Pathogenesis, Biology

Assignment Help:

The interactions between the human host and selected microorganisms that culminate in IE involve the vascular endothelium, hemostatic mechanisms, the host immune system, gross anatomic abnormalities in the heart, surface properties of microorganisms, and peripheral events that initiate bacteremia. Endothelial damage results in platelet-fibrin deposition, which in turn is more receptive to colonization by bacteria than is the intact endothelium. It is hypothesized that platelet-fibrin deposition occurs spontaneously in persons vulnerable to endocarditis and that these deposits, called nonbacterial thrombotic endocarditis (NBTE) are the sites at which micro organisms adhere during bacteremia to initiate IE. Bacteremia is the initiating event that ultimately converts NBTE to IE.  Bacteremia rates are highest for events that traumatize the oral mucosa, particularly the gingiva, and progressively decrease with procedures involving the genitourinary tract and the gastrointestinal tract.

The platelet-thrombin deposits are found at the valve closure-contact line on the atrial surfaces of the mitral and tricuspid valves and on the ventricular surfaces of the aortic and pulmonic valves, the sites of infected vegetations in patients with IE. Three hemodynamic circumstances may injure the endothelium, initiating NBTE: (1) a high velocity jet impacting endothelium (2) flow from a high to a low pressure chamber and (3) flow across a narrow orifice at high velocity.  Flow through a narrowed orifice, as a consequence of venturi's effect, deposits bacteria maximally at the low-pressure sink immediately beyond an orifice or at the site where a jet stream impacts a surface.

To cause IE, the organism must be able to persist and propagate on the endothelium. This requires resistance to host defenses. The complement-mediated bactericidal activity of serum limits the ability of susceptible aerobic gram-negative bacilli to cause IE. Those organisms that most frequently cause endocarditis adhere more vigorously in vitro to cardiac valves than do organisms that rarely cause IE.


Related Discussions:- Pathogenesis

What thing related to human biology, I need to come up with a thesis topic ...

I need to come up with a thesis topic for a 8-12 paper. It can be on anything related to Human Biology and I am struggling to come up with a topic/thesis statement. Any help will b

Male reproductive system - penis, PENIS - Intromittent organ. Erecti...

PENIS - Intromittent organ. Erectile, its apex is penis glanse. Covered by prepuce (part of skin). Main function is insemination (To transfer sperms in vagina in deep).

Quantitative or analytical method for estimation of nitrogen, Define Quanti...

Define Quantitative or Analytical Method for Estimation of Nitrogen and Protein? You may recall reading earlier that proteins contain nitrogen along with carbon, hydrogen and s

Etiology, Etiology -Although this approach less desirable, it is useful...

Etiology -Although this approach less desirable, it is useful, short-term option if the etiology of the condition remains unknown. - The patient must inform about what will

Phylum protozoa, Classification of the phylum protozoa

Classification of the phylum protozoa

Transport of macromolecules, Nuclear transport is an energy-dependent proce...

Nuclear transport is an energy-dependent process mediated through saturable receptors. Export and Import receptors are by to distinguish and bind to nuclear localization signals or

Define polysaccharides (dp: > 9) - carbohydrates, Define Polysaccharides (D...

Define Polysaccharides (DP: > 9) - carbohydrates? Polysaccharides are high molecular weight polymers of monosaccharide units formed by glycosidic bonding. They may be long unbr

What is catalyzes a substrate level phosphorylation, The enzyme in the TCA ...

The enzyme in the TCA cycle that catalyzes a substrate level phosphorylation is -citrate dehydrogenase -succinate thiokinase -isocitrate dehydrogenase

Respiration, explain the 4 stages of aerobic respiration

explain the 4 stages of aerobic respiration

How plant use day-night length to solve the paradox, How plants use the pat...

How plants use the pattern of changes in day/night length to solve the paradox that day length is equal twice a year. Plants possess the ability to balance the daily changes in

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd