FINAL EXAM - Lecture 4 Flashcards
BP regulator of kidney
Chronic high blood pressure can be due to kidneys, possibly because it doesnt notice high BP, but could be anything.
pH regulation of kidney
kidney can produce bicarb, and it also decides how much bicarb to reabsorb (small, so easy to reabsorb). It is also in charge of getting rid of H+ protons.
RBC regulation of kidney
Kidneys have pxygen sensors DEEP inside kidney, and they assess oxygen tension in deep medullary portions of kidney. If O2 is low, kidney releases erythropoietin, which will stimulate bone marrow to produce more RBCs. Improves ability to perfuse.
Electrolyte regulation of kidney
Kidneys can sometimes pick and choose which electrolytes to reabsorb, but for the most part its all reabsorbed.
Vitamin D regulation of kidney
Kidney can determine how much calcium to reabsorb, but also how much it absorbs from the food, via vitamin D activation in kidney.
Blood glucose regulation of kidney
Reabsorbs glucose, typically all of it. But if BG is super high (900 for a few days), kidneys cant reabsorb it and it will excrete it out via urine. Its technically a safety valve/blow off valve for ridiculous BG levels.
Drug clearance regulation of kidney
Typically, a secretory process of removing drugs from kidney
Metabolic waste disposal by kidney
Nitrogenous waste compounds such as with severe diabetes, Urea.
Osmolarity regulation of kidney
Decides how much water to reabsorb SEPERATE from NaCl that it is reabsorbing. Can remove water without salt, or salt without water. Controls the osmolarity.
If pt is hypernatremic, it can remove salt without removing water. Cause if you remove both, the osmolarity doesnt change.
How is the osmolarity regulator managed?
ADH, osmoreceptors in the brain.
Including all of the roles of the kidney, everything is usually managed by
GFR.
Secretory can also be included, but its mostly GFR.
Complete order of blood flow in kidney from entry to exit
Renal artery -> segmental arteries -> interlobar arteries -> Arcuate arteries -> interlobular arteries -> afferent arterioles -> glomerular capillaries -> efferent arterioles -> peritubular capillaries -> interlobular veins -> arcuate veins -> interlobar veins -> segmental veins -> renal veins
What structures form the nephron?
Afferent arteriole -> peritubular capillaries + the tubular network.
How many nephrons are we born with?
Each kidney has 1 million. 2 million total.
Start to lose nephrons around the age of 40 due to wear and tear
A 10 year old should still have 2 million.
2 types of nephrons
Deep and superficial
Where are most nephrons found?
Cortical superficial nephrons, 90-95%
Where are less nephrons found?
Deep medullary nephrons (inner medulla). 5-10%
A superficial nephron in the cortex will have peritubular capillaries where?
In the outer medulla
What’s in the inner medulla?
Deep medullary nephrons with their peritubular capillaries.
What is different about the PT caps in the deep inner medullary nephrons?
There’s more ascending blood vessels than descending bloods vessels. The ascending blood vessels have split points and may split into 2 or 3 blood vessels.
Why are the PT caps different in the deep medullary nephrons? (Reason)
It slows down the velocity of the blood flow, which is important for maintaining solutes in the deep inner medulla. It prevents washout of solutes, to help with reabsorption.
What are the blood vessels of deep PT caps called?
Vesa recta capillaries.
Downside of deep medullary nephrons
Limited supply of blood, so it will be very sensitive to hypoperfusion.
AVR and DVR stands for
Ascending vesa recta and descending vesa recta
What is right above the kidneys?
Diaphragm
Renal artery and vein is right beneath
Mesenteric artery
On top of each kidney is
Adrenal glands
Kidney cancer is relatively rare because
Kidneys don’t really reproduce new nephrons, so since there’s not a fast reproductive rate, there’s a less chance of cancer.
Kidney pain is referred to
Lower back
Difference between men and women urinary anatomy
Men have prostate gland and a prostate enlargement will squeeze the urethra and make it difficult to empty the bladder. Will cause frequent bathroom breaks cause the bladder is always full.
What controls emptying of bladder?
Mix of PNS and SNS.
Controlled by the pudendal nerve, which comes off spinal nerves S2,3,4
What spinal nerves control bowel and bladder emptying?
S2,3,4
Risk of prostate surgery
Surgeon can cut pudendal nerve and make patient lose controls of bowels and bladder
What nerve is responsible for erections in men?
Pudendal nerve
First part of tubule is called
proximal convoluted tubule
Corpuscle is also referred as
Bowman’s capsule
Complete order of renal tubular structure
PCT -> PST -> DTL -> ATL (ascending thin limb) -> TAL -> MD -> DCT -> CT -> CCD -> oMCD -> iMCD
Loop of henle has 3 parts
Thin descending limb, thin ascending limb, thick ascending limb
Located within TAL, a structure called
Macula densa
Macula densa is responsible for
Where kidney monitors filtration rate. There’s a “speedometer” that tells kidney how much fluid is being filtered.
What tubular structure comes into contact with blood vessels?
Macula densa, because it’s monitoring filtration rate.
Medullary collecting duct is divided into two parts
Outer (superficial) and inner (deep).
The macula densa has cells connected to
Juxtaglomerular cells in Afferent and efferent arterioles.
When the macula densa senses that flow is low, what happens?
Renin is released from the juxtaglomerular cells at Afferent and efferent srterioles. Renin increases angiotensin II levels, which will constrict EFFERENT arteriole. Restores flow in macula densa.
Chemist Pauline took what to slow down his cancer?
Vitamin C
How could vitamin C possibly slow down cancer?
Aiding with oxidative stress
Renal clearance describes
Amount of substance cleared from plasma per unit of time
Renal clearance will always be measured in
mL/min
Uppercase V with dot over it is
Volume per unit of time
Could also be U
If we have something that is easily filter able, the concentration in the bowman’s capsule should be what compared to the blood before it was filtered?
The same
What % of “stuff” is reabsorbed into proximal tubule?
2/3rds
How much glucose is reabsorbed into proximal tubule?
Should be all of it in a healthy patient
If 2/3rds of “stuff” is reabsorbed, but 99% of fluid is reabsorbed after filtration, what does that do to the osmolarity?
Becomes much more concentrated
If a compound is filtered but NONE of it is reabsorbed, what does that do to the concentration?
If the compound is concentrated in 125mL, that entire concentration has to pack into 1mL, making it very concentrated.
If compound X is filtered and not reabsorbed, talk about the concentration in the proximal tubule and peritubular capillaries
Highly concentrated in PCT, low concentration in peritubular capillaries because what didn’t get filtered is now in PT, but now has 124mL of extra fluid that doesn’t contain the compound
If X = 1mg/dL, and theres 125mL filtered per minute, that’s how many mg?
1.25mg/min
If there’s 1.25mg per minute excreted, how many mLs is that?
1mL
How many mLs is a dL?
100
If there is a compound that is filtered but not reabsorbed , it should be similar to
GFR
Renal clearance formula
Urinary flow rate x urinary concentration divided by plasma concentration
E.g. (1mL/min x 1.25mg/mL) / 1mg/100mL = 125mL/min
What is compound x?
Inulin. Gold standard to measure GFR.
Why is creatinine measurement inaccurate for GFR?
Creatinine is also secreted so it will read a falsely high GFR
If compound Y is fairly filtered, and highly highly secreted to take the rest of Y out of the peritubular capillaries into the tubule, what does this result in?
Highly concentrated tubule and zero compound Y post peritubular capillary. Very high clearance rate, will give us a good estimate of our renal plasma flow.
What is compound Y?
PAH
What is the clearance rate of PAH?
90%
