Renal -17 Flashcards
Because the CV system and renal system are BFFS, a decrease in blood pressure will lead to:
x= increase in angiotensinogen (this is always in blood so not affected)
x=decrease in renin
x=relaxation in afferent arteriole (good if you wanted to die)
INCREASE IN ANGIOTENSIN 1
The Nephron
slide on how it works (near beginning)
What Happens to Filtrate
We make about 180L of filtrate
-some is completely reabsorbed (glucose, amino acids, bicarbonate ion)
-some is regulated and thus partially reabsorbed (water, sodium, potassium, chloride)
-some is excreted as wasted (urea, creatinine, drugs)
What is Gained/Lost per day in Filtrate
-180L of water in filtrate, 1-2 liters of urine
-162g of glucose in filtrate but none in urine
-570g of Na in filtrate, but 4g secreted
-uric acid (protein metabolism) 8.5g but 0.8g in urine
-creatinine (break down of muscle) 1.6g in filtrate and 1.6g in urine
Kidneys Reabsorption
reabsorption happens 1/2 ways:
- active transport (requires energy)
- passive transport (chemicals follow electrochemical gradients)
-movement of water is by osmosis (a passive mechanism as water follows concentration gradient through semi-permeable membrane)
-90% water reabsoprtion is obligatory (water dragged by solutes) in convoluted tubule or descending loop of henle as these 2 areas are permeable to water
-last 10% is facultative (absorption can increase/decrease on body’s need) under control of ADH, so cells in collecting duct are permeable to water
Passive Transport
-the movement of solutes often doesn’t involve energy (move down gradient instead)
-some solutes can slip between tight cell junctions (paracellular route) or in/out the cells of the tubules (transcellular route)
-transcellular is facilitated by transport proteins
-leakage channels also allow some ions to facility their walk down concentration gradient
NOKIA
-sodium is less concentrated in cell so it wants to enter
2 Types of Active Transport
- primary active transport = functions strictly with ATP use
- secondary active transport = uses energy of movement of ions down concentration gradient to transport other solutes like ions and larges uncharged molecules like glucose or amino acids
-symporter = secondary active transport protein moves ion and solute in same direction
antiporter = secondary active transport protein moves ion in one direction and solute in the opposite
Both Active Transport Methods require a carrier protein
-carrier proteins assist movement of the ions and solutes
-because transports are proteins that can only bind and then move solutes according to number of binding sites, they have a maximum rate at which they can function
-the saturation of transport protein limits reabsorption of substances like glucose
-glucosuria occur strictly because maximum rate on active transporter has been reached
-active transport in kinder uses 6% of atp at rest
Glucose Symporter
secondary active transport in proximal convoluted tubule coupled to Na/K pump and facilitated diffusion of glucose
1 glucose uses energy of 2 sodium molecules to go through glucose symporter - but this drags in a lot of water
glucose facilitated diffusion transporter get glucose into interstitial fluid
Na/H Antiporter in Proximal Ct
slides 14-18
Sodium glucose transporter of renal tubules
moves glucose along apical membrane, and can be overwhelmed by high glucose levels in filtrate
Kidney Failure
na, k, ca, cl, and waste products build up and blood pH decrease
-masive edema results from salt retention
-acidemia results from inability to excreter acids
-when potassium levels are too high (hyperkalemia) cardia arrest occurs
-dialysis (chemo or peritoneal needed, kidney transplant)
Pitting Edema
-press down and skin doesn’t fill back in
-generlaized weakness, nausea, normal vitals, high potassium
-squiggly ekg (curved qrs) not reploarzing well
-emergenxy dialysis needed?
