Lecture 11/13: Renal Physiology Flashcards
Final
Basic Roles of the Kidney: Describe the Kidney’s role in: BP regulation
Kidney is the long term manager of BP
if you have HTN, the kidney is suppose to fix it.
If you have chronic HTN –> something wrong with your kindeys
Basic Roles of the Kidney: Describe the Kidney’s role in: pH regulation
Kidneys produce more or less bicarb which helps balance out protons, and decide how much is reabsorbed.
-Also get rid of excess protons in urine
this helps with acid/base balance
What is the short term regulator of pH? How does this process work?
The respiratory system
-blows off CO2 to decrease protons in blood temporarily –> cant get rid of protons, kidney has to.
Basic Roles of the Kidney: Describe the Kidney’s role in: Red blood cells
Hct sensors in deep inner medulla of the kidney detect if O2 levels are low –> triggers Epoetin release (Epo) –> increase bone marrow –> increase RBC
This increase in RBC ultimately allows more oxygen to flow through the VR in the deep inner medulla
Basic Roles of the Kidney: Describe the Kidney’s role in: electrolyte regulation
Kidneys are the primary long term regulator in filtering ions bc almost everything gets reabsorbed that we eat.
Basic Roles of the Kidney: Describe the Kidney’s role in: Vitamin D
Kidney choices how much Ca++ to reabsorb–> Vitamin D is activated at the kidney
Activated vitamin D promotes Ca++ reabsorption
Basic Roles of the Kidney: Describe the Kidney’s role in: Serum glucose
It figures out how much glucose needs to be reabsorbed
If elevated a little = all reabsorbed
Elevated alot = max reabsorbed & the rest excreted
this is a safety valve bc if we just keep reabsorbing all the glucose then serum glucose would just stay high
Basic Roles of the Kidney: Describe the Kidney’s role in: Drug clearance
The kidney will filter and secrete drugs to excrete them out of the body
Basic Roles of the Kidney: Describe the Kidney’s role in: Metabolic waste
Rids of nitrogen waste products; urea
Basic Roles of the Kidney: Describe the Kidney’s role in: Osmolarity
Able to get rid of salt while hanging on to water (ADH)
Ex) hypernatremia
What are all the roles of the kidney?
- LT BP regulator
- LT PH regulator
- LT RBC regulator
- LT electrolyte regulator
- LT vitamin D regulator
- LT serum glucose regulator
- Drug clearance
- LT metabolic waste disposal
- osmolarity regulator
These things are dependent on a normal GFR
Hence why auto regulation is important
What is the order of blood flow through the renal artery and out the renal vein?
Renal artery –> Segmental arteries–> Interlobar arteries –> arcuate arteries –> interlobular arteries –>
AA –> GC –> EA –> PT cap–>
Interlobular veins –> arcuate veins –> interlobar veins –> segmental veins –> renal vein
The ______ is the function unit of the kidney
Nephron
How many nephrons are in each kidney? How many total?
1 million in each kidney
2 million total
______% of your nephrons are located in the cortex
90-95%
Where is the PT cap located? VR?
PT cap: Outer medulla/cortex
VR: deep inner medulla
____% of nephrons located in the deep inner medulla
5-10%
What is the role of the VR?
-Help concentrate the renal ISF
-Preserves osmotic gradient by minizing washout
How many descending VR do we have? Ascending? What is the purpose of this?
Descending: 1
Ascending: 2
We have MORE ascending VR to decrease the velocity of blood going up to maintain normal levels of solute in the deep inner medulla
Preventing wash out
What were to happen if the velocity of the VR were high?
The solutes in the renal ISF would be diluted!!!!
Wash out <– know this term
This creates a problem bc this messes with the gradient for reabsorbing and secreting solutes
When would it be beneficial to increase velocity of the VR to wash out the solutes in the renal ISF?
A condition where the renal ISF has a hyperosmolarity:
AKI/CKD?
If BP is decreased, which part of the kidney is most effected? why?
Deep inner medulla
Only 5-10% of capillaries are in the deep inner medulla, therefore only 5-10% of oxygen carrying blood gets to that area. Making this area very sensitive to small amount of decreased perfusion.
This can cause ischemia in the area very easy
What area of the kidney is most likely to become ischemic? Why?
Deep inner medulla
Only 5-10% of capillaries
The mesenteric artery sits _______ the renal artery & vein. It also supplies blood to the _______
on top of
intestines
The kidneys are located _________ the diaphragm
under
The adrenal gland is ______ the kidney
on top of
What is the ureter?
Collection system for fluids left in the collecting duct to empty bladder
Adrenal glands =
suprarenal glands
What does the R kidney come in contact with?
Liver: top lateral
Colon
What does the L kidney come in contact with?
Stomach: top
Spleen: lateral
Pancreas: middle (same side as stomach)
Colon
Which organ comes in contact with both kidneys?
Colon
T/F: You can grow new podocytes and nephrons
F
Why is it rare for cancer to originate in the kidneys?
Cancer cells depend on proliferation and kidney cells dont replicate. Usually kidney cancer is caused by cancer from another organ in close proximity metastasizing to the kidney.
Kidney cancer orginating in the kidney can still happen
What are the organs in close proxmity to the kidneys?
Stomach
colon
pancreas
liver
spleen
The Pancreas comes in contact with the _____ kidney
left
The L kidney is in the _____ & the R kidney is the RUQ
LUQ
What comes together to form the ureter?
Minor/major calyx
Describe the pathology of kidney stones
They can happen at the: urethra, ureter, bladder
Block pathway for urine excretion
causes urine backup
This causes back pain & increase work of the kidney
If you have random back pain without trauma, what should you expect?
Kidney stones
What is the main difference between the male & female urinary anatomy?
males: prostate gland that surround urethra
What are the risk associated with Prostate gland removal?
Cutting the pudendal gland –> this will make the problem worse that they were trying to fix.
Pudendal gland also responsible for erections
What is a common problem with men as they get older? What is the Tx for this?
Prostate enlargement
- prostate squeezes urethra –> harder to fully empty bladder –> needing to urinate often
Tx: Prostate removal
think risks
Who is Linus Pauling?
-Chemist: studied antioxidants/oxidative stress in cancer prevention
-Took 25000u of vitamin C daily to slow down prostate cancer
-Lived for 25 more years
Who is the chemist who took vitamin C to live for 25 more years with prostate cancer?
Linus Pauling
A combination of what systems control empyting of the bladder?
SNS & PNS
Hence why if youre nervous it might be hard to go to the bathroom, or you might lose control of your bladder.
What nerve runs close to the prostate gland?
pudendal nerve
What is the pudendal nerve?
Consist of Sacral Nerves:
S1, S2, S3
Manages being able to control bladder AND bowel
What nerves keep stuff off the OR floor?
S2, S3, S4
The pudendal nerves
What is the order of the tubular system of the nephron?
- Bowman’s capsule (corpuscle)
- Proximal Convoluted Tubule (PCT)
- Proximal straight tubule (PST)
- descending thin limb (DTL)
- Ascending thin limb (ATL)
- Thick ascending limb (TAL)
- Macula Densa (MD) (part of TAL)
- Distal convoluted tubule (DCT)
- Collecting tubule (CT)
- Cortical collecting duct (CCD)
- outer medullary collecting duct (oMCD)
- inner medullary collecting duct (iMCD)
Know this order even the last part :(
What does the Macula Densa cells do?
Monitor filtration rate by acting as a Na & Cl counter
–Comes in contact with the juxtaglomerular cells in the EA & AA
Part of autoregulation of GFR
What happens when the MD senses that filtration is low?
juxta cells release renin –> ANG II increased –> EA constricts –> Pressure in GC increases –> GFR increases
What are the cells that surround the EA & AA?
Juxtaglomerular cells
What 2 main things make up the juxtaglomerular apparatus?
MD
Juxtaglomerular cells
What is the 1 thing that should come to mind when we think of juxtaglomerular apparatus?
ANG II
Describe clearance
Quality of plasma that is cleared of a substance in an amount of time
Ex) ml/min
Equation: Clearance
C = (V x U) / P
V = urine volume flow
U = urine concentration of compound
P = plasma concentration of compound
Equation: Excretion Rate
Excretion rate = V x U
V = urine volume flow
U = urine concentration of compound
If glucose is WNL, what should clearance be? why?
0
All should be filtered
All should be reabsorbed
None should be excreted
Where should all glucose be reabsorbed at in the nephron?
Proximal Tubule via SGLT2 and SGLT1 transporters
What is the gold stadard calculating GFR?
Inulin
Describe Inulin
Gold standard for calculating GFR
-Freely filtered
-Not reabsorbed or secreted
-Not made by the body (exogenous; given IV)
—–Should all end up in the urine—–
-Concentration of inulin increases through nephron bc not reabsorbed with fluids
-Concentration of inulin in plasma decreases as filtered through kidney & fluids reabsorbed back in PT cap
Clearance of this substance is a good estimate of GFR
For a substance that is freely filtered at the GC, what should be the concentration of that sustance at bowman’s capsule? For substances that are not reabsorbed?
The same as the plasma concentration
The concentration should increase as it moves down the nephron and fluid is reabsorbed
How do you find the concentration of a substance in the urine?
(Plasma concentration of item) x GFR
What do we normally use to calculate clearance? What are the variables in it?
Creatinine
-body produces it
-body secretes small amount
-have to know the time that went by
-byproduct of skeletal muscle metabolism
These variables can cause an overestimate of GFR
Describe PAH
Good estimate of Renal plasma flow
-freely filtered & HIGHLY secreted (90%)
Clearance should be equal to RPF
_____% of PAH is filtered/not reabsorbed/secreted then excreted
90%
1 dL =
100 ml
.1 L
