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Questions and Answers
What type of leukocyte is primarily involved in the first line of defense through phagocytosis?
Which type of immunity is primarily activated by B cells?
Which leukocyte type contributes to cell-mediated immunity?
What is the function of Helper T-cells?
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Which of the following is NOT a characteristic of T cells?
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Which type of T cell is known for killing infected or cancerous cells?
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What is the primary function of an antigen in the immune response?
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What is the role of antibodies in the immune response?
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Which type of leukocyte primarily lacks granules in its cytoplasm?
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Which type of white blood cell is primarily responsible for responding first to inflammation?
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What role do lymph nodes play in the immune system?
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Which of the following best describes the function of mast cells?
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What is one of the key functions of eosinophils in the immune system?
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Which of the following is considered a primary physical barrier in the immune system?
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Which component of the immune response releases cell mediators to coordinate the immune reaction?
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What is the role of the spleen in the immune system?
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What type of immunity is present at birth?
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Which of the following is an example of passive acquired immunity?
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How is active acquired immunity developed?
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What is a characteristic of inactivated vaccines?
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HIV primarily attacks which type of immune cells in the body?
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What does 'attenuated' refer to in live attenuated vaccines?
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Which of the following statements about natural immunity is true?
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How can HIV be transmitted from mother to child?
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What is one of the recommended methods for reducing the risk of HIV transmission during sexual activity?
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What does PrEP involve for individuals engaging in high-risk behaviors?
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What is the purpose of Post-Exposure Prophylaxis (PEP)?
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Why is it recommended not to reuse condoms?
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Which of the following is part of the standard precautions to protect against HIV in healthcare settings?
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What characterizes HIV as a retrovirus?
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What type of products should infected individuals refrain from donating?
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Which of the following is NOT a method to prevent HIV infection?
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What is primarily emptied into the CD4 T cell during the uncoating/fusion process of HIV?
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What process converts HIV's RNA into double-stranded DNA?
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Which enzyme facilitates the blending of new viral DNA with the DNA of the CD4 T cell?
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During which stage of HIV infection can the viral load reach very high levels, often above 100,000 copies per milliliter of blood?
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What occurs during the transcription phase of HIV infection?
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What role does the HIV protease enzyme play in the viral lifecycle?
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Which of the following is a characteristic of the chronic stage of HIV infection?
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What is the first step after the viral DNA integrates with the CD4 T cell's DNA?
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Study Notes
Immune System Terminology
- Antigen: A substance that stimulates antibody production.
- Antibody: A protein produced by the immune system that targets harmful substances.
- Humoral Immunity: Immunity provided by antibodies in the body fluids.
- Cell Mediated Immunity: Immunity provided by the T lymphocytes.
Immune system structures
- Bone Marrow: Produces white blood cells (WBCs).
- Lymphoid Tissues: Sites of WBC activity.
- Spleen: Filters blood, removing old and injured red blood cells.
- Lymph nodes: Remove foreign material from the lymph system.
- Physical and Chemical Barriers: First line of defense.
- Physical: Skin, mucous membranes, cilia of the respiratory tract.
- Chemical: Mucus, gastric secretions, enzymes in tears and saliva.
White Blood Cells (WBCs)
- Granular Leukocytes (Granulocytes):
- Neutrophils: Most abundant WBC, first responders to inflammation.
- Eosinophils: Fight multicellular parasites.
- Basophils: Involved in allergic reactions.
- Mast cells: Role in wound healing and allergic reactions.
- Nongranular Leukocytes:
- Monocytes/Macrophages: Larger phagocytic cells than granulocytes.
- Lymphocytes:
- B cells: Responsible for humoral immunity, producing antibodies.
- T cells: Responsible for cell-mediated immunity.
- Helper T cells: Stimulate B cells and killer T cells.
- Killer T cells: Destroy infected or cancerous cells.
Types of Immunity
- Natural/Nonspecific immunity: Present at birth.
- Acquired/Specific immunity: Develops after birth.
- Active acquired immunity: Develops after exposure to pathogens.
- Examples: Vaccination, infectious disease.
- Passive acquired immunity: Temporary immunity from external sources.
- Examples: Maternal antibodies, immune globulin injections.
- Active acquired immunity: Develops after exposure to pathogens.
Human Immunodeficiency Virus (HIV)
- A retrovirus that attacks the human body's immune system, specifically CD4+ cells.
- Transmission:
- Body fluids: blood, seminal fluid, vaginal secretions, amniotic fluid, breast milk.
- Mother-to-child: in utero, during birth, breast feeding.
- Sharing needles, unsafe sexual contact, organ transplantation.
HIV Prevention:
- Use condoms.
- Reduce the number of sexual partners.
- Don't share needles, razors, toothbrushes, or blood contaminated articles.
- Pre-Exposure Prophylaxis (PrEP): Daily medication to prevent HIV infection.
- Avoid anal intercourse.
- Get tested regularly.
HIV Prevention for Healthcare Providers:
- Standard Precautions: Hand hygiene, personal protective equipment.
- Post-Exposure Prophylaxis (PEP): Antiretroviral medications taken within 72 hours of potential exposure.
HIV Pathophysiology:
- HIV cannot replicate without a host cell.
- HIV uses a CD4+ cell to reproduce.
- Attachment/Binding: HIV glycoproteins bind to the CD4 receptor on the host cell.
- Uncoating/Fusion: HIV releases its genetic material (RNA and enzymes) into the CD4 cell.
- DNA synthesis: Reverse transcriptase converts HIV RNA into DNA.
- Integration: Integrase inserts the viral DNA into the host cell’s DNA.
- Transcription: The integrated DNA produces messenger RNA (mRNA) to build new viruses.
- Translation: mRNA creates proteins and enzymes necessary for viral replication.
- Cleavage: Protease enzyme cuts the polyprotein chain into individual components.
- Budding: New proteins and viral RNA assemble at the cell membrane, forming new viruses.
HIV Stages:
- Acute Stage:
- Characterised by flu-like symptoms (aches, fever, fatigue etc.).
- Occurs weeks to a month after infection.
- High viral load, CD4 count is still high.
- Chronic Stage (Asymptomatic Stage):
- HIV remains undetected for many years.
- Viral load is low, but HIV replicates.
- CD4 count is typically above 500 cells/mm^3.
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Description
Test your understanding of key terms and structures related to the immune system. This quiz covers terminology such as antigens and antibodies, as well as various immune cells and their functions. Challenge yourself and reinforce your knowledge about this vital biological system.
