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161 Cards in this Set
- Front
- Back
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everything in the kidney moves by
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symporters and antiporters
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choose drugs based on
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kidney function
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erythropoeitin
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releases RBC's from the bone marrow
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functions of the kidney include
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excreting metabolic waste and foreign chemicals
regulating water and electrolytes, arterial blood pressure, erythrocyte production,and acid-base balance, secretion, metabolism, and excretion of hormones vitamin D production gluconeogenesis |
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hormones affected by the kidneys include
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renin and eryhthropoeitin and the active form of vitamin D
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major causes of periop morbidity and mortality include
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fluid overload, hypovolemia, and postop renal failure
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important drugs for periop care
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diuretics
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diuretics are often given to patients with
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hypertension, cardiac, hepatic, or renal disease
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surgeries that commonly use diuretics are
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neurosurgical, cardiac, major vascular, ophthalmic, and urological
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the three basic processes of kidney function is
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glomerular filtration, tubular reabsorption, and tubular excretion
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glomerular filtration is when
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the plasma is filtered through the glomerulus
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tubular reabsorption is when
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the fluid, ions, and other compounds are reabsorbed into the vascular space from the filtrate
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tubular excretion is when
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compounds, ions, and fluid is excrete in the urine
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review symporter and antiporter systems
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diseaseshttp://highered.mcgraw-hill.com/sites/dl/free/0072437316/120068/bio04.swf
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urea is a
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byproduct of amino acid breakdown
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creatinine is a
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byproduct of muscle breakdown
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uric acid is a
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byproduct of nucleic acid breakdown
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bilirubin is
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a byproduct of hemoglobin breakdown
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what all is excreted by the kidneys
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urea, creatinine, uric acid, bilirubin, cations, anions
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are cations or anions more likely to be excreted
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cations
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metabolism of substrates in the liver usually involves
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conjugation
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conjugation is
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the process by which the liver attaches a chemical substrate onto a molecule to make the molecule more negative or positive
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nonpolar molecules will
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cross membrane easily and be quickly reabsorbed
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attaching substrates to a molecule by conjugation
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makes a molecule much more likely to be excreted
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anatomical location of the kidneys
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posterior wall of the abdomen outside the peritoneal cavity. Upper pole is at T12 and the lower pole is at L3. Left kidney is slightly higher than the right kidney because the liver displaces the right kidney downward
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what to remember about the kidney's location
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blood can collect in that space undetected
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the indented area of the kidney contain
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the renal artery and vein, the incoming nerves, ureter and lymph vessels.
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nerves and vessels
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tend to travel together in bundles
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label on a diagram of the kidney
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calyces, renal pelvis, medulla, cortex, ureters, artery, vein,
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sign of retroperitoneal bleeding
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back pain - not seen in diagnostic tests or laparotomies
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adrenal glands and the kidneys have
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cortexes and medullas
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two major sections of the kidney are
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outer cortex and inner medulla
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the inner medulla is divided into
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multiple cone shaped pyramids
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the functional unit of the kidney is
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the nephron
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two units within the nephron are
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tubular or collecting component and the vascular component
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the six divisions of the nephron include
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glomerular capillaries, PCT, loop of Henle, distal renal tubule, collecting tubule, juxtaglomerular apparatus
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the proximal end of the nephron is
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Bowman's capsule
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in the Bowman's capsule
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an ultrafiltrate of blood is formed which passes through the nephron with its volume and composition being changed by the reabsorption and secretion of solutes until urine is made
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blood flow of the kidney is
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supplied from the descending aorta where the renal artery branches off of and the renal arteries branch more. the blood leaves the kidneys by the renal vein and empties into the inferior vena cava
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renal artery stenosis is
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a substantial component of renal induced hypertension
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crossclamping of the aorta may cause
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infarction of the spinal cord and impaired kidney function
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what % of the cardiac output goes to the kidneys
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22% - 1100 ml/min (7x that of the brain and twice the extraction rate)
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why is blood flow through the kidneys so high
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so that enough plasma moves through the kidney to be filtered allowing the kidneys to precisely regulate fluid and electrolyte concentration.
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the kidney can autoregulate between
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pressures of 80 - 180 mmHg
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a large amount of oxygen is
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used by the adrenal glands
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on a diagram of the renal blood flow, please label
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the renal artery, segmental arteries, interlobar arteries, arcuate arteries, interlobular arterioles
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why does the kidney need a lot of oxygen
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to be used by the cortex for ATP production to run the various ion pumps - especially sodium moving pumps
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on a diagram of the nephron please label
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glomerulus, JGA, afferent arteriole, arcuate artery, arcuate vein, proximal tubule, cortical collecting tubule, distal tubule, loop of Henle, collecting duct, bowman's capsule
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describe blood flow through the renal capillary system
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blood enters the afferent arterioles, then enters the 1st capillary system called the glomerulus, then exits the glomerulus into the efferent arterioles, then to the peritubular capillary system, then into the venous system
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the afferent and efferent arterioles control
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hydrostatic pressure in both sets of capillaries.
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average pressure in the glomerular capillaries is
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60 mmHg
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the average pressure in the peritubular capillaries is
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13 mmHg
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on the bowman's capsule please label
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capsular space, mesangial cells, glomerulus, PCT, parietal epithelium, visceral epithelium, afferent arteriole, efferent arteriole, distal convoluted tubule
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how many nephrons in each kidney
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1 million
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by 40 you lose
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10% of your nephrons every 10 year - nephrons accomodate the loss but the electrolytes don't balance as well
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2 different types of nephrons are
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the cortical nephron and the juxtamedullary nephron
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the cortical nephrons are
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located in the cortex and has short loops of Henle
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the juxtamedullary nephron
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begins in the cortex however the loop of Henle transverses deep into the medulla
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the capillary system surrounding the juxtamedullary nephron is
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the vasa recta
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the vasa recta helps with
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urine concentration
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describe the glomerulus
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tufts of capillaries that jut into bowman's capsule to provide a large surface for the filtration of blood
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mesangial cells
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contract and relax to increase or decrease filtration rates in response to hormones
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hormones that cause the mesangial cells to relax (increasing filtration) are
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atrial natriuretic peptide, prostaglandin E2 and dopamine
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hormones that cause mesangial cells to contract, decreasing filtration are
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angiotensin II, vasopressin, norepi, histamine, endothelins, thromboxane A2, leukotienes (C4 and D4), prostaglandin F2 and platelet activating factor
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what separates the glomerulus from the bowman's capsule
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nothing except the fused epithelial and endothelial cell membranes
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what provides the filtration in the glomerulus?
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the fused membranes are perforated but interdigitate tighly making them effective against large mw molecules and cells. anionic sites make the membrane have an overall negative charge which makes it easier to filter cations
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mesangial cells are located
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between the basement membrane and the epithelial cells near an adjacent capillary
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mesangial cells contain
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contractile proteins that respond to vasoactive substances, secrete substances, and take up immune complexes
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blood flow in the bowmans capsule is
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provided by one afferent arteriole and on efferent arteriole
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endothelial cell fenestrae aer how big
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70 - 100nm
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filtration slits are how big
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25 nm (because the epithelial cells interdigitate)
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four steps of filtration are
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filtration, reabsorption, secretion, excretion
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how much does the glomerulus filter a day
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180 Liters
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how much plasma in your body
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3 Liters
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the plasma is filtered how many times a day
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60 times a day
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high pressure in the glomerular capillary
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drives fluid out of the capillary
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filtration is
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when the high pressure in the glomerular capillary drives fluid out of the capillary
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the lower pressure in the peritubular capillary
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allows reabsorption
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the amount of urine produced is
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the sum of the amount filtered plus the amount secreted minus the amount reabsorbed
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the GFR is determined by
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the hydrostatic force in the glomerular capillary (60 mmHg),
the hydrostatic pressure in Bowman's capsule (18 mmHg), the glomerular colloid osmotic pressure (32 mm Hg), the colloid osmotic pressure in Bowman's capsule (should be none) |
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why is the colloid osmotic pressure in Bowman's capsule 0
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because there should be no proteins in the urine therefore there is no colloid pressure
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the glomerular colloing osmotic pressure is due to
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proteins
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the hydrostatic force in the glomerular capillary
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60 mmHg
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the hydrostatic pressure in Bowman's capsule is
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18 mmHg
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the glomerular colloid osmotic pressure is
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32 mmHg
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the colloid osmotic pressure in Bowman's capsule is
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0 mmHg
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why aren't proteins usually filtered
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big, but also because they typically carry a negative charge
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net filtration pressure is usually around
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10 mmHg
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the glomerular hydrostatic pressure is determined by
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the arterial blood pressure (autoregulation should take care of this), the afferent arteriole vessel size or resistance, the effernt vessel size or resistance
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why don't you give toradol to old people
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because it inhibits the cyclooxygenase pathway that leads to prostaglandin synthesis which would decrease the GFR in an old kidney
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low dose dopamine and NO can cause
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afferent dilation
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afferent arteriole dilation will effect the GFR by
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increases GFR
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increasing efferent arteriole resistance will
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increase the GFR
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most common hormones that produce vasoconstriction of the afferent arteries are
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norepi, ADH, and angiotensin II
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prostaglandins promote
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afferent arterial dilation thus improving GFR
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the juxtaglomerular complex has a specialized cell
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the macula densa
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the macula densa is located
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in the initial potion of the distal tubule and the juxtaglomerular cells in the walls of the afferent and efferent tubules
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the macula densa has
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golgi apparatus that secrete substances to affect the arterioles
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macula densa can detect
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sodium concentration which triggers a decrease in resistance in afferent arteriole raising the glomerular hydrostatic pressure returning the GFR to normal or
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the macula densa can also work by
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increasing the release of renin from the JXT cells of the afferent and efferent arterioles. Renin - angiotensin I to angiotensin II which the constricts the efferent arterioles and increases the glomerular hydrostatic pressure and the GFR
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primary active transporters in the kidneys are
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Na - K pump,
hydrogen pump hydrogen potassium pump calcium pump |
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tubular reabsorption occurs by
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passive and active mechanisms - protein channels, junctional spaces between cells, paracellular path, transcellular path, osmosis,
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different sections of the endothelial segments
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filter different ions
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pumps may run by
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osmosis, atp, antiport, symport
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the brush border is
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the villi that extend into the nephron tubule to increase surface area
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the PCT has
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extensive brush border whereas the collecting tubules do not
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things that are different between different parts of the nephron
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brush border, number of mitochondria,
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more mitochondria are found in the segments of the nephron that
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transport substances in and out the most
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which ion is most transporters based off of
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sodium
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most drugs are filtered for excretion in the
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proximal convoluted tubules
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the PCT is
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the 1st section after the glomerulus, is a thick and constantly active segment
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the PCT reabsorbs
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60% of all solute - 100% glucose and amino acids, 90% of bicarb, 80-90% of phosphate, and water
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most solute reabsorption is
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active
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water is reabsorbed via
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osmosis
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when in doubt, stuff is reabsorbed in the
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PCT
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water flows in and out of the PCT because
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follows solute concentrations
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describe transport of substances in and out of the PCT
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Na/K pump on the epithelial cell basolateral membrane sets up the concentration gradient which allows Na to act as a cotransporter in the apical membrane to reabsorb nutrients and electrolytes.
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Solutes exit PCT via
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channels
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the osmolarity of the filtrate in the PCT
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remains constant even as the volume decreases because water flows via osmosis in the PCT
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Vmax of glucose transport in the PCT is
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200 mg
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urine at the end of the PCT is
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isotonic (290 mOsm)
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the loop of Henle has 3 regions
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thin walled descending limb, thin walled lower portion of the ascending limb, and the thick walled upper portion of the ascending limb
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the descending limb of the loop of Henle is
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highly permeable to H2O but almost impermeable to solutes and ions
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as water flow out of the loop of Henle in the descending limb, the filtrate becomes
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isotonic with the outside environment - but significantly hypertonic to the blood (1200 mOsm)
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the thin ascending and thick ascending limbs are
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impermeable to water
sodium is actively transported out of these segments |
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the thick ascending limb reabsorbs
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25% of the sodium, Cl, K and some of the other ions - Ca, Mg, bicarb
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the descending loop of Henle
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"saves the water and passes the salt"
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the descending loop of Henle functions as
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part of the counter current multiplier, is freely permeable to water and impermeable to salt, receives filtrate from the PCT, allows reabsorption of water and sends salty filtrate on to the next segment
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thick ascending segments has symporters that move what ions
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Na, 2Cl, K into the cell
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thick ascending limb has two antiporters that move what ions
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Na in and H out,
Na out and K in (Na/K pump) |
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loop diuretics affect
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the sodium, 2 chloride, 1 potassium cotransporter of the thick ascending limg
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examples of loop diuretics are
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furosemide, bumetanide, ethacrynic acid
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the tubular fluid of the ascending thick limb is
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more positive than the interstitial fluid
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the 8 mv charge of the tubular lumen in the thick ascending segment causes
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Mg, Ca, and some Na, K through the paracellular spaces (junctions) between the cells
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the thick ascending limb has many
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Na/K ATP pumps which pump Na out of the tubular cell and into the interstitial fluid in exchange for K
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how does furosemide affect potassium level
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decreases K level because K is peed out
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do loop diuretics cause acidosis or alkalosis
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alkalotic because they block the Na/2Cl/K pump which allows more build up of Na ions which are then available to run the Na/H pump causing more H+ to leave the cell and get peed out causing alkalosis in the blood stream
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the vasa recta is
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a component of the counter current multiplier, reaches deep into the medulla of the kidney, follows the long loops of Henle, and the primary function is to return water to the vascular system and keep the medullary interstition salty
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the primary function of the vasa recta is
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primary function is to return water to the vascular system and keep the medullary interstition salty
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the vasa recta capillary system is
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freely permeable to water and salt
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the counter current multiplier is
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the method by which urine is concentrated and sodium and water may be conserved
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describe the counter current multiplier
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1 - the ALOH pumps out NaCl so interstitium becomes salty. 2 - osmolarity of fluid decreases so the tubules in the medulla conserve Na. 3 - b/c of the salty interstitum, the DLOH loses water to the interstitium and the filtrate becomes more concentrated. 4 - the collecting tubule fine tunes the amount of H2O leaving based on ADH level
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ADH level affects
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the collecting tubules and how much water is reabsorbed
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aldosterone affects the
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upper thick ascending loop of henle
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lasix affects the
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lower thin ascending loop of Henle
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too much ADH means
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less pee
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less ADH means
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more aquaporins in the collecting tubules and more pee
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what do you use to treat Diabetes insipidus
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vasopressen (ADH) because it helps stop them from peeing out all the potassium
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Distal Convoluted Tubules (DCT)
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receives the dilute fluid from the ascending loop of henle
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the DCT is the
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variably active portion of the nephron
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when aldosterone is present the
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DCT absorb sodium and secrete K with water and chloride following the sodium
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how does mannitol work
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mannitol is a high concentration of a huge sugar molecule - once it gets filtered it can not get reabsorbed, so it pulls lots of H20 out with it.
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mannitol works predominantlty in the
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PCT
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the late DCT contain
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Principle and intecolated cells
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principle cells
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reabsorb Na and excrete K
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intercolated cells
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reabsorb K and secrete hydrogen
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the early portion of the DCT contains
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the juxtaglomerular apparatus
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the middle portion of the DCT is
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the diluting segment accounting for 5% of sodium reabsorption - it is essentially impermeable to water but not solutes
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the DCT contains
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Na/K pumps and the Na/Cl symporter
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thiazide diuretics work by
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inhibiting the Na/Cl symporter that move sodium from the tubular lumen back into the cell.
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aldosterone works on
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the principle cells by increasing their activity - causing more sodium to be absorbed at the expense of potassium
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