NR507 WEEK 4 MIDTERM STUDY GUIDE

The abnormal build-up of Ag-Ab complexes signals the immune system that something is wrong, causing an activation of the complement system and WBC infiltration to the site. Complement proteins, in conjunction with the ...

The abnormal build-up of Ag-Ab complexes signals the immune system that something is wrong, causing an activation of the complement system and WBC infiltration to the site. Complement proteins, in conjunction with the enzymes released by phagocytic cells, attack not only the complexes, but also cause collateral damage to the glomerular area. The damage weakens the glomerular structure to the extent that plasma proteins (albumin) and blood cells leak into the tubular system and pass out into the urine. Proteinuria and hematuria are two clinical indicators that this is occurring. The loss of albumin from the bloodstream reduces plasma oncotic pressure and contributes to another clinical indicator: edema. The coagulation cascade is also activated as a result of the vessel damage and fibrin (the building block of clots) deposits in the glomerular structure, creating blockages that decrease capillary perfusion, and consequently, decrease GFR. A decrease in GFR means that nitrogenous wastes like creatinine will remain in the bloodstream and not be excreted. The presence of elevated plasma creatinine and other nitrogenous wastes (azotemia) are clinical indicators. Finally, if the glomerular structure is damaged enough, the nephron structure is no longer functional as an ultra-filtration unit and urine output diminishes (oliguria).  treatment of renal failure: Treated with dialysis, supportive therapy and renal transplant. Renal failure related to diabetic nephropathy can be significantly reduced with control of hyperglycemia, hypertension and hyperlipidemia. Ace inhibitors or receptor blockers are often used to control systemic hypertension and provide renoprotection, particularly in the presence of diabetes mellitus. Management involves dietary control, management of protein intake, vitamin D supplementation, sodium and fluid maintenance, potassium restriction, adequate caloric intake, management of dyslipidemias and erythropoietin as needed.  blood hydrostatic pressure: · o Hydrostatic pressure works to push water out of a space o ·Hydrostatic pressure: the mechanical force of water, in this case, driven by the heart  a.Aka blood pressure, pushing against the capillary membrane to move fluid out, a process known as filtration  Occurs at the arterial end of the capillaries, movement of fluid from vascular space into interstitium, called filtration/perfusion o ·The glomeruli filter 180 L fluid/day à plasma is cleansed 1X every 100 min  HOW? High hydrostatic pressure of the glomerular capillary beds facilitates filtration  kidney filtration, The anatomy and physiology of the renal filtration process is analogous to how a coffee filtration system works. The water and coffee grounds represent the blood; the coffee filter represents the glomerulus; the basket represents Bowman’s capsule; and the carafe represents the tubule system. Pressure, in this case – gravity, forces the water through the filtering system, extracting material from the coffee grounds as it moves through the basket into the carafe. A properly designed and operating filtration system will only allow the desired material to enter the carafe. Very low pressure or water volume would result in poor extraction of the coffee from the grounds, resulting in a low output of weak coffee. However very high pressure or damage to the coffee filter could cause an undesirable leakage of grounds into the carafe. That is a good analogy to keep in your mind when we discuss some renal pathologies in a few minutes! The filtration process dumps quite a bit of material into the tubule system. And remember, anything that enters and stays in the tubule system could potentially be eliminated in the urine. And now the nephron is ready for the last step: urinary excretion, the final elimination of wastes (urea, creatinine, NH3, H+) and excess H2O and ions and the filtrate is now called urine. The kidneys rely on constant blood flow (perfusion) to facilitate the process of filtration.  role of angiotensin converting enzyme (ACE): Angiotensin converting enzymes are a central component of the renin–angiotensin system, which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasoconstrictor angiotensin II. ACE inhibitors Inhibit formation of angiotensin II and aldosterone, resulting in decreased blood pressure and decreased renal sodium reabsorption. Immunity:  role of macrophages o Macrophages are involved in activation of the Adaptive immune system. o Macrophages, especially those residing in the tissues, are often important cellular initiators of the inflammatory response. o Macrophages are the primary cells that infiltrate tissue in wounds, remove cells and cellular debris, and produce cytokines that suppress further inflammation and initiate healing. o Monocyte-derived macrophages from the circulation may appear at the inflammatory site as soon as 24hrs after the initial neutrophil infiltration but usually arrive 3 to 7 days later. They migrate to the site more slowly than neutrophils because they move more sluggishly and also because many of the chemotactic factors that attract them, such as macrophage chemotactic factor, must first be release by neutrophils. o Macrophages are better suited than neutrophils to long-term defense against infectious agents because they can survive and divide in the acidic inflammatory site or where there is low oxygen tension.