CHAPTER 6 — INNATE IMMUNITY, INFLAMMATION & WOUND HEALING FLASHCARDS

What is the purpose of the immune system?

To protect the body from infection, injury, and harmful agents.

What are the two major types of immunity?

Innate immunity and adaptive immunity.

What are the three lines of defense?

First line: natural barriers; second line: inflammation; third line: adaptive immunity.

What is innate resistance?

Natural barriers and the inflammatory response.

What is adaptive immunity?

Acquired immunity involving lymphocytes, antibodies, and memory cells.

What are physical barriers in innate immunity?

Skin, GI/GU/respiratory linings, tight junctions, sloughing cells.

What mechanical processes help remove pathogens?

Coughing, sneezing, vomiting, urinating, washing.

What biochemical barriers protect the body?

Antibacterial peptides, lysozyme, defensins, cathelicidins, collectins.

What is the normal microbiome?

Beneficial microorganisms that inhibit pathogen colonization.

What bacteria dominate the vaginal microbiome?

Lactobacillus.

What substances does the intestinal microbiome produce?

Ammonia and phenols.

What does the gut microbiome help with?

Digestion, vitamin synthesis, pathogen inhibition, immune support.

What is dysbiosis?

Imbalance where beneficial bacteria decrease and harmful bacteria increase.

What can dysbiosis affect?

Digestion, immune health, overall well‑being.

Name three harmful organisms that may proliferate in dysbiosis.

Candida, Klebsiella, Proteus.

What diseases are linked to microbiome dysbiosis?

Atherosclerosis, autism, IBD, skin disorders, asthma, autoimmune disease, type 2 diabetes.

What are opportunistic pathogens?

Microorganisms that cause disease when immunity is weakened or barriers are damaged.

Give examples of opportunistic pathogens.

Candida albicans, Pseudomonas aeruginosa, Clostridioides difficile.

What triggers inflammation?

Infection, mechanical damage, ischemia, nutrient deprivation, temperature extremes, radiation.

What are the four classic signs of inflammation?

Heat, redness, swelling, pain.

What causes heat and redness?

Vasodilation and increased blood flow.

What causes swelling?

Exudate accumulation and increased capillary permeability.

What causes pain?

Pressure from exudate, prostaglandins, bradykinins.

What is serous exudate?

Watery fluid indicating early inflammation.

What is fibrinous exudate?

Thick, clotted fluid indicating advanced inflammation.

What is purulent exudate?

Pus indicating bacterial infection.

What is hemorrhagic exudate?

Exudate containing blood.

How does inflammation prevent infection?

Exudate dilutes toxins; neutrophils and macrophages eliminate pathogens.

How does inflammation limit its own spread?

Clotting factors and plasma enzymes restrict inflammation to injured tissue.

How does inflammation promote healing?

Removes microorganisms, dead cells, and debris.

What are the three plasma protein systems?

Complement, clotting, kinin.

What activates these systems?

Sequential activation of proenzymes.

What does C3b do?

Opsonizes pathogens to enhance phagocytosis.

What does C5a do?

Attracts leukocytes (chemotaxis).

What do C3a and C5a trigger?

Mast cell degranulation and histamine release.

What is the membrane attack complex (MAC)?

C5b–C9 complex that forms pores and lyses pathogens.

What is the purpose of the clotting system?

Stop bleeding, trap microorganisms, provide repair framework.

What activates the extrinsic pathway?

Tissue factor from damaged cells.

What activates the intrinsic pathway?

Contact with damaged vessel surfaces.

What is the main product of the kinin system?

Bradykinin.

What does bradykinin cause?

Vasodilation, increased permeability, pain, smooth muscle contraction.

What does H1 receptor activation cause?

Bronchoconstriction and vascular inflammation.

What does H2 receptor activation cause?

Increased gastric acid secretion and reduced inflammation.

What does H3 receptor regulate?

CNS histamine release, cognition, sleep, appetite.

What does H4 receptor promote?

Mast cell release of histamine and cytokines.

What do eosinophils defend against?

Parasites.

What do basophils release?

Histamine and leukotrienes.

How long does chronic inflammation last?

Months to years.

What diseases are linked to chronic inflammation?

Heart disease, cancer, autoimmune disease, neurologic disease.

What causes redness and warmth?

Vasodilation.

What causes edema?

Increased vascular permeability.

What are the primary initiators of inflammation?

Mast cells and macrophages.

What do dendritic cells do?

Link innate and adaptive immunity.

What do PRRs detect?

PAMPs and DAMPs.

What do TLRs recognize?

Microbial components.

What do NLRs detect?

Intracellular microorganisms and damage.

What activates mast cells?

Physical injury, chemical agents, immunologic processes.

What are the two ways mast cells release chemicals?

Degranulation and synthesis.

What does mast cell degranulation release?

Histamine, heparin, cytokines, proteases, leukotrienes.

What do leukotrienes do?

Produce histamine‑like effects, important in later inflammation.

What do prostaglandins do?

Cause pain and inflammation.

What does platelet‑activating factor do?

Acts like leukotrienes and activates platelets.

What do macrophages originate from?

Monocytes.

Name tissue‑specific macrophages.

Kupffer cells (liver), alveolar macrophages (lungs), microglia (brain).

When do neutrophils arrive at injury sites?

Within 6–12 hours.

What do neutrophils ingest?

Bacteria, dead cells, debris.

What is opsonization?

C3b “glues” phagocyte to target cell.

What forms after engulfment?

Phagosome.

What is a phagolysosome?

Fusion of phagosome with lysosomal granules.

What is granulomatous inflammation?

Macrophages form granulomas around persistent pathogens.

What causes fever?

IL‑1 acting on the hypothalamus.

What is a left shift?

Increase in immature leukocytes (bands).

What are the three goals of wound healing?

Fill the wound, seal the wound, shrink the wound.

What is regeneration?

Most favorable outcome; tissue returns to original structure.

What is repair?

Replacement with scar tissue.

What happens during hemostasis?

Clot formation and platelet activation.

What happens during inflammation?

Neutrophils remove debris; macrophages release cytokines.

What happens during proliferation?

Granulation tissue forms; epithelialization occurs.

What happens during remodeling?

Collagen reorganizes; wound contracts.

What causes impaired collagen assembly?

Malnutrition.

What is dehiscence?

Wound pulls apart at suture line.

When does dehiscence occur?

5–12 days after suturing.

Why are infants more susceptible to infection?

Limited innate immunity and low complement levels.