15 - Lymphatic & Immune System Flashcards
What is an Antigen?
- surface marker that the body can perceive as foreign
What is an Antibody?
- a protein molecules that is released by a plasma cell & binds to a specific antigen (Ag)
What is the lymph Pathway?
flowchart
Bloodstream capillaries -> Interstitial space -> lymphatic capillaries -> lymphatic vessels -> lymphatic trunks -> lymphatic ducts -> venous blood
How are lymph capillaries different from blood capillaries?
- blind-ended
- very permeable
- endothelial cells create one-way minivalves
- anchored by collagen filaments
What are Lacteals?
- specialized lymph capillaries in small intestinal mucosa (lining layer of GI tract)
- Absorb digested fat & deliver chyle to bloodstream
What does the right lymphatic duct drain?
- right body superior to diaphragm
What does the Thoracic duct drain?
- drains everything inferior to diaphragm & left body superior to diaphram
What are the types of lymphocytes?
- T cells - cytotoxic T cells, Helper T cells, Supressor T cells
- B cells - plasma cells
- NK cells
What do Natural Killer cells do?
- survey surface markers
- NK recognizes abnormal Ag
- NK Golgi moces, produces secretory vesicles containing perforin
- perforin are exocytosed & diffuse across gap
- pores are made in target cell, can’t maintain internal-external envmt -> dies
What are other lymphoid cells?
- Macrophages - phagocytize foreign substances & help activate T cells, APC
- Dendritic cells - capture Ags & deliver them to lymph nodes, APC
- Reticular cells - produce stroma that supports other cells in lymphoid organs
What are Primary Lymphoid organs?
- where B cells & T cells mature
What are Secondary Lymphoid organs?
- where B cell & T cell encounter Ag
Where do lymphcytes arise & where do they develop?
- Lymphocyte precursors start in red bone marrow
- T cells -> develop in thymus
- B cells -> develop in bone marrow
What does the Thymus do?
- T cell university
- positive selection- must recognize self-MHC
- Negative selection - must not recognize self-antigen in self-MHC
- if it fails -> apoptosis
What are the 2 types of Lymphoid tissue?
- Diffuse lymphatic tissue - Lymphoid cells & some reticular fibers, in almost every organ
- Lymphoid follicles (aka lymphoid nodules), Germinal center composed mainly of proliferating B cells
What is the lymph node structure?
- cortex - contain follicles w/ germinal centers
- medulla - medullary cords (extensions of cortex w/ B & T cells), Medullary sinuses (capillaries w/ macrophages)
- germinal centers & meduallry cords provide oppurtunities to encounter Ag
What is the spleen & its structure?
- similar to lymph node but filters blood
- white pulp - lymphocytes & reticular fibers
- Red pulp - macrophages
What is apart of Innate immunity?
overview
- surface barriers
- internal defenses
What is apart of adaptive immunity?
overview
- humoral immunity (B cells)
- cellular immunity (T cells)
What is the 1st line of defense?
surface barriers
What is the 2nd line of defense?
Internal defenses
What is the 3rd line of defense?
Humoral immunity & cellular immunity
What does Humoral immunity do?
- B cells produce Abs, bind Ags & PLAN
- Precipitation - make Ag soluble
- Lysis - activate innate
- Agglutination - clump for phagocytes
- Neutralize
Active vs. Passive Humoral immunity
- active have memory, passive does NOT
- active - naturally (infection) & Artifically acquired (vaccine)
- passive - naturally (mother to fetus) & artifically (injection of Abs)
What are the 5 Antibody Classes?
- IgM - big clusters
○ If you have IgM in blood, you are in primary response - IgA - in breast milk
- IgD - B cell surface marker
- IgG - know its been exposed for a while
- IgE - allergies
What does Cellular immunity do?
- All nucleated cells - MHC I - good for anything already in the body
○ Says kill anything w/ this Ag
○ Tc cells - APCs - MHC II - says this is what the foreign invader looks like, come let’s go find it
○ TH cells
