Non-Specific Defenses Flashcards
1
Q
Give an overview of nonspecific (innate_ defenses (6)
A
- 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
2
Q
Give an overview of Specific/Aquired Defenses
A
- 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
3
Q
What are barriers and how do they prevent invasion
A
- exterior non-specific defenses located at body surfaces (portals of entry)
- prevent invasion by preventing adhesion or dislodging already adhered pathogens
4
Q
what are the 3 types of barriers?
A
- ) Physical (structural)=Cells
- ) Mechanical (physiological)=movements
- ) Biochemical
5
Q
what makes up physical barriers?
- what it involves (what cells/surfaces)
- intact skin
- intact mucus membrane
A
- 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
6
Q
Describe Mechanical (physiological) barriers -what systems/organs involved
A
-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
7
Q
Give examples of Biochemical barriers
-what systems/organs involved (6)
A
- 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)
8
Q
Cationic peptides are considered biochemical barriers. what are the 3 types? describe them
A
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)
9
Q
what are Defensins? (3)
A
- peptides are are open-ended, rich in arginine, and cysteine
- disulfide linked
- found in neutrophils, intestinal paneth cells, and intestinal & respiratory epithelial cells
10
Q
slide 12
A
broad interior non-specific defenses
11
Q
What 3 leukocytes are granulocytes?
A
neutrophils, eosinophils, and basophils
12
Q
describe neutrophils (6)
A
- 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
13
Q
describe eosinophils (5)
A
- ~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)
14
Q
describe basophils (4)
A
- <1% circulating leukocytes
- not phagocytic
- related to mast cells (in tissues, help regulate inflammation)
- release inflammatory mediators (i.e.: histamine)
15
Q
stem cells in marrow can become myeloid or lymphoid in nature. What cells evolve from myeloid (6) and which from lymphoid (2) ?
A
Myeloid: -erythroblast--> RBC -megakaryoblast--> platelets -mast cells -granulocytes (eosinophils, basophils, neutrophils) -monocytes -macrophages Lymphoid: -lymphocytes (T and B cells) -natural killer cells
