Lecture 4 Final Flashcards
Considered as the long term manager of our BP
Kidneys
Chronic high BP can ruin kidneys by….
Obscuring how the kidney senses the increased BP in the system
How is the kidney a pH regulator? Normally for long term pH regulation
It produces bicarb by removing excess protons (H+) and how much bicarbonate to reabsorb in the body
What is considered a short term pH regulator?
the respiratory system by blowing off excess co2
How does the kidneys control RBC levels?
It controls the levels of HCT by its blood o2 sensors, if it’s low, it’ll produce erythropoietin to stimulate the bone marrow to create more RBCs
How is the kidney a longterm electrolyte regulator?
Ex. if you eat something high in Na, it’ll make you either retain more water or excrete Na in urine. For Ca++ it’ll decide how much to reabsorb as needed.
Kidneys and longterm blood glucose management
NML healthy person - filtered glucose are reabsorbed.
DM - excess glucose reabsorption are at max level, excess glucose excreted in urine.
Kidneys and drug clearance:
secretory process
Drugs we use will be metabolized in the liver and put in the kidneys for excretion.
DM and nitrogen compounds in the blood
excess nitrogen compounds in the blood known as urea are excreted by the kidneys.
T/F:
The kidney can also differentiate between Na and water reabsorption depending on the osmolarity levels. It will reabsorb either or both by the use of ADH.
True
Where does most of the regulation occur?
This is mostly done in the GFR.
List of renal blood vessels (biggest to smallest)
Renal artery > Segmental artery > interlobar artery > arcuate arteries > interlobular arteries
List the full renal blood vessels starting from the arteries down to the veins
Renal artery > Segmental artery > interlobar artery > arcuate arteries > interlobular arteries > afferent arterioles > glomerular capillaries > efferent arterioles > peritubular capillaries > interlobular veins > arcuate veins > interlobular veins > segmental veins > renal veins
What are the 2 types of nephrons
90%-95% (superficial) Cortex
5%-10% (Deep) Intermedulla
How many nephrons are there?
1M each kidney = 2M/person
At age 40 you start to lose some
T/F:
Deep nephrons known as inter medullary nephrons do not have their own peritubular capillaries.
FALSE:
They have their own peritubular capillaries but there’s fewer of them and less blood vessels.
Unequal; less descending and more ascending capillaries (splits into 2-3) used to slow down the velocity coming back up.
Why does the inter medullary capillaries have uneven descending/ascending vessels? What is the other name for this?
It has about 1 descending vessel that splits into 2-3 ascending to help decrease the velocity of blood flow. This allows the regulation of normal solute levels in the deep interstitium of the renal medulla.
AKA VASA RECTA
Why is the vasa recta sensitive to BP?
Since it’s only 5-10% of the capillary flow, it has limited supply of peritubular cap’s for reabsorption and o2 delivery to the deep tissues. Low BP/inadequate perfusion will greatly diminish the inner part of the kidneys and more prone to ischemia.
What is DVR and AVR?
DVR - descending vasa recta
AVR - ascending vasa recta
Where are the kidneys located?
below the diaphragm
What is the hepatic surface?
Right side of the renal that comes into contact with the liver
What is the right colic flexure surface?
It’s what comes into contact with the colon
what is the gastric surface?
Its the left top part of the kidney that is in contact with the stomach
What is the splenic surface?
Left Area in contact with the spleen
What is the left pancreatic surface?
Left Area in contact with the pancreas
What is the descending colic surface?
Left side in contact with the colon
Why is it good to know what part of the renal is in contact with?
In cancer, because of metastasis.
both kidneys are in contact with the colon
Why don’t we hear about heart cancer?
Because heart cells don’t divide and multiply.
Never say never but It’s very rare and highly unlikely.
Minor and major calyx meets to form the?
Ureter
Issues with kidney stones
Blockage in the ureter may cause a back up in flow, l/t increase pressure upstream > pain > visceral pain to lower back.
Prostate gland issues…
Cancer; swelling that may cause impingement of urethra to obscure urine outflow l/t constant fullness of urine
What controls the urine emptying?
Pudendal nerve from the spinal nerves 2, 3, 4
What else does the spinal nerve 2, 3, 4 do?
Bowel control and urine control
Why are men worried about getting the prostate gland removed?
Pudendal nerve may get cut and cause uncontrolled GI/GU or erection.
Label the renal tubular structure
PCT > PST > Thin descending loop > Ascending thin loop > TAL (MD) > DCT > connecting tubule > cortical collecting duct > medullary collecting duct (iMCT (real deep); oMCT (superficial))
“speedometer” of the renal system
Macula Densa
If the Macula Densa senses low pressure….
It will activate the juxtaglomerular cells to release renin into the afferent/efferent > angiotensin II is activated > efferent arteriole constricts > increase glomerular pressure > increase GFR > blood flow restored
If the Macula Densa senses high pressures?
Renin release is reduced > dilates efferent arterioles > reduced glomerular pressures > reduced GFR > lower blood flow
T/F: Sometimes the “speedometer” Macula Densa can have an inaccurate reading
True
Famous chemist using Vit C to fight prostate cancer (x 25 yrs)
Linus Pauling. Use of (antioxidants)
Renal clearance definition
A quantity of plasma that is cleared of a substance per time (ml/min)
If the kidneys reabsorb lots of fluid and doesn’t reabsorb the stuff filtered, results in?
High renal clearance (ml/min)
If the kidney reabsorbs all of the fluids and filtered compounds, results in?
Low renal clearance (ml/min)
Formula for renal clearance
Clearance = volume concentration * urine flow rate/Plasma
(Cl = V * U/P). 1ml/min x 1.25mg/ml divided by 1mg/100ml (plasma)
Normal filtration per minute
125ml/min
Normal reabsorption rate
99% (124ml/min)
Normal urine output
1ml/min (V with a dot at the top)
V = volume
Dot at top = unit/min
With a normal clearance of glucose, how much should be seen in the urine?
None
If you had compound “x” that’s left behind in the tubule and more fluid is reabsorbed, what happens to the compound X?
Higher concentration of “X” inside the 1ml of urine
- higher concentration of “X” in the renal artery vs renal vein.
What is 1 mg/dl?
125 ml/min =?
1mg/100ml
1.25mg/dl = 1.25mg/min
urine output is 1ml/min
= 1.25mg/min
Cl ratio formula
Cl/concentration
Excretion rate formula
U x V
Clearance of PAH can also be used as
Renal plasma flow
How to convert renal plasma flow into renal blood flow
RPF/ 1- HCT (0.4)
reabsorption rate formula
filtered fluids - excreted fluids
Excretion
filtration - reabsorption + secretion
