Lymphatic Basics
What are the two major functions of the lymphatic system?
-immune system
-assist the circulatory system via fluid balance, blood volume, and lipid absorption (digestive)
What do the lymph nodes do?
monitor lymph for foreign materials/pathogens
What is the innate immune system?
a general, always-ready, system that provides protection against a wide variety of pathogens
-the response is very fast
What is the red bone marrow's role in the lymphatic system?
produce leukocytes and site of B-lymphocyte maturation
What is edema?
BONUS: What is elephantiasis?
fluid accumulation causing swelling
BONUS:
extreme lymphedema due to filarial roundworms causing blockage in lymphatic vessels
What are the lymphatic capillaries and what do they do?
BONUS!
Where are lymphatic capillaries found in respect to the circulatory system?
valve-containing lymph filled tubes that absorb water from the interstitial fluid and return that fluid to the veins
BONUS!
intertwined with (but not connected to) the capillary beds of the circulatory system
What are the two non-specific defenses of innate immunity?
fever and inflammation
What are the broad components of the innate immune system? List one example of each.
barriers to entry and internal non-specific defenses
Examples: Barriers: skin, mucous membranes
non-specific: Inflammation, fever
What cellular components are in secondary lymphoid structures?
Mostly: T-lymphocytes, B-lymphocytes,
macrophages, dendritic cells, and NK cells
What are the commensal microbiota in the skin?
good bacteria on the skin that help prevent growth of pathogenic organisms
What are the secondary lymphoid structures? What is their role?
tonsils, lymph nodes, spleen, and MALT/lymphoid nodules
-house both lymphocytes and other immune cells; sites for initiating immune response
What is an immune complex?
an antibody-pathogen protein complex (antibody bound to pathogens)
What do perforins do?
What do granzymes do?
What are these substances (where they come from)?
-protein complex that pokes holes in the host cell membrane
-granual enzymes that enter the cells through pores and induce apoptosis (programmed cell death)
-Proteins secreted by NK cells
What are the cellular components of the adaptive immune system?
Lymphocytes:
-T-cells: helper T-cells (TH cells) and cytotoxic T-cells(TC cells/ CTLs)
-B-cells
When in your life is the thymus largest? How does it change over the lifecycle?
-Children have very large thymus and in adulthood is smaller compared to rest of organs
-the thymus is slowly turned into fat as you grow which decreases immune function as you age
What is the spleen structure?
-afferent vessel: splenic artery
-white pulp: immune system function
-red pulp: destroy old erythrocytes and convert the material into useable components
-efferent vessel: splenic vein
Why must the immune system be flexible to new stimulus?
The immune system must be able to recognize a variety of infectious agents (eukaryotes, prokaryotes, and viruses) it has never seen before and distinguish it from your own cells
What are the 4 major classes of cytokines? What do they do?
BONUS: Define the function of one
-interleukins (IL)
-tumor necrosis factor (TNF)
-colony-stimulating factor (CSF)
-interferons (IFN)
BONUS:
-interleukins (IL): communication between leukocytes
-tumor necrosis factor (TNF): destroy tumor cells and other functions
-colony-stimulating factor (CSF): stimulates leukopoesis (production of WBCs) in red bone marrow
-interferons (IFN): interfere with the replication of pathogens that enter cells (intracellular pathogens)
What is the general function of each of the cellular components of the adaptive immune systems?
Helper T cells: activate other lymphocytes
cytotoxic T cells: kill infected host cells
B-cells: secrete antibodies
What are the 6 portals of entry (where pathogens can enter)?
eyes, respiratory, orally, parenteral (direct injection to bloodstream), urogenital, and skin
What are the three tonsils and where are they within the oral cavity?
pharyngeal: back of sinus cavity
palatine tonsil: roof of mouth
lingual tonsil: back of tongue
Within the innate immune system, is the complement system, what are it's components and what are the 4 functions?
Set of proteins found in the blood plasma
1. increases inflammation by stimulating cells (mast, basophil, neutrophil, and macrophages)
2. eliminate immune complexes
3. Opsonization
4. induce cytolysis
How do phagocytes recognize and break down pathogens? (Hint: 4 steps of phagocytosis)
1. On the outside of the membrane of phagocytes are toll-like receptors (TLRs) that recognize PAMPs on pathogens
2. the phagocyte consumes a pathogen and places it in phagosome
3. The phagosome fuses with the lysosome (forming the phagolysosome) and the pathogen is broken down by digestive enzymes
4. The leftover residue of the digested pathogen is then excytosed out of the cell (via exocytosis)
What cell types are phagocytic and what does this mean?
macrophages, dendritic cells, and neutrophils
engulf pathogens by phagocytosis
What is the process of inflammation (Hint: 4 steps)?
1. pro-inflammatory cells (mast cells and basophils) secrete pro-inflammatory chemicals and chemotactic factors
2. Vascular changes occur
-vasodilation
-gaps are placed between endothelial cells
3. Leukocyte recruitment
-vasodilation allows more blood flow to area therefore more leukocytes can migrate into the tissue (attracted by chemotactic factors)
4. delivery of plasma proteins (complement proteins) and antibodies