Exam 3: Topic 16 Flashcards
Briefly, how does the immune system recognize self from non-self?
• The immune system distinguishes “self” from “nonself” by identifying unique antigens. Where “self” antigens belong to the body’s own cells and “nonself” antigens are foreign, like those found on bacteria or viruses; this recognition process primarily occurs through specialized receptors on immune cells that specifically bind to these antigens, triggering an immune response when a nonself antigen is detected
What are some consequences or diseases that result when the immune system doesn’t respond, responds incorrectly, or has an overactive response?
• 3 ways the immune system can malfunction:
I. Immunosuppression: failure to adequately respond to a real threat.
II. Hypersensitivity/allergy: way overblown response to a foreign molecule that is not actually a threat.
III. Autoimmune disease: targets self as “non-self” in error.
List and describe the five major classes of leukocytes as discussed in class. Identify the phagocytes and the granulocytes
• Leukocytes:
○ Neutrophil: Small eater
§ First line of defense:
§ Neutrophils are among the first immune cells to respond to infection, traveling to the site of infection to destroy microorganisms through phagocytsosis and by the release of enzymes.
§ Release cytokines (induce inflammation)and chemokines to recruit other immune cells to fight infection.
○ Macrophage: Big eater
§ Among the first line of defense by destroying microorganisms such as bacteria, viruses, and parasites.
§ Help repair damaged tissue, remodeling bone and erythropoiesis.
§ Present antigens to T cells, initiate inflammation, and control blood pressure.
○ Lymphocytes: acquired immunity only
○ Eosinophils: jack of many trades; worm killers
○ Basophils: 911 dispatcher
• Phagocytes:
○ Neutrophil
○ Macrophage
○ Eosinophils
• Granulocytes:
○ _phil contains large amount of immune molecules in vesicles/granules
○ Can degranulate and release a huge # all at once (histamine, cytokines, and chemotactic factors).
Differentiate between: monocyte vs. macrophage; mast cell vs. basophil.
• Monocyte vs macrophage:
○ A monocyte is a precursor to a macrophage and is inactive in the blood. It becomes an activated monocyte when it enters the tissue.
○ A key part of the innate immune system and are involved in both inflammatory and anti-inflammatory processes. Monocytes can phagocytose and present antigens, and they can differentiate into macrophages
○ Macrophages are effector cells of the innate immune system that detect and destroy harmful organisms, such as bacteria. Play a role in tissue homeostasis and the resolution of inflammation.
• Mast cell vs basophil:
○ A basophil is present in blood and mast cell in tissues.
○ Mast cells are often the first cells to interact with pathogens and other environmental threats. They release inflammatory mediators, such as histamine.
○ Basophils are part of the innate immune system and are responsible for inflammatory reactions. They release enzymes from granules inside them when an infection is detected or an allergic reaction.
Describe the ‘3 lines of defense’ that protects our body.
• Physical barriers (like skin), the innate immune system (non-specific response), and the adaptive immune system (specific response), with the first line being physical barriers like skin, the second being the innate immune system with cells like neutrophils, and the third being the adaptive immune system with lymphocytes like B and T cells.
Briefly differentiate between innate immunity and acquired (adaptive) immunity: Speed, Specificity, Memory, Components, and Role.
Innate: This is the body’s inborn resistance to infection, which is present at birth. Innate immunity is nonspecific, fast, and uses barriers to keep harmful materials out of the body.
Acquired: This is a specific response that develops after exposure to a foreign substance or microorganism; learns, adapts, and remembers how to attack a specific antigen.
BIG OBJECTIVE: Give a detailed account of the inflammation response.
- Pathogen enters tissue (often with accompanying trauma)
- Mast cells nearby sense “something is wrong” (e.g. ribosomes in extracellular fluid) and degranulate, releasing . . .
- Histamine - causes vasodilation and makes capillaries leaky
○ Chemotaxins - attracts leukocytes to high concentration
○ Cytokines - “permission” molecules
○ Pyrogen - resets internal thermostat (if concentrated enough - Upstream blood vessels vasodilate, directing more blood (and therefore WBC) to area.
- Neutrophils - being more common - emerge first through leaky capillaries and move towards area with high concentration of chemotaxins
- Under cytokine permission neutrophils begin phagocytosis
- Monocytes emerge last and transform into active macrophages (again, under cytokines)
- Active macrophages efficiently phagocytize bacteria/pathogens, dead neutrophils and debris.
Describe the role of the following cells: macrophages, neutrophils, mast cells
• Macrophages:
○ Immune system: Macrophages are part of the innate immune system and are involved in detecting, phagocytosing, and destroying harmful organisms.
○ Tissue homeostasis:
§ Remove dead cells and tissue debris.
§ Repair tissue injuries.
• Neutrophils:
○ Neutrophils are one of the first immune cells to respond to microbes. They travel to the site of infection and destroy the microorganisms by ingesting them and releasing enzymes that kill them.
• Mast cells:
○ Primarily responsible for initiating allergic reactions by releasing histamine and other chemicals when they encounter allergens.
Describe the role of the following chemicals: histamine & nitric oxide, chemotaxins, pyrogens, cytokines. Explain what complement is, and its role in innate immunity.
• Histamine:
○ plays a key role in allergic reactions, primarily causing symptoms like sneezing, itching, and swelling.
○ inflammatory response throughout the body.
• Nitric Oxide:
○ acts as a key antimicrobial agent, primarily produced by host immune cells to defend against invading pathogens
• Chemotaxins:
○ attracts leukocytes to high concentration
• Pyrogens:
○ substances that can cause fever and other inflammatory responses in living organisms
• Cytokines:
○ direct immune cells to infection sites.
○ Initiated cell differentiation and proliferation.
○ assist dendritic cells in presenting antigens to generate cytotoxic T-cells and produce neutralizing antibodies
• Complement:
○ Complement: a collection of plasma proteins; activates a cascade to create a membrane attack complex (MAC).
§ Works well with G-
§ Enveloped viruses.
§ Foreign human cells.
Distinguish the following terms: plasma proteins, complement, and MAC.
• Plasma proteins:
• Complement:
○ a collection of plasma proteins; activates a cascade to create a membrane attack complex (MAC).
• MAC:
○ nonspecific pore in foreign membrane’ The final product of these reactions is a large, donut-shaped enzyme that punctures small pores through the membranes, leading to cell lysis.
