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WorksheetsLecture Notes: Immune System
Total questions: 61
Worksheet time: 31mins
What is the immune system? Fill in the blank: The immune system is the intricate network of _______, _______, and _______ that work together to protect the body from harmful foreign substances (pathogens), toxins, and abnormal cells (e.g., cancerous cells).
cells, tissues, organs
bones, muscles, nerves
enzymes, hormones, vitamins
veins, arteries, capillaries
Which of the following is NOT a branch of the immune system?
Non-specific/innate/immediate immunity
Specific/acquired/adaptive immunity
Digestive immunity
Both A and B are branches
Fill in the blank: The 1st line of defense without needing prior exposure, which recognizes common patterns on microbes, is called _______ immunity.
non-specific/innate/immediate
adaptive/acquired
passive
humoral
Fill in the blank: Highly specific immunity that targets particular pathogens, allergens, and toxins and remembers them for faster future response is called _______ immunity.
specific/acquired/adaptive
innate
passive
nonspecific
What is an antigen? Fill in the blank: Antigens are on the _______, _______, and _______; they activate antibody production.
pathogens, allergens, toxins
hormones, enzymes, vitamins
cells, tissues, organs
proteins, lipids, carbohydrates
What are antibodies also known as?
Immunoglobulins
Antigens
Enzymes
Hormones
What does APC stand for in the context of the immune system?
Antigen presenting cells
Adenosine phosphate complex
Active protein carrier
Autoimmune processing cell
Which type of immune cell kills infected and cancerous cells?
T cell (T lymphocyte)
B cell (B lymphocyte)
Red blood cell
Platelet
Professional APCs display both _______ and _______ molecules; they are important in the immune response.
MHC class I, MHC class II
CD4, CD8
IgG, IgM
Interleukin-2, Interleukin-4
What is the definition of the body's first line of defense in the immune system?
The body's immediate and non-specific defense system that is always 'on' and ready to act, providing the first line of protection against a wide range of pathogens without needing prior exposure.
The body's adaptive immune response that targets specific antigens.
The process of producing antibodies after infection.
The production of red blood cells.
Which of the following is NOT a function of the stratum corneum in the skin?
Forms a tough, impenetrable barrier for most microbes.
Produces antibodies.
Is the outermost layer of dead, keratinized cells.
Helps prevent microbial proliferation.
Fill in the blank: Sweat and sebaceous gland secretions create an acidic environment on the skin with a pH of ____ that inhibits bacterial growth.
4.0-6.0
6.5-7.5
7.5-9.0
2.0-3.0
What is the role of normal flora on the skin?
They cause infections.
They competitively inhibit the growth of pathogenic organisms.
They produce antibodies.
They increase skin dryness.
Which of the following best describes the function of mucous membranes in the first line of defense?
They produce antibodies.
They line all body cavities that open to the exterior and trap microbes and foreign particles.
They secrete hormones.
They increase the pH of the body.
What is the function of stomach acid (hydrochloric acid - HCl) in the first line of defense?
It neutralizes toxins.
It denatures proteins and kills most ingested bacteria and viruses.
It produces antibodies.
It increases microbial growth.
Tears and saliva contain lysozyme, an enzyme that breaks down ______ in bacterial cell walls.
peptidoglycan
cellulose
chitin
lipopolysaccharide
Cerumen (earwax) creates an acidic environment in the ear canal, inhibiting bacterial and fungal growth.
True
False
What is the beneficial microorganisms residing on and within the body called?
Normal Flora (Microbiome)
Pathogens
Antibodies
Enzymes
What is the process called when beneficial microorganisms outcompete pathogens for nutrients and adhesion sites?
Competitive Exclusion
Pathogenic Invasion
Antibiotic Resistance
Symbiotic Displacement
What is the function of the production of antimicrobial substances by some normal flora?
They produce bacteriocins or other compounds that inhibit pathogen growth.
They increase the rate of host cell division.
They promote the growth of all bacteria, including pathogens.
They neutralize all nutrients in the environment.
What is the role of immune system modulation by normal flora?
They play a role in training and developing the immune system.
They cause immediate immune suppression in all cases.
They eliminate all pathogens from the body.
They prevent the absorption of nutrients.
What are the immune cells that respond immediately once a barrier is breached called?
Cellular Responses (Internal Defenses of Innate Immunity)
Adaptive Immunity Cells
Memory B Cells
Helper T Cells
Which type of phagocyte is the most abundant type of white blood cell and is the first responder to infection sites?
Neutrophils
Eosinophils
Basophils
Monocytes
What is the main function of Natural Killer (NK) cells?
To identify and kill host cells that are infected with viruses or have become cancerous.
To produce antibodies against pathogens.
To phagocytose bacteria and debris.
To activate helper T cells.
What are the four signs of inflammation?
Redness (rubor), swelling (tumor), heat (calor), pain (dolor)
Redness (rubor), fever (febris), cough (tussis), pain (dolor)
Swelling (tumor), heat (calor), rash (exanthem), fatigue (lassitude)
Redness (rubor), swelling (tumor), nausea (nausea), vomiting (vomitus)
What is the purpose of fever (pyrexia) in the immune response?
Inhibits the growth of some pathogens, increases metabolic rate of immune cells, and enhances some immune responses.
Reduces the production of white blood cells and slows down immune responses.
Decreases the metabolic rate of immune cells and suppresses inflammation.
Promotes the spread of pathogens throughout the body.
What is the definition of the adaptive immune system? Fill in the blank: The adaptive immune system is a highly specific defense system that targets particular pathogens and "remembers" them for future encounters. It takes longer to activate upon first exposure but provides ________ immunity.
long-lasting
temporary
partial
innate
Which of the following is NOT a key characteristic of the adaptive immune system?
Specificity
Memory
Diversity
Immediate response
Self-Recognition/Tolerance
Fill in the blank: Each adaptive immune cell (lymphocyte) is programmed to recognize and respond to a single, specific ________.
antigen
hormone
enzyme
neuron
What is the main function of memory cells in the adaptive immune system?
To enable a much faster, stronger, and more efficient immune response upon subsequent exposure to the same antigen.
To directly destroy pathogens upon first exposure.
To produce antibodies continuously regardless of infection.
To act as physical barriers to prevent pathogen entry.
Which process allows the adaptive immune system to recognize an enormous number of different antigens?
Genetic recombination of receptor genes
Clonal deletion of self-reactive cells
Phagocytosis by macrophages
Antigen presentation by dendritic cells
The adaptive immune system can distinguish between 'self' and 'non-self' to prevent autoimmune attacks.
True
False
Match the following terms to their correct descriptions:
The process of stem cell development
2
A cell that can turn into many types, but only one type at a time
3
Stem cell that can turn into either common myeloid or lymphoid progenitor cells
1
Where do B lymphocytes mature?
Bone marrow
Thymus
Spleen
Lymph nodes
What is the primary function of plasma cells?
To produce and secrete antibodies into the bloodstream and tissues.
To engulf and destroy pathogens through phagocytosis.
To transport oxygen throughout the body.
To initiate blood clotting at the site of injury.
Which of the following is NOT a function of antibodies?
A) Directly killing pathogens
B) Neutralization
C) Opsonization
What is the primary responsibility of T lymphocytes (T cells)?
Primarily responsible for cell-mediated immunity, acting against intracellular pathogens (viruses, some bacteria, fungi), cancerous cells, and transplanted cells.
Production of antibodies to neutralize extracellular pathogens.
Phagocytosis of bacteria and debris in the bloodstream.
Regulation of blood clotting and wound healing processes.
Where do T cells mature?
In the thymus.
In the bone marrow.
In the spleen.
In the lymph nodes.
Which type of T cell acts as the 'central commander' or 'orchestrator' of the adaptive immune response?
Helper T Cells (CD4+ T Cells)
Cytotoxic T Cells (CD8+ T Cells)
Regulatory T Cells (Tregs)
Memory T Cells
What is the main function of Cytotoxic T Cells (CTLs or CD8+ T Cells)?
To directly identify and kill target cells by inducing apoptosis.
To produce antibodies against pathogens.
To present antigens to helper T cells.
To secrete histamine during allergic reactions.
Which T cell type is responsible for suppressing or down-regulating the immune response to prevent excessive or autoimmune reactions?
Regulatory T Cells (Tregs; Formerly Suppressor T Cells)
Helper T Cells (Th cells)
Cytotoxic T Cells (Tc cells)
Memory T Cells
What is the function of Memory T Cells?
They are long-lived T cells that provide rapid responses upon re-exposure to the same antigen.
They produce antibodies to neutralize pathogens.
They directly engulf and digest pathogens.
They suppress the immune response to prevent autoimmunity.
What is an antigen?
Any substance that can trigger an immune response. They are unique molecular signatures, often proteins or carbohydrates, found on the surface of pathogens, toxins, or abnormal cells.
A type of white blood cell that engulfs pathogens.
A chemical that neutralizes stomach acid.
A hormone that regulates blood sugar levels.
What are the two main classes of Major Histocompatibility Complex (MHC) molecules?
MHC Class I and MHC Class II
MHC Alpha and MHC Beta
MHC Type A and MHC Type B
MHC Class X and MHC Class Y
MHC Class I molecules are found on almost all nucleated cells in the body and present which type of antigens to CD8+ Cytotoxic T cells?
intracellular antigens
extracellular antigens
bacterial antigens only
fungal antigens
MHC Class II molecules are found only on Antigen-Presenting Cells (APCs) and present which type of antigens to CD4+ Helper T cells?
extracellular antigens
intracellular antigens
self-antigens
viral antigens only
Which of the following cells are considered Antigen-Presenting Cells (APCs)?
Red blood cells
Macrophages
Platelets
Neurons
What is the primary function of Antigen-Presenting Cells (APCs)?
To engulf pathogens or their components, process them into antigen peptides, and display these peptides on their MHC molecules to T cells.
To directly destroy infected cells by releasing cytotoxic granules.
To produce antibodies that neutralize pathogens in the bloodstream.
To transport oxygen and carbon dioxide throughout the body.
In the scenario where a cut introduces bacteria, what is the first step in the immune response?
Breaching the Barrier: The skin, a primary physical barrier, is compromised.
Antibodies immediately neutralize the bacteria.
White blood cells engulf the bacteria at the site.
Fever develops to kill the bacteria.
Which immune cells are the first phagocytes to arrive and engulf bacteria at the site of infection?
Neutrophils
Eosinophils
Basophils
Lymphocytes
What is the role of complement activation in the immune response?
Proteins in the blood plasma are activated, leading to opsonization (coating) of bacteria, direct lysis, and increased inflammation.
It directly produces antibodies to neutralize pathogens.
It suppresses the activity of all immune cells to prevent autoimmunity.
It only functions in the removal of dead host cells, not pathogens.
In the lymph node, dendritic cells present bacterial antigens on MHC II to specific Helper T cells, activating them.
True
False
What do plasma cells secrete in response to bacterial antigens?
Massive amounts of antibodies specific to the bacterial antigens.
Enzymes that digest bacterial cell walls.
Hormones that regulate immune response.
Cytokines that suppress immune activity.
What types of cells are generated to ensure a much faster and stronger response if the same bacteria are encountered again?
Memory B and T cells
Plasma cells
Red blood cells
Macrophages
Infection Control: Understanding how pathogens overcome defenses and how the immune system fights back informs ______ practices, antibiotic development, and infection prevention strategies.
hygiene
surgical
nutritional
recreational
Vaccines: The entire concept of vaccination relies on the immune system's ______. Vaccines safely introduce antigens to elicit a primary immune response and generate memory cells without causing disease.
memory
digestion
mobility
respiration
Autoimmune Diseases: When the immune system mistakenly attacks 'self' tissues, therapies aim to ______ or modulate the immune response.
suppress
stimulate
ignore
enhance
Allergies: An exaggerated immune response to harmless substances is called ______.
allergies
immunity
infection
mutation
Cancer Immunotherapy: Harnessing the immune system's ability to recognize and destroy abnormal cells is a major frontier in ______ treatment.
cancer
diabetes
arthritis
asthma
Transplantation: Preventing rejection of transplanted organs requires suppressing the recipient's immune system, which recognizes the transplanted organ as ______.
non-self
self
neutral
friendly
The immune system has two main branches: the innate (immediate/non-specific) and the adaptive/specific/acquired (memory-based B and T cells).
True
False
