C4 - Immunity Flashcards
What is the function of the lymphatic system?
Maintains fluid balance, collects and circulates excess fluid, carries fats before they enter the blood, and works with white blood cells to fight infection.
What is lymph?
Fluid in lymphatic vessels made of interstitial fluid (surrounding cells).
What are lymph vessels?
Interwoven with capillary beds, absorb fluid escaping blood capillaries, have a large turnover with blood plasma and interstitial fluid, and are blind-ended (do not form circuits).
What are lymph nodes?
Glands with maturing lymphocytes and macrophages that filter lymph and trap pathogens.
What are the three lines of defense in the body’s defense system?
- Physical and chemical barriers 2. Non-specific defenses (cell-mediated immunity) 3. Specific defenses (antibody- and cell-mediated).
What are examples of physical and chemical barriers?
Skin (dry, keratinized), oil (bactericides), sweat (acidic layer), eyelashes, eyelids, cilia, tears, mucous, stomach acid, ear wax.
What are macrophages and what do they do?
Develop from monocytes, found in liver, spleen, brain, lungs, digest microbes via phagocytosis, move towards infection via chemotaxis, and form pus after digestion.
What is chemotaxis?
Movement of WBCs toward chemical signals from infected tissue.
What is pus made of?
Dead white blood cells, digested invaders, and protein fragments.
What are non-specific defenses?
Use WBCs like macrophages and neutrophils, do not target specific pathogens, and involve cell-mediated immunity.
What are specific defenses?
Involve production of specific T and B cells, protect against particular pathogens, and consist of two types: cell-mediated and antibody-mediated.
What is cell-mediated immunity?
Involves T-cells, fights intracellular pathogens and cancer, and uses lysis to destroy infected cells.
What is antibody-mediated immunity?
Involves B-cells, produces antibodies for extracellular pathogens, and is activated by helper T-cells.
Where do B-cells mature?
Bone marrow.
Where do T-cells mature?
Thymus gland.
What are helper T-cells?
Activate killer T-cells, stimulate plasma B-cells, and respond to antigen info from infected cells/macrophages.
What are killer (cytotoxic) T-cells?
Target infected and cancerous cells and destroy cells using lysis.
What are suppressor T-cells?
Stop immune response after pathogen elimination and prevent overactive immune system.
What are memory T-cells?
Remain in bloodstream, ‘remember’ antigens, and enable faster secondary response.
What are plasma (effector) B-cells?
Produce specific antibodies, fight extracellular pathogens, and are stimulated by helper T-cells.
What are memory B-cells?
Remain in bloodstream, ‘remember’ antigens, and respond quickly to future infections.
What are autoimmune disorders?
Immune system attacks body’s own cells and treats them as if they are foreign.
What is rheumatoid arthritis?
Autoimmune disorder where the immune system attacks joints, causing inflammation, pain, stiffness, fatigue, and can lead to permanent damage.
What are allergies?
Exaggerated immune response to harmless substances.
What’s the difference between immediate and delayed allergic reactions?
Immediate: Antibodies trigger histamine release (e.g., asthma). Delayed: T-cells react after prior exposure, slower and longer (e.g., cosmetic allergy).
