Immune System - A&P II Exam 2

innate vs adaptive immunity?

innate = nonspecific, immediate/general defense; adaptive = specific + has memory

what are 1st, 2nd, and 3rd lines of defense?

1st = surface barriers; 2nd = innate internal defenses; 3rd = adaptive immunity

main physical barriers of innate immunity?

skin + mucous membranes

main skin defenses?

keratin, acidic surface, antimicrobial lipids

main mucous membrane defenses?

acid, lysozyme, digestive enzymes, nasal hairs, cilia, mucin, + defensins

what does mucin do?

forms mucus that traps microorganisms

what do defensins do?

act as antimicrobial peptide

three main innate immune cell types?

macrophages, neutrophils, natural killer (NK) cells

macrophages vs neutrophils?

both phagocytose; macrophages can keep doing it, neutrophils die during the process

phagocytosis sequence?

recognize → engulf → lysosome fuses → pathogen destroyed

what do NK cells do?

kill infected body cells by triggering apoptosis

how do NK cells cause apoptosis?

perforin makes pores → granzymes enter → apoptosis

what do interferons do?

virus infected cells signal nearby cells to make antiviral proteins

what triggers inflammation?

tissue injury or infection

what are the cardinal signs of inflammation?

redness, heat, swelling, pain; impaired function can also occur

why does redness and heat occur?

vasodilation → increased blood flow

why does swelling occur?

capillary permeability increases → fluid/proteins enter tissues

main inflammatory chemicals?

histamine, kinins, prostaglandins, cytokines

what do inflammatory chemicals do to blood vessels?

dilate arterioles + make capillaries leakier

what is the goal of inflammation?

contain/clear pathogens or damage and promote repair

what is chemotaxis?

chemical signals cause immune cells to move toward the problem

which phagocytes arrive first during inflammation?

neutrophils first → monocytes second → monocytes become macrophages

what does fibrin do during inflammation?

traps bacteria & provides a scaffold for repair

humoral vs cellular immunity?

humoral = B cells + antibodies; cellular = T cells

what is an antigen?

a specific foreign or altered target recognized by the immune system

what happens if a pathogens antigen changes?

existing antibodies may bind less effectively

where do B and T cell precursors originate?

red bone marrow

where do B cells mature?

bone marrow

where do T cells mature?

thymus

what happens when a lymphocyte binds its specific antigen?

activation → multiplication → differentiation

what is an antigen-presenting cell (APC)?

a cell that displays antigen on its surface for T cell recognition

main APC examples examples from lecture?

dendritic cells + macrophages

can T cells bind free antigens?

no. antigen must be displayed on a cell surface

humoral immune response sequence?

B cell matches antigen → activation → clones → plasma cells + memory B cells

what do plasma cells do?

secrete antibodies

what do memory B cells do?

allow a faster, larger response if the antigen returns

what does a helper T cell do for B cells?

releases cytokines that increase B cell activation/division

primary vs secondary humoral response?

primary = slower/smaller; secondary = faster/larger

why is the secondary response faster + larger?

memory B cells rapidly produce more plasma cells + antibodies

main T cell types from lecture?

helper T, regulatory T, cytotoxic T, memory T

what is the role of MHC proteins?

display antigens on cell surfaces for T cell recognition

what do helper T cells do?

coordinate immunity & help activate B cells + cytotoxic T cells

what do cytotoxic T cells do?

directly kill infected cells displaying their specific antigen

how do cytotoxic T cells kill?

perforin makes pores → granzymes enter → apoptosis

NK cell vs cytotoxic T cell?

NK = innate/nonspecific; cytotoxic T = adaptive/specific

simple cellular immune response sequence?

antigen displayed on MHC → specific T cell recognizes it → activation → response → memory T cells remain

primary vs secondary cellular response?

primary = slower first exposure; secondary = faster due to memory T cells

type 1 diabetes beta cell destruction: which cells directly kill?

cytotoxic T cells

active vs passive immunity?

active = your immune system makes the response; passive = you receive antibodies

naturally acquired active immunity?

infection/contact with pathogen

artificially acquired active immunity?

vaccination

naturally acquired passive immunity?

maternal antibodies through placenta or breast milk

artificially acquired passive immunity?

injected exogenous antibodies/gamma globulin

a vaccine booster is what kind of response?

secondary response

vaccine immunity is what type?

artificially acquired active immunity