8. Immune System Flashcards
Where are all leukocytes produced? Where do B and T cells mature? T cell maturation facilitated by what?
Bone marrow via hematopoiesis; bone marrow and thymus. Thymosin (peptide hormone secreted by thymin cells) facilitates T cell maturation
What is the spleen for?
Blood storage and activation of B cells that later turn into plasma cells for adaptive immunity and destruction of damaged B cells, destruction of damaged or old RBCs, filters blood to help immune system
What is GALT? List examples
Gut-associated lymphoid tissue. Ex: tonsils, adenoids, Peyer’s patches, appendix
Which cells are part of humoral immunity and cell-mediated immunity?
B cells and ab for humoral, T cells for cell-mediated
Name different barriers of nonspecific/innate immunity
Skin (defensins), GI tract (stomach acid), mucous membranes, complement system (classical and alternative pathway)
What is the complement system?
innate immunity where proteins in blood act as nonspecific defense against bacteria –> punch holes in bacteria cell walls to make them osmotically unstable; activated thru 2 pathways: classical: Requires ab binding to ag, and alternative: doesn’t require ab
What are interferons?
Proteins that prevent viral replication
Functions of neutrophils`
Detects opsonized bacteria; most abundant; found in bloodstream
Functions of eosinophils`
Allergies and parasites; release histamines –> vasodilation and inflammation
Functions of basophils and mast cells
Allergies; release histamines; least abundant
Know the structure of ab
light chain, heavy chain, variable region binds to epitope, constant region, disulfide bond. Constant heavy chain is diff for each isotype
Primary response vs secondary response
1st new response against pathogen vs 2nd repeated response against same pathogen
Positive selection vs negative selection vs clonal selection
Allow maturation of cells that can respond to ag on MHC correctly vs not allowing maturation of cells that are self-reactive –> so they undergo apoptosis vs B and T cells cloning themselves to generate specificity of ab against ag
What are the 3 types of T cells?
helper T cells, regulatory/suppressor T cells, cytotoxic T cells
Suppressor T cells tone down immune system after infection and promote self tolerance
Which MHC do Th and Tc cells respond to?
Th respond to exogenous ag presented on MHC II; Tc cells react directly to endogenous ag on MHC I
What are the 5 types of infectious pathogens?
bacteria, viruses, fungi, parasites, prions (infectious MISFOLDED proteins)
Describe the structure of the lymphatic system
A bunch of vessels that carry lymph (fluid) and join together to make a thoracic duct; along the lymphatic vessels are lymph nodes (bean shaped structure) that give a place for immune cells to be exposed to pathogens
Lymphatic systems helps reduce edema by taking in excess fluid from interstitial spaces, can also carry proteins, dissolved solutes, and water from periphery to blood (in a way this filters blood); they also have one way valves like veins, and is actively pumped by skel muscle contraction
What are lacteals? What is chyle?
Small lymphatic vessels located in center of villus in small intestines that transport fats that are packaged in chylomicrons. Chyle = lymphatic fluid carrying a lot of chylomicrons –> milky white appearance
What are germinal centers in lymph nodes?
Where B cells can undergo somatic hypermutation (inc chance of mutation after ab binds to its specific ag) and affinity maturation (ab w/ greater affinity to its ag via somatic hypermutation are selected for; if weaker affinity –> apop) and proliferate
Active vs passive immunity. Give examples of natural and artificial of each
Ab made during immune response vs ab passed down. Actually getting dz; vaccines vs mom passing ab to fetus via placenta; getting IV ab
What is opsonization? What’s the order for ab-mediated ag disposal?
Marking of pathogens for destruction by WBCs. Neutralization, agglutination (gathering multiple pathogens), opsonization
Where are MHC I vs MHC II found and what do they do?
All nucleated cells; presents endogenous proteins for CD8+ cells => “endogenous pathway”; primarily responsible for presenting viral ag vs APCs: B cells, macrophages and dendritic cells, present exogenous antigens for CD4+ cells => “exogenous pathway”, primarily responsible for presenting bacterial ag
T cells are most effective at fighting which pathogen?
Virus. T cells in general are the only specific defense against intracellular pathogens
(Somatic) Hypermutation vs affinity maturation vs clonal selection
Process in which B cells undergo mutations to find the best matching ag-binding region for the ab vs ab w/ greater affinity to its ag via somatic hypermutation are selected for; if weaker affinity –> apop vs B and T cells cloning themselves to generate specificity of ab against ag
