Introduction by Period 6, 2014
• Vessels- A network of
lymphatic vessels, often
called lymphatics, begins
in peripheral tissues and
ends at connections to the
venous system.
• Fluid- A fluid called lymph
flows through the
lymphatic vessels. Lymph
resembles plasma but
contains a much lower
concentration of
suspended proteins.
1
Vessels and
Fluid
• Lymphocytes- Specialized cells
that preform an array of specific
functions in defending the body.
• Lymphoid Tissue and OrgansTissues are collections of loose
connective tissue and
lymphocytes. Organs are more
complex structures that contain
large number of lymphocytes and
are connected to lymphatic
vessels.
The
Lymphs
1
Functions: Part 1
• The production, maintenance,
and distribution of
lymphocytes
• The return of fluid and solids
from peripheral tissues to
blood
• The distribution of hormones,
nutrients, and waste products
from their tissues of origin to
general circulation
2
Functions: Part 2
• Lymphocytes are produced and stored within
lymphoid organs, such as spleen, thymus, and
bone marrow.
• Lymphocytes mount a defense against
invading bacteria with a immune response.
• Immunity is the body’s ability to resist
infection and disease.
2
Lymphatic Capillaries
• Smallest lymphatic vessel
• They don’t have basement
membranes, so viruses, fluid,
and bacteria can flow in to
the lymph. capillaries
• From lymph capillaries,
lymph flows into larger
vessels, then to the trunk of
the body.
3
Lymphatic Ducts
Two main Lymphatic
Ducts
 Thoracic Duct- collects lymph
from the lower abdomen.
 Right Lymphatic DuctDelivers lymph from the right
side of the body above the
diaphragm and empties into
right subclavian vein.
3
What are lymphocytes?
• Lymphocytes are specialized
cells that perform specific
functions in defending the body
They account for roughly 25%
of the circulating white blood
cell population
The blood contains three
classes of lymphocytes: T cells,
B cells, and NK cells
•
•
4
T Cells (thymus-dependant cells)- they attack foreign
cells and body cells infected by viruses. 80% of
circulating
B Cells (Bone Marrow Derived Cells)- They produce
and secrete antibodies and these bind specific
chemical targets called antigens, which are usually
pathogens. 10-15% of circulating lymphocytes
NK Cells (Natural Killer Cells)- these lymphocytes
attack foreign cells, normal cells with viruses, and
cancer cells in tissues. 5-10% of circulating lymphocytes
4
•
•
•
•
Lymphoid nodules are masses of lymphoid
tissue that are not surrounded by a fibrous
capsule.
Their size can increase or decrease,
depending on the number of lymphocytes
present at any given moment.
Lymphoid nodules are located beneath the
epithelia lining various organs of the
respiratory , digestive, and urinary systems.
We have lymphoid nodules because our food
usually contain foreign proteins that often
contain bacteria. Therefore, our lymphoid
nodules play apart in our digestive tract as an
important role as the defense in our body.
5
Common Lymphoid Nodules
5
• The tonsils, large lymphoid nodule in the walls of
the pharynx, guard the entrance to the digestive
and respiratory tracts.
• Fused lymphoid nodules dominate the walls of
the appendix, a blind pouch located near the
junction of the small in large intestine.
o When the nodules
become inflamed, an
infection develops
such as tonsillitis or
appendicitis
Lymph Organs
Lymph Nodes- small, oval shaped organs covered
by a fibrous capsule. They filter lymph fluid before
it reach the veins. Located in regions where they
can find and get rid of pathogens.
Thymus- pink gland, site of where T cells are
made. Gradually decreases in size with age.
Divided into two parts called lobules and septae.
Each one contains a central medulla. Secrete
hormones called thymosins.
6
6
• The Spleen- filters blood and removes
abnormal blood cells. Tells B cells and T cells
to circulate through blood. Located between
the stomach and the left kidney. Divided into
areas of white pulp and red pulp.
Autoimmune Disorders
7
-develop when the immune response
mistakenly targets normal body cells and
tissues.
-autoantibodies target self-antigens that
are usually ignored
-examples include Rheumatoid Arthritis and
Insulin-Dependent Diabetes Mellitus
Immunodeficiency Diseases
-either the immune system fails to
develop normally or the immune
response is blocked in some way
-severe combined immunodeficiency
disease: fail to develop either cellular or
antibody-mediated immunity
-Because the immune response doesn’t
work correctly, any mild infections can be
fatal.
-Examples= AIDS, HIV, etc…
7
Allergies
• Type I-Immediate
hypersensitivity
reactions- is a rapid
and epically severe
response to the
presence of an antigen
• The severity of this
reaction depends on
the persons location
and severity
8
• Type II-cytotoxic
hypersensitivity• the antibodies
produced by
the immune response
bind to antigens on the
patient's own cell
surfaces.
• The cross reactions
that occur following
the transfusion of an
incompatible blood
type
Allergies
• Type III-immune
complex disorders
• Result if phagocytes are
not able to rapidly
remove circulating
antigen-antibody
complexes.
• The presence of these
complexes leads to
inflammation and tissue
damage.
8
• Type IV- delayed
hypersensitivity
• Inflammatory response
that occurs two to three
days after exposure to an
antigen (i.e. poison ivy
or poison oak)