648
UNIT FOUR
d. Immune complex allergic reactions involve
autoimmunity, an immune reaction against self
antigens.
e. Delayed-reaction allergy, which can occur in
anyone and infl
ame the skin, results from repeated
exposure to allergens.
8. Transplantation and tissue rejection
a. A transplant recipient’s immune system may react
against the donated tissue in a tissue rejection
reaction.
b. Matching cell surface molecules (MHC antigens)
of donor and recipient tissues, transplanting
stem cells from the donor, and discontinuing
immunosuppressive drugs after the procedure can
help the body accept the foreign tissue.
c. Transplants may take place between genetically
identical twins, from one body part to another,
between unrelated individuals of the same species,
or between individuals of different species.
9. Autoimmunity
a. In autoimmune disorders, autoantibodies attack
the body’s tissues.
b. Autoimmune disorders may result from a previous
viral infection, faulty T cell development, or
reaction to a nonself antigen that resembles a self
antigen.
c. Retained fetal cells can cause a condition that
resembles an autoimmune disorder.
16.10
LIFE-SPAN CHANGES (PAGE 644)
1. The immune system begins to decline early in life, in
part due to the shrinking thymus.
2. Numbers of T cells and B cells do not signiF
cantly
change, but activity levels do.
3. Proportions of the different antibody classes shift.
b. A secondary immune response occurs rapidly as
memory cells respond to subsequent exposure to
an antigen.
6. Practical classiF
cation of immunity
a. A person who encounters a pathogen and has
a primary immune response develops naturally
acquired active immunity.
b. A person who receives a vaccine containing a
dead or weakened pathogen, or part of it, develops
artiF
cially acquired active immunity. Herd
immunity protects populations.
c. A person who receives an injection of antibodies
or antitoxin has artiF
cially acquired passive
immunity.
d. When antibodies pass through a placental
membrane from a pregnant woman to her fetus,
the fetus develops naturally acquired passive
immunity.
e. Active immunity lasts much longer than passive
immunity.
7. Allergic reactions
a. Allergic or hypersensitivity reactions are excessive
misdirected immune responses that may damage
tissues.
b. Immediate-reaction allergy is an inborn ability to
overproduce IgE.
(1) Allergic reactions result from mast cells
bursting and releasing allergy mediators such
as histamine and serotonin.
(2) The released chemicals cause allergy
symptoms such as hives, hay fever, asthma,
eczema, or gastric disturbances.
(3) In anaphylactic shock, allergy mediators
ood throughout the body, causing severe
symptoms, including decreased blood pressure
and difF culty breathing.
c. Antibody-dependent cytotoxic allergic reactions
occur when blood transfusions are mismatched.
16.1 Introduction
1
Explain the functions of the lymphatic system. (p. 617)
16.2 Lymphatic Pathways
2
Trace the general pathway of lymph from the interstitial
spaces to the bloodstream. (p. 617)
16.3 Tissue Fluid and Lymph
3
Distinguish between tissue F
uid and lymph. (p. 619)
4
Describe the primary functions of lymph. (p. 620)
16.4 Lymph Movement
5
Explain why physical exercise promotes lymphatic
circulation. (p. 621)
6
Explain how a lymphatic obstruction leads to edema.
(p. 621)
CHAPTER ASSESSMENTS
16.5 Lymph Nodes
7
Draw a lymph node, and label its parts. (p. 621)
8
On a drawing of the body locate the major body regions
containing lymph nodes. (p. 622)
9
Explain the functions of a lymph node. (p. 623)
16.6 Thymus and Spleen
10
Indicate the locations of the thymus and spleen. (p. 623)
11
Compare and contrast the functions of the thymus and
spleen. (p. 623)
16.7 Body Defenses Against Infection
12
Defense mechanisms that prevent the entry of many
types of pathogens and destroy them if they enter
provide _____________ (nonspeci±
c) defense. Precise
mechanisms targeting speci±
c pathogens provide
_______________ (speci±
c) defense. (p. 626)
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