Unit 10 - Kidney & Nephron Pt 2 Flashcards
What does an increase in GFR mean?
Implies a decreased absorption of fluid and solutes.
What does a decreased GFR mean?
would result in increased reabsorption of fluid and solutes.
Where is the majority of glucose reabsorbed?
at the proximal convoluted tubules and is coupled to sodium transport.
What is the concentration of glucose in the urine?
Approx. .5mmol/L
What is glucosuria?
Where glucose appears in the urine
When does glucosuria occur?
If plasma glucose is above renal threshold for glucose or if there is defective tubular reabsorption (maximum tubular transport rate for glucose is decreased).
What is Renal Threshold for glucose and Tmglucose (maximum tubular reabsorption rate)?
10-11 mmol/L
approx. 2.08 +/- 0.5 mmol per min
What is the most common cause of glucosuria?
A plasma glucose level above the renal threshold which results in excretion of the excess glucose into the urine.
diabetes mellitus, hyperthyroidism, acromegaly, acute myocardial infarction (SNS), and malignant neoplasms of the pancreas.
Where are Amino Acids reabsorbed?
at the proximal convoluted tubules and the amount excreted into the urine is dependent on the renal threshold and tubular reabsorption
What is creatinine?
The rate of formation of creatinine is proportional to the total creatine phosphate content of muscle and is therefore a reflection of an individual’s total muscle mass. The release of creatinine is so constant that the intra-individual variation in serum creatinine is less than 5 % per day. Creatinine is filtered at the kidney glomerulus and is excreted into the urine. Very small amounts are secreted by the renal tubules.
What is Urea?
A low molecular weight molecule.
It passes into the filtrate in the glomerulous of the kidney. Approx. 40-50% of the filtered load is reabsorbed by the renal tubules. This is passive to the transport of sodium.
What is uric acid?
The end product of purine degradation is uric acid.
Urates are completely filtered at the glomerulus and tubular reabsorption and secretion occurs. Most of the filtered urate is reabsorbed by then renal tubules.
What does Renin do?
Acts in the regulation of water and electrolytes.
And does active vitamin D do?
Stimulates the absorption of calcium from the small intestine. The renal cortex contains enzymes that hydroxylate 25-hydroxycalciferol, which is synthesized by the liver, to 1,25-dihydroxcalciferolm, the biologically active hormone.
What does erythropoietin do?
A glycoprotein which is also produced by the liver. Under normal conditions, the kidney is the major source of this glycoprotein. There is continuoussecretion of erythropoietin and its daily production is a function of the pO2 (the partial pressure of oxygen) of the blood perfusing the kidney. Hypoxia is a major stimulus to erythropoietin production.
