Renal Week 1
function of macula densa
monitor salt
What is the charge on the glomerular filtration barrier?
negative repels the negatively charged proteins to prevent filtration and excretion albumin is the most abundant protein in the blood and is important for maintaining oncotic pressure albumin is negatively charged at the body ph body doesnt want to waste albumin, so it shouldnt get filtered glycocalyx formed by sialoglycoproteins coating the glomerular basement membrane and endothelial cells contribute to the negative charge
what contributes to the GFR?
net filtration pressures from Starling's forces glomerular capillary blood flow filtration coefficient (permeability & surface area)
General management for Nephrotic syndrome
preadolescent = try corticosteroids , do a renal biopsy if not responsive primary NS -- normal complement and renal function all adults, adolescents and children w/ hypocomplementemia, decreased renal function, gross hematuria = renal biopsy -Steroid treatments are more effective in children than adults. if they have a dependence, then use cytotoxic agents or calcineurin inhibitor - control of edema, good nutrition, low protein diet, anticoagulation, antibiotic prophylaxis, immunization
Clinical definition of Nephrotic syndrome
proteinuria hypoproteinemia hypercholesterolemia edema
Movement of solute from bloodstream into tubule lumen
secretion
function of lacis cells
mesangial cells --structural support, phagocytosis, secretion
What happens when you constrict the Afferent arteriole?
GFR decreases RBF decreases
Transient Proteinuria
BENIGN proteinuria occurs with fever, CHF, seizures, acute metabolic derangements, sympathomimetic drugs, vigorous excercise isolated usually < 3+ on dipstick Glomerular proteinuria
where does the proximal tubule arise from?
Bowman's capsule
What structures form the filtration barrier?
Fenestrated endothelium, GBM, slit pores between podocyte foot processes
Movement of solutes or water out of the glomerular capillaries into the Bowman's space
Filtration
What happens when you dilate the Afferent arteriole?
GFR decreases RBF increases
What happens when you constrict the Efferent Arteriole?
GFR increases RBF decreases
What happens when you dilate the Efferent arteriole?
GFR increases RBF increases
if you see increased albumin in the urine, what is it?
Glomerular process
JGA cell types
Granular cells/ Juxtaglomerular cells = mak that RENIN bishhhhhh Extraglomerular mesangial cells (Lacis cells) = ouside bowman's capsule, do structural support and phagocytosis. Macula Densa cells = act as salt sensors in the nephron --> Podocytes are NOT in the JGA!!!!!!!!!!
What is a risk with nephrotic syndrome?
Hypercoagulability because there is a loss of anti-coagulant proteins in the urine predisposes to thrombosis and increases the risk for atherosclerotic vascular disease
What cells is renin secreted from?
Juxta-glomerular cells they line the afferent arteriole in the region of the juxtaglomerular apparatus
Where are the podocytes situated
Outside of the glomerular basement membrane, on the side of the bowman's capsule they form the INNER or visceral layer of the Bowman's capsule outside the bowman's capsule are the tubules and intersitum
movement of solute from nephron tubular lumen --> blood stream ?
Reabsorption
What type of collagen is present in the glomerular basement membrane?
Type 4
Clearance of solute equation
Urine concentration x (urine flow rate)/plasma concentration so for K+ clearance = urine K+ x urine flow rate/ plasma K+
GFR equation
[plasma]/flow rate
Tubular Proteinuria
altered / insufficient tubular function mechanisms - tubular damage limiting reabsorption of filtered proteins ( myoglobinuria, acute tubular necrosis ) - tubular capacity for reabsorption exceeded by increased filtered plasma proteins (multiple myeloma) - tubular injury causing increased local secretion of tubular and plasma protiens (pyelonephritis, nephrotoxic drugs)
types of tubular proteinuria
benign and pathologic benign = transient and orthostatic
Orthostatic Proteinuria
benign tubular proteinuria! peak onset --adolescent more common in females, taller teens exaggerated in LORDOTIC position glomerular proteinuria usually < 2 gms/day isolated supine and upright urines for diagnosis
Where is the JGA apparatus located?
between the distal tubule and afferent arteriole of the glomerulus it gives tubuloglomerular feedback, after the filtrate has passed through the entire length of the proximal tubule and the descending and ascending loops of henle, and after most of the reabsorption and secretion processes have been completed most important fxn = to maintain normal glomerular filtration pressure --through renin-angiotensin axis
Purpose of the tubule brush border?
to increase SA of absorption in proximal tubules
Pathologic Proteinuria
tubular damage/ impaired reabsorption : - hereditary--fanconi syndrome - acquired -- myoglobulin, hemoglobinuria, drugs, toxins increased plasma proteins (Overflow) - multiple myeloma tubular injury -hereditary --dyplasia, obstruction -acquired -- obstruction, pyelonephritis
If you see an increase in low MW proteins what is it?
tubular disease
