Lymphatic and Immune system
• Chapter 17
Lymphatic
System
• System consists of
– Lymph fluid
– Lymphatic vessels
– Structures and organs
consisting of
lymphatic tissue
– Red bone marrow
– Lymphocytes
Tortora
Pages 454-455
Functions of
Lymphatic System
• Draining interstitial
fluid
• Transporting lipids
and lipid soluble
vitamins A,D, E, and
K
• Carries out immune
responses
Tortora
Page 456
Lymphatic and Interstitial fluid
• Same fluid - different areas.
– Interstitial fluid bathes cells.
– Lymphatic fluid is I.F. in lymphatic vessels.
• Contains same materials as plasma except no proteins
Lymphatic capillaries
– Lie between cells
– Open
– Collect interstitial
fluid.
– Fluid moves due to
pressure.
– Flaps open, allow fluid
in, then close
Tortora 456
Lymphatic Vessels
• Lymphatic vessels
– Carry lymph fluid
– Similar structure as
veins with
– Thinner walls & more
valves.
– Skeletal and muscular
pumps move it
towards the heart.
Tortora pg 457
Return to veins
• Lymphatic fluid is
returned to
circulatory system
via the jugular &
subclavian veins
• 20 L of plasma
become IF every day
• 17 L goes back to
heart via the veins
• 3 L becomes lymph
Tortora
456-457
Lymph Nodes
– Located along
lymphatic vessels.
– Arranged in groups.
– Afferent vessel leads
to node.
– Efferent leads away.
– Valves do not let
lymph fluid move
backwards.
Tortora pg 458-459
Lymphatic nodes
– 600 located in the body
– Concentrated at axillae,
mammary glands, throat
and groin
– Foreign materials are
filtered and destroyed in
nodes.
– Macrophages destroy by
phagocytosis
– Lymphocytes destroy by a
variety of immune
responses
Tortora pg 458
Macrophages
Two cross sections of a lymph node: macrophages, which appear
as red in the top image, are sticky cells that act like flypaper,
trapping viruses and bacteria when they enter the lymph node.
Green and blue show other structural elements of the node. In the
bottom picture, B cells are red and the structural elements of the
node are in green and blue
Swollen lymph nodes
Tonsils & spleen
• Tonsils:
– Large nodules grouped
together.
– Contains T and B
lymphocytes.
• Spleen
– Largest mass of lymphatic
tissue.
– Stores blood.
– Stores 1/3rd of the body’s
platelets
– Destroys broken RBCs &
platelets.
Thymus gland
– Contains T cells, dendritic
cells, and macrophages.
– Immature T cells arrive
here from the red bone
marrow.
– 2% “graduate” to be
mature T cells.
– Mature T cells leave the
thymus via the blood, are
carried to the lymph
nodes, spleen, and other
lymphatic tissues.
Tortora 458
Lymph Circulation
• Fluid from plasma of
blood.
• Interstitial fluid.
• Lymph Vessels and nodes
– Lymphatic capillaries
– Lymphatic vessels.
– Lymph nodes.
• Back to plasma.
Thursday 5/8/03
Pages 383-388
Lymph Circulation
• Lymph fluid is moved by;
– Skeletal muscles compressing
vessels.
– Valves insure one way flow.
• Edema
– Fluid gain in the interstitial
spaces.
– Can be due to blocked
lymphatic vessels or nodes.
Thursday 5/8/03
Pages 383-388
Innate Resistance to
Disease
• Pathogens are disease
causing organisms.
• Pathogens produce
toxins or toxic waste
products.
• Your ability to ward off
pathogens is resistance.
• Lack of resistance is
susceptibility.
Monday 5/12/03
Pages 388-388
Skin & Mucous
Membranes
• Skin is 1st defense
against pathogens.
• Mechanical factors
– Many layers of epithelial
cells.
– Role of keratin.
– Role of Mucus membranes.
– Mucus
– Cilia
– Role of lacrimal apparatus
– Role of Saliva
Monday 5/12/03
Pages 388-388
Skin & Mucous
Membranes
• Chemical Factors
factors;
– Oil glands secrete
sebum.
– Perspiration
– Lysozymes
– Gastric juice
– Vaginal Secretions.
Monday 5/12/03
Pages 388-388
Defenses Against
Microbes
• Second line of defense.
– Interferon
• Proteins produced by
cells infected by
viruses.
• Binds to receptor sites
of other cells.
– Complement
• Group of about 20
proteins.
• Found in the plasma of
blood.
• Inhance immune system.
Monday 5/12/03
Pages 388-388
Defenses Against
Microbes
• Natural killer cells
– Type of lymphocyte.
– Ability to kill microbes and
some cancer cells.
– Located in spleen, lymph
nodes, bone marrow, and
blood.
• Phagocytes
– Macrophages are
monocytes that morph.
• Wandering and fixed.
– Neutrophils
• Hi
Monday 5/12/03
Pages 388-388
Phagocytosis
• Chemotaxis
– Phagocytes move towards
higher concentration of
chemicals.
• Adherence
– Phagocytes attach to
microbe.
– Role of complement.
• Ingestion
– Pseudopod surrounds
microbe.
– Phagocytic vesicle is formed.
– Vesicle fuses to lysosome.
– Microbe is digested.
– Wastes are released by
exocytosis.
Monday 5/12/03
Pages 388-388
Inflammation
• Caused by pathogens,
abrasions, chemical
irritations.
• Symptoms
– Redness
– Pain
– Heat
– Swelling
Monday 5/12/03
Pages 388-392
Inflammation
• Stages of
inflamation
– Vasodialation &
increased
permeability of blood
vessels.
– Phagocyte migration.
• Usually within an
hour.
• Chemotaxis &
emigration
• Repair
Monday 5/12/03
Pages 388-392
Types of Immunity
Monday 5/12/03
Pages 388-392
• Immunity refers to “specific” resistance to
certain pathogens.
• An antigen is any substance that triggers an
immune response.
• Acquired immunity is gained due to contact
with an antigen.
Types of Immunity
•
Monday 5/12/03
Pages 388-392
Four types of acquired immunity:
1. Naturally acquired active immunity.
•
Response to pathogens in every day life.
•
Natural transfer of resistance. Nursing baby.
•
Acquired through vaccinations.
•
Injection of antibodies.
2. Naturally acquired passive immunity.
3. Artificially acquired active immunity.
4. Artificially acquired passive immunity.
Types of Immunity
Tortora
Pages 428-437
• Two forms of adaptive immunity:
– Cell mediated immunity
• Cells directly attack specific antigen (pathogens)
– Antibody mediated immunity
• Antibodies are produced to attack specific
antigen.
– Self tolerance is critical
•
Lack of self tolerance results in autoimmune diseases
T Cells and Cell
Mediated Immunity
•
Role of MHCs
–
–
•
Major
histocompatibility
complex proteins
Role of MHCs in
transplants
T Cells destroy
antigen
–
–
–
Macrophages present
antigen to T cells.
T cells sensitize.
T cells clone.
Tortora
Pages 428-437
Antigens and
Antibodies
• Antigens are
chemical
substances
not recognized
as self.
•
–
–
–
Whole pathogens
Toxins
Parts of pathogens
Antibodies are
plasma proteins
called globulins
Tortora
Pages 428-437
B Cells and AntibodyMediated immunity
• Antibodies are
proteins
produced by
plasma cells.
–
–
–
–
Converted B lymphocytes.
B lymphocytes were
shown the antigen by
macrophages.
B cells now recognize
antigen.
Some B cells become
memory cells,
Tortora
Pages 428-437
B Cells and AntibodyMediated immunity
• Primary response
–
Slower to develop
–
Much faster and
stronger.
• Secondary
response
Tortora
Pages 428-437
Action of Antibodies
• Neutralizing the
antigen.
• Immobilize
bacteria.
• Agglutination of
antigen.
Tortora
Pages 428-437
Structure of
Antibodies
• Made by B
lymphocytes
• Shaped like a “Y”
• One arm is always
the same.
• Other two arms
are specifically
shaped to antigen.
• B cells become
“memory cells”.
Tortora
Pages 428-437