Transcript The integrated view

The
INTEGRATED
View
A series of visual reminders…
A series of visual reminders…
A series of visual reminders…
A series of visual reminders…
The
whole
enchilada
Organs of the immune system…
BONE MARROW:
• Site of pluripotent stem cells.
• Those in the lymphoid lineage develop into B-cells
and T-cells.
• T-cells are “educated” in the thymus;
• B-cells are “educated” in the bone marrow.
– B-cells receive signals from STROMAL cells which
include:
• fat cells, endothelial cells, fibroblasts, and macrophages.
The THYMUS…
The distribution system…
The great escape….
Cells circulate and migrate…
The principal drainage system…
Liquids of the circulatory system
“leak out”; become interstitial
fluids.
The fluid which permeates
connective tissue constitutes a
few per cent of the total blood
volume.
This plasma is not actively
pumped; rather it is moved by
the constriction of the
surrounding musculature; as
such, the liquid becomes a
drainage system. Valves
prevent back flow.
The fluids drain into
progressively larger ducts and,
ultimately, into the thoracic duct
which returns the fluid to the
circulatory system by emptying
into the subclavian vein.
The lymph node…
The lymph node…
Lymph arrives in afferent vessels
and leaves in efferent vessels.
Afferent delivers Ag; efferent, Ab.
Node is divided into cortex,
paracortex, and medulla.
Paracortex is the command center.
There T-cells see Ag’s on stromal
cells (interdigitating dendritic cells
and macrophages); contact B-cells.
B-cells migrate to cortex and into
primary follicles;
Ag stimulation continues with Agpresentation on follicular dendritic
cells; proliferative response
transforms primary follicle into
secondary follicle.
Mature B-cells differentiate into
plasma cells that migrate to
medulla (to be away from Ag
stimulating the response)
Plasma cells secrete a single type
of Ag-specific Ab into efferent fluids.
Another view of a lymph node…
The spleen…
The spleen…
Red pulp: degradation and consumption of exhausted erythrocytes.
White pulp: site of immunological monitoring of blood.
Red and white pulp are separated by “marginal zone.”
PALS (“periarteriolar lymphoid sheaths) surround blood arteries;
arteries deliver blood to sinuses of the marginal zone. Ag’s are
displayed on dendritic cells. PALS have follicles (like lymph nodes).
MALT (mucosal-associated lymphoid tissue)
Back to the effector cells…