Transcript Non-specific Immunity

Blood and Lymph
• Components of Blood
– Plasma
– Cells—RBC’s, WBC’s,
Platelets
• Production and
elimination of blood
cells
• WBC’s move in and
out of blood
• Role of lymph vessels
• Lymph organs
Components of blood—plasma
• Plasma is water with dissolved
solutes
• 46-63% of blood volume is plasma
• Plasma is 92% water
• Dissolved proteins make 7%
– Albumins—for osmotic pressure,
transport
– Globulins—immune function,
transport
– Fibrinogen—clotting
– Regulatory proteins/hormones
• Other solutes make 1% including
– salts/electrolytes—why important?
– organic nutrients (what is included
here?)
– Organic wastes (from cellular
respiration and cell breakdown)
Components of blood—cells
• Red Blood Cells (RBC’s, erythrocytes): Full of
Hemoglobin (Hb) for oxygen transport
• Platelets: Cell pieces important in clotting
• White Blood Cells (WBC’s, leukocytes):
Immune function
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Neutrophils
Eosinophils
Basophils
Monocytes
Lymphocytes
Red Blood Cells (RBC) Fun Facts
• One drop of blood has 250 million RBC’s
• Adult human has total of 25 trillion RBC’s—1/3 of all cells in the body
• Each RBC lives about 120 days and travels 700 miles. Membrane rupture
or other damage is noticed by phagocytes which then engulf the cell
• One percent of RBC’s are replaced each day at a rate of about 3 million per
second
• Each RBC contains about 250 million Hb molecules
• So, number of Hb molecules in body is about equal to stars in the universe
How old and damaged RBC’s are processed
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Blood Cell
Production
RBC production/
only in red bone
marrow
WBC’s begin
development in bone
marrow
– Monocytes enter
bloodstream and
complete
development into
macrophage in
peripheral tissues
– Many Lymphoid
Stem Cells
complete
development in
lymph tissues
(thymus, spleen,
lymph nodes)
– Some Band Cells
complete
development in
bloodstream.
Blood Cell Production—
focus on lymphocytes (T-cells and B-cells)
– Many Lymphoid
Stem Cells
complete
development in
lymph tissues
(thymus, spleen,
lymph nodes)
• WBC’s move out
of blood to fight
infections—
immune
response
• Some stay in the
peripheral
tissues as
macrophages
• Others move
back into blood
via lymph
vessels
(lymphocytes)
• Fluid also leaks
from capillaries
and can be
taken back into
bloodstream
through lymph
vessels
Where is immune
response needed?
More on immunity coming up…but how do these
immune cells (WBC’s) move around the body?
Lymphatic vessels
• Open-ended lymph capillaries pick up
interstitial fluid and also WBC’s
• Gradual movement through flimsy lymph
vessels takes cells to lymphoid organs
• Eventually fluid returns to circulation
through major lymph vessels
• Return of lymph to circulatory system is at subclavian veins
• Lymph travels through lymphoid organs:
lymph nodes/nodules, thymus, spleen
Lymph nodes
• At lymph nodes, lymph is “filtered” by
presence of lymphocytes (B-cells).
• Most foreign antigens are removed from
lymph
• Incoming (afferent lymph) is from lymph
capillaries—picked up in tissues where
infections/foreign invaders might be
present
• Outgoing (efferent) lymph is returned to
ever larger lymph vessels and then
back into blood circulation at subclavian
veins
• Presentation of antigens to initiate
immune response can also happen in
lymph nodes
• Lymph nodes are clustered at sites
where blood is returning from major
regions of body, like axilla and groin
Lymphoid
nodules
• Work much
like lymph
nodes, but
closer to
site of
potential
entry of
foreign
invaders
• Tonsils,
Wall of
intestines
• Site of development of
development and clonal
selection of T-cells
(more on this later)
• Draped over
mediastinum and great
vessels
• Much larger early in life
through adolescence
• In elder individuals, can
be tiny, impossible to
see
• Produces hormones
that stimulate
lymphocyte maturation
Thymus
Spleen
• Left upper quadrant
of abdominal cavity
• Tears/ruptures
easily on impact
• Hard to repair, but
can be removed
with little affect—
higher risk of
bacterial infection,
especially
pneumococcal
bacteria
• Spleen is site of
large concentration
of lymphocytes that
“filter” blood, much
like lymph nodes
work on lymph
WBC/Leukocyte function in immunity
Coming up next: The Immune Response