Immune System Flashcards
What is the primary job of the immune system
To protect the body from infection
What is the name for something that stimulates the immune system
Immunogens
What are pathogens
Anything that causes disease
What is a carcinogen
A type of pathogen that specifically causes cancer
What is an allergen
Something the immune system responds to as if it’s a threat that causes allergies
What 4 microorganisms act as pathogens in humans and what are 5 ways they enter
Bacteria, fungi, parasites, and viruses enter via inhalation, ingestion, injection, and breaks in the skin, etc.
How can someone protect themselves from pathogens
Face masks, gloves, medical gear, antibacterial gels, toilet seat covers, hands-free devices, condoms, etc.
What are 2 other key functions of the immune system
To recognize and destroy abnormal (virus-infected or cancerous) ‘self’ cells, and remove dead/damaged cells
How does the immune system differentiate self from non-self
Via molecular markers on their surface (proteins, glycoproteins, and lipopolysaccharides)
What are the types of self molecular markers
For nucleated cells: major histocompatibility complex (MHC) and human leukocyte antigens (HLA)
For erythrocytes (RBCs): ABO and Rh blood types
What are non-self markers
Antigens (eg. pathogen molecular markers/PAMPs)
What are antigens
Molecules that trigger the body’s immune response
Are self markers identical
No, they are a family of proteins that varies from person to person (usually based on alleles), and only identical twins will have the same set
How are antigens expressed in RBCs
They are inherited (one allele from each mom and dad), A and B are codominant and O is recessive (neither A or B)
What are the 4 possible blood types
A, B, AB, and O
What are antibodies for blood antigens
Anti-A, anti-B, both, or neither
What happens if antigens and antibodies mix
Blood cells agglutinate/clump, which is used for blood typing
When planning blood transfusions, what are the most important things to consider
In the recipient, what antibodies they have, and what antigens are coming in from donor RBCs
Is it important to consider donor antibodies during a blood transfusion
No because they are only giving packed RBCs (minimal antibodies transfused, and what is will be diluted by the recipient’s plasma)
What are the 3 ways the immune system protects against pathogens
Barriers, innate immune response, and adaptive immune response
What are the 3 ways the immune system protects against pathogens
Barriers, innate immune response, and adaptive immune response
What 2 kinds of barriers does the immune system form against pathogens
Physical: Skin and mucous membranes (both with large surface area)
Chemical: Secretions of stomach acid, tears, saliva, sweat, and mucus
What is present in immune system secretions that protects against pathogens
Lysozymes (antimicrobial enzymes)
What is immunity
The ability of the body to protect itself from pathogens
What are the 2 kinds of acquired (adaptive immunity)
Natural and artificial (induced)
What are the 2 kinds of natural adaptive immunity
Passive (maternal) and active (from an infection)
What are the 2 kinds of artificial adaptive immunity
Passive (antibody injection) and active (immunization by injecting deactivated antigens)
What are the 4 characteristics of the recognition mechanisms of innate immunity
1st defense/rapid response (hours), fixed (won’t respond to new stimuli), limited number of specificities, and constant during response
What are the 4 characteristics of the recognition mechanisms of adaptive immunity
Slow response (days to weeks), variable (can learn to recognize more things), numerous highly selective specificities, and improves during response
What are the common effector mechanisms for the destruction of pathogens
Inflammation and immunological memory
How does the innate immune response work
The innate immune cells express pattern recognition receptors (PRRs) that let them recognize different antigens like pathogen-associated molecular patterns (PAMPs)
What is the goal of the innate immune response
To identify a pathogen and eliminate or contain it
How does the adaptive immune response work
Adaptive immune cells express antigen receptors specific to one antigen (can only recognize and react to that one), has immunological memory that allows it to remember a previously encountered pathogen
How do adaptive immune cells work
Some release antibodies that bind and mark cells for destruction and some have antibody receptors
What are the 3 characteristics effector functions of innate immunity
2nd line of defense, immediate but non-specific (acts within minutes), and recognizes and responds to broad range of pathogens (PAMPs binding to PRRs)
What are the 2 responses of innate immunity
Clearing the infection via phagocytosis (engulfing the pathogen and releasing destructive enzymes) or containing it via inflammation until adaptive immunity is activated
What are the 3 key cells involved in adaptive immunity
Phagocytes (macrophages and neutrophils), mast cells, and natural killer (NK) cells
What are the 3 characteristics of phagocytes
Attracted by chemical signals (chemotaxins), release chemotaxins to recruit more cells, use phagocytosis
What are 3 examples of chemotaxins
Bacterial toxins, cell wall components, and products of tissue injury (fibrin and collagen fragments)
What are the 3 characteristics of phagocytosis
Receptor-mediated (can’t recognize all bacteria), lysosomal enzymes destroy ingested bacteria, and can activate adaptive response via antigen presentation (links innate and adaptive branches)
What are the 2 characteristics of mast cells
Concentrated in skin, lungs, GI tract (places exposed to external environment), release histamine (signals body to respond) when in contact with a pathogen
What is inflammation
Redness, swelling, heat, pain that is one of the body’s first responses to infection or irritation, mediated by cytokines, chemokines, and histamines
What are cytokines and chemokines
Chemical signals released by tissue macrophages that attract phagocytes (especially neutrophils)
What does histamine do during an immune response
Causes redness and increases permeability so that a pathogen can get out (swelling)
What are the 3 characteristics of natural killer (NK) cells
Eliminates virus-infected or cancerous cells, inhibited by ‘self’ proteins, not phagocytic (attacks cell’s membranes to pop like a balloon via lysis)
What is another name for NK cells
Cytotoxic lymphocytes
What are the 3 groups of leukocytes involved in acquired immunity
Antigen-presenting cells (APCs), T lymphocytes (T cells), and B lymphocytes (B cells)
How do APCs activate T cells
Macrophages engulf and digest antigen in lysosome, then present antigen fragments on top of ‘self’ markers, and bind to T cells
What are the 2 kinds of T cells
Cytotoxic (cell killing) and helper
What are the 3 characteristics of cytotoxic T cells
Directly attack virus-infected and tumor cells (pathogen inside cell), use juxtacrine signaling, and implicated in transplant rejection
How do helper T cells work
Secrete cytokines to help activate other leukocytes (B cells)
How do B cells work
The become effector cells that are only good for extracellular pathogens (plasma effector cells and memory cells)
What are plasma effector cells
The secrete antibodies (immunoglobulins) and attach to antigens to target for destruction by nonspecific defenses (macrophages)
Which type of B cell lasts for a long time in the body and which kind dies within days
Plasma/effector cells die within days while memory cells stick around and continue to reproduce (immunological memory)
Does the first or second exposure illicit a faster and stronger immune response
The second exposure
What are the 3 kinds of pathologies of the immune system
Autoimmune diseases (women more prone), allergies, and immunodeficiency
What is an autoimmune disease
When the immune system has an incorrect response and attacks cells of the body
What are allergies
Overactive immune response to something that’s not really a pathogen (dust, etc.) and can cause anaphylaxis
What is immunodeficiency
Lack of immune response when needed (e.g. HIV which causes AIDS and suppresses the immune system
What is neuroimmunomodulation
Interaction between the neurological, endocrine, and immune systems due to shared common signal molecules and receptors
What outside factors are involved in neuroimmunomodulation
Stress and illness (decrease immune activity and mind-body therapeutics (enhance immune response)
