Renal Flashcards
(159 cards)
What are some functions of the kidney?
- H20 and Na homeostasis
- control of ECF ion concentration
- acid base balance
- excretion of waste products and xenobiotics
- endocrine functions
- EPO
- renin
- vit D3
- PGI2
- formation of concentrated urine
- formation of diluted urine
What are the forces that affect filtration?
- hydrostatic P in glomerular capillaries (50mmHg)
- hydrostatic P in Bowmans capsule (10mmHg)
- oncotic P in glomerular capillaries (25-40mmHg)
- oncotic P in Bowmans capsule (0mmHg)
What happens to GFR when the afferent arteriole is constricted?
GFR decreases
What happens to GFR when the efferent arteriole is constricted?
GFR increases
What part of the nephron is considered the filtration unit?
the glomerulus
What part of the nephron is considered the workhorse?
the proximal tubule
What part of the nephron is considered the concentrator?
descending loop of henle and the thin ascending loop of henle
What part of the nephron is considered the dilutor?
thick ascending limb of henle
What part of the nephron is considered the fine tuner?
the distal tubule
Nephrons that have a short loop of henle/ascending limb are called
cortical nephrons
Nephrons that have a long loop of henle/ascending limb are called
juxtamedullary nephron
What does the term autoregulation mean?
- function= it maintains ~ constant GFR in the face of changing MAP between 80-180mmHg
- glomerular P is held constant against changing systemic P
- mechanisms
-
myogenic response
- when s.muslce of vv are stretched by increased blood vol, they open ion channels which causes depolarisation–> s muscle contraction–> decreased BF and decreased GFR
-
tubuloglomerular feedback
- when GFR is increased, flow through tubule and macula densa is increased–> macula densa detects decreased Cl- conc–> releases paracrine substances–> afferent arteriole constriction–> increased resistance in afferet arteriole–> hydrostatic P decreases–> GFR decreases to normal
-
myogenic response
Describe the filtration, reabsorption, secretion and excretion of the various electrolytes
Describe the clearance of penicillin
- =150mL/min
- freely filtered, not reabsorbed, and fully excreted
- also secreted which is why the clerance is > than GFR
Describe the clerance of inulin
- =GFR = 100mL/min
- because it is freely filtered, not reabsorbed and fully excreted
- this is the max clearance of a substance that ISNT secreted
Describe the clearance of glucose
- =0ml/min
- 100% is reabsorbed
- therefore no glucose is in the urine normally
What is the equation for excretion?
Excretion= Urine concentration x urine volume
What is the equation for renal clearance? and what does the term mean?
Renal clearance= excretion/plasma concentration
The amount of plasma clerared of the substance per time
How much oxygen does the kidney consume?
- 80% of oxygen is consumed by the kidney
- it has a high O2 requirement
- it is absorbed by active transport
Describe the reasorption processes that occur in the early proximal tubule
Describe the reabsorption processes that occur in the late proximal tubule
Describe the reabsorption processes that occur in the thin ascending limb of the loop of henle
- Na is reabsorbed via passive diffusion (in response to a conc gradient) across the tight junctions of the paracellular pathway
Describe the reabsorption processes that occur in the thick ascending limb of the loop of henle
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Describe the reabsorption processes that occur in the distal convoluted tubule
