Immune Function and Stress Flashcards
(38 cards)
What is immunity?
-ability of the body to fight infection and/or foreign invaders by producing antibodies or killing infected cells
What is the immune system?
-system in the body responsible for maintaining homeostasis by recognizing harmful from nonharmful organisms and produces an appropriate response.
What are foreign invaders?
-called pathogens: viruses, bacteria or other living thing that causes disease/immune response [out in the world]
-antigens: toxins that pathogens produce that cause harm to an organism [inside our body]
What does the Immune system consist of?
-not simply blood cells
-collection of organs
-vital for survival
4 components:
1. blood - white blood cells
2. lymph nodes [where white blood cells meet to exchange info]
3. thymus gland - produces T lymphocytes
4. bone marrow - produces B lymphocytes
(also the spleen creates other lymphocytes)
What is the first line of defense?
-the skin - provides physical and chemical barriers
-physical: hard to penetrate, made of indigestible keratin
-chemical: tears, sweat [push out pathogens]
What is the second line of defense?
-nonspecific immune response - defenses body uses no matter the invader, including:
-phagocytosis - done by macrophages
-natural killer cells
-inflammation - caused by release of histamine from leukocytes
-fever - caused by histamines. The high temp kills invaders by denaturing their proteins
[macrophage: a phagocytic cell found in the liver, spleen, brain and lungs. Travels to all areas of the body to find and eat pathogens]
What is the third line of defense?
-specific immune response - specific response to a specific pathogen/antigen
-the response involved the creation of antibodies
What are antibodies?
-Y-shaped protein molecule
-made up of variable and constant regions
-made up of heavy and light chains
-produced by B-lymphocytes
-function: recognize antigens [variable region], bind to and deactivate them
What is the pathway of specific immune response?
-pathogens [bacteria, viruses, fungi, foreign proteins] enter the body
-Step 1: antigens eaten by macrophage
-Step 2: displays portion of antigen on surface
-Step 3: helper-T cell recognizes antigen
-then activates cytotoxic T-Cell [which kills infected cells right away and forms memory T-Cell] and B-Cell [which forms Memory B-Cell and makes antibodies]
What is the difference between Cellular vs Antibody immunity?
-cellular immunity: carried out by T-Cells; infected cells are killed by Cytotoxic T-Cells
-antibody/humoral immunity: carried out by B-cells; antibodies are produced and dumped into blood stream;
What are the full 10 steps of the immune response?
- antigen infects cells
- macrophage ingests antigen and displays portion on its surface.
- helper T- Cell recognizes antigen on the surface of the macrophage and becomes active.
- active Helper T-Cell activates Cytotoxic T-Cells and B-Cells.
- cytotoxic T-Cells divide into Active Cytotoxic T-cells and Memory T – Cells.
- active Cytotoxic T-Cells kill infected cells.
- at the same time, B-Cells divide into Plasma Cells and Memory B- Cells.
- plasma cells produce antibodies that deactivate pathogen.
- memory T and Memory B cells remain in the body to speed up the response if the same antigen reappears.
- suppressor T-Cells stop the immune response when all antigens have been destroyed.
What are the primary and secondary immune response?
-Primary Immune Response: response to an invader the first time it infects the body.
-no measurable immune response for first few days.
-next 10 – 15 days antibody production grows steadily
-Secondary Immune Response: more rapid response to an invader the 2nd time it invades the body.
-antibody production increases dramatically and in a much shorter time period.
What is active immunity?
-body is “actively” producing antibodies to fight infection.
-Vaccination: an injection of a weakened strain of an infectious microbe (pathogen) that causes the body to undergo active immunity (produce antibodies).
What is passive immunity?
-antibodies are given to a person from the blood of another person or animal.
-this immunity only lasts for a short period of time.
-ex: breastfeeding mothers pass antibodies to their children through the milk.
What is Autoimmune Disease?
-Autoimmune diseases are diseases where the immune system begins to attack itself.
Examples include:
-Rheumatoid Arthritis – crippling disease of the joints
-Lupus – disease of blood and organs
-Multiple Sclerosis – disease of nervous system
What is an allergy and allergen?
-Allergy: an exaggerated response by the immune system to an allergen.
-Allergen: a normally harmless substance that causes an allergic reaction.
-ex: dust, pollen, mould, food, insect stings
What are the two types of allergic reactions?
-immediate: occurs within seconds and normally lasts for about 30mins
-delayed: takes longer to react and can last for a much longer time
What is Psychoneuroimmunology?
-investigations of the bidirectional linkages between the CNS, the endocrine system and the immune system, and the clinical implications of these linkages
Learn slide 29
How does NE and E affect lymphocytes?
-immediate exposure (30min): increased number of lymphocytes [natural killer cells]
-longer exposure (days): decreased number of natural killer cells
How does NE influence immune function?
-NE can alter both innate and adaptive immune function in organs and circulation by “fine-tuning” immune responses, enabling rapid adjustments within minutes.
-it also shifts the immune balance from Th1 (pro-inflammatory) to Th2 (anti-inflammatory).
What is the immune system response to acute stressor [short-term effect of cortisol]?
-redistribution of immune cells (increase in leukocytes in blood)
-increase in innate, non-specific immunity (increased NK cell activity)
-decrease in specific immunity
What’s the effect of cortisol over the long-term?
-inhibiting lymphocyte proliferation
-inhibiting production of pro-inflammatory cytokines
-shift from Th1 to Th2 cell
What happens to the immune system after long-term exposure to chronic stress?
-decrease in both Th1 cellular and Th2 humoral immune response
-decreases in innate, non-specific immune responses (except inflammatory activity)
-persistent inflammatory activity (e.g., increased pro-inflammatory cytokine production)
