Mechanisms of self-defense/immunity

Question 1

What is the First Line of Defense in the immune system?

Answer 1

Innate Immunity

Includes physical and chemical barriers such as skin and mucous membranes, as well as antimicrobial peptides and the microbiome.

Question 2

What is the purpose of inflammation?

Answer 2

Minimize the effects of injury or infection, remove damaged tissue, generate new tissue, facilitate healing

Characterized by rapid, nonspecific responses including redness, warmth, swelling, and pain.

Question 3

What are the systemic responses to inflammation?

Answer 3

Fever, leukocytosis, increased plasma proteins by the liver

Fever is a temporary resetting of the hypothalamus in response to pyrogens.

Question 4

What is leukocytosis?

Answer 4

An increase in white blood cell (WBC) count

Normal WBC count ranges from 4,000-10,000.

Question 5

What does a ‘left-shift’ in a CBC indicate?

Answer 5

Increased numbers of immature neutrophils (bands)

This occurs to meet the demand for phagocytosis during infection.

Question 6

What are the key cells involved in the inflammatory response?

Answer 6

Mast cells, macrophages, neutrophils

These cells play critical roles in initiating and propagating the inflammatory response.

Question 7

What is the primary function of mast cells?

Answer 7

Release chemical mediators such as Histamine

They are located in tissues close to blood vessels and respond quickly to stimuli.

Question 8

What are the two types of histamine receptors?

Answer 8

Histamine 1 and Histamine 2

Histamine 1 causes vasodilation and increased capillary permeability; Histamine 2 increases gastric acid secretion.

Question 9

What is the role of leukotrienes?

Answer 9

Increase vascular permeability, promote bronchoconstriction and airway edema

They promote slower and more prolonged responses compared to histamine.

Question 10

What is the function of cytokines?

Answer 10

Mediate immune responses

Includes chemokines that attract WBCs and colony-stimulating factors that stimulate WBCs to divide and mature.

Question 11

What are the main types of exudative fluids?

Answer 11

Serous, fibrinous, purulent, hemorrhagic

Each type indicates different stages or causes of inflammation.

Question 12

What are the key characteristics of adaptive immunity?

Answer 12

Inducible, antigen-specific, and has memory

Involves B lymphocytes (humoral immunity) and T lymphocytes (cell-mediated immunity).

Question 13

What is the difference between active and passive immunity?

Answer 13

Active immunity is produced by the person in response to exposure; passive immunity is transferred from another source

Active immunity provides long-term protection, while passive immunity is short-term.

Question 14

What is the process of phagocytosis?

Answer 14

Recognition → Engulfment → Phagosome → Phagolysosome → Destruction

Opsonins like C3b and antibodies enhance this process.

Question 15

What is the primary immunoglobulin found in mucosal secretions?

Answer 15

IgA

Found in saliva, sweat, tears, mucus, bile, and colostrum.

Question 16

What characterizes acute inflammation?

Answer 16

Rapid, short-term, resolves in 8–10 days

Chronic inflammation is persistent and involves lymphocyte/macrophage infiltration.

Question 17

What are memory cells?

Answer 17

Long-lived B and T cells that allow rapid secondary responses

They remember antigens and respond quickly upon future encounters.

Question 18

What is the role of immunoglobulin IgG?

Answer 18

Most abundant antibody, crosses placenta

Responsive to viruses and bacteria.

Question 19

What is the role of the microbiome in the immune system?

Answer 19

Provides competition and immune modulation

Disruption can lead to superinfection or opportunistic infections.

Question 20

What is immunosenescence?

Answer 20

Age-related decline in immune function

Characterized by decreased naïve T/B cells and reduced vaccine response in the elderly.

Question 21

Fill in the blank: The process whereby the affinity between the phagocyte and the target cell is strengthened is called _______.

Answer 21

Opsonization

Question 22

True or False: Eosinophils are primarily involved in the defense against bacteria.

Answer 22

False

Eosinophils primarily defend against parasites and are predominant in allergic reactions.

Question 23

What is the main function of T Helper Cells?

Answer 23

Activate macrophages and stimulate B cells

They help in the antigen-driven maturation of B and T cells.

Question 24

What is the significance of fibronectin in neonatal immunity?

Answer 24

Enhances phagocytosis and is a major component in neonatal immunocompetency

Levels peak after birth and are reduced in certain conditions.

Question 25

What are anaphylatoxins?

Answer 25

Substances that induce rapid degranulation of mast cells ## Footnote C3a and C5a are examples of anaphylatoxins.

Question 26

What are autoantibodies?

Answer 26

Autoantibodies are antibodies produced by the immune system that mistakenly target and react with a person's own tissues. ## Footnote Autoantibodies can lead to autoimmune diseases.

Question 27

What is the effect of autoantibodies on vaccine response?

Answer 27

Autoantibodies can decrease vaccine response and increase infection/cancer risk. ## Footnote This is significant for individuals with autoimmune conditions.

Question 28

What is Normal Flora (Microbiota)?

Answer 28

Normal Flora refers to bacteria that normally inhabit internal and external surfaces of the body, providing mutual benefits to the host. ## Footnote For example, they assist in vitamin K synthesis in the colon.

Question 29

What can disrupt normal flora?

Answer 29

Illness, malnutrition, and medical therapies can disrupt normal flora, leading to superinfection and opportunistic infections. ## Footnote Superinfection is caused by broad-spectrum antibiotics disturbing normal flora.

Question 30

Define communicability in infectious diseases.

Answer 30

Communicability is the ability of a disease to spread from person to person. ## Footnote Diseases like measles and pertussis have high communicability compared to HIV.

Question 31

List the portals of entry for pathogenic microorganisms.

Answer 31

* Direct contact * Inhalation * Ingestion * Animal/insect bites

Question 32

Name the classes of infectious microorganisms.

Answer 32

* Viruses * Bacteria * Fungi * Protozoa * Chlamydia * Rickettsia * Mycoplasma * Helminths

Question 33

What is antigenic variation?

Answer 33

Antigenic variation includes mutation, antigenic drift and shift, recombination, and gene switching. ## Footnote These mechanisms help pathogens evade the immune response.

Question 34

What is Privileged Immunity in maternal-fetal-neonatal relationships?

Answer 34

Privileged Immunity refers to the fetus being accepted immunologically despite paternal antigens. ## Footnote IgG is actively transported from mother to fetus.

Question 35

What are some neonatal immune deficits?

Answer 35

* Defective neutrophil chemotaxis * Decreased bone marrow reserve * Poor T cell cytokine production * Low IgG * Low NK cell activity * Immature complement system

Question 36

What is the incidence of sepsis in neonates?

Answer 36

The incidence of sepsis in neonates is 2 per 1,000 live births, with untreated mortality up to 50%. ## Footnote Prompt treatment is crucial to improve outcomes.

Question 37

What is the recommended empiric antibiotic therapy for early-onset sepsis?

Answer 37

Ampicillin + Gentamicin are recommended for early-onset sepsis to cover GBS and gram-negative bacteria.

Question 38

Describe the process of viral replication.

Answer 38

DNA or RNA virus enters the cell, uncoats, and RNA viruses produce mRNA to synthesize viral proteins, while DNA viruses integrate into host DNA. ## Footnote Virions are released via budding.

Question 39

What are mycoses?

Answer 39

Mycoses are diseases caused by fungi, which can be superficial, deep, or opportunistic. ## Footnote Dermatophytes invade skin, hair, or nails, causing conditions like tinea.

Question 40

List the types of hypersensitivity.

Answer 40

* Type I: Immediate (IgE-mediated) * Type II: Antibody-mediated (IgG, IgM) * Type III: Immune complex-mediated * Type IV: T-cell mediated

Question 41

What is autoimmunity?

Answer 41

Autoimmunity occurs when the immune system attacks self-antigens. ## Footnote Examples include Systemic Lupus Erythematosus and Rheumatoid Arthritis.

Question 42

Fill in the blank: Type AB blood has A & B antigens and _______.

Answer 42

no antibodies

Question 43

What is the significance of Rh alloimmunity?

Answer 43

Rh alloimmunity occurs when an Rh-negative mother produces anti-D IgG against an Rh-positive fetus, leading to fetal hemolysis in subsequent pregnancies. ## Footnote This can cause hemolytic disease of the newborn.

Question 44

What are the outcomes of chronic stress?

Answer 44

Chronic stress can lead to cardiovascular disease, GI disorders, immune dysfunction, and mental health issues. ## Footnote It may also worsen outcomes in individuals with poor coping mechanisms.

Question 45

What is a primary immunodeficiency?

Answer 45

Primary immunodeficiencies are congenital immunodeficiencies caused by genetic anomalies, resulting in increased susceptibility to infections. ## Footnote Early detection is crucial for treatment success.

Question 46

What is SCID?

Answer 46

Severe Combined Immunodeficiency (SCID) is characterized by no T/B cell function and requires IVIG and bone marrow/stem cell transplant for treatment. ## Footnote X-linked SCID typically presents around 3 months of age.

Question 47

What are common opportunistic infections in HIV/AIDS?

Answer 47

* Candidiasis * Kaposi sarcoma * Tuberculosis * Encephalopathy * Cervical cancer

Question 48

What is the general adaptation syndrome?

Answer 48

General adaptation syndrome includes three stages: alarm, resistance, and exhaustion. ## Footnote This describes the body's response to stress.

Question 49

What are the characteristics of benign tumors?

Answer 49

Benign tumors grow slowly, have well-defined capsules, are not invasive, well differentiated, and do not metastasize. ## Footnote Examples include lipomas and gliomas.

Question 50

How do malignant tumors differ from benign tumors?

Answer 50

Malignant tumors grow rapidly, are not encapsulated, invasive, poorly differentiated, and can metastasize. ## Footnote Examples include carcinomas and sarcomas.

Question 51

What is a common neonatal tumor marker?

Answer 51

Alpha-fetoprotein (AFP) is a common neonatal tumor marker used to diagnose specific types of tumors. ## Footnote Tumor markers can also help observe the clinical course of cancer.

Question 52

Fill in the blank: Pediatric cancers often originate from _______ tissue.

Answer 52

embryonic

Question 53

How do childhood cancers differ from adult cancers?

Answer 53

Childhood cancers are often rapid, advanced at diagnosis, and responsive to treatment, while adult cancers are slow, often detected early, and lifestyle-linked. ## Footnote Cure rates for pediatric cancers can exceed 70%.