Unit 3- Non-Specific Resistance (Innate Immunity) Flashcards
innate immunity
defense mechanisms present at birth
acquired immunity
defense mechanisms acquired by exposure to pathogens
first line of defense
surface protection, anatomical/physiolgoical, genetic barriers, non-specific chemical barriers
second line of defense
cellular and more specific chemical barriers
third line of defense
specific immune response developed against individual pathogens
physical barrier of respiratory tract?
epithelial tissue lining along the tract
chemical barrier of respiratory tract?
mucous secreted into tract
anatomical barrier of respiratory tract?
hair-like cilia sweeping mucous out of tract
what line of defense are T and B lymphocytes, and antibodies?
third line
what line of defense are phagocytosis, inflammation, fever and interferon?
second line
what are 3 behaviours that act as 1st line barrier?
hygine, contagion avoidance, healthy choices (avoid high-risk behaviours)
what are 2 physical first line barriers?
1) skin
2) mucous/wax (lines portals of entry)
what are 3 chemical barriers of 1st line defense?
1) acid (stomach, lactic)
2) salt (tears, sweat)
3) proteins (lysozymes and defensins in tears, digestive enzymes)
mechanism of lysozymes?
targets peptidoglycans of bacterial cell wall (non-specific defense)
Example of how some have a 1st line genetic barrier to HIV?
HIV-1 R5 requires CCR5 receptor to infect cells, but some Caucasian populations have a 32 bp deletion in the CCR5 gene, conferring to some resistance to infection
how does H.pylori overcome physical barriers of body?
uses flagellum to burrow into mucosal layer
how does H.pylori overcome chemical barriers of the body?
it produces basic NH4+ through urease to neutralize stomach acid
How does H. pylori overcome genetic barriers of the body?
It is well-adapted to survive in the human stomach
what are WBCs/leukocytes
cells of the immune system; they recognize non-self cells and molecules
which leukocytes are not active at birth?
B-cells and T-cells. all other leukocytes are part of the innate immune system and are active at birth
what is the common stem cell WBCs and RBCs share?
hematopoietic stem cell
what 4 locations can WBCs be found in?
1) bloodstream
2) lymphatic vessels
3) reticuloendothelial system (mesh-like network of connective tissue holding tissues together)
4) extracellular fluid
what are the components blood separates into after centrifugation?
plasma (blood minus cells), buffy coat (WBCs), red blood cells (unclotted)
what is serum?
plasma minus clotting proteins
Neutrophil (class, action)
most abundant WBC, first responder, granulocyte, phagocytic (polymorphonuclear cell)
what are PRR?
pattern recognition receptors (special proteins) that can feel abnormal proteins on non-self cells
PAMPs?
pathogen associated molecular patterns (abnormal proteins on invading cells)
TLRs?
toll-like receptors, whcih are special PRRs (pattern recognition receptors) that are on phagocytes (neutrophils, macrophages)
lysosome?
destructive body
phagolysosome?
an eating and destructive body
7 steps of phagocytosis?
1) PRRs recognize PAMPs
2) phagocytic cell engulfs pathogen
3) bubble forms inside the cell- phagosome
4) destructive chemicals/enzymes stored in lysosomes and granuals
5) phagolysosome forms (fused together)
6) digestion and nutrient absorption into the cell
7) waste is excreted from cell
phagocytosis results in…
intracellular killing of microbes