L18 Pt.2- Innate Host Defense

Flashcard 1 Q: What does cellular defense depend on?

A: Cellular defense depends on cells found in the blood.

Flashcard 2 Q: What is the composition of blood?

A: Blood consists of 60% plasma (liquid) and 40% formed elements.

Flashcard 3 Q: What are the formed elements of blood?

A: Erythrocytes, platelets, and leukocytes.

Flashcard 4 Q: Where do all blood cells originate?

A: From stem cells found in the bone marrow.

Flashcard 5 Q: Which immune cells are involved in both innate and adaptive immunity?

A: Leukocytes.

Flashcard 6 Q: What are granulocytes?

A: Leukocytes with granulated cytoplasm and irregular-shaped nuclei.

Flashcard 7 Q: From which stem cells are granulocytes derived?

A: Myeloid stem cells in the bone marrow.

Flashcard 8 Q: What is the primary function of basophils?

A: Release histamine to support innate inflammatory and allergic responses.

Flashcard 9 Q: What immune responses are basophils involved in?

A: Inflammation and allergic reactions.

Flashcard 10 Q: When are eosinophils found in high numbers?

A: During allergic reactions and worm (helminth) infections.

Flashcard 11 Q: How do eosinophils destroy worms?

A: By releasing digestive enzymes such as nuclease and glucuronidase.

Flashcard 12 Q: What additional role do eosinophils have?

A: Detoxifying foreign substances and turning off inflammation using histamine-degrading enzymes.

Flashcard 13 Q: What is the primary role of neutrophils?

A: Guard blood, skin, and mucous membranes against infection.

Flashcard 14 Q: What special enzyme do neutrophils contain?

A: Myeloperoxidase, which creates antimicrobial substances.

Flashcard 15 Q: Describe neutrophil lifespan and response time.

A: They do not divide, are replaced every few days, and are very fast responders to infection.

Flashcard 16 Q: Where are mast cells commonly found?

A: In connective tissue and near blood vessels.

Flashcard 17 Q: What is the function of mast cells?

A: Release histamine involved in local inflammation and allergic responses.

Flashcard 18 Q: Are mast cells phagocytic?

A: No, mast cells are not phagocytic.

Flashcard 19 Q: What defines agranulocytes?

A: They lack granular cytoplasm and have round nuclei.

Flashcard 20 Q: Which cells are classified as agranulocytes?

A: Monocytes and lymphocytes.

Flashcard 21 Q: From which stem cells are lymphocytes derived?

A: Lymphoid stem cells.

Flashcard 22 Q: What type of immunity do lymphocytes contribute to?

A: Adaptive immunity.

Flashcard 23 Q: Where are lymphocytes commonly found?

A: Lymph nodes, spleen, thymus, and tonsils.

Flashcard 24 Q: What is the function of monocytes?

A: Phagocytosis of dead cellular debris and invading microorganisms.

Flashcard 25 Q: How do monocytes mature?

A: They migrate from bone marrow to blood to tissue and become macrophages or dendritic cells.

Flashcard 26 Q: How do monocytes compare to neutrophils in response time?

A: They are slower but arrive in larger numbers.

Flashcard 27 Q: What are fixed macrophages?

A: Macrophages located in specific tissues that remain stationary.

Flashcard 28 Q: What are wandering macrophages?

A: Macrophages that circulate throughout the body like neutrophils.

Flashcard 29 Q: What structural feature characterizes dendritic cells?

A: Long membrane extensions.

Flashcard 30 Q: Why can’t macrophages ingest worms?

A: Worms are too large to be phagocytosed.

Flashcard 31 Q: How are worms destroyed by the immune system?

A: Eosinophils release toxic enzymes such as major basic protein (MBP).

Flashcard 32 Q: What do natural killer cells recognize?

A: Glycoproteins on the surface of virus-infected cells.

Flashcard 33 Q: How do NK cells destroy infected cells?

A: By releasing cytotoxins.

Flashcard 34 Q: When are NK cells most important?

A: Early viral infections before adaptive immunity begins.

Flashcard 35 Q: What are the primary lymphatic organs?

A: Thymus and bone marrow.

Flashcard 36 Q: What are the secondary lymphatic organs?

A: Spleen, lymph nodes, GALT, and SALT.

Flashcard 37 Q: Where do B lymphocytes differentiate?

A: In the bone marrow.

Flashcard 38 Q: What is the function of B lymphocytes?

A: Antibody production.

Flashcard 39 Q: Where do T lymphocytes differentiate?

A: In the thymus.

Flashcard 40 Q: Which cells perform phagocytosis?

A: Macrophages, neutrophils, and dendritic cells.

Flashcard 41 Q: What are the four steps of phagocytosis?

A: Finding/recognition, adherence, ingestion, digestion.

Flashcard 42 Q: What process guides phagocytes to infection sites?

A: Chemotaxis.

Flashcard 43 Q: What receptors help macrophages recognize pathogens?

A: Toll-like receptors (TLRs).

Flashcard 44 Q: How many TLRs exist in humans and mice?

A: 10 in humans and 14 in mice.

Flashcard 45 Q: What does TLR4 recognize?

A: Lipopolysaccharide of Gram-negative bacteria.

Flashcard 46 Q: Which TLRs recognize viral nucleic acids?

A: TLR 3, 7, and 8.

Flashcard 47 Q: What does TLR5 recognize?

A: Proteins in bacterial flagella.

Flashcard 48 Q: What are cytokines?

A: Small soluble proteins involved in inflammation.

Flashcard 49 Q: What are chemokines?

A: Cytokines that attract additional phagocytes.

Flashcard 50 Q: What allows phagocytes to bind microbes?

A: Binding of specific surface molecules.

Flashcard 51 Q: How do capsules help bacteria evade phagocytosis?

A: They prevent adherence (e.g., Streptococcus pneumoniae).

Flashcard 52 Q: How does the host overcome poor adherence?

A: Using antibodies to bind microbial surfaces.

Flashcard 53 Q: What organelles digest microbes inside phagocytes?

A: Lysosomes.

Flashcard 54 Q: What structure forms when lysosomes fuse with phagosomes?

A: Phagolysosome.

Flashcard 55 Q: How long does microbial destruction take?

A: About 20 minutes.

Flashcard 56 Q: Which bacterium can survive inside macrophages?

A: Yersinia pestis.

Flashcard 57 Q: What is a parasitophorous vacuole?

A: A vacuole that cannot fuse with lysosomes.

Flashcard 58 Q: What happens after neutrophils digest microbes?

A: They release microbial components.

Flashcard 59 Q: How do macrophages and dendritic cells trigger adaptive immunity?

A: By presenting antigens on MHC molecules.

Flashcard 60 Q: What are signs of inflammation?

A: Increased temperature, redness, and pain.

Flashcard 61 Q: What is acute inflammation?

A: Short-term inflammation where the host quickly eliminates pathogens and repairs tissue.

Flashcard 62 Q: What is pus composed of?

A: Dead phagocytes.

Flashcard 63 Q: What is an abscess?

A: Accumulation of pus in a cavity formed by tissue damage.

Flashcard 64 Q: When does inflammation become chronic?

A: When neither host nor pathogen is destroyed.

Flashcard 65 Q: What is a granuloma?

A: A pocket of tissue that walls off an inflammatory agent.

Flashcard 66 Q: What are gummas associated with?

A: Syphilis.

Flashcard 67 Q: What are lepromas associated with?

A: Leprosy.

Flashcard 68 Q: What are tubercles associated with?

A: Tuberculosis.

Flashcard 69 Q: How can meningitis be harmful?

A: Swelling around the brain can cause brain damage.

Flashcard 70 Q: How does lung inflammation affect breathing?

A: Swelling decreases airflow.

Flashcard 71 Q: Why can vasodilation benefit pathogens?

A: It increases oxygen and nutrients available to both host and pathogen.