What are the 3 layers of human defense? What happens during each? -Correct Answer Physical- protect against damage and infection are composed of tightly associated epithelial cells including those of the skin and of the membranous sheets lining the gastrointestinal, genitourinary, and respiratory t...
WGU D115 OBJECTIVE ASSESSMENT
(OA) EXAM STUDY QUESTIONS AND
ANSWERS 2025
What are the 3 layers of human defense? What happens during each? -Correct Answer
✔Physical- protect against damage and infection are composed of tightly associated
epithelial cells including those of the skin and of the membranous sheets lining the
gastrointestinal, genitourinary, and respiratory tracts. Mechanical- "washing" the
surfaces (sloughing off of dead skin, vomiting, urination, coughing). Biochemical
barriers- secrets substances meant to trap of destroy microorganisms. (Mucus, sweat,
saliva, tears, sebaceous glands, and earwax).
What is the second line of defense and the process? -Correct Answer ✔Inflammatory
response- rapid and nonspecific, protective response to cellular injury from any cause. It
can occur only in vascularized tissue.
How do acute and chronic inflammation differ? -Correct Answer ✔Acute- Short duration,
8-10 days from onset to healing. The three systemic changes associated with the acute
inflammatory response are fever, leukocytosis, and plasma protein synthesis. Chronic
inflammation- can be a continuation of acute inflammation that last 2 weeks or longer. It
can also occur as a distinct process without much preceding acute inflammation.
What are the phases of wound healing and the process that takes place during each? -
Correct Answer ✔Phase 1- Inflammation- includes coagulation and the infiltration of
cells that participate in wound healing, including platelets, neutrophils, and
macrophages. Phase 2- Proliferation and New Tissue Formation (Reconstruction)-
wound begins to heal. This stage begins 3-4 days after injury and continues for as long
as 2 weeks. Phase 3- Remodeling and Maturation- phase for recovering normal tissue
structure that can persist for years
How does the inflammatory response differ in neonates? -Correct Answer ✔Neonates
often have transiently depressed inflammatory function, particularly neutrophil
chemotaxis and alternative complement activity.
How and why does aging affect innate immunity? -Correct Answer ✔Aging alters the
tissue microenvironment and macrophage function with changes in wound healing
neoangiogenesis and fibrosis.
What is the third line of defense and the process that takes place? -Correct Answer
✔Adaptive immunity (immune response or immunity)- the third line of defense in the
human body. Consists of lymphocytes and serum proteins called antibodies. -
Secondary responder-augments the initial defenses against infection and provides long
WGU D115 OBJECTIVE ASSESSMENT (OA) EXAM
, WGU D115 OBJECTIVE ASSESSMENT (OA) EXAM
term security against re-infection. - B cells- humeral can kill free floating pathogens - T
cells- cell - mediated- can kill pathogens hiding inside cells.
How and why does the neonate have a poorly developed immune response? -Correct
Answer ✔The human neonate has a poorly developed immune response, particularly in
the production of IgG. The fetus and neonate are protected in utero and during the first
few post-natal months by maternal antibody that was actively transported across the
placenta.
What terms are collectively known as hypersensitivity reactions? -Correct Answer
✔Allergy, autoimmunity, and alloimmunity are collectively known as hypersensitivity
reactions. Hypersensitivity Response I - IgE mediated- primary cause of common
allergies. Binds with mast cells which release histamine. (initiates allergic reaction).
Histamine release leads to bronchial smooth muscle contraction, bronchoconstriction,
and immune response II- tissue specific- wrong blood type administered or hemolytic
disease of the newborn. Complement pathway activated III- Immune complex mediated
IV- cell mediated - graft rejection
What are some causes of autoimmune diseases? -Correct Answer ✔Autoimmune
disease can be caused by the exposure of a previously sequestered antigen, the
development of a neoantigen, the complications of infectious disease, the emergence of
a forbidden clone of lymphocytes, or the consequence of ineffective peripheral
tolerance. The mechanisms for imitation of autoimmune diseases may already be within
humans.
What are some examples of alloimmune disorders? And why do these occur? -Correct
Answer ✔Alloimmunity is the immune systems reaction against antigens on the tissues
of other members of the same species. - Transient neonatal disease - Transplant
rejection - Transfusion reaction
What causes an immune deficiency? -Correct Answer ✔Immune deficiencies are either
congenital or acquired. Primary immune deficiencies are caused by genetic defects that
disrupt lymphocyte development, whereas secondary immune deficiencies are
secondary to disease or other physiologic alterations.
What are autoinflammatory diseases characterized by? -Correct Answer
✔Autoinflammatory disorders are characterized by abnormally high levels of
inflammation secondary to mutations in control of inflammasome activation or in defects
in cellular receptors of cytokines designed to decrease inflammation.
What are some causes of Acquired immunodeficiencies? -Correct Answer ✔Acquired
immunodeficiencies are caused by superimposed conditions, such as aging,
malnutrition, infections, malignancies, physical or psychologic trauma, environmental
factors, some medical treatments, or other diseases.
WGU D115 OBJECTIVE ASSESSMENT (OA) EXAM
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