Kidney Function and Structure Flashcards
What is the function of the kidney?
- Regulation of water and electrolyte balance
- Excretion of metabolic waste
- Excrete drugs and hormones
- Regulation of arterial blood pressure
- Produce erythropoietin
- Vitamin D activation
- Gluconeogenesis (starving animal)
What is the basic functional unit of the kidney?
Nephron
What functions does the nephron have on kidney function?
Filtration
Reabsorption
Secretion
What is the relationship between body weight, blood volume, and number of nephrons per kidney?
Number of nephrons increase as bw and bv go up
What can cause loss of functional nephron unit?
Polycystic kidney disease. Can see this disease in cats and humans (especially Persians)
What makes up the basic unit of the nephron?
- Renal corpuscle/ glomerulus
- Proximal tubule
- Loop of henle
- Distal tubule
- Collecting duct
What makes up the renal corpuscle?
- Glomerulus - capillary tuft
- Bowmans capsule- responsible for filtration of solutes
How are solutes discriminated for in the renal corpuscle?
- Size
- Change
- Shape
Where is most of filtered solutes reabsorbed?
Proximal tubule
How are solutes reabsorped in the proximal tubule?
- Na coupled transport- glucose, aa, HCO3
- Isotonic transport- High water and junctional permeabilities
How much of glucose is absorbed?
All should be absorbed before it leaves the PT
What are the segments of the PT?
- S1 much taller and lots of mitochondria and long brush border
- S2 little smaller than S2
- S3 much smaller with less mitochondria
What are the two types of nephrons?
Cortical nephrons and juxtamedullary nephrons
What is the type of nephron important in concentrating mechanism?
Juxtamedullary nephrons
How do desert animals combat low water level?
High concentration ratios of urine to plasma
What are the portions of the loop of Henle?
- Thin descending
- Thin ascending
- Thick ascending
What are the permeabilities in the loop of Henle?
- TD high H2O and no NaCl
- TA High NaCl no H2O
- ThickA High active transport of NaCl no H2O
Fluid leaving loop of Henle is what?
Very dilute
How do you coordinate renal blood flow and glomerular filtration rate?
- Tubuloglomerular feedback
- Salt sensing and regulation by macula densa cells in the juxtaglomerular apparatus
What cells secrete renin?
Granular cells
Which parts of the nephron are hormonally regulated?
Distal convoluted and collecting duct
What happens in the Distal convoluted tubule?
Absorption of Na, Cl, and Ca
What is the function of the collecting duct?
-Fine tune salt, H2o and Acid base balance
What increases Ca absorption in the DCT?
Parathyroid hormone
What are the parts of the collecting duct?
- Cortical
- Outer medullary
- Inner medullary
What kind of cells are found in the collecting ducts?
Heterogenous
What hormones act on the collecting duct system?
Aldosterone- Increase Na absorption
ADH- Increase aquaporins and water absorption
