Topic 4 - Non specific diseases Flashcards
examples of mechanical barriers
- GI tract (peristalsis)
- urinary traction (urination)
- eye - tearing and blinking
- Lower respiratory tract (mucociliary escalator)
Biochemical barriers
skin - keratin, salt, certain fatty acids
stomach - acid and low ph
respiratory tract - mucus
blood - transferrins (sequesters bodily iron and keeps it from pathogens)
lysozyme - anti-bacterial enzyme found in person’s tears, nasal secretions, and saliva
normal flora of L.I. bacteriocins
three types who biological activity is related to their ability to damage bacterial plasma membranes
cationic peptides
three types of cationic peptides
- first class: linear, alpha-helical peptides that lack cysteine amino acids residues (cathelicidin - produced by a variety of cells)
- second class: defensins (peptides that are open ended, rich in arginine and cysteine, and disulfide linked)
- third class: larger peptides that are enriched for specific amino acids and exhibit regular structural repeats (histanine, present in human saliva, has anti-fungal activity)
Neutrophils
percentages
most present when?
when do they arrive during inflammation?
important component of them?
60-70%
most numerous leukocyte during non-disease time
first ones to arrive during inflammation
important phagocytic cells
Eosinophil
percentages?
what do they release to regulate inflammation?
when are they present? (in what kind of reaction)
2-4%
cytokines
allergic and parasitic reactions
Basophils
percentages?
unique characteristic?
what do they release?
less than 1%
they are NOT phagocytic
release inflammatory mediators
What percentage of leukocytes are monocytes?
3-8%
When monocytes leave capillaries and enter tissues, what do they become?
Macrophages
Dendritic cells
Most efficient macrophage
Secretes cytokines
APC
Macrophages
In tissues
Phagocytic
Major APC of body
Dendritic cells
Where do dendritic cells come from?
Lymphoid and myeloid lines
Where are dendritic cells present?
Blood, skin, and mucous membranes of nose, lungs, and intestines
What NK killer cells bind to?
Tumor cells - induce apoptosis
Viral infected host cells - induce apoptosis
Work larvae - release cytotoxic substances
Purpose of phagocytosis
- kill pathogen
2. antigen presentation - digest pathogen to present antigens to T-helper cells as a part of the specific response
Phases of phagocytosis
- Attraction/chemotaxis
- Recognition/adherence of phagocyte to pathogen (PAMP/PRR, opsonins, can be inhibited by capsules/M proteins)
- Indigestion (endocytosis/phagocytosis – invagination of cell membrane or with pseudopods)
- Killing/digestion (lysosome, enzymes that digest cell, enzymes that release toxic O2 products that kill pathogen)
- Expulsion of waste (exocytosis)
- Antigen presentation to T helper cells
What is complement?
A group of blood proteins that, when activated, function together to produce certain antibacterial chemicals
- Inflammatory mediators (C3a, C5a) – (causes mast cell degranulation)
- Opsonin - enhances phagocytosis (C3b)
- Membrane attack complex (puts pores in cell membrane of prokaryotes) C5-C9
What activates complement?
- Prokaryotic polysaccharides
2. Antibody - due to prior exposure
What is an interferon?
Chemical released by a host cell that has been invaded by a virus which binds to receptors on neighboring, yet to be infected cells, and induces an antiviral state in those neighboring cells
Examples of physical barriers
- epithelial cells
- dermal cells
- mucus membranes
- normal flora
Released from mononuclear phagocytes
Monokines
Released from T lymphocytes
Lymphokines
Released from one leukocyte and act on another leukocyte
Interleukins
Stimulate growth and differentiation of immature leukocytes in bone marrow
Colony stimulating factors
Stimulate chemotaxis and chemokinesis
Chemokines
Acute phase protein
Macrophage activation by bacteria –> cytokine release –> liver stimulation –> acute phase protein production (includes C-reactive protein, mannan-binding lectin, surfactant proteins A and D [can bind bacterial surfaces and act as opsonins]
