Lymhocyte Circulation and Species Differences of Lymph Node

Secondary Lymphoid Organ

mobile

Cells are highly —

Bone marrow- thymus- secondary lymphoid organs – sites of microbial invasion

lymphocyte origin

t cells

— constantly circulate around the body in the blood and tissue

blood and tissue

T cells- constantly circulate around the body in the —

blood

T cells: Predominant lymphocytes in the—

T cells

They survey the body for foreign antigens and preferentially home to sites of microbialinvasion & inflammation.

1st route

Naïve T cells bind to HEV in lymph nodes.

HEV ; lymph nodes

1st route : Naïve T cells bind to — in —

1st route

Endothelial cells- not joined by tight junctions but are linked by discontinuous “spot-welded”junctions.

spot-welded junctions

1st route : Endothelial cells- not joined by tight junctions but are linked by discontinuous —

1st route

Lymphocytes can pass easily

1st route

Migrate into the paracortex

paracortex

1st route : Migrate into the —

1st route

Endothelial surface (adhesion of WBCs)binding to selectins

selectins

1st route : Endothelial surface (adhesion of WBCs) binding to —

1st route

Activated and expressed integrins

integrins

1st route : Activated and expressed—

1st route

Complete arrest and emigration

2nd route

T cells leave the bloodstream through conventional blood vessels in tissues and are then carried to lymph nodes through afferent lymphatics.

conventional blood vessels ; tissues ; lymph nodes ; afferent lymphatics

2nd route : T cells leave the bloodstream through — in — and are then carried to — through —

efferent lymphatics.

2nd route: Leave the lymph node through —

Afferent lymph (sheep)

85 % T cells, 5 % B cells, 10% dendritic cells.

85 % T cells, 5 % B cells, 10%dendritic cells.

Afferent lymph (sheep) - —

2nd route

Afferent lymph (sheep)- 85 % T cells, 5 % B cells, 10%dendritic cells.

2nd route

Efferent lymph- 75 % T cells, 25 % B cells

Efferent lymph

- 75 % T cells, 25 % B cells

75 % T cells, 25 % B cells

Efferent lymph- —

thoracic duct

Efferent- large lymph vessel : —

Pigs, hippotamus, rhinoceros and some dolphins

consist of several lymphoid “nodules”

Pigs, hippotamus, rhinoceros and some dolphins

Cortex of each nodule- toward the center of the node

cortex ; center

Pigs, hippotamus, rhinoceros and some dolphins: — of each nodule- toward the — of the node

Pigs, hippotamus, rhinoceros and some dolphins

Medulla is at the periphery

medulla

Pigs, hippotamus, rhinoceros and some dolphins: — is at the periphery

single afferent ; central cortex ; lymph sinus

Pigs, hippotamus, rhinoceros and some dolphins: Each nodule has — lymphatic enters the — as —

cortex

Pigs, hippotamus, rhinoceros and some dolphins: surrounds the lymph sinus

efferent vessels

Pigs, hippotamus, rhinoceros and some dolphins: — drain the region between nodules

cortex and paracortex

Pigs, hippotamus, rhinoceros and some dolphins: — - similar structures

medulla

Pigs, hippotamus, rhinoceros and some dolphins: contains few sinuses but consists of a dense of cells that are relatively impermeable to cells in the lymph.

impermeable

Pigs, hippotamus, rhinoceros and some dolphins: Medulla- contains few sinuses but consists of a dense of cells that are relatively— to cells in the lymph.

medulla

Pigs, hippotamus, rhinoceros and some dolphins: Few cells migrate to —

HEV

Pigs, hippotamus, rhinoceros and some dolphins: T cells enter through the —

T cells

Pigs, hippotamus, rhinoceros and some dolphins: — enter through the HEV

marine mammals

Structure is highly variable

conventional

Bottlenose dolphins- —

conventional

Striped dolphins- —

inverted

Mediastinal- —

conventional

Mesenteric- —

marine mammals

Both forms of lymph node may be present in a single individual.