Which network of cells, tissues, and organs helps defend the body?
A Immune system
B Digestive system
C Skeletal system
D Endocrine system
Answer: A. Immune system. The immune system is a network of cells, tissues, and organs that helps fight infections and other diseases.
How does intact skin help protect the body from microbes?
A It makes every antibody
B It forms a physical barrier
C It filters all blood
D It digests pathogens
Answer: B. It forms a physical barrier. Intact skin is one of the body’s first physical barriers against microbes.
Which body lining can trap microbes before they enter tissues?
A Bone marrow
B Red blood cells
C Mucous membranes
D Tendon fibers
Answer: C. Mucous membranes. Mucous membranes line many body passages and produce mucus that can trap microbes.
In an immune response, what is an antigen?
A A type of antibody
B A lymphatic organ
C A blood pressure reading
D A substance recognized by defenses
Answer: D. A substance recognized by defenses. An antigen is a substance the immune system recognizes and may respond to.
What describes innate immunity?
A Inborn first-line protection
B Only vaccine-based protection
C A transferred antibody dose
D A response to one antigen
Answer: A. Inborn first-line protection. Innate immunity is present from birth and provides an early, broadly acting defense.
Compared with innate defenses, what characterizes adaptive immunity?
A No immune-cell involvement
B Specific recognition and memory
C Only skin barriers
D Identical response to every threat
Answer: B. Specific recognition and memory. Adaptive immunity targets particular antigens and can form immune memory.
Which immune response generally acts rapidly and broadly?
A Passive immunity
B Humoral immunity
C Innate immunity
D Allergic immunity
Answer: C. Innate immunity. Innate defenses respond quickly and recognize broad features shared by many microbes.
What do white blood cells help the body do?
A Carry oxygen exclusively
B Make digestive enzymes
C Build bone tissue
D Fight germs and disease
Answer: D. Fight germs and disease. White blood cells are immune cells that help fight infections and other threats.
Where are many white blood cells produced?
A Bone marrow
B Stomach lining
C Pancreas
D Outer skin layer
Answer: A. Bone marrow. Bone marrow produces many types of blood cells, including white blood cells.
Which lymphocytes can produce antibodies?
A Red blood cells
B B lymphocytes
C Platelets
D Muscle cells
Answer: B. B lymphocytes. B lymphocytes can develop into antibody-producing cells.
What are antibodies?
A Minerals that build bones
B Cells that carry oxygen
C Proteins that bind antigens
D Hormones that digest starch
Answer: C. Proteins that bind antigens. Antibodies are proteins that bind specific antigens and help the immune system respond to them.
Which lymphocytes can directly kill infected cells?
A Red blood cells
B Platelets
C Bacterial cells
D Cytotoxic T cells
Answer: D. Cytotoxic T cells. Cytotoxic T cells can recognize and kill certain infected or abnormal cells.
What is immunological memory?
A Remembering previously seen antigens
B Forgetting a past infection
C Producing red blood cells
D Filtering lymph through kidneys
Answer: A. Remembering previously seen antigens. Immune memory helps the adaptive immune system recognize a previously encountered antigen.
Which immunity develops through a person’s own immune response?
A Passive immunity
B Active immunity
C Innate-only immunity
D Temporary barrier immunity
Answer: B. Active immunity. Active immunity develops when a person’s own immune system responds to an antigen, including after infection or vaccination.
What defines passive immunity?
A Making antibodies after exposure
B Building a skin barrier
C Receiving antibodies from another source
D Producing new red blood cells
Answer: C. Receiving antibodies from another source. Passive immunity occurs when a person receives antibodies rather than making them through their own immune response.
What can provide passive antibodies to a newborn?
A Bone marrow cells
B Stomach acid
C Platelets
D Maternal antibodies
Answer: D. Maternal antibodies. Newborns can receive antibodies from their mother, providing temporary passive protection.
Why does passive antibody protection usually fade over time?
A Received antibodies gradually decline
B The body stops making skin
C All antigens disappear forever
D White cells become red cells
Answer: A. Received antibodies gradually decline. Transferred antibodies are eventually broken down, and passive immunity generally does not create lasting immune memory.
Where do immune cells commonly encounter antigens carried in lymph?
A Tendons
B Lymph nodes
C Lung alveoli
D Stomach muscle
Answer: B. Lymph nodes. Lymph nodes filter lymph and provide sites where immune cells can encounter antigens.
What important immune-cell development occurs in the thymus?
A Red cells mature
B Platelets digest microbes
C T cells mature
D Antibodies become antigens
Answer: C. T cells mature. T lymphocytes mature in the thymus.
Which organ filters blood and supports immune functions?
A Gallbladder
B Appendix only
C Thyroid gland
D Spleen
Answer: D. Spleen. The spleen filters blood and contains immune cells that respond to blood-borne antigens.
What do phagocytes do when they encounter some microbes?
A Engulf and digest them
B Produce insulin
C Carry oxygen
D Build antibodies only
Answer: A. Engulf and digest them. Phagocytes can engulf and break down microbes and cellular debris.
What is phagocytosis?
A Antibody transfer between people
B Cellular engulfment of particles
C T cell maturation
D Release of digestive hormones
Answer: B. Cellular engulfment of particles. Phagocytosis is a process in which a cell surrounds and takes in particles such as microbes.
Which innate immune cells can attack some abnormal cells?
A Red blood cells
B Platelets
C Natural killer cells
D Fat cells
Answer: C. Natural killer cells. Natural killer cells are part of innate immunity and can attack certain infected or abnormal cells.
How does the complement system support immune defense?
A It stores oxygen in muscle
B It makes food antibodies
C It replaces every white cell
D It helps target microbes
Answer: D. It helps target microbes. Complement proteins can help mark microbes, recruit immune activity, and damage some pathogens.
What is inflammation in basic immune biology?
A A local response to damage
B A type of antibody
C A permanent infection
D A blood group
Answer: A. A local response to damage. Inflammation is a protective response to infection or tissue injury that brings immune activity to the area.
Why can inflammation bring immune cells to an injured area?
A To stop all blood flow
B Contain threats and aid repair
C To create new antigens
D To prevent every fever
Answer: B. Contain threats and aid repair. Inflammatory signals help recruit defenses and support tissue repair.
What is an allergy?
A A bacterial infection every time
B A broken bone
C Immune response to allergen
D A missing red blood cell
Answer: C. Immune response to allergen. An allergy is an immune response to a substance that is usually harmless to most people.
What happens in an autoimmune disease?
A Antibodies carry oxygen
B Skin grows into bone
C Microbes digest the stomach
D Defenses mistakenly attack healthy tissue
Answer: D. Defenses mistakenly attack healthy tissue. In autoimmune diseases, immune responses mistakenly target the body’s own healthy cells or tissues.
What is immunodeficiency?
A Impaired immune-system function
B An unusually strong bone
C A specific antibody
D A digestive enzyme
Answer: A. Impaired immune-system function. Immunodeficiency means the immune system does not work properly, which can increase vulnerability to infection.
Which virus can damage immune white blood cells?
A Rhinovirus
B HIV
C Norovirus
D Adenovirus
Answer: B. HIV. HIV attacks important white blood cells and can weaken immune defenses if untreated.
What is one role of mucus on a respiratory surface?
A Produce red blood cells
B Digest bone minerals
C Trap particles and microbes
D Make every antibody
Answer: C. Trap particles and microbes. Mucus can trap particles and microbes on mucous membranes.
How can stomach acid contribute to innate defense?
A It makes T cells mature
B It creates antibodies
C It filters lymph
D It can kill some microbes
Answer: D. It can kill some microbes. Stomach acid can destroy some microbes that are swallowed.
Which body fluids contain the antimicrobial enzyme lysozyme?
A Tears and saliva
B Blood and bile only
C Sweat and urine only
D Synovial fluid only
Answer: A. Tears and saliva. Lysozyme is present in fluids such as tears and saliva and can damage certain bacterial structures.
Why do antibodies bind particular antigens?
A All antibodies bind everything
B Their binding sites are specific
C Antigens are always identical
D Antibodies are digestive acids
Answer: B. Their binding sites are specific. Antibody binding sites fit particular antigen structures, giving antibodies specificity.
How can vaccination prepare adaptive immune defenses?
A Remove every white blood cell
B Create passive antibodies only
C Build antigen-specific immune memory
D Prevent all future infections
Answer: C. Build antigen-specific immune memory. Vaccination can expose the immune system to an antigen in a way that supports adaptive immune memory.
Which group includes first-line innate defenses?
A Bones, tendons, and cartilage
B Insulin, bile, and enzymes
C Hair, nails, and teeth
D Skin, mucus, and immune cells
Answer: D. Skin, mucus, and immune cells. Innate defenses include physical barriers such as skin and mucus, along with cells and protective molecules.
What makes adaptive immunity more targeted than innate immunity?
A Specific antigen recognition
B Identical response to all germs
C Only physical barriers
D No immune memory
Answer: A. Specific antigen recognition. Adaptive immune cells recognize particular antigens rather than responding identically to every threat.
How do B cells contribute to humoral immunity?
A They carry oxygen
B They produce antibodies
C They digest food
D They form skin barriers
Answer: B. They produce antibodies. B cells and the antibodies they produce are central to humoral immunity.
Which term describes antibody-based defense in body fluids?
A Cell-mediated immunity
B Innate barrier defense
C Humoral immunity
D Passive inflammation
Answer: C. Humoral immunity. Humoral immunity refers mainly to antibody-mediated defense in body fluids.
Which adaptive response relies especially on T-cell activity?
A Humoral immunity
B Passive immunity
C Skin-barrier immunity
D Cell-mediated immunity
Answer: D. Cell-mediated immunity. Cell-mediated immunity is carried out chiefly by T cells and other immune cells.
When a familiar antigen appears again, what can memory cells enable?
A A faster targeted response
B Permanent loss of immunity
C Immediate bone growth
D A nonspecific skin barrier
Answer: A. A faster targeted response. Memory cells can help the immune system respond more quickly to a familiar antigen.
Does immunity to one disease protect against every other disease?
A Yes, all diseases are identical
B No, protection is often specific
C Only for bacterial diseases
D Only after fever
Answer: B. No, protection is often specific. Immune protection is generally specific to a pathogen or closely related organisms.
Can inflammation occur without an infection?
A No, infection is required
B Only after vaccination
C Yes, injury can trigger it
D Only in the lungs
Answer: C. Yes, injury can trigger it. Inflammation can be triggered by tissue injury as well as by infection.
What is one possible effect of immune overreaction to allergens?
A A stronger bone structure
B Improved oxygen transport
C A broken chromosome every time
D Allergy symptoms
Answer: D. Allergy symptoms. An immune response to an allergen can produce symptoms such as sneezing, itching, or swelling.
Which group of body parts belongs to the lymphatic immune system?
A Thymus, spleen, lymph nodes
B Heart, liver, pancreas
C Tendons, ligaments, cartilage
D Stomach, gallbladder, colon
Answer: A. Thymus, spleen, lymph nodes. The thymus, spleen, lymph nodes, and lymph vessels are among the structures of the lymphatic and immune systems.
How does the innate response generally compare in timing with adaptive immunity?
A It always begins years later
B It acts more rapidly
C It requires antibody transfer
D It only follows vaccination
Answer: B. It acts more rapidly. Innate defenses are available immediately, while adaptive responses often take longer to develop.
What may happen to transferred antibodies after passive immunization?
A They become permanent memory cells
B They turn into bacteria
C Their levels gradually decrease
D They create lifelong protection always
Answer: C. Their levels gradually decrease. Transferred antibodies provide temporary protection and decline over time.
Which conditions can result from immune responses to harmless substances?
A Broken bones and sprains
B Food poisoning only
C High blood pressure only
D Allergies and asthma
Answer: D. Allergies and asthma. An immune response to harmless substances can contribute to allergies and asthma.
Why can weakened immune defenses increase infection risk?
A Germ-fighting responses may be reduced
B Every pathogen disappears
C Skin becomes a vaccine
D Antibodies carry less oxygen
Answer: A. Germ-fighting responses may be reduced. When immune function is impaired, infections may occur more often, last longer, or become more serious.
What do lymph vessels transport between tissues and lymph nodes?
A Oxygen and red cells
B Lymph and immune cells
C Bile and digestive enzymes
D Urine and kidney salts
Answer: B. Lymph and immune cells. Lymph vessels carry lymph and immune cells between tissues and lymph nodes.