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Immune system Erika Castro-Dominguez Period: 1 - Coggle Diagram
Immune system
Erika Castro-Dominguez
Period: 1
Lymphatic System
Second circulatory system
Lymphatic vessels
collect and carry
away excess tissue fluid
from interstitial spaces,
eventually return to blood
lymphatic vessels are thinner than veins
but same layers
Have flaplike valves on the
inside like veins
Lymph nodes
near lymphatic vessels
contain lymphocytes,
they help the body against diseases
Lymphatic Pathways
lymphatic capillaries merge to
form larger vessels
Lymphatic vessels
form lymphatic trunk
and empty's in
veins in thoracic cavity
Lymphatic capillary
Afferent lymphatic vessel:
enter on the convex surface
Lymph node
Efferent lymphatic vessel:
Filtered lymph leaves
Lymphatic trunk
Collecting Duct
Subclavian vein
Tissue Fluid and Lymph
Tissue
fluid
Tissue fluid that entered lymphatic capillary
Lymph formation depends on fluid formation
Lymph
movement
Hydrostatic
pressure
tissue fluid drives entry of fluid into
lymphatic capillaries
Where the fluid is now called lymph
Muscular
activity
moves lymph through lymphatic vessels
Edema
accumulation of lymph in the interstitial spaces
Usually caused by
interference in the flow
such as lymphatic
vessels or tissues
are removed or disturbed
Lymphatic Tissues
& Organs
Lymphatic tissue contains
lymphocytes, macrophages,
and other cells
Tissue associated with the
digestive, respiratory, urinary, and reproductive systems
is called mucosa-associated lymphoid tissue (MALT)
Tonsils, appendix, and Peyer’spatches are compact masses of
lymphatic nodules
Encapsulated
Lymphatic organs
Thymus
Shrinks in size during the lifetime
replaced by adipose & connective tissue in the elderly
Lobules contain lymphocytes
Some mature into T cells
or T lymphocytes
leave the thymus to provide immunity
Spleen
Lies in the upper left abdominal cavity
Largest lymphatic organ
almost like lymph node but
contains blood instead
of lymph
Filters the blood and removes
damaged blood cells and bacteria
Lymph nodes
Lymph Nodes
located in groups or chains along lymphatic vessels
Lymph nodes are bean-shaped
Filtered lymph leaves lymph node
through efferent lymphatic vessels
removing many pathogens
Afferent lymphatic vessels enter on the convex surface
not found in CNS
Areas to be found
cervical, thoracic,
axillary, supratrochlear,
abdominal, pelvic,
and inguinal regions
Functions
Filter lymph: removes bacteria and cellular debris in
lymph before it's returned to the blood
Immune surveillance: Monitor body fluids with the help of lymphocytes and macrophages
lymphocyte production
Lymphocytes: attack viruses, bacteria and parasitic cells
Macrophages: engulf and destroy foreign particles, debris, and
damaged cells
Red bone marrow releases undifferentiated lymphocyte
precursors
half go to thymus, and specialize into
T lymphocytes or T cells
Make up 70 to 80% of circulating lymphocytes
some settle in the lymph nodes, spleen, and thoracic duct
Other lymphocytes become B lymphocytes or B cells
Represent 20 to 30% of circulatinglymphocytes
settle in lymphatic organs, lymph nodes,
spleen and lining of intestines
Lymphocytes require activation before they can respond to
antigens
Immune system
Pathogens
Disease-causing agents
Presence and multiplication can produce an infection
Can be bacteria, viruses, fungi or protozoans
The two
mechanism
Innate defenses
(nonspecific)
Guard against many pathogens
respond quickly
species resistance:
Not affected by diseases
of different species
Different chemical environments
body temperature that does
not provide the conditions
required by the pathogens
Presence or absence of receptors for a particular type of pathogen
mechanical barriers: Prevent the entry of
certain pathogens by providing a physical
separation of pathogens and internal tissues
unbroken skin
mucous membranes
hair
mucus
sweat
first line of defense
chemical barriers:
Chemicals that kill
many pathogens
Acidic environment:: provided by HCl in gastric juice is lethal to
some pathogens
Enzymes: such as pepsin in the stomach and lysozyme in tears,
destroy many pathogens
Interferons: hormone-like peptides secreted by lymphocytes
and fibroblasts when viruses or tumor cells are present, block
viral replication and slow tumor growth
natural killer cells:
Small group of
lymphocytes,
other than T cells
and B cells
Defend the body against viruses and cancer cells by secretingcytolytic substances called perforins, which lyse (break apart) cell membranes of pathogens
secrete substances that enhance inflammation
inflammation:
tissue response to
injury or infection
stop the spread of pathogens
and infection
Causes redness, swelling, heat, and pain
Dilation of blood vessels, to
increase of blood volume (Reason for redness)
Increased capillary permeability,
which leads to edema and heat
Increased capillary permeability,
which leads to edema and heat
Blood clotting & fibrin thread formation
Fibroblasts secrete chemicals that
produce a sac around the area to wall
off infection; inhibits spread of infection
phagocytosis: Engulfment
and digestion of pathogens,
foreign particles, and debris
active phagocytes are neutrophils and
monocytes leave bloodstream in areas of injury
Phagocytes are attracted to the injured area by chemotaxis
Neutrophils engulf smaller particles
monocytes attack larger ones
Monocytes give rise to
macrophages outside the blood, which are
either free or become fixed in various tissues
fever:when body temperature
is re-set to a higher set point
elevated body temperature
Fever provides a hostile environment for pathogens that
reproduce best under normal human conditions
causes the liver and spleen to take
up iron, reducing the amount in the blood, and keeping it from
fungi or bacteria, which need it for growth and metabolism
Phagocytic cells attack with greater vigor when the temperature
rises
Adaptive defenses
or immunity (specific)
Respond against only a specific pathogen
respond slowly
has specialized lymphocytes
secrete cytokines or antibodies
Third line of defense
Performed by lymphocytes and macrophages that recognize pathogens
Include cellular immune response and humoral immune
response
Antigen
Before birth, body makes an inventory of “self” antigens
large molecule that can trigger an immune response
T Cells and the
Cellular Immune Response
T cell activation
requires an
encounter with an
antigen-presenting cell
e.g. B cell or macrophage that
already encountered and
phagocytized the antigen
Macrophages acting as APCs digest the pathogen
display the antigenic fragments on their own cell membrane
major histocompatibility
complex (MHC)
MHC proteins help T cells recognize
displayed antigens
T cells recognize and bind to antigenic fragments that match their receptors
Cellular immune response
response
through cell-to-cell contact