Renal Function Flashcards
1-1.5million functional units in the kidney
nephrons
Identify the nephron:
responsible for the removal of wastes and reabsorption of nutrients in the kidney
cortical nephrons
Identify the nephron:
responsible for the concentration of urine
juxtamedullary nephrons
give the 4 renal functions
- renal blood flow
- filtration (glomerular)
- reabsorption (PCT)
- secretion (PCT)
in what tubule does the reabsorption of essential substances happen?
proximal convoluted tubule (pct)
in what tubule does the final adjustment of urinary composition happen?
distal convoluted tubule (dct)
Where do the major water and salt exchanges occur between the blood and medullary interstitium?
loops of Henle
total renal blood flow per minute
1200mL/min
total renal plasma flow per minute
600-700mL/min
beginning of the renal tubule
Bowman’s capsule
serves as a nonselective filter of plasma substances
glomerulus
Where does the glomerulus reside?
inside the Bowman’s capsule
intertwining foot processes seen in the inner layer of Bowman’s capsule
podocytes
primary protein with positive charge assoc. with renal disease
albumin
What phenomenon repels positive charge molecules (e.g., albumin) in the glomerular filtration barrier?
shield of negativity
What system regulates the flow of blood to and within the glomerulus?
Renin-Angiotensin-Aldosterone System (RAAS)
components of juxtaglomerular apparatus
juxtaglomerular cells of afferent arterioles and macula densa of DCT
What monitors the changes in BP and plasma sodium content?
juxtaglomerular apparatus
an enzyme produced by juxtaglomerular cells that react with angiotensinogen to produce angiotensin I
renin
a hormone that causes vasodilation of afferent arteriole + constriction of efferent arteriole → release of aldosterone and ADH
angiotensin II
What is the difference between the compositions of filtrate and plasma?
absence of plasma protein, any protein-bound substances, and cells
specific gravity of urine
1.010
Identify the cellular mechanism involved in tubular reabsorption:
- substance to be absorbed is bound to carrier protein
- needs electrochemical energy
active transport
Identify the cellular mechanism involved in tubular reabsorption:
- molecules move due to differences in their concentration or electric potential on opposite sides of the membrane
passive transport
Identify the cellular mechanism involved in tubular reabsorption:
- glucose, amino acids, and salts
- chloride
- sodium
active transport
Identify the cellular mechanism involved in tubular reabsorption:
- water
- urea
- sodium
passive transport
Identify the location and mechanism of transport:
- glucose, amino acids, salts
active - PCT
Identify the location and mechanism of transport:
- chloride
active - ascending loop of Henle
Identify the location and mechanism of transport:
- sodium
active - pct and dct
passive (w/chloride) - ascending loop of Henle
Identify the location and mechanism of transport:
water
passive - pct, descending loop of Henle, collecting duct
Identify the location and mechanism of transport:
urea
passive - pct, ascending loop of Henle
True or False:
Passive reabsorption of water takes place in all parts of the nephron except the ascending loop of Henle
True
plasma concentration at which active transport stops
renal threshold
renal threshold of glucose
160-180mL
What is the cause of the presence of glucose in the urine?
tubular damage
Where does renal concentration begin?
loops of Henle
selective reabsorption process that serves to maintain the osmotic gradient of the medulla
countercurrent mechanism
Where does the final concentration of urine happen?
collecting ducts
What happens to water reabsorption and urine volume if ADH decreases?
↑H2O and ↑Urine Volume
What happens to water reabsorption and urine volume if ADH increases?
↓H2O and ↓Urine Volume
What controls the production of aldosterone?
salt
2 major functions of tubular secretion
- waste elimination
- regulation of acid-base balance
major site of removal of unfiltered substances
proximal convoluted tubule
normal blood pH
7.4
True or False:
Bicarbonate ions (HCO3-) are excreted in the urine.
False (it is reabsorbed back into the blood to maintain its pH)
What tubules/ducts produce ammonium ions?
pct (main)
for additional needs: dct and collecting duct
inability to produce an acid urine
metabolic acidosis/renal tubular acidosis
In what loop of Henle reabsorbs water?
descending
In what loop of Henle reabsorbs sodium and chloride?
ascending
earliest glomerular filtration test for urea
urea clearance
Original reference method for clearance tests (golden standard)
inulin clearance
What is the most common glomerular function test that uses 24-hour urine collection?
Creatinine clearance
substrate for renin enzyme
angiotensin
