Unit 3 Reveiw

Flashcards covering key concepts of hypersensitivities, autoimmune diseases, immunodeficiencies, and related immunopathology.

What are the four major categories of hypersensitivities?

Type I: Allergy; Type II: Antibody-mediated; Type III: Immune-complex; Type IV: Cell-mediated (T-cell).

What characterizes Type I hypersensitivity?

It is a rapid reaction to an antigen mediated by Immunoglobulin E (IgE), which can result in conditions like allergies and anaphylaxis.

What is the mechanism of action in Type I hypersensitivity?

Sensitization occurs during the initial exposure leading B cells to produce IgE; subsequent exposures cause allergens to bind to IgE, triggering degranulation of mast cells.

Define autoimmunity.

Autoimmunity is a condition where the immune system mistakenly attacks the body's own tissues.

Differentiate between primary and secondary immunodeficiencies.

Primary immunodeficiencies are present from birth due to genetic mutations; secondary immunodeficiencies develop later in life due to external factors.

What is hypersensitivity?

Hypersensitivity is an immune overreaction to antigens.

Name an example of a Type II hypersensitivity reaction.

Transfusion reactions occur when mismatched blood types activate the complement system leading to cell lysis.

What causes Rh incompatibility in pregnancy?

When an Rh- mother becomes sensitized to Rh+ blood during the first pregnancy and produces anti-Rh antibodies.

How do IgG and IgM antibodies function in Type II hypersensitivity?

They activate the complement system causing cell lysis in response to antigens.

What characterizes Type III hypersensitivity?

It occurs when soluble antibodies react with soluble antigens to form immune complexes that cause tissue damage.

What is the Arthus reaction?

A localized acute reaction after second exposure to an antigen, resulting in immune complexes depositing in tissues.

Define Type IV hypersensitivity.

Type IV hypersensitivity is a delayed-type T-cell mediated immune response against specific antigens.

Give two examples of Type IV hypersensitivity reactions.

Infectious allergy (e.g., Tuberculosis skin test) and contact dermatitis (e.g., poison ivy reactions).

What is systemic lupus erythematosus (lupus)?

An autoimmune disorder characterized by autoimmunity affecting multiple body systems.

What are B-cell defects in primary immunodeficiencies?

Conditions such as agammaglobulinemia that impair antibody production leading to recurrent infections.

What defines hyposensitivity?

Hyposensitivity is an immune underreaction, resulting in immunodeficiency.

What is the role of IgE in hypersensitivity?

IgE is primarily involved in allergic reactions and protection against parasitic infections.

What symptoms are typical for Type I hypersensitivity reactions?

Symptoms can include itching, swelling, rashes, and even anaphylaxis.

What is desensitization in the context of allergy treatment?

A process where specific amounts of allergens are gradually injected to shift the immune response toward IgG, reducing allergy severity.

What are the defining features of autoimmune diseases?

Autoimmune diseases occur when the immune system attacks the body's own tissues, often due to genetic, environmental or infectious triggers.

What are molecular mimicry and its role in autoimmune diseases?

Molecular mimicry occurs when microbial antigens bear resemblance to self-antigens, causing cross-reactive immune responses.

How does HIV affect the immune system?

HIV targets CD4+ T cells leading to their destruction and progressive immune system failure.

Describe the symptoms of anaphylaxis.

Anaphylaxis involves extreme systemic reactions including airway obstruction, circulatory collapse, and can be life-threatening.

What is serum sickness?

A systemic immunological response that occurs when immune complexes form after exposure to certain medications or antigens.

Explain the importance of RhoGAM during pregnancy.

RhoGAM is administered to prevent Rh incompatibility by preventing the mother from producing anti-Rh antibodies.

What factors contribute to primary immunodeficiencies?

Genetic mutations affecting components of the immune system from birth.

What is the general impact of secondary immunodeficiency?

Increased vulnerability to infections and diseases due to factors like malnutrition, chronic stress, or immunosuppressive treatments.

List the main types of immunoglobulins.

IgG, IgA, IgM, IgD, IgE.

What is the primary difference between IgA and IgG?

IgA plays a crucial role in mucosal immunity, while IgG is the most prevalent antibody in blood and serum important for long-term immunity.

Describe the role of confirmatory tests in diagnosing infections.

Confirmatory tests provide definitive identification of pathogens through phenotypic, immunologic, or genotypic methods.

How can specimens be contaminated during collection?

Contamination can occur via improper techniques, such as failure to use aseptic methods during specimen collection.

What is the significance of nasal hair in respiratory defense?

Nasal hair traps large particles from inhaled air, preventing them from entering the respiratory tract.

What causes conjunctivitis?

Conjunctivitis is caused by infections from pathogens such as Neisseria gonorrhoeae and Chlamydia trachomatis.

What are the symptoms of keratitis?

Severe eye pain, redness, blurry vision, and photophobia.

How is tuberculosis primarily transmitted?

Tuberculosis is primarily spread through airborne particles.

What confers protection against gastrointestinal infections?

Secretory IgA, stomach acid, bile, mucus, and beneficial microbiota all contribute to gastrointestinal defense.

What is the relationship between climate change and infectious disease trends?

Climate change can influence the spread of vector-borne diseases and impact the transmission dynamics of pathogens.

Define zoonoses and their significance in public health.

Zoonoses are diseases that are transmitted from animals to humans, representing a significant threat to public health.

What are the benefits of understanding the One Health concept?

It promotes collaboration across human, animal, and environmental health disciplines to enhance overall health outcomes.

Why is antibiotic resistance a public health concern?

Antibiotic resistance leads to longer hospital stays, higher medical costs, and increased morbidity and mortality.

What is the causative agent of malaria?

Malaria is caused by Plasmodium species, primarily transmitted by Anopheles mosquitoes.

What is the difference between food poisoning and acute diarrhea

Food poisoning is typically caused by consuming contaminated food or beverages, resulting in symptoms like nausea and vomiting, while acute diarrhea is characterized by frequent loose stools that can be caused by various infections, including viruses or bacteria.