Dr. Houston (Renal)-Exam 5 Flashcards
- What is the most superior layer around the kidney?
- What is superior to the medulla?
- What is around the glomerua?
- What vessels go away and towards the glomerus?
- Super. layer: Renal Capsule
- Cortex is superuor to medulla
- Bowman’s capusle is around the glomerus
- Towards the glom=afferent artery
- away the glom=efferent artery
What is the difference between cortical and JM nephrons?
JM nephrons are longer and more in the inner medulla. This area is salty therefore better at pulling in water
* See more dry area animals with more JM nephrons
What is the pathway of nephron out to the urethra?
Papillary duct (end of collecting duct)-> papilla-> minor calyx-> major calyx-> renal pelvis-> ureter-> bladder-> urethra
What is the blood supply of JM nephron vs cortical nephron?
- JM: Vasa recta (around loop of henle)
- Cortical: Peritubular capillaries (aroung prox and distal tubules)
Explain the breakout of the arteries and veins of the kidney
* What do you change in order to affect flow?
Explain the breakout of the arteries and veins of the kidney
* What do you change in order to affect flow?
Urine formation involves what three basic processes?
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
What is the excreted formula?
Excreted=filtered-Reabsorbed+secreted
What area of the nephron reaborbs about 65% of glomerular filtrate? What does it remove?
PCT reabsorbs about 65% of glomerular filtrate, removes some substances from blood, and secretes them into tubular fluid for disposal in urine
Proximal Convoluted Tubule
* What type of reabsorption?
* What is absorbed there? (3)
- Nonregulated reabsorption
- 70% of Na+ and H2O are absorbed here
- All glucose is absorbed here
Proximal Convoluted Tubule
* What are the characterisitics?
- Many microvilli (increase SA to allow mvt)
- Many mitochondria (lots of active transporters so need mitochondria for ATP)
- “Leaky” tight junctions (allow mvt)
Loop of Henle (juxtamedullary nephrons only)
* What does it create?
* Critical in what?
- Creates an osmotic gradient in the renal medulla
- Critical in water conservation
Distal Tubule and Collecting Duct
* More what than proximal tubule?
* What is there less of?
* What type of junctions?
* What hormone receptors are there?
- More regulated than proximal tubule
- Smaller and fewer microvilli
- Less mitochondria
- “Tight” tight junctions
- Hormone receptors: ADH (insertion of aquaporin channels) , aldosterone (na reabsorption and K secretion), etc.
Glomerular Filtration Rate (GFR)->(volume of plasma filtered per unit time)
* What is the rate?
* How much volume is filtered?
* How much urine is made daily?
- Average GFR = 125 ml/min
- 180 L filtered daily
- Only 1.5 L urine made daily
- Most filtered fluid is reabsorbed
Glomerular Filtration Rate
* What impacts GFR?
Changes in MAP could impact GFR by changing Glomeular Capillary Pressure (PGC)
Long lol
What are all the different forces on the glomerus?
- Hydrostatic Pressure in Glomerular Capillaries (PGC 55 out): This is the blood pressure within the glomerular capillaries, pushing water and solutes out of the blood into Bowman’s capsule. The value is 55 mm Hg, directed outward.
- Colloid Osmotic Pressure in Glomerular Capillaries (COP 30 in): This pressure is due to plasma proteins in the blood that draw water back into the glomerulus from Bowman’s capsule. The value is 30 mm Hg, directed inward.
- Capsular Hydrostatic Pressure (CP 15 in): This is the pressure exerted by the fluid already in Bowman’s capsule, which opposes further filtration. The value is 15 mm Hg, directed inward.
- Colloid Osmotic Pressure in Bowman’s Capsule (COP 0 out): Typically, there are no proteins in Bowman’s capsule to exert this pressure, hence it is zero.
- Net Filtration Pressure (NFP 10 out): This is the net pressure driving the filtration process. It is calculated by subtracting the inward pressures (COP in and CP in) from the outward pressures (PGC out and COP out). Here, NFP is 10 mm Hg, directed outward, indicating the overall force favoring filtration.
What range does GFR does not change? Why?
Between 80 – 180 mmHg, GFR does not change much with changes in MAP because of intrinsic regulatory mechanisms
GFR controlled by what?
adjusting glomerular blood pressure from moment to moment