CHAPTER 16: LYMPHATIC SYSTEM AND IMMUNITY
OBJECTIVES:
1.
Name the organs that compose the lymphatic system and give three general functions
performed by this system.
2.
Trace the flow of lymph from interstitial tissues to the bloodstream.
3.
Discuss the function of anchoring filaments that surround lymphatic capillaries.
4.
Name four tissues that do not contain lymphatic capillaries.
5.
Give the special name for lymphatic capillaries within the wall of the small intestine.
6.
Distinguish between an afferent and efferent lymphatic vessel.
7.
Explain how lymphatic vessels are similar to veins.
8.
List the six primary body regions drained by lymphatic trunks.
9.
Name the two lymphatic collecting ducts and indicate the portion of the body that is
drained by each.
10.
Name the vein that each of the two collecting ducts deposit their lymph.
11.
Discuss the composition of interstitial fluid and lymph.
12.
List the functions of lymph, noting its major function.
13.
Explain the forces involved in the movement of lymph.
14.
Name the condition that occurs when lymphatic flow is obstructed.
15.
Discuss the structure, location, and major function of lymph nodes.
16.
Discuss the structure, location, and major function of the spleen.
17.
Distinguish between the body fluids filtered by lymph nodes and those filtered by the
spleen.
18.
Name the cell responsible for the filtering action of the lymph node and spleen.
19.
Discuss the structure, location, and major function of the thymus.
20.
Name the hormone secreted by the thymus that causes maturation of lymphocytes that
have migrated to other tissues.
21.
Describe what happens to the thymus as one ages.
22.
Define the term pathogen.
23.
Distinguish between the body's two types of defense mechanisms against infections.
24.
Define the term nonspecific resistance and discuss the body's six major mechanisms.
25.
Name the antibacterial enzyme present in tears.
26.
Discuss how interferons, defensins, and collectins aid in fighting infection.
27.
List the cardinal signs of inflammation.
28.
List the steps involved in the inflammatory process.
29.
Discuss the importance of phagocytosis, and indicate the origin of phagocytic cells.
30.
Define the term specific resistance/ immunity.
31.
Define the term antigen, and discuss how antigens cause immune responses to occur.
32.
Discuss the origin and maturation of lymphocytes.
33.
Discuss the process by which an immune response occurs, beginning with the “antigenpresenting cell”.
34.
Distinguish between T cells and B cells.
35.
Distinguish between Cell-Mediated Immunity (CMI) and Antibody-Mediated (or
humoral) Immunity (AMI).
36.
Discuss the general structure of an antibody (immunoglobulin [Ig]).
37.
Name the five major classes of immunoglobulins and list the major characteristics of
each.
38.
Name the most abundant Ig.
39.
Name the only Ig that can cross the placenta.
40.
Name the Ig produced during a primary immune response (IR).
41.
Name the Ig produced in abnormal amounts during allergic reactions.
42.
Discuss the many actions of antibodies.
43.
Distinguish between agglutination, precipitation, neutralization, and lysis.
44.
45.
Name the positive feedback mechanism that is activated by antibodies and list its effects.
Compare and contrast a primary IR vs. a secondary IR.
46.
Discuss the four practical classifications of immunity.
47.
Explain how immediate-type allergic reactions occur and proceed.
48.
Name the four types of transplants performed.
49.
Discuss the major problem that occurs in autoimmune disorders, and list some possible
causes of autoimmunity.
50.
I.
Explain the theory of “microchimerism”, as it relates to autoimmunity.
INTRODUCTION
The lymphatic system is closely associated with the cardiovascular system. The primary
organs of the lymphatic system are the bone marrow and thymus gland, and the
secondary lymphatic organs include the lymph nodes and spleen. These organs work
together to transport excess tissue (interstitial) fluid to the blood stream, transport dietary
fat, and help defend the body against disease-causing agents.
II.
LYMPHATIC PATHWAYS
Lymphatic pathways begin as lymphatic capillaries, which come together to form
afferent lymphatic vessels, which lead to lymph nodes. The vessels that leave the lymph
nodes are called efferent lymphatic vessels, which come together to form lymphatic
trunks, which lead to two collecting ducts, which finally join the subclavian veins,
where the lymph enters the cardiovascular system.
See General Overview Figure 16.1, page 609 and Fig 16.7, page 611.
A.
Lymphatic capillaries:
See Fig 16.2, page 609 and Fig 16.8, page 611.
B.
1.
are microscopic closed-ended tubes that extend into interstitial spaces;
2.
receive lymph through their thin walls;
3.
are associated with anchoring filaments, which serve an important
function during edema (discussed later);
4.
are located throughout the body, except in:
a.
avascular tissues;
b.
CNS;
c.
splenic pulp;
d.
bone marrow.
5.
include lacteals that are lymphatic capillaries within villi of the small
intestine.
Lymphatic vessels (LV): See Fig 16.3, page 609, 16.4 & 16.5, page 610.
1.
are formed by the merging of lymphatic capillaries;
2.
have walls similar to veins and possess valves that prevent backflow of
lymph;
3.
II.
lead to lymph nodes as "afferent" LVs, leave lymph nodes as "efferent"
LVs, and then merge into lymphatic trunks.
LYMPHATIC PATHWAYS
C.
Lymphatic trunks:
See Fig 16.4, page 610.
1.
drain lymph from relatively large body regions;
2.
Principal lymphatic trunks include the following:
a.
b.
c.
d.
e.
f.
3.
D.
2.

pass their lymph into venous blood by joining one of two collecting ducts.
Collecting ducts: See Fig 16.6, page 610.
1.

lumbar;
intestinal;
bronchomediastinal;
subclavian;
jugular;
intercostal.
Two within the thoracic cavity:
a.
right lymphatic duct drains the right upper body (25% of total
body);
b.
thoracic (left lymphatic) duct drains the remaining 75% of the
body's lymph;
join the subclavian veins.
See the above figures to study the relationship of lymphatic system to
cardiovascular system.
See Summary Figure 16.7, page 611.
III.
TISSUE FLUID AND LYMPH
A.
Tissue Fluid Formation
1.
Tissue fluid is blood plasma that has passed through cardiovascular
capillary walls into interstitial spaces, minus large plasma proteins.
2.
Recall the constituents of plasma from Chapter 14:
a.
primarily water
b.
dissolved substances including small plasma proteins, nutrients,
wastes, gases, electrolytes, enzymes and hormones.
B.
Lymph Formation
1.
As protein concentration in interstitial spaces increases, its pressure
increases.
2.
Increasing pressure forces tissue fluid into lymphatic capillaries.
3.
This fluid is now called lymph.
4.
Lymph formation prevents accumulation of excess tissue fluid (i.e.
prevents edema).
C.
Lymph Function
1.
returns small leaked plasma proteins back to the blood
stream.
2.
transports foreign particles to the lymph nodes.
3.
transports lipids and lipid-soluble vitamins absorbed in GI tract to
bloodstream.
D.
Lymph Movement
1.
2.
Lymph Flow
a.
Lymph is under low pressure and may not flow readily without aid
from external forces (similar to venous return).
o
The squeezing action of skeletal muscles aids movement.
o
The low pressure in the thoracic cavity created by breathing
movements, moves lymph up from abdominal to thoracic
region.
o
Recall the presence of one-way valves.
Obstruction of lymph movement
a.
Any condition that interferes with the flow of lymph results in
edema.
o
Edema = accumulation of excess interstitial fluid leading to
swelling of tissues.
b.
Tissue swelling pulls on anchoring filaments making openings
between cells even larger so that more fluid can move into the
lymphatic capillary (i.e. reducing swelling). See Fig 16.8, p. 611.
c.
The surgical removal of lymph nodes causes obstruction and
results in edema (i.e. accompanying mastectomy).
IV.
LYMPHATIC TISSUES
A.
Introduction
Lymphatic tissue occurs in the body in various forms.
1.
2.
3.
4.
B.
When it is not encapsulated, it is called diffuse lymphatic tissue (i.e.
found in submucosa of mucous lining).
When it is aggregated into a solitary, oval-shaped mass, it is called a
lymphatic nodule (i.e. tonsils, and recall the lymphatic nodule in the
small intestine model).
Primary lymphatic organs are the sites of production of immunocompetent
cells, B cells and T cells. These cells can carry out an immune response.
a.
bone marrow (red)
b.
thymus.
Secondary lymphatic organs are the sites where most immune responses
occur.
a.
lymph nodes
b.
spleen.
Lymph Nodes
1.
Structure of a lymph node (See Fig 16.9, page 612.)
a.
Overview: Lymph nodes are located along lymphatic pathways,
contain lymphocytes and macrophages, which destroy invading
microorganisms.
b.
Size is usually less than 2.5 cm, and shape is bean-like, with blood
vessels, nerves, and efferent lymphatic vessels attached to the
indented region (hilum);
o
Afferent lymphatic vessels enter at points on the convex
surface.
c.
Node is enclosed in a dense CT capsule that extends into the node
and subdivides it into nodules.
d.
Outer region = cortex; contains germinal centers of densely
packed B cells (+ macrophages) in spaces called lymphatic
nodules (or follicles).
e.
Inner region = medulla; contains T cells (+ macrophages and
plasma cells) arranged as medullary cords (spaces through which
lymph flows).
IV.
LYMPHATIC TISSUES
B.
Lymph Nodes (continued)
2.
Flow of Lymph through Lymph Node:
See Fig 16.9, page 612 and Fig 16.10, page 613.
a.
b.
c.
d.
3.
Locations of lymph nodes (See Fig 16.11, page 613.)
a.
b.
c.
4.
One-way direction only.
Lymph enters the node through one of several afferent lymphatic
vessels on convex surface,
flows inward through sinuses (between medullary cords), and
exits the node via one of two efferent lymphatic vessels at the
hilum.
Lymph nodes generally occur in groups or chains along the paths
of larger lymphatic vessels.
They occur primarily in the following regions:
o
cervical
o
axillary
o
inguinal.
They also occur within the following body cavities:
o
pelvic
o
abdominal
o
thoracic.
Functions of lymph nodes
a.
b.
Removal and destruction of potentially harmful foreign
particles from lymph.
o
Accomplished through phagocytosis by macrophages.
Centers for the production of lymphocytes that act against foreign
particles.
IV.
LYMPHATIC TISSUES
C.
Thymus
4.
D.
Spleen
2.
3.
4.
*
See Fig 16.12 page 615.
1.
soft, bilobed organ located within the mediastinum.
2.
decreases in size (atrophy) after puberty.
3.
composed of lymphatic tissue that is subdivided into
lobules.
Each lobule contains an outer (dark-staining) cortex filled with densely
packed lymphocytes around a central medulla (light staining) filled with
swirled epithelial cells (called Hassall's Corpuscles). See Fig 16.12b,
p615.
5.
Functions:
a.
immature T cells migrate from the bone marrow to the thymus
(via) the blood.

which will
leave the thymus and provide immunity)
b.
The epithelial cells secrete a hormone called thymosin, which
stimulates further maturation of T cells after they leave the thymus
and migrate to other lymphatic tissues.
See Figure 16.14 page 616.
1.
is located in the upper left portion of the abdominal cavity
(behind stomach).
resembles a large lymph node that is encapsulated and subdivided into
lobules by connective tissue.
contains two types of tissue. See Fig 16.14b, page 616.
a.
white pulp = lymphocytes arranged around central arteries.
b.
red pulp = blood filled sinuses (venous blood that also serves as
blood reservoir).
Functions:
a.
Removal and destruction of foreign particles and worn blood
cells from blood.

Macrophages remove and destroy bacteria and
damaged or worn red blood cells and platelets through
phagocytosis.
b.
stores and releases blood during hemorrhage.
c.
in immunity as a site of B cell proliferation into plasma cells.
See summary Table 16.1, page 617, which summarizes the locations and major
functions of lymph nodes, thymus, and spleen.
V.
BODY DEFENSES AGAINST INFECTION
A.
Introduction:
Infection is caused by the presence and multiplication of pathogens. Pathogens
are viruses and microorganisms (bacteria, fungi, protozoans, parasites) that
cause disease. The body is equipped with two types of defense mechanisms to
fight infection:
o
innate (nonspecific) resistance, the 1st and 2nd lines of
defense
o
adaptive (specific) resistance (immunity), the 3rd line of
defense.
B.
Innate (Nonspecific) Defenses = protection against a wide range of pathogens.
Mechanisms include species resistance, mechanical barriers, chemical barriers,
fever, inflammation and phagocytosis.
1.
Species resistance
Each species of organism is resistant to certain diseases that may affect
other species, but susceptible to diseases that other species may be able to
resist. (See cryptosporidiosis, blue box page 617).
2.
Mechanical barriers (First Line of Defense)
a.
include the skin and mucous membranes.
b.
As long as mechanical barriers remain unbroken, they prevent the
entrance of some pathogens.
3.
Chemical Barriers (First and Second Line of Defense)
a.
Enzymes
o
The enzyme in gastric juice (i.e. pepsin) is lethal to many
pathogens.
o
The enzyme in tears (i.e. lysozyme) has antibacterial
action.
b.
Acid
o
Low pH in stomach (hydrochloric acid) prevents growth of
some bacteria.
c.
Salt
o
High salt concentration in perspiration kills some bacteria.
d.
Interferons
o
Interferon is a group of hormone-like peptides produced by
certain uninfected cells in response to the presence of
viruses.
o
These antiviral proteins interfere with the proliferation of
viruses, stimulate phagocytosis, and enhance the activity of
cells that help resist infections and the growth of tumors.
e.
Defensins
o
Destroy bacteria by making holes in their cell walls and/or
membranes.
f.
Collectins
o
Protect by attaching themselves to a variety of microbes.
Provide broad protection against them.
V.
BODY DEFENSES AGAINST INFECTION
B.
Innate (Nonspecific) Defenses
4.
Fever
a.
Infection (by bacteria and viruses) causes some lymphocytes to
produce Interleukin I, which increases body temperature.
b.
Other factors can also increase body temperature, including
exposure to heat, UV light, acids, and bases.
c.
Increased body temperature decreases blood iron levels, which
increases phagocytic activity.
Natural Killer Cells (NK cells)
a.
special lymphocytes
b.
attack foreign material; microbes, cancer cells, other
abnormal cells
c.
use perforins to rupture cell membranes
d.
enhance inflammation
Inflammation:
Second Line Of Defense
See Table 16.2, page 618.
a.
Inflammation is a tissue response to damage, injury, or infection.
b.
Blood vessels dilate, increasing capillary permeability.
o
The response includes localized tissue redness (rubor),
swelling (tumor), heat (calor), and pain (dolor).
c.
Chemicals released by damaged tissues attract various white blood
cells to the site of injury.
o
Pus may form as WBC’s, bacterial cells, and debris
accumulate.
d.
Tissue fluid leaks into area.
o
A clot (fibrin) may form in affected tissues.
e.
Fibroblasts arrive.
o
A fibrous connective tissue sac may form around the
injured tissue and thus prevent the spread of pathogens.
Phagocytosis:
Second Line of Defense
a.
Definition:
Phagocytosis is the process by which
specialized cells engulf and ingest foreign particles in order to
destroy them.
o
Recall function of lysosomes.
b.
The most active phagocytes in the blood are neutrophils and
monocytes.
c.
Monocytes give rise to macrophages (through diapedesis, Chap 14)
that migrate to various body tissues.
d.
Phagocytic cells associated with the linings of blood vessels in the
bone marrow, liver, spleen, and lymph nodes constitute the
reticuloendothelial tissue.
e.
Phagocytes remove and destroy foreign particles from tissues
and body fluids.
5.
6.
7.
*
See Summary Table 16.3, page 619 to review nonspecific resistance mechanisms.
V.
BODY DEFENSES AGAINST INFECTION
C.
Adaptive (Specific) Defenses or Immunity is protection against particular
disease-causing agents. It is our third line of defense against infection.
1.
Antigens (Ag's)
a.
Definition: An antigen is a substance (usually a protein) that
causes the formation of an antibody and reacts specifically with
that antibody.
b.
How does this process occur?

Before birth, body cells inventory the proteins and
other large molecules present in the body (i.e. “self”
proteins).

After the inventory, lymphocytes develop receptors
that allow them to differentiate between foreign (non-self)
antigens and self-antigens.

When non-self or foreign antigens (Ag's) enter human
tissues, they combine with T cell and B cell surface
receptors, and stimulate these cells to cause an immune
response/reaction (IR) against them.
2.
Lymphocyte Origins:
See Fig 16.16, page 620.
a.
Lymphocytes originate in red bone marrow and are released
into the blood before they become differentiated.
b.
About half of these undifferentiated lymphocytes reach the thymus
where they are processed into T cells.
c.
Some undifferentiated lymphocytes are (probably) processed in the
bone marrow and become B cells.
d.
Both T cells (70%-80% of circulating lymphocytes) and B (20%30%) cells are transported through the blood to the lymphatic
organs (lymph nodes, spleen, thymus) where they reside and act in
immune responses against foreign antigens.
e.
See SEM of circulating lymphocyte in Fig 16.15, page 619.
3.
Lymphocyte Function
a.
Antigen-Presenting Cells Begin the Immune Response
b.
A macrophage is typically the first cell to respond to an antigen. It
then alerts lymphocytes to the invader.
c.
After digestion of the antigen (by the macrophage), a self-protein
attaches a copy of the foreign antigen to the cell membrane of the
macrophage.
o
A gene of the major histocompatibility complex (MHC)
codes for this self-protein.
d.
A lymphocyte now recognizes and binds to the antigen-presenting
cell.
o
T cells and B cells are activated and begin a chain of
reactions that ultimately destroy/neutralize the invading
antigen.
V.
BODY DEFENSES AGAINST INFECTION
C.
Adaptive (Specific) Defenses or Immunity
4.
T cells provide cell-mediated immunity (CMI):
a.
T cells respond to antigens directly (by cell-to-cell contact).
b.
T cells secrete cytokines (lymphokines) to enhance other immune
responses to antigens. See Table 16.4, page 621.
o
o
o
o
c.
Colony stimulating factors stimulate bone marrow to
produce lymphocytes.
Interferons block viral replication, stimulate macrophages
to engulf viruses, stimulate B cells to produce antibodies,
attack cancer cells.
Interleukins control lymphocyte differentiation.
Tumor necrosis factor stops tumor growth, etc.
Types of T cells:
o
o
o
o
Helper T cells (CD4) become activated when they
encounter a displayed antigen (on macrophage) for which it
is specialized to react (see 3.c. above)

Once activated, helper T cells stimulate B cells to
produce antibodies (see B. 5. below).

CD4 Helper T cells stimulate Antibody Mediated
Immunity (AMI) and secrete cytokines (CMI).

The HIV virus cripples these cells.
Memory T cells are produced upon initial exposure to an
antigen.

They allow for immediate response against
subsequent exposure(s) to the same antigen.
Cytotoxic T cells (CD8) recognize foreign antigens on
tumor cells and virus-infected cells.

Stimulated cytotoxic T cells proliferate into a large
clone of cells that secrete perforin to destroy target
cells.
Natural Killer Cells also use perforins to destroy tumor
cells.

Both cytotoxic T cells and natural killer cells can
lyse antigens in other ways also.
V.
BODY DEFENSES AGAINST INFECTION
C.
Adaptive (Specific) Defenses or Immunity
5.
B cells provide Antibody-mediated immunity (or humoral) (AMI):
a.
B cells interact with antigen-bearing agents indirectly, by
secreting proteins called antibodies.
b.
B Cell Activation
o
o
o
o
o
B Cell becomes activated when it binds to an activated T
cell.
Once activated, a B cell proliferates, enlarging into its
clone.
Activated B cells specialize into plasma cells that secrete
antibodies.
Antibodies react against the specific antigen-bearing agent
that stimulated its production.
A diverse population of B cells defends one against a large
number of pathogens.
See Fig 16.17, page 622, Fig 16.18, page 623, and Fig 16.19, page 626 to
see the complex cascade of CMI and AMI events involved in an immune
response.
c.
Antibody molecules:
o
o
o
o
See Figure 16.20, page 627.
Antibodies are proteins called immunoglobulins.
They constitute the gamma globulin fraction of plasma.
Each immunoglobulin molecule consists of four chains of
amino acids linked together.

Two heavy chains.

Two light chains.
Variable regions at the ends of these chains are specialized
to react with antigens.

Comprise antigen-binding sites.
V.
BODY DEFENSES AGAINST INFECTION
C.
Adaptive (Specific) Defenses or Immunity
5.
B cells provide Antibody-mediated immunity (or humoral) (AMI):
d.
Types of immunoglobulins: See Table 16.7, page 627.
The five major types of immunoglobulins are IgG, IgA, IgM, IgD,
and IgE.
o
o
IgG





IgA




o
o
o
IgM





IgD



IgE



most abundant circulating antibody (80% of total)
occurs in plasma and tissue fluids
defends against bacterial cells, viruses & toxins
activates complement
only antibody to cross placenta.
about 13% of circulating antibodies
occurs in exocrine gland secretions (i.e. tears,
saliva, breast milk, etc.)
defends against bacterial cells and viruses
levels decrease during stress, lowering resistance to
infection.
about 6 % of circulating antibodies
first antibodies to be secreted after initial exposure
to an antigen
occurs in plasma
produced in blood transfusions
activates complement.
< 1% of antibodies
occurs on the surface of most B cells
involved in activation of B-cells.
< 0.1 % of antibodies
occurs in exocrine gland secretions.
promotes inflammation and allergic reactions
because they cause the release of histamine from
mast cells (basophils).
V.
BODY DEFENSES AGAINST INFECTION
C.
Adaptive (Specific) Defenses or Immunity
5.
B cells provide Antibody-mediated immunity (or humoral) (AMI):
e.
Antibody Action: See Table 16.8, page 628.
Antibodies attack antigens directly, activate complement, and
stimulate local tissue changes that hinder antigen-bearing agents.
o
Direct attachment involves the following:

agglutination

precipitation

neutralization.
o
Activation of complement (a positive feedback
mechanism) involves the following: See Table 16.8, p 628.

opsonization

chemotaxis

inflammation

lysis.
o
See Table 16.6, page 624, which summarizes the steps in
antibody production and compares T & B cell activity.
6.
Immune responses (IR): See Fig 16.21, page 628.
a.
When B cells or T cells first encounter an antigen for which they
are specialized to react, the reaction is called a primary IR.
o
During this response, antibodies are produced for several
weeks (IgM).
o
Some B cells and T cells remain dormant as memory cells.
b.
A secondary IR occurs rapidly if the same antigen is encountered
at a later time (IgG).
7.
Practical Classification of Immunity
See Table 16.9, page 630.
a.
A person who encounters a live pathogen, which stimulates a
primary IR, and suffers symptoms of a disease, develops naturally
acquired active immunity.
b.
A person who receives a vaccine containing
a dead or weakened pathogen. However, stimulation of the IR
causes the person to develop artificially acquired active
immunity.
c.
A person who receives an injection of
gamma globulin that contains ready-made antibodies has
artificially acquired passive immunity. In this instance, the
patient does not have time to develop active immunity (i.e.
hepatitis), no IR occurs, and the immunity provided is only shortterm.
d.
When antibodies (IgG) pass through a
placental membrane from a pregnant woman to her fetus, the fetus
develops naturally acquired passive immunity. This provides
short-term immunity without development of an IR.
VI.
Disorders/Homeostatic Imbalances of the Immune System
A.
Allergic or Hypersensitivity Reactions (IR gone awry)
1. Allergic reactions involve antigens combining with antibodies (IgE); The
resulting IR is likely to be excessive or violent and may cause tissue damage.
2.
Types of allergic reactions:
a.
Delayed-reaction allergy (type IV), which can occur in anyone
and can cause inflammation of the skin, results from repeated
exposure to antigenic substances (i.e. household detergents,
cosmetics).
b.
Antibody-dependent cytotoxic allergic reactions (type III)
occur when blood transfusions are mismatched (review
incompatible donors from Chapter 14).
c.
Immune complex allergic reactions (type II) involve
autoimmunity, which is an IR against self-antigens (see VI. C.
below).
d.
Immediate-reaction allergy (type I), which is inherited, causes
the production of an abnormally large amount of IgE (animal
dander, pollen, etc.).
o
o
o
o
See Fig 16.22, page 631 that summarizes steps involved.
Allergic reactions result from mast cells (recall from Chap
14 that mast cells are basophils that have traveled from the
blood into tissues) bursting and releasing allergy mediators,
such as histamine and serotonin.
In anaphylactic shock, these allergy mediators are
responsible for the symptoms of the allergic reaction,
including decreased blood pressure (vasodilation) and
difficulty breathing (bronchoconstriction).
Suppressor cells that inhibit the production of IgE usually
terminate an allergic reaction.
VI.
Disorders/Homeostatic Imbalances of the Immune System
C.
Transplantation and Tissue Rejection
1.
2.
D.
There are four types of tissue transplants: See Table 16.10, page 632.
a.
Isografts occur between identical twins.
o
i.e. A bone marrow transplant from a healthy twin to one
with leukemia.
b.
Autografts are “self” grafts.
o
i.e. a skin graft from one part of the body to another.
c.
Allografts occur between individuals of the same species.
o
i.e. kidney transplant from a relative
d.
Xenografts occur between individuals of different species.
o
i.e. A pig heart valve into a human.
o
A transplant recipient’s immune system may react with donated (non-self)
tissue in a tissue rejection reaction.
3.
Matching cell surface molecules of donor and recipient tissues (MHC) and
using immunosuppressive drugs can minimize tissue rejection.
4.
Immunosuppressive drugs increase the recipient’s susceptibility to
infection (decreases resistance).
Autoimmunity
1.
In autoimmune disorders, the body produces antibodies against “self”
antigens, resulting in an attack on one’s own tissues.
2.
The cause of autoimmune disorders is unknown, but researchers feel that
they may be caused by:
a.
a previous viral infection,
b.
faulty T cell development,
c.
reaction to a self antigen that is close in structure to a non-self
antigen,
d.
by persistent fetal cells, where fetal cells persist in the female’s
circulation as an adult.
o
For some unknown reason, these “hiding” fetal cells in
tissues such as skin, emerge stimulating antibody
production.
o
This mechanism called “microchimerism” may explain
why so many more females are stricken with autoimmune
disorders than males.
o
In scleroderma, which means “hard skin”, patients are
typically diagnosed between ages 45-55.

Symptoms include fatigue, swollen joints
(See Fig 16.23, page 634), stiff fingers and masklike face.

Hardening may also affect blood vessels, lungs, and
esophagus.
VI.
Disorders/Homeostatic Imbalances of the Immune System
C.
Autoimmunity (continued)
3.
D.
Some autoimmune diseases are presented in Table 16.11, page 633.
a.
Glomerulonephritis where antibodies attack kidney cells that
resemble streptococcal antigens. See Clinical Application 20.2,
page 780.
b.
Grave’s Disease where antibodies attack thyroid gland. See Fig
13.22, page 488.
c.
Type I Diabetes (IDDM) where antibodies attack beta cells of
Islets of Langerhans of pancreas. See CA 13.4, page 499.
d.
Hemolytic anemia where antibodies attack erythrocytes.
e.
Myasthenia Gravis where antibodies attack acetylcholine
receptors in skeletal muscle. See Clinical Application 9.1, page
284.
f.
Pernicious Anemia where antibodies attack the vitamin B
binding sites in gastric mucosa. See box on page 516.
g.
Rheumatic Fever where antibodies attack heart valves that
resemble streptococcal antigens.
h.
Rheumatoid arthritis where antibodies attack synovial
membranes. See Clinical Application 8.2, page 272.
i.
Systemic Lupus Erythematosus (SLE) where antibodies attack
DNA, neurons, and blood cells.
j.
Ulcerative Colitis where antibodies attack colon cells. See
Clinical Application 17.5, page 684.
Other Disorders/Homeostatic Imbalances of the Immune System
1.
Severe Combined Immune Deficiency (SCID), page 629.
2.
Chronic Fatigue Syndrome, page 634.
3.
Immunity Breakdown: AIDS. Clinical Application 16.1, pp. 635.
VII.
LIFE SPAN CHANGES
A.
The immune system declines early in life, partially due to the decreasing size of
the thymus.
B.
The activity level of T cells and B cells declines as we age.
C.
The proportions of the five types of immunoglobulins shift as we age.
VIII.
Other interesting Topics
A.
Immunotherapy. See pages 624-625
B.
Vaccines, page 629.
C.
Tuberculin skin test, page 632.
IX.
Innerconnections of the Lymphatic System. See page 636.
X.
Clinical Terms Related to the Lymphatic System and Immunity. See page 637
Chapter 16 Lymphatic System and Immunity
1. Explain how the lymphatic system is related to the cardiovascular system.
The lymphatic and cardiovascular systems include a network of capillaries and vessels that
assist in circulating the body fluids. The lymphatic vessels transport excess fluid away from
the interstitial spaces of tissues and return it to the bloodstream. The walls of both vessels
are alike. For instance, they both contain a single layer of epithelial cells that allows fluids
and substances to cross into them.
2. Trace the general pathway of lymph from the interstitial spaces to the bloodstream.
The lymphatic capillary system is found next to the systemic and pulmonary capillary
networks. It then travels through lymph vessels into lymph nodes. It returns to lymph vessels
and then is returned into the bloodstream at various points.
3. Identify and describe the locations of the major lymphatic trunks and collecting ducts.
The lymphatic trunks are named for the regions they serve. The locations can be found in
fig. 16.4, on page 623.
The collecting ducts are:
Thoracic duct—It begins in the abdomen. It passes upward medially through the
diaphragm to the left subclavian, where it empties.
Right lymphatic duct—It begins as the union of the right jugular, right subclavian, and
right bronchomediastinal trunks. It empties into the right subclavian vein.
4. Distinguish between tissue fluid and lymph.
Lymph is tissue fluid that has entered into a lymphatic capillary.
5. Describe the primary functions of lymph.
The primary functions of lymph are to return the proteins to the bloodstream that have
leaked out of the blood capillaries and to transport bacteria and other foreign particles to the
lymph nodes.
6. Explain why physical exercise promotes lymphatic circulation.
The contractions of the skeletal muscles, pressure changes due to the actions of breathing
muscles, and smooth muscle contractions of the larger lymphatic trunks all aid in the
movement of lymph through the body.
7. Explain how a lymphatic obstruction leads to edema.
Continuous movement of fluid from the interstitial spaces into the lymphatic system
stabilizes the volume of fluids in these spaces. When an obstruction occurs, the tissue fluid
builds up and causes edema.
8. Describe the structure of a lymph node, and list its major functions.
Each lymph node is enclosed in a capsule of fibrous connective tissue and subdivides into
compartments. The compartments contain dense masses of lymphocytes and macrophages.
These masses, called nodules, are the structural units of a lymph node. Lymph nodes
function in lymphocyte production and phagocytosis of foreign substances, damaged cells,
and cellular debris.
9. Locate the major body regions occupied by lymph nodes.
The major body regions include: cervical region, axillary region, inguinal region, pelvic
cavity, abdominal cavity, thoracic cavity, and supratrochlear region.
10. Describe the structure and functions of the thymus.
The thymus is a soft, bilobed structure whose lobes are surrounded by a capsule of
connective tissue. It is composed of lymphatic tissue, which is subdivided into lobules by
connective tissues. The lobules contain many lymphocytes. It functions to produce Tlymphocytes that help in the immune response. It also secretes thymosin, which is thought to
stimulate the maturation of T-lymphocytes after they leave the thymus.
11. Describe the structure and functions of the spleen.
The spleen is the largest lymphatic organ. It resembles a large lymph node and is subdivided
into chambers or lobules. The spaces within the chambers are filled with blood instead of
lymph. There are two types of tissues within the lobules of the spleen. They include:
White pulp - distributed throughout the spleen in tiny islands, composed of splenic
nodules, and containing large numbers of lymphocytes.
Red pulp - surrounds the venous sinuses and contains many red blood cells along with
numerous lymphocytes and macrophages.
The spleen functions to filter the blood.
12. Distinguish between innate (nonspecific) and adaptive (specific) body defenses against infection.
Nonspecific body defenses include species resistance, mechanical barriers such as the skin
and mucous membranes, and chemical barriers such as enzymes, interferon, inflammation,
and phagocytosis. Specific body defenses include immune mechanisms, where certain cells
recognize the presence of particular foreign substances and act against them. Lymphocytes
and macrophages achieve this.
13. Explain species resistance.
Species resistance is referring to the fact that a given kind of organism or species develops
diseases that are unique to it. A species may be resistant to diseases that affect other species,
because its tissues somehow fail to provide the temperature or chemical environment needed
by a particular pathogen.
14. Name two mechanical barriers to infection.
The skin and the mucous membranes are two mechanical barriers to infection.
15. Describe how enzymatic actions function as defense mechanisms against pathogens.
Enzymes provide a chemical barrier to pathogens. By splitting components of the pathogen
or decreasing the pH, the enzyme can have lethal effects on pathogens.
16. Distinguish among the chemical barriers (interferons, defensins, and collectins), and give examples of
their different actions.
Interferons stimulate uninfected cells to synthesize antiviral proteins that block proliferation
of viruses; stimulate phagocytosis; and enhance activity of cells that help resist infections
and stifle tumor growth. Defensins make holes in bacterial cell walls and membranes.
Collectins provide broad protection against a wide variety of microbes by grabbing onto
them.
17. List possible causes of fever, and explain the benefits of fever.
Viral or bacterial infection stimulates certain lymphocytes to secrete IL-1, which
temporarily raises body temperature.
Physical factors, such as heat or ultraviolet light, or chemical factors, such as acids or bases,
can cause fever.
Elevated body temperature and the resulting decrease in blood iron level and increased
phagocytic activity hamper infection.
18. Describe Natural Killer (NK) Cells and their action.
NK cells are a small population of lymphocytes. NK cells defend the body against various
viruses and cancer by secreting cytolytic substances called perforins.
19. List the major effects of inflammation, and explain why each occurs.
Localized redness-result of blood vessel dilation and the increase in blood volume of
affected tissues.
Swelling-result of increased blood volume and increased permeability of nearby capillaries.
Heat-due to the presence of blood from deeper body parts, which is generally warmer than
that near the surface.
Pain-results from the stimulation of nearby pain receptors.
20. Identify the major phagocytic cells in the blood and other tissues.
The most active phagocytic cells of the blood are neutrophils and monocytes.
Macrophages are fixed phagocytic cells found in lymph nodes, spleen, liver, and lungs.
This constitutes reticuloendothelial tissue.
21. Distinguish between an antigen and a hapten.
An antigen is a foreign substance, such as a protein, polysaccharide or a glycolipid, to
which lymphocytes respond. A hapten is a molecule that by itself cannot stimulate the
immune response. It must combine with a larger molecule.
22. Review the origin of T cells and B cells.
T cells originate in the thymus. B cells are those processed in another part of the body,
probably the fetal liver.
23. Explain the immune response.
The lysosomal digestive process of phagocytosis of an invading bacterium releases antigens.
They are moved to the macrophage's surface membrane. They are then displayed on the
membrane with major histocompatibility complex. If the antigen then fits the helper T cell,
it becomes activated. At this point, the helper T cell seeks out the appropriate T cell and by
attaching to it, activates the T cell into a response. Cell-mediated immunity (CMI) is when
a T cell, for example, attaches itself to antigen-bearing cells and interacts with the foreign
cells directly.
24. Define cytokine.
Cytokines (lymphokines) are a variety of polypeptides that are synthesized and secreted by
T cells and macrophages. These enhance various cellular responses to antigens. They
stimulate the synthesis of lymphokines from other T cells, help activate resting T cells,
cause T cells to proliferate, stimulate the production of leukocytes in the red bone marrow,
cause growth and maturation of B cells, and activate macrophages.
25. List three types of T cells and describe the function of each in the immune response.
a. Helper T cells—mobilize the immune system to stop a bacterial infection through a series of complex
steps.
b. Memory T cells—provide for no delay in the response to future exposures to an antigen.
c. Cytoxic T cells—recognize non-self antigens that cancerous or virally infected cells display on their
surfaces.
26. Define clone of lymphocytes.
Clone of lymphocytes refers to cells that are derived from one early cell that are capable of
responding to a certain antigen. As there are many differing antigens, there are also many
differing varieties of clones.
27. Explain humoral immunity.
A B cell is activated when it binds to an activated T cell.
An activated B cell proliferates, enlarging its clone.
Some activated B cells specialize into antibody-producing plasma cells.
Antibodies react against the antigen-bearing agent that stimulated their production.
An individual’s diverse B cells defend against a very large number of pathogens.
28. Explain how a B cell is activated.
B cells become activated when they encounter an antigen whose molecular shape fits the
shape of the B cell's antigen receptors. As a result of this combination, the B-cells proliferate
by mitosis and its clone is enlarged. This mechanism for activation is similar to the lock and
key model used by enzymes and substrates.
29. Explain the function of plasma cells.
Plasma cells are some of the newly formed members of the activated B cell's clone. They
make use of their DNA information and protein-synthesizing mechanism to produce
antibody molecules.
30. Describe an immunoglobulin molecule.
An immunoglobulin molecule consists of two identical light changes of amino acids and
two identical heavy chains of amino acids. See figure 16.20, page 637.
31. Distinguish between the variable region and the constant region of an immunoglobulin molecule.
Variable regions are the portion of one end of each of the heavy and light chains consists of
variable sequences of amino acids making them specific for specific antigen molecules.
Constant regions are the remaining portions of the chains whose amino acid sequences are
very similar from molecule to molecule.
32. List the major types of immunoglobulins, and describe their main functions.
Immunoglobulin G (IgG)—occurs in plasma and tissue fluids.
Immunoglobulin A (IgA)—occurs in milk, tears, nasal fluid, gastric juice, intestinal juice, bile, and
urine.
Immunoglobulin M (IgM)—develops in blood plasma.
Immunoglobulin D (IgD)—is important in activating B cells.
Immunoglobulin E (IgE)—occurs in exocrine secretions and is associated with allergic reactions.
33. Describe three ways in which antibody attack on a direct antigen helps in the removal of antigen.
Agglutination—antibodies combine with antigens and clumping results.
Precipitation—antibodies combine with antigens and insoluble substance forms.
Neutralization—antibodies cover the toxic portions of antigen molecules and neutralize their
effects.
Lysis—antibodies cause the cell membranes to rupture.
34. Explain the function of complement.
It is a group of inactive enzymes that become activated when certain IgG or IgM antibodies
combine with antigens and the reactive sites become exposed. The activated enzymes
produce chemotaxis, agglutination, opsonization, and lysis. It can also promote the
inflammation reaction.
35. Distinguish between a primary and a secondary immune response.
A primary immune response occurs when B cells or T cells become activated after first
encountering the antigens to which they are specifically reactant. A secondary immune
response happens when memory cells are activated and increased in size, so they can
respond rapidly to the antigen to which they were previously sensitized.
36. Distinguish between active and passive immunity.
Active immunity can be either naturally acquired or artificially acquired. Naturally acquired
active immunity is stimulated as a result of exposure to live pathogens. Artificially acquired
active immunity is stimulated by exposure to a vaccine containing weakened or dead
pathogens. Passive immunity can also be either naturally acquired or artificially acquired.
Naturally the antibodies passed to a fetus from a mother with active immunity stimulate
acquired passive immunity. Artificially acquired passive immunity is stimulated by an
injection of gamma globulin that contains antibodies.
37. Define vaccine.
A vaccine is a substance that contains an antigen that can stimulate a primary immune
response against a particular disease-causing agent, but does not cause severe disease
symptoms.
38. Explain how a vaccine produces its effect.
A vaccine contains bacteria or viruses that have been killed or weakened so they cannot
cause a serious infection; or it may contain a toxin of an infectious organism that has been
chemically altered to destroy its toxic effects. The antigens present still retain the
characteristics needed to simulate a primary immune response.
39. Describe how a fetus may obtain antibodies from the maternal blood.
Receptor-mediated endocytosis utilizing receptor sites on cells of the fetal yolk sac transfers
IgG molecules to the fetus.
40. Explain the relationship between an allergic reaction and an immune response.
Allergic reactions are closely related to immune responses in that both may involve the
sensitizing of lymphocytes or the combining of antigens with antibodies. Allergic reactions
are likely to be excessive and to cause tissue damage.
41. Distinguish between an antigen and an allergen.
An antigen is a substance that stimulates cells to produce antibodies. An allergen is a
foreign substance capable of stimulating an allergic reaction.
42. Describe how an immediate-reaction allergic response may occur.
In an immediate-reaction allergy, the individuals have an inherited ability to synthesize
abnormally large quantities of antibodies in response to certain antigens. In this instance, the
allergic reaction involves the activation of B-cells.
43. List the major events leading to a delayed-reaction allergic response.
It results from repeated exposure of the skin to certain chemical substances. As a
consequence of these repeated contacts, the foreign substance and a large number of T cells
collect in the skin and eventually activate the T cells. Their actions and the actions of
macrophages they attract cause the release of various chemical factors. This causes eruptions
and inflammation of the skin. It is called delayed since it takes about forty-eight hours to
occur.
44. Explain the relationship between a tissue rejection and an immune response.
Tissue rejection is when the immune system sees transplanted tissue as foreign and starts
the immune response to try to rid the body of it.
45. Describe two methods used to reduce the severity of a tissue rejection reaction.
Matching the donor and recipient tissues may reduce it. It can also involve giving drugs that
suppress the immune system.
46. How do immunosuppressant drugs increase the likelihood of success of a transplant, yet place the
patient at a higher rise of developing infections?
An immunosuppressive drug interferes with the recipient’s immune response by suppressing formation of
antibodies or production of T cells. This will ultimately leave the recipient relatively unprotected against
infection.
47. Explain the relationship between autoimmunity and an immune response.
Autoimmunity occurs when the immune system does not distinguish between self and
nonself and manufactures autoantibodies that attack the body's own cells. For whatever
reason, the autoantibodies treat a certain cell type in the body as a foreign object and signal
the immune system to defend against the perceived invader.
48. Describe the causes for a decline in the strength of the immune response in the elderly.
The immune system begins to decline early in life, in part due to the decreasing size of the
thymus.
Numbers of T cells and B cells do not change significantly, but activity levels do.
Proportions of the different antibody classes shift.
Chapter 16: Lymphatic System and Immunity
A.
I. Introduction
A. The lymphatic system is closely associated with ______________________________
________________________________________________________________________
B. Lymphatic vessels transport ___________________________________________ and
return it to the ____________________________________________________________
C. Lacteals are _____________________ and function to _________________________
________________________________________________________________________
D. The organs of the lymphatic system also defend ______________________________
________________________________________________________________________
B.
II. Lymphatic Pathways
A. Lymphatic Capillaries
1. Lymphatic capillaries are ________________________________________that
extend into_________________________________________________________
2. The walls of lymphatic capillaries are similar to _________________________
3. The thin walls of capillaries make it possible for ________________________
__________________________________________________________________
4. Lymph is _______________________________________________________
B. Lymphatic Vessels
1. The walls of lymphatic vessels are similar to those of ____________________
2. Lymphatic vessels have _______________ which prevents backflow of lymph.
3. Larger lymphatic vessels lead to _____________________________________
4. After leaving nodes, lymphatic vessels merge together to form _____________
__________________________________________________________________
C. Lymphatic Trunks and Collecting Ducts
1. Lymphatic trunks drain _________________________________________ and
are named for ______________________________________________________
2. Examples of lymphatic trunks are ____________________________________
__________________________________________________________________
3. Lymphatic trunks join _____________________________________________
4. The two collecting ducts are ________________________________________
5. The thoracic duct is located _________________________________________
_________________________ and empties into __________________________
6. The thoracic duct drains ____________________________________________
__________________________________________________________________
7. The right lymphatic duct is located ___________________________________
________________________ and empties into ___________________________
8. The right lymphatic duct drains ______________________________________
__________________________________________________________________
9. After leaving the two collecting ducts, lymph enters __________________ and
becomes part of _____________________________________________________
C.
III. Tissue Fluid and Lymph
A. Introduction
1. Lymph is _______________________________________________________
2. Lymph formation depends on _______________________________________
B. Tissue Fluid Formation
1. Capillary blood pressure filters ______________________________________
_______________________________________________________________ and
the resulting fluid consists of __________________________________________
2. Water is drawn back into capillaries because ___________________________
__________________________________________________________________
C. Lymph Formation
1. Filtration from the plasma normally exceeds___________________________ ,
leading to __________________________________________________________
2. Tissue fluid moves into lymphatic capillaries because ____________________
__________________________________________________________________
3. Lymph formation prevents __________________________________________
D. Lymph Function
1. Lymphatic vessels in the small intestine play a major role in _______________
__________________________________________________________________
2. Lymph returns ___________________________________ to the bloodstream.
3. Lymph transports ____________________________________ to lymph nodes.
4. Lymphatic capillaries can receive proteins and foreign particles that blood
capillaries cannot because _____________________________________________
__________________________________________________________________
5. The lumen of a lymphatic capillary remains open because _________________
__________________________________________________________________
D.
IV. Lymph Movement
A. Introduction
1. The _______________ pressure of tissue fluid drives lymph into ___________
__________________________________________________________________
2. _____________________________________ largely influences movement of
lymph through lymphatic vessels.
B. Lymph Flow
1. Lymph is under __________________________________________ pressure.
2. Contracting _______________________________ compress lymphatic vessels.
3. Lymph does not flow back because ___________________________________
4. Breathing aids lymph circulation by __________________________________
__________________________________________________________________
C. Obstruction of Lymph Movement
1. Conditions that interfere with lymph movement causes ___________________
__________________________________________________________________
2. The continuous movement of lymph from______________________________
__________________________________________ stabilizes the volume of fluid
in interstitial spaces.
E.
V. Lymph Nodes
A. Introduction
1. Lymph nodes are located ___________________________________________
2. Lymph nodes contain ________________________________________ , which
fight ______________________________________________________________
B. Structure of a Lymph Node
1. The hilum of a lymph node is _______________________________________
2. Afferent lymphatic vessels are _______________________________________
3. Efferent lymphatic vessels are _______________________________________
4. Lymph nodules are ________________________________________________
5. Germinal centers contain ___________________________________________
6. Tonsils are composed of ___________________________________________
7. Peyer’s patches are located ______________________________________ and
are composed of ____________________________________________________
8. Lymph sinuses are ________________________________________________
C. Locations of Lymph Nodes
1. Lymph nodes generally occur in ______________________ along the paths of
______________________________________________________ but are absent
__________________________________________________________________
2. Major locations of lymph nodes are___________________________________
__________________________________________________________________
3. Lymph nodes of the cervical region are associated with lymphatic vessels that
drain _____________________________________________________________
4. Lymph nodes of the axillary region are associated with lymphatic vessels that
drain _____________________________________________________________
5. Lymph nodes of the inguinal region are associated with lymphatic vessels that
drain _____________________________________________________________
6. Lymph nodes of the pelvic cavity are associated with lymphatic vessels that
drain _____________________________________________________________
7. Lymph nodes of the abdominal cavity are associated with lymphatic vessels that
drain _____________________________________________________________
8. Lymph nodes of the thoracic cavity are associated with lymphatic vessels that
drain _____________________________________________________________
9. Lymph nodes of the supratrochlear region are associated with lymphatic vessels
that drain __________________________________________________________
D. Functions of Lymph Nodes
1. The two primary functions of lymph nodes are __________________________
__________________________________________________________________
2. Along with ______________________________ , lymph nodes are centers for
lymphocyte production.
3. Lymphocytes attack _______________________________________________
4. The functions of macrophages are ____________________________________
__________________________________________________________________
F.
VI. Thymus and Spleen
A. Thymus
1. The thymus is composed of _________________________________________
and is located_______________________________________________________
2. After puberty, the thymus __________________________________________
3. Most cells of the thymus gland are ___________________________________
4. The hormones secreted by the thymus gland are called ___________________
5. Thymosins function to _____________________________________________
B. Spleen
1. The largest lymphatic organ is _______________________________________
2. The spleen is located ______________________________________________
3. The spleen resembles ______________________________________________
__________________________________________________________________
4. White pulp contains _______________________________________________
5. Red pulp contains _________________________________________________
6. The functions of the spleen are ______________________________________
__________________________________________________________________
VII. Body Defenses Against Infection
A. A pathogen is _________________________________________________________
B. An infection is _________________________________________________________
C. Examples of pathogens are _______________________________________________
D. Innate defenses are ___________________________________________ and include
________________________________________________________________________
E. Adaptive defenses are _____________________________________________ and are
carried out by ____________________________________________________________
VIII. Innate Defenses
A. Species Resistance
1. Species resistance refers to _________________________________________
__________________________________________________________________
2. A species may be resistant to diseases that affect other species because ______
__________________________________________________________________
B. Mechanical Barriers
1. Mechanical barriers prevent _________________________________________
2. Examples of mechanical barriers are __________________________________
__________________________________________________________________
3. The first line of defense is __________________________________________
4. The second line of defense is ________________________________________
C. Chemical Barriers
1. Chemical barriers are ______________________________________________
2. Examples of chemical barriers are ____________________________________
__________________________________________________________________
3. Interferon is produced by ________________________________________ and
its functions include _________________________________________________
4. Defensins are produced by __________________________________________
5. The functions of defensins are _______________________________________
__________________________________________________________________
6. Collectins are _________________________________________________ and
their functions include________________________________________________
D. Fever
1. A fever begins when ______________________________________________
__________________________________________________________________
2. The functions of fever are __________________________________________
__________________________________________________________________
E. Natural Killer Cells
1. Natural killer cells are _____________________________________________
2. Functions of natural killer cells are ___________________________________
__________________________________________________________________
3. Perforins are _____________________________________________________
F. Inflammation
1. Inflammation produces ____________________________________________
2. Redness of inflammation is the result of_______________________________
__________________________________________________________________
3. Swelling of inflammation is the result of _______________________________
__________________________________________________________________
4. Heat of inflammation is the result of __________________________________
__________________________________________________________________
5. Pain of inflammation is the result of __________________________________
__________________________________________________________________
6. Cells that commonly migrate to areas of inflammation are _________________
__________________________________________________________________
7. Pus is the result of ________________________________________________
8. The functions of inflammation are ____________________________________
__________________________________________________________________
G. Phagocytosis
1. Phagocytosis removes _____________________________________________
__________________________________________________________________
2. Examples of phagocytic cells are _____________________________________
__________________________________________________________________
3. The mononuclear phagocytic system is ________________________________
__________________________________________________________________
IX. Adaptive Defenses or Immunity
A. Introduction
1. Immunity is _____________________________________________________
2. An immune response is based on _____________________________________
__________________________________________________________________
3. Antigens are _____________________________________________________
4. ________________________________________carry out immune responses.
B. Antigens
1. Receptors on lymphocyte surfaces enable cells to recognize _______________
__________________________________________________________________
2. Antigens may be _________________________________________________
__________________________________________________________________
3. The antigens most effective in eliciting an immune response is _____________
__________________________________________________________________
4. A hapten is ______________________________________________________
5. Examples of haptens are ___________________________________________
C. Lymphocyte Origins
1. T cells are derived from ____________________________________________
__________________________________________________________________
2. B cells are derived from ____________________________________________
__________________________________________________________________
3. The blood distributes _________________________________________ cells.
4. B cells and T cells are abundant in ___________________________________
__________________________________________________________________
D. Lymphocyte Functions
1. The cellular immune response is _____________________________________
__________________________________________________________________
2. Cytokines are produces by __________________________________________
3. Examples of cytokines are __________________________________________
4. Functions of cytokines are __________________________________________
__________________________________________________________________
5. T cells may also secrete toxins that __________________________________ ,
growth-inhibiting factors that _______________________________________ , or
interferon that ______________________________________________________
6. B cells differentiate into ____________________________________________
7. Plasma cells produce ______________________________________________
8. The humoral immune response is ____________________________________
__________________________________________________________________
9. A clone is _______________________________________________________
10. Different varieties of T cells and B cells have a particular type of __________
___________________________________________ on their cell membranes that
__________________________________________________________________
E. T Cells and the Cellular Immune Response
1. A lymphocyte must be __________________________ before it can respond to
an antigen.
2. T cell activation requires ___________________________________________
__________________________________________________________________
3. Antigen-presenting cells are ________________________________________
__________________________________________________________________
4. T cell activation begins when _______________________________________
__________________________________________________________________
5. The major histocompatibility complex is ______________________________
__________________________________________________________________
6. MHC antigens help _______________________________________________
7. Class I MHC antigens are located ____________________________________
__________________________________________________________________
8. Class II MHC antigens are located ___________________________________
__________________________________________________________________
9. The functions of helper T cells are ___________________________________
__________________________________________________________________
10. The functions of cytotoxic T cells are ________________________________
__________________________________________________________________
11. The functions of memory T cells are _________________________________
__________________________________________________________________
F. B Cells and the Humoral Immune Response
1. Introduction
a. B cells may become activated when ____________________________
____________________________________________________________
b. Upon activation, B cells ______________________________________
c. T cells help B cells by _______________________________________
____________________________________________________________
d. The functions of memory B cells are ____________________________
____________________________________________________________
e. The functions of plasma cells are _______________________________
____________________________________________________________
f. An immune response may include several types of antibodies
manufactured against a single microbe because ______________________
____________________________________________________________
g. A polyclonal response is _____________________________________
2. Antibody Molecules
a. Antibodies are _____________________________________________
b. Each antibody is composed of _________________________________
____________________________________________________________
c. The light chains are _________________________________________
d. The heavy chains are ________________________________________
e. The five major types of antibodies are distinguished by _____________
____________________________________________________________
f. The variable region is ________________________________________
____________________________________________________________
g. Variable regions are specialized to _____________________________
____________________________________________________________
h. Antigen-binding sites are _____________________________________
i. Idiotypes are _______________________________________________
j. Constant regions are _________________________________________
3. Types of Immunoglobulins
a. The five major types of immunoglobulins are _____________________
____________________________________________________________
b. The three types of immunoglobulins that make up the bulk of circulating
antibodies are ________________________________________________
c. IgG is found in _____________________________________________
d. The functions of IgG are _____________________________________
____________________________________________________________
e. IgA is found in _____________________________________________
f. The functions of IgA are ______________________________________
____________________________________________________________
g. IgM is found in_____________________________________________
h. The functions of IgM are _____________________________________
____________________________________________________________
i. IgD is found in _____________________________________________
j. The functions of IgD are ______________________________________
____________________________________________________________
k. IgE is located ______________________________________________
l. The functions of IgE are ______________________________________
____________________________________________________________
4. Antibody Actions
a. The three ways antibodies react to antigens are ____________________
____________________________________________________________
b. In a direct attack, antibodies combine with _______________________
and cause them to _____________________________________________
c. Phagocytic cells can engulf antigens more readily when _____________
____________________________________________________________
d. Antibodies can also cover _________________________________ and
neutralize ___________________________________________________
e. Complement is _____________________________________________
f. Complement is activated by ___________________________________
g. Functions of complement are __________________________________
____________________________________________________________
h. IgE antibodies are usually attached to membranes of _______________
i. Mast cells release their biochemicals when _______________________
____________________________________________________________
G. Immune Responses
1. The primary immune response occurs when ____________________________
__________________________________________________________________
2. Following a primary immune response, some B cells produce ______________
__________________________________________________________________
3. The secondary immune response occurs when __________________________
__________________________________________________________________
H. Practical Classification of Immunity
1. Naturally acquired active immunity develops when ______________________
__________________________________________________________________
2. Artificially acquired active immunity develops when _____________________
_________________________________________________________________ `
3. A vaccine is _____________________________________________________
4. Artificially acquired passive immunity occurs when______________________
__________________________________________________________________
5. Naturally acquired passive immunity occurs when _______________________
__________________________________________________________________
I. Allergic Reactions
1. An allergic reaction is _____________________________________________
__________________________________________________________________
2. Allergens are ____________________________________________________
3. An immediate-reaction allergy occurs when ____________________________
__________________________________________________________________
4. Anaphylactic shock is _____________________________________________
__________________________________________________________________
5. Antibody-dependent cytotoxic reactions occur when _____________________
__________________________________________________________________
6. Immune complex reactions occur when _______________________________
__________________________________________________________________
7. Autoimmunity refers to ____________________________________________
__________________________________________________________________
8. A delayed-reaction allergy occurs when _______________________________
__________________________________________________________________
J. Transplantation and Tissue Rejection
1. Transplanted tissues and organs include _______________________________
__________________________________________________________________
2. A tissue rejection reaction is ________________________________________
__________________________________________________________________
3. Tissues are rejected because ________________________________________
__________________________________________________________________
4. Isografts are _____________________________________________________
5. Autografts are____________________________________________________
6. Allografts are ____________________________________________________
7. Xenografts are ___________________________________________________
8. Immunosuppressive drugs are used to _________________________________
__________________________________________________________________
K. Autoimmunity
1. Autoantibodies are ________________________________________________
2. Reasons people develop autoimmunities are ____________________________
__________________________________________________________________
__________________________________________________________________
3. Scleroderma is ___________________________________________________
__________________________________________________________________
G.
X. Life-Span Changes
A. The immune system begins to decline ______________________________________
________________________________________________________________________
B. By age 70, the thymus ___________________________________________________
C. Elderly people have a higher risk of developing cancer and infections because ______
________________________________________________________________________
D. AIDS is more difficult to diagnose in older people because______________________
________________________________________________________________________
E. Elderly people may not be candidates for certain medical treatments because _______
________________________________________________________________________