Non-Specific Defenses Flashcards
Give an overview of nonspecific (innate_ defenses (6)
- born with them
- first line of defense
- function same way against many different pathogens
- no improvement (enhancement) on subsequent encounters with same pathogen
- no memory
- examples: fever, inflammation
Give an overview of Specific/Aquired Defenses
- takes time to develop after birth (usually reaches optimum later in life)
- third line defenses after non-specific
- improves with multiple encounters with same pathogen (enhancement)
- given cells/proteins protect only against one or a few different pathogens
- has memory
What are barriers and how do they prevent invasion
- exterior non-specific defenses located at body surfaces (portals of entry)
- prevent invasion by preventing adhesion or dislodging already adhered pathogens
what are the 3 types of barriers?
- ) Physical (structural)=Cells
- ) Mechanical (physiological)=movements
- ) Biochemical
what makes up physical barriers?
- what it involves (what cells/surfaces)
- intact skin
- intact mucus membrane
- Involves:
- epithelial cells (epidermis) of skin
- dermal cells
- mucus membranes (epithelial)
- mucus
- normal microbiota
- Intact skin: outer layers keratinized, dead, packed together- relatively impermeable to pathogens; sloughing off
- Intact Mucus Membrane: mucus and normal flora can block attachment to portals of entry
Describe Mechanical (physiological) barriers -what systems/organs involved
-Movements along certain body surfaces Systems: -GI tract--> peristalsis -Urinary--> urinatiuon -Eye--> tears/blinking -Lower respiratory--> mucociliary escalator--> mucus traps particles and ciliated epithelial cells move particulate material up the respiratory tract (1-3 cm/hr) tp throat--> swallow as post nasal drip
Give examples of Biochemical barriers
-what systems/organs involved (6)
- Skin= keratin, salt (perspiration), certain fatty acids (sebum)
- Stomach= acid (Hal) and low pH
- Respiratory= mucus
- Blood= transferrins–> iron binding proteins that sequester bodily iron and keeps it from pathogen
- Lysozyme=antibacterial enzyme found in tears, saliva, and nasal secretions
- Normal Flora of L.I. (bacteriocins)
Cationic peptides are considered biochemical barriers. what are the 3 types? describe them
Cationic Peptides can damage bacterial plasma membranes
- ) First Class: linear-alpha-helical peptides that lack cystine amino acid residues (i.e.: cathelicidin)
- ) Second Class= defensins
- ) Third Class: larger peptides that are enriched for specific amino acids and exhibit regular structural repeats (i.e.: histamine, in saliva, has anti0-fungal activity)
what are Defensins? (3)
- peptides are are open-ended, rich in arginine, and cysteine
- disulfide linked
- found in neutrophils, intestinal paneth cells, and intestinal & respiratory epithelial cells
slide 12
broad interior non-specific defenses
What 3 leukocytes are granulocytes?
neutrophils, eosinophils, and basophils
describe neutrophils (6)
- polymorphonuclear leukocyte (PMN)
- most numerous leukocyte during non-disease times (60-70%)
- live 2-3 days
- can leave capillaries and enter tissues
- first to arrive during inflammation
- important phagocytic cell
describe eosinophils (5)
- ~2-4% circulating leukocytes
- minor phagocyte
- release cytokines which help regulate inflammation
- release anti protozoal and anti helminths chemicals
- number increases during worm and protozoal infections (eosinophilia)
describe basophils (4)
- <1% circulating leukocytes
- not phagocytic
- related to mast cells (in tissues, help regulate inflammation)
- release inflammatory mediators (i.e.: histamine)
stem cells in marrow can become myeloid or lymphoid in nature. What cells evolve from myeloid (6) and which from lymphoid (2) ?
Myeloid: -erythroblast--> RBC -megakaryoblast--> platelets -mast cells -granulocytes (eosinophils, basophils, neutrophils) -monocytes -macrophages Lymphoid: -lymphocytes (T and B cells) -natural killer cells
From greatest to least which cells types are the most abundant? include specific WBC
Most= RBC
- platelets
- neutrophils
- lymphocytes
- monocytes
- eosinophils
- basophils
see hand made sheets for information on slides 21-26
Look at slide 27!
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Describe Phagocytosis and the process 28-35
Slides 28-35
See hand written out sheets in notebook
Complement System
Slides 36-40
What is an interferon?
chemical released by a host cell that has been invaded by a virus
- it binds to receptors on neighboring (currently un-invaded) cells and induces an antiviral state in those neighboring cells
- these antiviral proteins are activated if the virus enters that previously un-invaded cell and increased synthesis of surface MHC molecules
- this enhances susceptibility to cytotoxic T cells
what does it mean if a cell is in an antiviral state?
special, antiviral proteins are made (nucleases, proteases)
Describe ADCC (antibody-dependent cellular cytotoxicity)
See slide 44
What is a fever? describe the processes
Fever= elevated body temperature
Process:
exogenous pyrogen from pathogen–> phagocytes–> IL1, TNF–> hypothalamus–> prostaglandins–> elevated body temperature
Results in:
-shivering
-vasoconstriction (prevent heat loss)
-increase in metabolism (generate more heat)
what mechanisms does the body implement to return back to a normal temperature after a fever?
vasodilation and sweating
are fevers typically higher with cellular or viral pathogens
typically higher with cellular (few exceptions)
what are the positives of a fever? any negatives?
positives:
-at 38-40C–> enhancement of phagocytosis and interferon; as well as less availability of iron to microbes
-inhibits growth of certain pathogens
-person incapacitated–> promotes healing
Negatives:
high temperatures can kill cells
what are cytokines?
soluble proteins or glycoproteins that are released by one cell population
- act as intercellular mediators or signaling molecules
- must bind to specific receptors on target cells
- many activities (i.e.: differentiation, proliferation, apoptosis)
- chemokines–> stimulate chemotaxis and chemokinesis
name 3 different cytokines and something about each
- ) Monokines: released from mononuclear phagocytes
- ) Lymphokines: released from T lymphocytes
- ) Interleukin: released from one leukocyte and act on another leukocyte
What is the purpose of Colony Stimulating Factors (CSFs)?
stimulate growth and differentiation of immature leukocytes in bone
