Term
| where is most of the blood volume of the CV located? |
|
Definition
|
|
Term
| what compartment of the entire body has the most volume? |
|
Definition
| the intravascular compartment |
|
|
Term
| what is different about electrolyte concentrations intra vs extracellularly? |
|
Definition
intracellularly: more Na
extracellularly: more K (anionic proteins at the physiological pH help maintain this gradient) |
|
|
Term
| why is renal function vital knowledge when administering drugs? |
|
Definition
| some drugs can become nephrotoxic if the pt's kidneys are unable to clear them as quickly as normal |
|
|
Term
| when do osmotic gradients become very important? |
|
Definition
| brain injury - there is very little space available for brain swelling to go before vascular compression occurs (mannitol is used to treat this - will shrink brain back to size) |
|
|
Term
| what are the 2 main ways that kidney volume is regulated? |
|
Definition
| self-regulation and the neuro-hormonal endocrine system |
|
|
Term
| what is plasma clearance? |
|
Definition
| this is calculated by how much plasma is cleared of creatinine as it goes through the kidney ins a unit of time. this helps doctors titrate their drug administrations |
|
|
Term
| what are the main things the kidney regulates? |
|
Definition
| water/electrolyte balance, body fluid osmolality and electrolyte concentrations (the pituitary contains osmoreceptors which signal to retain fluid if osmolarity goes up via ADH), and acid-base balance (acidemia shifts O2 curve if kidneys fail, which can depress cardiac function. aklalosis can affect myocardial contractility as well as O2 unloading) |
|
|
Term
| do the kidneys play a part in regulating metabolic waste? |
|
Definition
| yes, especially in excretion of water soluble drugs |
|
|
Term
| how can the kidneys regulate arterial pressure? |
|
Definition
| yes, arterial pressure can be lowered or raised depending on urinar output |
|
|
Term
| what hormone is secreted by the kidney? |
|
Definition
|
|
Term
| are the kidneys involved w/gluconeogenesis? |
|
Definition
| yes. if a diabetic undergoes a nephrectomy - their medications will need to be re-assessed |
|
|
Term
| how much to kidneys usually weight? |
|
Definition
|
|
Term
| how extensive is nerve supply to the kidneys? |
|
Definition
|
|
Term
| why is the R kidney slightly lower? |
|
Definition
|
|
Term
| why do the kidneys have high hydrostatic pressure? |
|
Definition
| they sit right off the aorta |
|
|
Term
| what is a common way for kidney stones to form? |
|
Definition
| if the kidneys are stressed, the protein conc will go up, the pH changes and solvent decreases/solute increases = kidney stone |
|
|
Term
| what is a ureter affected by backed-up ultrafiltrate called? what can this lead to? |
|
Definition
| a hydroureter - which can lead to hydronephrosis (ions build up, volume overload, acidemia, hyperkalemic etc) |
|
|
Term
| what is blood in the urine called? |
|
Definition
|
|
Term
| where is a common site of impingement w/kidney function? |
|
Definition
| the hilum, pelvic brim, and entrance into the bladder |
|
|
Term
| what is the relationship of the psoas with kidney pain? |
|
Definition
| movement/elevation of the pt's leg causes movement around the ureter, which make cause pain and be indicative of pathology |
|
|
Term
|
Definition
| a tap on the back to check for pain in the CVA (costo-vertebral angle), pts with kidney disease can present with back pain |
|
|
Term
| how should CTs be performed for pts w/suspected kidney stones? |
|
Definition
| w/out contrast - which highlights vasculature, obliterating the view of the kidney |
|
|
Term
| what is useful about the perirenal fat? |
|
Definition
| this allows ultrasounds looking for hydronephrosis/kidney stones to be performed, however it is dependent on the circumstances |
|
|
Term
| how much of CO do the kidneys receive? what is the rate of flow? |
|
Definition
| 21% the rate of flow is 1200 mL/min of blood. |
|
|
Term
| how does resting affect kidney function? |
|
Definition
| at rest, kidney flow increases |
|
|
Term
| how does dehydration affect renal flow? |
|
Definition
| flow is the same, there is just decreased urine output |
|
|
Term
| what is the level of innervation to the kidney capsule? |
|
Definition
| high - if the kidney is stretched, it will become quite painful |
|
|
Term
| which is longer, the cortical or medullary nephron? |
|
Definition
|
|
Term
| how is blood flow to nephrons controlled? |
|
Definition
| constriction of afferent arterioles, (which both bradykinin and prostaglandin control play a part in) |
|
|
Term
|
Definition
| afferent = going towards kidney, efferent = going away from the kidney (smaller) |
|
|
Term
| how much of solute does the PCT reabsorb? |
|
Definition
|
|
Term
| what hormone affects the DCT? |
|
Definition
| ADH (coming from the adrenal) - which can change the permeability of the DCT to allow reabsorption of water by changing the gradient across membranes |
|
|
Term
| how should the glomerular filtrate compare to the blood flow coming into the kidney? |
|
Definition
| they should be iso-osmotic |
|
|
Term
| why does the PCT have a brush border? mitochondria? |
|
Definition
| the brush border is needed to facilitate reabsorbtion via increased surface area. it also has increased mitochondria to power absorption |
|
|
Term
| how do the sizes of the arterioles in the kidney help maintain hydrostatic pressure? |
|
Definition
| the efferent arteriole has a smaller hole, and thus due to poiseuille's law - resistance is higher inside the glomerulus (easier to get in than out) |
|
|
Term
| who would massive bleeding affect kidney function? |
|
Definition
| the kidneys will constrict the afferent arterioles, enough to maintain filtration - electrolytes are still being created in other parts of the body and thus need to be filtered out, but due to blood volume loss in other areas, less will be lost from the kidneys |
|
|
Term
| what is it called if there is functional flow through the kidneys, but ultrafiltrate is not being made? |
|
Definition
| oliguric/anuric - this is indicative of hypovolemia, which needs to be checked before the kidneys go into acute renal failure, stop filtering and result in dysrrhythmias or edema |
|
|
Term
| what are the fenestrae in glomerular capillaries supposed to be retaining? |
|
Definition
|
|
Term
| can inflammation cause hematuria/proteinuria? |
|
Definition
| yes, inflammation can cause the fenestrae to become enlarged, thus leaking blood, protein, etc (treated with steroids and or antibx) |
|
|
Term
| what is the function of the juxaglomerular apparatus? |
|
Definition
| the juxaglomerular apparatus is communication between the afferent arteriole and the DCT (when they come close together), and are thus able to monitor what is going in and out and what to adjust via water absorbtion, ADH release, etc |
|
|
Term
| what function do mesangial cells perform? |
|
Definition
| the mesangial cells have podocytes that serve as a secondary filter on the level of the glomerulus - and prevent large proteins from passing as well as serving as back up if the membrane of the capillary endothelium becomes damaged. |
|
|
Term
| what kind of epithelium is the DCT? |
|
Definition
|
|
Term
| are the mitochondria in the PCT vulnerable to destruction? |
|
Definition
| yes, the mitochondria are sensitive to chemicals and can be easily compromised |
|
|
Term
| how do the cortical and medullary nephrons generally treat salt levels? |
|
Definition
| cortical - salt wasting (shorter), medullary - salt sparing (longer) |
|
|
Term
| how much fluid do we ingest every day? |
|
Definition
|
|
Term
| how much fluid do we make (via metabolism) every day? |
|
Definition
|
|
Term
| what is the avg total intake of fluid for a day? how should this compare to output? |
|
Definition
| 2.3 L -> which should be matched by output |
|
|
Term
| how does exercise affect volumetric loss? |
|
Definition
| exercise increases volumetric loss tremendously (by ~3x) |
|
|
Term
| how much volume is in the plasma? interstitial space? intracellular? |
|
Definition
| plasma: 3L, interstitial space: 11 L, and intracellular: 28 L (2x as much intracellular as extracellular) |
|
|
Term
| can renal function affect the clearance of a drug? |
|
Definition
| yes as well as the compartment the drug is being injected into |
|
|
Term
| what is the main cation in the extracellular compartment? anion? |
|
Definition
| anion: Na+ cation: Cl- (these balance each other out) |
|
|
Term
| what is the main cation in the intracellular compartment? anion? |
|
Definition
| anion: K+ cation: PO4-, organic anions, and protein (these balance each other out) |
|
|
Term
| plasma needs sodium, chloride, calcium, bicarbonate to be maintained, but what are some other components not monitored as closely? |
|
Definition
| phospholipids, glucose, urea, creatinine (this breakdown product of muscle metabolism is not necessarily maintained persay, but it does function as a flag for kidney damage) |
|
|
Term
| what is the quick and dirty method of calculating osmolarity? |
|
Definition
| 2x Na conc (but a completely accurate osmolarity includes glucose, BUN, etc) |
|
|
Term
| how can adding salt result in fluid pressure being generated? |
|
Definition
| salt will cause the movement of water toward it across a membrane if all other factors are equal = osmotic pressure |
|
|
Term
| what are 2 factors which can be manipulated to change compartment size and tonicity? |
|
Definition
|
|
Term
|
Definition
| increased Na+ from excessive Na+ intake or dehydration (Na+ and H2O can independently move in and out of cells) |
|
|
Term
| how can kidney dysfunction (specifically that which would lead to high volume) lead to CHF? |
|
Definition
| high volume loads overstretch the sarcomeres in the heart, actin and myosin cannot optimally interact - and the heart cannot effectively eject blood |
|
|
Term
| how can kidney dysfunction (specifically that which would lead to high volume) lead to HTN? |
|
Definition
| HTN increases with increased resistance to blood flow, past a certain capacitance, the more volume = the more pressure |
|
|
Term
| which is larger, afferent or efferent arterioles? |
|
Definition
|
|
Term
| when the blood goes through the glomerulus into the PCT is it isotonic with the rest of the blood in the body? when does this change? |
|
Definition
| the blood immediately after having gone through the glomerulus is isotonic with the rest of the blood in the body, but the urine as it is increasingly reabsorbed upon becomes less isotonic w/the blood in the body as necessity dictates |
|
|
Term
| what are filtration, reabsorption, secretion and excretion as they apply to the kidney? |
|
Definition
| filtration: going across a membrane, reabsorption: body takes it back, secretion: body dumps it out, excretion: the final product |
|
|
Term
| where is the juxaglomerular apparatus? what does it do? |
|
Definition
| these cells are found in the macula densa, which is an area of closely packed specialized cells lining the wall of the distal tubule at the point of return of the nephron to the vascular pole of its parent glomerulus. these sense the osmotic gradient and release renin or affect hormone release in other parts of the body to modify the final excreted product |
|
|
Term
| what is the GFR usually? what sorts of factors could bring it down? |
|
Definition
| the glomerular filtration rate is usually around 60, however inflammation in the bowman's capsule, immune complexes, disease complexes, kidney failure, and diet could all cause GFR to drop |
|
|
Term
| what does the creatinine clearance look at? |
|
Definition
| how much creatinine is in the blood, how much is in the urine and what fraction of he plasma was cleared of this substance (if creatine is up, renal function might be down) |
|
|
Term
| what are physical barriers to filtration? what are diseases which can affect these? |
|
Definition
| fenestra size and number in the endothelium, the basement membrane, and podocytes from mesangial cells. proteinura, hematuremia and inflammatory processes can affect these barriers (may require tx w/steroids, antibx, or dialysis) |
|
|
Term
| what is normal glomerular hydrostatic pressure? (normal capillary pressure is 38 mm Hg) why is this? |
|
Definition
| 60 mm Hg - due to proximity to descending aorta, large renal vessels, etc - this is needed to drive filtration |
|
|
Term
| why are the afferent to efferent capillary systems in the kidneys considered "portal systems"? |
|
Definition
| they are 2 capillary beds in series |
|
|
Term
| what can cause pressure in bowmans space - ultimately leading to glomerular pressure being backed up? |
|
Definition
| kidney stones farther down the ureter, BPH (constricts ureter) |
|
|
Term
| how do you calculate *total body water? what are some caveats for this calculation? |
|
Definition
| .6 x body weight in Kg (kg = lbs/2.2). caveats: age decreases apipose growth, females have more adipose, and obesity leads to less water (w/increase in fat) |
|
|
Term
| how can the volume of the vasculature be calculated? |
|
Definition
| injecting an indicator of known concentration and volume that will disperse evenly in the compartment, remain, and not be metabolized/excreted. some time is given for the indicator to disperse and then the same volume is taken out and the final concentration is calculated |
|
|
Term
| how can volume in the *ECF (vascular volume + interstitial fluid volume) be measured? |
|
Definition
| inulin may be used as an indicator (it can disperse in the plasma and interstitial fluid) |
|
|
Term
| how is intracellular volume calculated? why is this calculation necessary? |
|
Definition
| total body water - ECF = intracelluar volume (which is roughly 2x ECF). this calculation is necessary b/c when giving a drug IV, you want it to stay in that compartment and distribute to do what it was designed to do |
|
|
Term
| how is interstitial fluid volume calculated? |
|
Definition
| interstitial fluid volume = ECF - plasma. (plasma = vascular volume, which is calculated using a plasma-specific indicator - not inulin which gives ECF) |
|
|
Term
| how can you calculate a pt's hematocrit using TBV? when might you need to use this? |
|
Definition
| TBV = plasma volume/(1-hemtocrit). this would be used when a pt has massive blood loss and is being given a lot of fluids |
|
|
Term
| what are osmoles? what does van hoff's law relate them to? |
|
Definition
| a unit representing the total number of particles in a solution, as the number of particles increases, the osmolarity increases. van hoff's law relates osmoles to actual osmotic pressure. |
|
|
Term
| what is diffusion? how does it manifest itself in the kidneys? |
|
Definition
| the continuous movement of molecules among one another in a liquid - brownian motion. diffusion is one of the forces that allows water and solute to be reabsorbed |
|
|
Term
| what is osmosis? how is this force manipulated in the kidneys? |
|
Definition
| the movement of H2O from a higher concentration to a lower concentration. membrane pumps controlled by hormones can cause ion channels to open or close, creating an osmotic force to reabsorb or excrete fluid/solute (counter current multiplier) |
|
|
Term
| what is the take home point review thus far? |
|
Definition
| a)blood goes to kidneys, goes through glomerulus and is filtered (RBC, WBC, platelets stay; H2O-soluble things go into bowman’s space). b)PCT pulls back H2O and particles. c) goes down loop of henle and starts to get more concentrated. d) goes up ascending limb – pulls out some K+, Na+ and whatever else it needs. e) DCT – checks osmolarity - if normal, nothing happens and just pee it out, if you need H2O, retain it and dump salt |
|
|
Term
| can facilitated ion transporters be manipulated w/drugs to transfer more or less molecules across a membrane? |
|
Definition
| yes, either - they can be blocked or "revved up", (meaning they might be able to move 2 at a time) |
|
|
Term
| how does the size of molecules in the blood affect the body's (kidney's) ability to get rid of it? |
|
Definition
| macromolecules (such as albumin) will need to be metabolized before they can leave the vasculature (as the effective radius goes up, the longer it will take for body to get rid of it) |
|
|
Term
| what function do macromolecules in the blood perform in terms of glomerular filtration? |
|
Definition
| large macromolecules that don't filter create glomerular colloid osmotic pressure that pulls fluid back into circulation (usually about 1/2 the glomerular hydrostatic pressure - but it keeps something in the capillaries/glomerulus) |
|
|
Term
| what happens to colloid osmotic pressure and filtration fraction as fluid moves from the afferent to the efferent end of the glomerulus? |
|
Definition
| colloid osmotic pressure and filtration fraction start to go up |
|
|
Term
| what favors reabsorption back into circulation (peritubular capillaries)? |
|
Definition
| dropped hydrostatic pressure and increased colloid osmotic pressure |
|
|
Term
| how will increasing efferent arteriolar resistance affect glomerular filtration rate and renal blood flow? when might this benefit the body? |
|
Definition
| increased efferent arteriorlar resistance will increase glomerular filtration rate and decrease renal blood flow (increasing filtration fraction: FF = GFR/RPF). this would benefit the body if a pt loses a *moderate amount of blood volume (dehydration/bleeding), as it would enable the kidney to continue filter what blood still remains |
|
|
Term
| how will increasing afferent arteriolar resistance affect glomerular filtration rate and renal blood flow? when might this benefit the body? |
|
Definition
| increasing afferent arteriolar resistance will decrease both glomerular filtration rate and renal blood flow. this can happen when pts bodies are *extremely hypovolemic (renal failure, glomeruli not filtering), but can only be a temporary state b/c metabolites build up -> hyperkalemia/acidosis/volume overload are all now risks. blood levels of creatinine and BUN are all indicators of this (bicarbonate can be given to prevent creatine, myoglobin, etc from “gunking up” filters) |
|
|
Term
| what is renal autoregulation? |
|
Definition
| the maintenance of constant flow and GFR in the face of constant pressure via dilation/constriction of the afferent/efferent arterioles |
|
|
Term
| how does HTN affect urination rate? |
|
Definition
| HTN can cause an increase in urine output |
|
|
Term
| how does an increase in hydrostatic pressure affect GFR? |
|
Definition
|
|
Term
| how does an increase in hydrostatic pressure affect GFR? |
|
Definition
|
|
Term
| how does HTN affect urination rate? |
|
Definition
| HTN can cause an increase in urine output |
|
|
Term
| how does HTN affect urination rate? |
|
Definition
| HTN can cause an increase in urine output |
|
|
Term
| how does an increase in hydrostatic pressure affect GFR? |
|
Definition
|
|
Term
| how does increased pressure in bowmans space affect GFR? |
|
Definition
|
|
Term
| how does increased osmotic/oncotic pressure affect GFR? |
|
Definition
|
|
Term
| how does decreased resistance in the afferent arteriole affect GFR? |
|
Definition
|
|
Term
| how does increased resistance in the efferent arteriole affect GFR? |
|
Definition
|
|
Term
| hoes the *osmolarity of the ultrafiltrate change as it goes through the kidney? |
|
Definition
| yes, it starts isosomotic, immediately after leaving the glomerulus, becomes hyperosmotic (at the bottom of the loop), and then hypo-osmotic all as water and ions are reabsorbed back into circulation at different times |
|
|
Term
| can the macula densa affect the constriction/dilation of the afferent/efferent arterioles? |
|
Definition
|
|
Term
| how would the macula densa react to an increase in just fluids? |
|
Definition
| the kidney would tell the macula densa to tell the DCT to not respond to ADH (or not produce it in the pituitary) -> letting the extra water out |
|
|
Term
| how would the macula densa react to an increase in just salt? |
|
Definition
| the kidney would tell the macula densa to respond to ADH/tell the pituitary to produce it, to keep water to dilute the salt |
|
|
Term
| how much of the blood is reabsorbed in the PCT? |
|
Definition
|
|
Term
| what part of the nephron is found in the renal papilla? |
|
Definition
| the loop - hyperosmolar tip |
|
|
Term
| what is the basic function of the juxtaglomerular apparatus? |
|
Definition
| to monitor what is going in between afferent arteriole, DCT and efferent arteriole - see what needs to be reabsorbed/excreted and release enzymes to affect the afferent arteriole (constricting decreases GFR/dilating increases GFR). the efferent can also be selectively affected. |
|
|
Term
|
Definition
| the liver produces angiotensinogen. the juxtaglomerular apparatus produces renin, which makes angiontensinogen into angiotensin I, which becomes angiotensin II via ACE. angiotensin II stimulates: vasoconstriction (increased TPR), ADH secretion (increased permeability of DCT, water reabsorbed), aldosterone release (from zona reticularis of adrenal increased Na+ reabsorbtion to match water reabsorption due to ADH) |
|
|
Term
| what is the progression of osmolarity through the nephron? |
|
Definition
| isosmotic -> hyperosmotic -> hyposmotic |
|
|
Term
| are cortical nephrons salt-wasting? |
|
Definition
| yes, and medullary nephrons are salt-sparing |
|
|
Term
| what is the actual equation for osmolarity (not just the 2x Na+ conc)? |
|
Definition
| osmolarity = 2x[Na+] + [glucose]/18 + BUN/2.8 + EtOH/4.6 |
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