Lecture 3 Flashcards
What are the four goals of the kidneys
balance water/solutes, excreate metabolic waste, conserve nutrients, regulate acid/base
How do the kidneys impact our endocrine function?
It regulates our blood pressure by releasing renin
It is a part of erythrocyte (RBC) production through the secretion of erythropoietin (more when O2 is low)
Assists in the metabolism of calcium. The kidney plays a key role in this process by the fine regulation of calcium excretion. More than 95% of filtered calcium is reabsorbed along the renal tubules. Apart from activation of Vitamin D, the kidneys increase calcium and phosphorus reabsorption in the tubules under the influence of 1,25-dihydroxyvitamin D (1,25VD).
What is the trigone area in the bladder?
A triangle shaped area between the open of the two ureters that empty into the bladder and above the urethra.
How long is the female urethra?
3-4cm
How long is the male urethra?
18-20cm
What is the gate in the urethra for urine to escape from
A smooth muscle called the internal urinary sphincter at the junction of the urethra and the bladder
How much urine can your bladder hold before it has the urge to void?
230-300ml causes the bladder to stretch and activate the parasympathetic fibers of the ANS Micturition Reflex
Another word for void
micturition
Difference between to cortex and medulla of the kidney
The cortex is the meaty outer part and the medulla is a pyramid. There are renal columns between the pyramids that release into the renal pelvis
What are the three functions of the nephron
glomerular filtration, tubular reabsorption, tubular secretion
Describe the anatomy of the nephron
Capillary branches off into renal corpuscle where the capillaries turn into a ball of yarn (glomerulus) which releases excess waste products, ions, and amino acids (aka: filtrate) from blood into capsule. RBCs and proteins too big and stay in blood then exit through the peritubular capillaries (vasa recta). Filtrate then goes into elaborately twisting 3cm long renal tube 3 parts 1st proximal convoluted tubule (PCT) then drops into dramatic hairpin turn called nephron loop (loop of Henle) then distal convoluted tube (DCT) than empties out into a collecting duct each part filters out certain things
- Describe proximal convoluted tubule (PCT)
Walls made of cuboidal epithelial cells with big mitochondria that fund active transport of sodium ions and other good filtrate back into blood
- Describe distal convoluted tube (DCT)
Loop of Henle dips into medulla and comes back into cortex. Biggest job is to release water on the way down and create a salt concentration on the way up in constant cycle that keeps water drawn out. Then urea enters collecting duct and is recycled by going through medulla again to make even more salty.
Describe tubular transport
The last minute throw away of excess hydrogen, potassium, acids and bases from blood using active transport
Describe glomerular filtrate rate
Kidneys can only process so much filtration at once. When the blood pressure increases and ball of yarn (glomerulus) experiences increased pressure it activates stimuli that shrinks glomerulus and closes the fire hose a bit.
Why does caffeine and alcohol make you pee more
It inhibits ADH which makes the loop of Henle not reabsorb as much water so it stays in medulla and you pee it out
which sphincter do you control to pee
external urethral sphincters’ made of skeletal muscle
What is the structural and functional unit of the kidney?
Structural lobe, functional nephron
How many nephrons in the kidney
1.2 million
Quickly name the path through the nephron
- corpuscle 2. proximal convoluted tubule 3. loop of henle 4. distal convultuled tuble 5. collecting duct
Three parts of the renal corpuscle
bowman’s capsule, glomerulus, mesangial cells
What is the function of the intercalated cell in the DCT?
Secrete H+, reabsorb K+ and HCO3
What is the function of the principal cell in the DCT?
Secrete K+, reabsorb sodium and water
Which part of the nephron eliminates drugs?
proximal tubule
What part of nephron determines urine concentration?
Loop of henle
What chemical produced by the loop of henle helps prevent UTIs?
Uromodulin
Which part of the nephron is impacted by aldosterone (the bp hormone)
distal tubule
How much blood goes through the kidneys in under a minute?
1000-1200ml total blood, 600-700ml of plasma 180L/day (20-25% of cardiac output)
How much urine created per day?
1-2 liters/day
How much filtrate is reabsorbed back into the body?
99%
What is the minimum urine output per hour?
30ml/hr
T/F: Proteins can be found amongst the filtrate contents in the Bowmans space
no, it should be free of proteins and blood cells
Difference between reabsorption and secretion
Reabsorption is the movement of particles and water form the tubules to the plasma
Secretion is the movement from particles from plasma into the tubule.
What are some substances that are initially reabsorbed but secreted again?
H ions, Na, K
What are the three hormones that affect the nephron?
ADH (controls concentration for the final urine at the distal tubule and collecting ducts), Aldosterone (renin angiotensin aldosterone system stimulates reabsorption of Na and H2O in the distal tubule/collecting duct) , natriuretic peptides (inhibit absoption of water and sodium in the distal tubule results in the increase of urine formation)
T/F: Urodilatin does the same thing as natriuretic peptides?
Yup
How is vitamin d activated?
2 hydroxylation’s in the kidney/liver. Need it so small intestine can absorb calcium and phosphate
What is erythropoietin?
Hormone made by the kidney to ask bones to make more RBCs in response to hypoxia
How is kidney failure and anemia related?
You can’t make erythropoietin to ask the bones to make more RBCs
How is a patient with protein deprivation’s urine effected?
Urea is a product of protein metabolism. They struggle to maximize concentration of urine
Difference between renal failure, renal insufficiency, and end stage renal failure
renal failure: significant loss of renal function (general)
renal insufficiency: decline in renal function to about 25% of normal function
end stage renal failure: less than 10% of renal function remains
What is uremic syndrome
when your body has to much urea from stuff like proteins metabolism so you have a bunch of extra urea/creatine (toxic waste in general) in the blood and nausea
What causes azotemia?
Azotemia is elevated blood urea nitrogen (BUN) and serum creatine caused by renal failure and renal insufficient
Another Dx for renal failure
acute kidney injury (AKI) abrupt reduction of GFR, can happen for weeks usually dx by oliguria
3 types prerenal, intrarenal, postrenal
Describe the prerenal part of AKI
acute kidney injury (AKI) hypotension in the kidneys caused by:
hypovolemia, vascular pooling from vasodilation, increased renal vascular resistance, renal vascular obstruction, inadequate cardiac output
Describe the intrarenal injury type AKI
acute kidney injury (AKI) usually causes by acute tubular necrosis. can be ischemic/nephrotoxic
Describe the postrenal injury type AKI
acute kidney injury (AKI) obstruction to outflow through benign prostatic hypertrophy. Tumors
Describe acute tubular necrosis injury type AKI
acute kidney injury (AKI)
acute tubular necrosis most common type. Risk factors include depleted volume patients, elderly, preexisting renal disease, post-op pts. and post anesthia pts.
Describe the three phases of AKI recover
- initiation: 24-28 after initiating event that caused period of reduced perfusion when injury is evolving. NO DAMAGE YET can be reversed with increased volume to the kidney. How long this phase is has to do with the type of injury the received
- maintenance: the oliguric stage, occurs after an injury is established. can lasts for weeks to months. urine output is lowest. increased level of BUN and creatine. High K. Metabolic acidosis. Fluid retention
- recovery: diuretic stage b/c increased voiding (400+ml/day). ability to concentrate urine has redeveloped yet so that’s why more urine than usual. Need to regularly monitor creatine levels to determine level of recovery. monitor for up to 12 months and may never return to baseline
Describe the clinical manifestations of CKD (chronic renal disease)
azotemia/uremia is irritating to all body, almost everything impacted.
atherosclerosis of heart, hypertensions, pericarditis, CHF, increased risk for ischemic disease/stroke
uremic pneumonitis, pulmonary edema from sodium and water retention
reduced erythropoiesis, uremia platelet deactivation, risk for clots, rbc life span is half of normal, increased bleeding
uremic itching, paleness, inflammation, uremic frost (urea left on the skin)
uremic gastroenteritis, blood loss from bleeding ulcers, not enough absorption of nutrients leads to malnutrition, bad breath from digestive enzymes breaking down urea
drowsiness, poor memory, seizures, coma, asterixis (neuromuscular irritability causes hiccups and muscle twitching), peripheral neuropathy.
renal osteodystrophy (can’t regulate levels of phosphorous/calcium or activate vit d to make calcium usable which increases bone fractures
Describe chronic kidney disease (chronic renal failure)
Kidneys are able to maintain at least 50% function even when damaged. Defined as progressive loss of kidney function.
5 stages.
1 normal more than 90 GFR
2 mild disease 60-89
3 moderate disease 30-59
4 severe disease 15-29
5 kidney failure less than 15
prevention is key
Describe the treatment of CKD (chronic renal disease)
Dietary control (proteins, phosphorous
, K restricting. Sodium/water restrictions. watch caloric intake.
Where does mannitol work on the nephron
at the proximal convoluted tubule
Where does furosemide (loop diuretics) work on the nephron
loop of henle
Where do thiazides work on the nephron
early distal convoluted tubule
Where does K+ spring work on the nephron
late distal convoluted tubule
T/F most diaresis occurs at the beginning of the nephron?
False, most occurs at the beginning
What are the four types of diuretics?
loops, thiazides, K+ sparing, osmotics
What is the primary function of a diuretic
to increase the output of urine
Describe the loop diuretic
most effective diuretic, blocks significant amount of NaCl reabsorption. Acts within 60 minutes when taken orally. 5 minutes with IV. Lasts 2 hours for IV. 5 hours for PO.
Used for acute pulmonary edema w/ CHF. edema of liver disease, can cause diuresis even with low GFR/RBF
Side effects can include dehydration, hypotension, electrolyte imbalance, otoxicity (ringing in ears)
Drug interactions: Digoxin (for heart failure), lithium (mood stabilizer), ototoxic drugs (gentamycin), potassium sparing drugs, antihypertensive NSAIDs
Drug examples: furosemide (Lasix), ethacrynic acid (edecrin), bumetanide (bumex)
Describe the thiazide diuretic
Action dependent on adequate renal function.
block absorption of sodium, chloride in the distal convoluted tubule. Action dependent on adequate renal function. 1-2 hours PO, duration 6-12 hours. Some are slow release (24-48 hours). used for hypertension and CHF. lower level of diaresis than loop
all drugs end on thiazide
Describe the potassium sparing diuretics
Think K is going to stay and its delayed action. Use for hypertension,. edema, hypokalemia
spironolactone (Aldactone), excretion of sodium, retention of potassium, only small amounts of Na are absorbed. diuresis is minimal, action is delayed (up to 48 hrs)
Describe osmotic diuretics’
Ex: osmitrol IV ONLY
is a simple sugar that created osmotic forces in glomerulus. it pulls water into the glomerulus and the it is excreted out. Not reabsorbed back into the vasculature because of osmotic nature.
Doesn’t excrete that much electrolyte and the amount of urine produced is dependent on the amount of drug given.
Very effective at reducing intercranial edema (ICP) and intraocular pressure
does not cross blood/brain barrier but it easily moves out of the vasculature anywhere else which pulls fluid to wherever its located. Significant adverse drug reaction is significant edema.
