Kidney Flashcards
(22 cards)
What are the two general functions of the Kidneys
Regulatory function
Hormonal function
What are the 3 things kidneys regulate
Body volume fluid
Elimination of waste production
Electrolyte and acid base balance
what are the processes of regulation function
Glomerular filtration
Tubular reabsorption
Tubular secretion
what can and cannot pass through the glomerular capillary walls ?
Small molecules and water can pass through
- electrolytes
- creatine
- urea
- nitrogen
- glucose
Large particles that cannot and stay in blood
- RBC’s
- albumin
What is an unusual finding in urine?
Albumin
RBC
Glucose
Protein
Describe the process of glomerular filtration
Blood flows through renal artery —-> afferent arteriole —-> Glomerular
small molecules and water are filters across membrane–> renal tubule
This becomes the filtrate
Filtered by renal tubules and removed from body
Remaining blood leaves the glomerulus via efferent tubules and returns to blood stream
What is the glomerular filtration rate/
An estimate of the filtering capacity of the kidneys
Normal GFR?
120 ml/ minute
Which means 120ml of blood is filtered every minute
What is the relationship between increased or decreased GFR
The more blood that passes through the kidneys to be filtered= increased urine production = increased GFR rate
A decrease in the amount of blood being filtered = decreased urine production = decreased GFR rate
What conditions increase GFR
Drinking more fluids, IV hydration
These increase blood volume
Examples of conditions that will decrease GFR
Dehydration= less fluid, decrease in blood volume
Decreased cardiac output
Severe hypotension SBP 70>
Renal failure- inability to filter correctly
What percentage of functioning nephrons require consideration for renal replacement
Less than 20%
Why is the right kidney slightly lower than left?
Allows room for liver
Remember cirrhosis- will put pressure on other organs as it increased in size
Briefly describe the process of tubular reabsorption
99% of water and most electrolytes are reabsorbed back into the blood stream by the proximal convoluted tubule
about 1% of water and elect are excreted in urine
this allows normal urine output of 1-3 liters/day
Why does reabsorption happen?
This allows the body to prevent dehydration and excessive electrolyte loss
Creates about 1-3 liters of urine/day (1000-3000 ml)
What is the minimal output of urine/ hour
30ml/ hour
What is tubular secreation?
Certain substances; hydrogen and excess potassium- use active transport to move out of blood stream and into renal tubules to be excreted
NOT passive filtration
This helps regulate acid-base balance and potassium levels!
Too much K= excrete
Too little base= withhold hydrogen to balance acid base
What hormones are produced by the kidney
Renin
Erythropoietin
What other vitamin does the kidney have a role with
Converts vit D to active form that can be used by the body
What roll do the kidneys play in acid base balance?
They regulate acid base balance by excreting excessive hydrogen/retaining hydrogen ions
SLOW PROCESS
Why is kidney acid base balance slow?
d/t excretion of hydrogen ions in urine
Or retention of ions
For hydrogen ions to be excreted requires active transport which requires cellular energy
How do kidneys regulate BP?
Through the release of renin
Renin stimulates the production of angiotensin which increased aldosterone to increase BP and BV
