203 UG - Biochemistry Flashcards
3 lines of defense against pH changes
1st: Chemical buffer systems
2nd: Respiratory regulation
3rd: Renal regulation
The kidney plays key roles in extracellular fluid pH homeostasis by:
- Reclaiming bicarbonate (HCO3−) filtered at the glomerulus
- Generating the consumed HCO3− by secreting protons (H+) into the urine
(renal acidification)
What is carbonic anhydrase important for?
Resorption of carbonate back into the capillary
Lumen: HCO3- + H+ → CO2 + H2O
In cell: CO2 + H2O → HCO3- + H+
What tests are done for routine urine analysis?
Creatinine
Urea
Uric acid
Increased levels of creatinine signifies?
Creatinine is a waste product by muscle metabolism
Normally filtered by kidneys, if increased → renal dysfunction
What is a good marker of kidney function?
Creatinine
It is entirely excreted by kidneys, so directly proportional to kidney function
Why does abnormal serum creatine not always mean kidney disease?
Creatine levels are temporarily raised in some conditions
What may lead to increased level of urea in plasma?
Glomerular, tubular, interstitial or vascular damages
Disadvantages of assessing serum urea level
Many non-renal factors affect urea level (low specificity)
Rises quite late during renal dysfunction (low sensitivity)
What are the nitrogenous wastes excreted in urine?
Urea
Uric acids
Why do we need midstream urine while collecting urine samples?
The beginning of the stream may be contaminated
End-of stream pathogen may be washed away, as lat few drops are sterile. Which may dilute pathogen containing sample → false negative
When are urine samples examined?
Within 2 hours after collected
What pigment causes urine to be yellow?
Urochrome
What does fruity odor in urine indicate?
Ketoacidosis
- diabetic
- It occurs when the body starts breaking down fat at a rate that is much too fast. The liver processes the fat into a fuel called ketones, which causes the blood to become acidic.
Where is testosterone produced?
Leydig cells
