Secondary Lymphoid Organ (Part 1 - Lymph Node)

huge diversity of organs

Responds to a — than an animal may encounter.

antigen-specific lymphocytes

Includes—can encounter their target antigens.

late in fetal life

Arise — and persists in adults.

adults

Arise late in fetal life and persists in —

enlarges

— in response to antigenic stimulation.

antigenic stimulation.

Enlarges in response to —

antigen trapping

facilitates — and provides the optimal environment for the initiation of immune responses

initiation of immune responses

facilitates antigen trapping and provides the optimal environment for the —

blood and lymphoid systems

Connected to both the —

lymph node

Round/ bean-shaped lymphatic vessels filters placed on lymphatic vessels

lymphatic vessels filters

Round/ bean-shaped — placed on lymphatic vessels

lymphatic vessels

Round/ bean-shaped lymphatic vesselsfilters placed on —

lymph

Can sample antigens in —

capsule

filled with lymphocytes,macrophages and dendritic cells through which lymphatic sinuses penetrate

lymph fluid

Filter for

peripheral cortex, central-medulla, paracortex

interior of lymph node is divided into 3 regions:

peripheral cortex

B cells predominate, arranged in follicles

central-medulla

Lymph draining sinuses separates by medullary cords

medullary cords

central-medulla: Lymph draining sinuses separates by —

central-medulla

Plasma cells, macrophages, memory T cells

paracortex

T cells and dendritic cells predominate

T cells and dendritic cells

paracortex: — predominate

Germinal Centers (Cortex)

B cells grow, mutate and mature

B cells

Germinal Centers (Cortex):— grow, mutate and mature

Germinal Centers (Cortex)

Ovoid clusters of cells divided into a light and darkzone

light and dark zone

Germinal Centers (Cortex): Ovoid clusters of cells divided into a —

Germinal Centers (Cortex)

Originates when a few antigen-specific B cells enter a follicle

Germinal Centers (Cortex)

Divide rapidly to become the centroblasts that form the dark zone.

centroblasts ; dark zone

Germinal Centers (Cortex): Divide rapidly to become the — that form the —

Germinal Centers (Cortex)

Somatic mutation

B Light zone-

Germinal Centers (Cortex): site where immunoglobin class switching memory B cell formation

B Light Zone

Rich in antigen- trapping follicular dendritic cells andCD4+ cells

antigen-trapping follicular dendritic cells and CD4+ cells

Germinal Centers (Cortex): Rich in —

Rich in antigen- trapping follicular dendritic cells andCD4+ cells

HEVs (High Endothelial Venule)- Paracortical cord

are lined with tall, rounded endothelial cells

HEVs (High Endothelial Venule)- Paracortical cord

Surrounded reticular cells by concentric layers of fibroblastic

PERIVENULAR CHANNEL

Narrow space of HEV

chemical signals

cells coming in and going in response to —

reticular fibers

signals —

reticular fibers

provides a scaffolding of the lymph node

reticular fibers

Serve as conduits for the rapid transmission of signaling molecules

conduits

consists of collagen fibers ensheated by fibroreticular cells (not continuous)

lymph node

Facilitate the interactions between antigen-presenting cells and antigen-sensitive T and B cells.

chemokines

small proteins which stimulate the migration of cells

migration of cells

Chemokines- small proteins which stimulate the—

lymph node

Control the relocation and recirculation of lymphocytes ensuring they end upin the right place.

active and motile

T and B cells are highly —