Renal Physiology III Flashcards
What is the main contributor to the destruction of neurons in CKD?
Board Review:
In CKD, how is creatine and urea secreted? What happens to the concentrations of these solutes in plasma with decreasing GFR?
When do you start to see accumulations of PO4- and H+ ions in the plasma?
When would you see disturbances in Na and Cl in the progression of CKD?
Basically, in renal failure where you have to use dialysis
What are the three ways that the body defends itself against changes in H+ concentration?
Buffers, lungs, and kidneys
We have over 15,000 mEq/d of acid that we need to buffer. The body principally uses 3 systems to buffer this acid: A rapid buffering in the ECF by HCO3- & phosphate, rapid pulmonary exhalation of CO2, and slow renal excretion of H+ using NH3 and Phosphate as buffers.
How do the kidneys and lungs work together?
Physiological interpretation of the Henderson-Hasselbalch equation
Where are the receptors located that detect changes in CO2 and alter respiration rates?
Acidosis increases VA & increased VA reduces CO2
For acid/base disturbances, how do you know if the kidneys or lungs are the ones compensating?
What are the kidneys three main acid/base functions?
What promotes H+ secretion/HCO3- reabsorption?
Is normal urine acidic or basic?
Normal urine output is acidic (pH ~6 or less)
How is bicarbonate handled by the kidneys?
What is the main role of angiotensin II in this figure? And where is the majority of H+ ions secreted in the kidney?
Proximal Tubule and Thick Ascending Limb
Explain how principle cells and Type A intercalated cells work together to protect against hypokalemia in the distal tubule and collecting duct. What transporters and systems are involved?
What is the purpose of Type B cells in the distal tubule and collecting duct in states of alkalosis?
Board review:
Alkalosis has 2 major effects on K+ secretion. What are they?
1) a basic pH makes K+ channels in the CCD more likely to be open.
2) the negative charge of HCO3- in the lumen helps establish and electrochemical gradient for K+
Acute acidosis decreases what?
- All ATPase transporter activity
- The open probability (Po) of K+ Channels
- These changes reduce K+ secretion/excretion.
Chronic acidosis increases what?
- Sk.M. H/K+ activity leads to increasing Plasma[K+].
- Reduced Na+/K+ATPase activity leads to lower Na+/H20 Reabsorption
- This lowers the effective circulating volume (ECV) and increases tubular flow rate
- Higher Plasma [K+] & lower ECV both promote Aldosterone.
- Higher flow rates and Aldosterone promotes K+ secretion/excretion.
Main differences between acute and chronic acidosis?
Where does most H+ in the tubular lumen come from?
T or F. Bicarb is the main renal base
False
If the ratio of HCO3- to CO2 (pH decreases) in the extracellular fluid decreases because a fall in HCO3-, the acidosis is referred to as _________________.
Metabolic acidosis
If the pH falls because of an increase in PCO2, the acidosis is referred to as _________________.
Respiratory acidosis
What are the filtered urinary buffers for the acidic urine?
What is the source of NH3, NH4+ and bicarbonate in the proximal tubule?
Glutamine (synthesized in the liver)
Where is the location of ammonium reabsorption in the nephron, through what channel?
After being reabsorbed in the TAL, where is ammonium secreted and through what channel and type of cell?
What are the three questions to ask yourself when using a Davenport diagram?
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