IM Organs and Microenvironemnts

The lymphatic system functions

Regulation of fluid in tissues, carries waste products to blood stream filtered by the liver or kidneys, absorb fats from the intestine, and part of the immune system

Primary lymphoid organs

Fetal liver, adult bone marrow, and thymus gland

Primary lymphoid is responsible for

T/B cells are born and site of immune cell production

Secondary lymphoid organs

Spleen, lymph nodes, and lymphoid tissues (MALT and CALT)

Secondary lymphoid is responsible for

Initiation of immune response

Lymph

Protein rich fluid derived from plasma

Lymphatic vessels are responsible for

Circulation of excess lymph and filtering through the lymph nodes back into blood

Immune cells travel through the body to perform surveillance by the

Blood system and lymphatic system

Bone marrow

Responsible for development and replenishment of blood cells

BM structure (osteoblasts)

Bone growth and HSC differentiation

BM (endothelial)

Line blood vessels and HSC differentiation

BM (reticular)

Processes that connect cells to bone and blood vessels

BM (sympathetic neurons)

Control release of hematopoietic cells)

Bone marrow is the site for

B cells (migrate to secondary lymphoid tissue) and T cells (migrate to the thymus for further maturation)

BM endosteal niche

Directly surrounds bone

BM vascular niche

Directly surrounds vessels

Lymph nodes

Organized encapsulated organ containing follicles, germinal centers, stratified area, and process local antigens

Spleen

Organized encapsulated organ, stratified, and process local antigens

Mucosal associated lymphoid tissue (MALT)

Tonsils and appendix

Lymph node cortex

Contains follicles (Lymphocytes and macrophages)

Lymph node paracortex

Populated by T cells and dendritic cells

Lymph node medulla

Populated with plasma cells with antibody secretion

Primary follicle

Not activated by antigen composed of B cells and dendritic cells

Secondary follicle

Activated by antigen and ring of B cells (germinal center)

MALT/CALT function

Intercept invaders that enter the body by different routes