presented for processing

SECONDARY LYMPHOID ORGANS

Secondary Lymphoid Organs are made up connective tissue supported by ----- and -----

reticular cells and fibers

Secondary Lymphoid Organs reticular cells and fibers are surrounded by a large number of ----- and ----

lymphocytes
antigen presenting cells

what lymphoid tissue is encapasulated

dense lymphoid tissue

what lymphoid tissue is unencapsulate ot with a hemicapule

loose or diffuse lymphoid tissue

Secondary Lymphoid Organs have predominance of ---

lymphocytes

Secondary Lymphoid Organs formation of

lymphoid nodules

lymphoid nodules are also called

lymphatic nodules

characteristic feature of all secodary lymphoid organs

lymphoid nodules

Lymphoid nodules are spherical cluster of ----- that characterize ALL secondary lymphoid organs

B lymphocytes

Lymphoid nodules compose of large ----------- of B lymphoctes

spherical aggregates

Lymphoid nodules may appear differently depending on the activity of ------ within the organ

immune cells

2 stages of development of lymphoid nodule

primary lymphoid nodules
secondary lymphoid nodules

Stage of Lymphoid nodule which is represented as aggregates of smaller B cells with uniform cell density and staining

Primary lymphoid nodules

Stage of Lymphoid nodule that contain mature but naive B cells

Primary lymphoid organs

Stage of Lymphoid nodule that does not have germinal center

Primary lymphoid organs

Stage of Lymphoid nodule that cells are in a resting state

Primary lymphoid organs

Stage of Lymphoid nodule that show aggregates of large B lymphocytes with more euchromatic cells, seen as the lighter germinal center that represents the active sites of lymphocyte proliferation

Secondary lymphoid nodules

In secondary lymphoid nodules, this is where B cells proliferate and differentiatte after antigen exposure

Germinal Center

In secondary lymphoid nodules, this surrounds the germinal center, contains inactive B cells

Mantle Zone

In secondary lymphoid nodules, this is the outermost layer, contains medium-sized lymphocytes in a reticular framework

Marginal Zone

Lymph nodes is distribute throughout the body along the ----

lymphatic vessels

shape of Lymph Nodes

Bean shaped

Lymph nodes are en---

encapsulated

Where does the afferent LV enter?

convex surface

Where does the efferent LV leave?

concave hilum

Where does the blood vessels and nerve penetrate the organ?

concave hilum

Filter lymph that defend against the spread of antigens and tumor cells that have invaded the different organ tissues

Lymph Nodes

Lymphatic vessels coming from the right upper side of the body will drain into the ----------, returning lymph to the bloodstream by the -------

right lymphatic duct
subclavian vein

Lymphatic vessels from the rest of the body, the lower extremities, the left side of the trunk, the arms, and the face will drain lymph into the ------- and it will join the ------------ to bring lymph back to the circulation

thoracic duct
left subclavian veins

what lymphatic vessel bring lymph into the node?

Afferent lymphatic vessel

Afferent lymphatic vessels travel through

subcapsular sinus
cortical sinuses
medullar sinuses
efferent vessels

Lymph carries ------ and ------ for immune surveillance

antigen-presenting cells (APCs)

antigens

Lymph node is encapsulate by ---------- extending as ------ within the lymph node parenchyma

dense connective tissue
trabeculae

provides the main structural support for the lymph node and forms the core of lymphatic nodules in the cortex and the medullary cords and sinuses in the medulla

Reticular connective tissue

region of lymph node where: contains the lymphoid nodules

Cortex

region of lymph node where: Branches into cortical and trabecular sinuses.

Cortex

region of lymph node where: Separated from the capsule by the subcapsular sinus.

Cortex

region of lymph node where: deeper extension of the cortex without lymphoid nodules

Paracortex

region of lymph node where: T-cell-rich area (main site of antigen presentation).

Paracortex

region of lymph node where: Contains high endothelial venules (HEVs) → Allows lymphocytes to enter the lymph node from the blood.

Paracortex

region of lymph node where: has medullary cords and sinuses

Medulla

region of lymph node where: Innermost region of the lymph node.

Medulla

Contain B cells, plasma cells, and macrophages.

Medullary cords

Channels that collect filtered lymph before exiting via efferent lymphatic vessels.

Medullary sinuses

region of lymph node where: Separated from the connective tissue capsule by the subcapsular sinus, which branches out into cortical and trabecular sinuses

Cortex

region of lymph node where: presence of lymphoid nodules with or without germinal center

cortex

Region between cortex and medulla without lymphoid nodules

Paracortex

region of lymph node where: Contains mostly T lymphocytes (CD3+ T cells).

Paracortex

Paracortex region contain ______________ which allow lymphocyte to migrate from the blood into the lymph node

high endothelial venules (HEVs)

In ------------------ the T cell rich pracortex is more prominently stained

immunohistochemical staining

region of lymph node where it is light staining

Medulla

Two distinct feature of Medulla

Medullary cord
Medullary Sinuses

Feature of Medulla where it is brached cord like masses of lymphoid tissue containing both B and T lymphocytes and plasma cells

Medullary cords

Feature of medulla that is islands of lymphoid tissue

Medullary cords

Feature of medulla Dilated spaces separating the medullary cords that are continuous with the cortical sinuses.

Medullary sinuses

Medullay sinuses converge at the hilum of the lymph node to drain into the -------

efferent lymphatic vessels

Reticular cells and plenty of macrophages are found in the -----

medullary sinuses

Region of the lymph node containing B lymphocytes and lymphoid nodules

Cortex

Region of the lymph node containing T lymphocytes, lacks nodules, and has high endothelial venules (HEVs)

Paracortex

Region of the lymph node containing B and plasma cells, composed of medullary cords and sinuses

Medulla