Renal Function

1) Reviewa) Filters plasma at the glomerulus to produce a protein free

ultrafiltratei) 125 ml/min (18 L/day)ii) kidneys filter bloodiii) glomerulus looks like fist punch into ballooniv) ultrafiltrate filters so many substances. v) someone with normally fnxng kidneys normally has

concentrated urineb) Reabsorbs 99% of filtered fluid in renal systemc) Secretes selected substances d) Regulates ionic composition and tonicity of body by regulating

rate of absorption and secretione) Disposes of waste by filtration and secretion

2) Gross Anatomy (review or nephrons)a) Renal artery branches from abdominal aorta and there are many

sub levels of intrarenal arteriesb) Afferent (in) and Efferent (exit=out) Arterioles go in and out of

glomerulusc) Renal Cortex-contains 85% of all nephrons (why we wear kidney

pads in football)d) Renal Medulla- contains renal pyramids and columns, where the

nephrons in this area concentrate the urinee) Renal Pelvis the expanded proximal end of the ureters (2) (1

urethra)f) Ureters- drain urine into the bladder

3) Typical Kidney Placement

4)

5) Structures of the Kidney

6) Structures of the Kidney

7) Nephron Anatomya) Glomerulus tuft of capillaries where filtration occursb) Proximal Convoluted Tubule branches from Bowmans capsule

where 2/3 of electrolytes are reabsorbed, also, all glucose, all amino acids are reabsorbed

c) if see glucose or amino acids in urine, somethings wrong with the CT

d) Loop of Henle descending and ascending loops of the renal

tubule, reabsorbs Na, K, Cl e) Distal Convoluted Tubule - reabsorbs Na, Cl, reabsorbs or

secretes K, is hormonally controlled (ADH)f) Collecting Duct- Tubules that receive urine from several renal

tubules eventually direct urine to the pelvis of the kidney

8) Transport Functions of Nephrona) Glucose reabsorption

i) proximal tubule, has maximum, Na-dependentb) Acid Base Balance

i) secretes H+, results in HCO3 reabsorption or can be buffered by secreted buffers (NH3, HPO4)

c) Potassiumi) reabsorbed or secreted depending on need, secretion

regulated by aldosterone in distal tubuled) H20

i) follows Na in PT, DT, independently regulated by ADH in collecting tubule, gradient set up by loop

9) Nephron Function

10) Structure of the Glomerulus

11) Filtrationa) Nephrons filter plasma at the glomerulus. Fluid is filtered from

glomerular capillary into Bowmans spaceb) Glomerulus is freely permeable to water, but not large plasma

proteins (and glucose) when in a non-diseased state.c) Molecule size and electrical charge affect permeability of

substances. d) Fluid contains electrolytes and organic molecules such as

creatinine, urea, and glucose

12) Capillary Pressurea) Affects glomerular filtration.b) Hydrostatic pressure within capillary is major force for moving

water and solutes across the filtration membrane into Bowmans capsule. Blood (hydrostatic) pressure is higher than BP in other capillaries

c) Two forces oppose the filtration effects of this glomerular capillary hydrostatic pressure

a) The hydrostatic pressure in Bowmans space pushing against walls

b) The oncotic pressure of the glomerular capillary blood pulling things towards it

13) Tubo/glomerular Feedbacka) Juxtaglomerular apparatus - specialized region where distal

tubule contacts afferent and efferent arteriole of its nephroni) Synthesizes renin and act as baroreceptors monitoring bp

b) Feedback between the DT and the glomerular capillaries helps maintain homeostasis of

(a)-GFR (glomerular filtration rate)(b)-amount of urine produced(c) -overall blood volume and electrolyte concentration

c) Macula densai) Sense plasma sodium concentration and pass the message to

the renin-secreting cellsii) Are part of the thick ascending limb of the nephron

14) NaCla) the distal convoluted tubule controls GFR by changing diameter

of afferent and efferent arterioles. It can also change the permeability of the glomerulusi) increased NaCl in distal tubule decreases GFR

a) -whereever NA is it will hold fluid where its at.ii) decreased NaCl in DT increases GFR

a) bc that ind is urinating more out. Wherever NA is, fluid follows. NaCl is direct substance used at distal tubule ot either maintain/get ride of fluid volume

b) there are many diuretics that target distal tubule or loop of henle

15) Transport Functions of the Nephrona) Glucose transportb) Acid Base Balance- secretion of H+, results in HCO3 reabsorption c) Potassium- reabsorbed and secretedd) H20- follows Na in PT & DT, is independently regulated by ADH in

collecting tubule, gradient set up by loop of Henle

16) Renal Hormonesa) Erythropoietin stimulates red blood cell proliferation/production

in bone marrow, stimulated by kidney (sensors that recognize low levels of O2 in afferent mechanism) hypoxia (also available as a recombinant protein given as SQ injection)i) when person in state of kidney disease, will have alteration in

RBC count. Need to supplement exogenous injection of erythropoietin for oflks in hemodialysis

b) Atrial natriuretic peptide- secreted from cardiocytes in the right atruim when R atrial blood pressure increases. Inhibits sodium absorption in the collecting duct, increasing urine formation, thus

decreasing blood volume and blood pressurec) Hydroxylation (activation) of Vitamin D precursors -- what will

happen to Ca in renal failure? Without precurors, cant create vit D after being exposed to sunlight. Without D, cant absorb Calcium.

d) Inactive Vitamin D is synthesized by the action of ultraviolet radiation on cholesterol in the skin (face and hands)i) Since vitamin D is needed for the absorption of calcium, if

renal disease exists, calcium levels will adversely be affected.

17) Functional Testsa) Urinalysis b) BUN/Cr (blood urea nitrogen/ creatinine) need to take a sample

of someones blood.i) Cr is a by product of muscle metabolism (in steady state

produced and lost at constant rate) Blood levels depend on Glomerular Filtration Rate (rise as GFR decreases)

ii) dont want nitrogenous wastes circulating through blood cause youll go cookoo.

c) Creatine Clearance a measure of GFRd) Intravenous pyelograms (IVP) closer look. Insert radio-opaque

dye to visualize each kidney and how it uptakes dye or not uptaking dyei) pictures with radio-opaque dye

e) Ultrasound, CT, MRIf) Biopsy

18) Polycystic Kidney Diseasea) Cysts develop in nephron - polycystic kidneys enlarged fluid filled

spaces(a)either very young or older adult, cycst begin to grow in

nephron.(b)Polycystic kidneys have very large fluid-filled spaces

(i) puts pressure on surrounding tissue and can cause damage

b) Two types separated by genetic types that create themi) autosomal recessive: seen in chidlrenii) autosomal dominant: seen in adults

a) recessive manifests in children, dominant in adults 30 - 40c) Sx: flank pain (assessed through phys exam), urinary tract

infections, hematuria leading to chronic renal failurei) need of nephrons damaged to show any renal abnormality

19) Infection and Inflammationa) Pyelonephritis pussie neprons. inflammation of the renal pelvis

i) acute - usually from a bladder infection. Backs its way up into

kidney. recover if treatedii) chronic comes and goes. often from obstructive disorders;

leads to renal failure

b) Glomerulonephritis - inflammation of glomerulii) Acute - abrupt onset hematuria, proteinuria (proteins in urine)

with decreased Glmerular Filtration Rate (increased serum BUN/Cr). often secondary to infection or immune process (SLE, could be autoimune)

ii) Chronic comes and goes. hematuria, proteinuria with progressive decline in GFR, often autoimmunea) nephrons are super fragileb) blindness is super common side effect of diabetes as

retinal cells also super fragile and neurons in periphery also damaged easily in long-term uncontrolled diabetes

c) Kidney stonesi) Kidney Stones (renal calculi)ii) Crystallized material (Most are calcium crystals) forms in renal

calyces and pelvis; sometimes descend thru ureters iii) Cause not completely understood: decreased inhibitors in

urine? High concentrations of stone-forming substances? Gout causes uric acid stones

iv) Occur symptomatically in 1% of populationv) Often recurvi) VERY painful when they stretch ureter, obstruct flow. Shaped

with barbs. Bloody ureter. Urine gets backed up to kidney system.

vii) Sx: severe pain in flank or groin, hematuriaa) Narcotic analgesia for acute attackb) lithotripsy to break up stones (invasive snake the runs up

and pounds it down to sand)c) Prevent new one from forming (dilute urine, dietary

changes)

20) Kidney stones get lodgeda) Minor and major calyces and in ureter

21) More Obstructive Disordersa) Caused by

i) benign prostatic hyperplasia (prostate is growing and getting too big that its almost obstructing the urethra. Not cancerous.)

ii) early sx: cant write name in snow. Weakened flow. iii) neuro or muscular problems (more rare)

iv) other causes (congenital: may need surgery)b) Consequences:

i) depends on site of obstruction (think about physiology of obstruction and know anything behind obstrucxn will have prob)

ii) urine backs up: hydroureter (fluid fills in ureters, will be seen on ultrasound or xray) or hydronephrosis (fluid in kidneys. Cant funxn right)

iii) kidneys cant functioniv) infection common if chronic

22) Urinary Tract Obstruction

23) Urinary Tract Infectiona) Usually bacterial, most commonly E.Coli and other GI inhabitants

(wiping from front to back in female gentilia)b) Staphylococcusc) How do the bacteria get into the urinary tract? sexd) Who is most at risk of UTIs and why? Elderly women (wipe from

back to front) and sexually active owmen. Due to close

proximity. e) Cystitis is Inflammation of the bladder (infection, irritation from

stones, trauma, chemical irritants)f) Symptoms - frequency, urgency, dysuria (painful urination),

lower back pain, cloudy urine, hematuria, elderly may be asymptomatic

g) Diagnsed by Urine Analysis /Culturei) Bacterial infection- most common cause E coli bacterium

needs antibiotic ii) Recurrent (< 6 months apart) are cause for more concern

24) Extensive Urinary Tract Infectiona) Pyelonephritis= infection has ascended to renal pelvis, much

more seriousi) all of cystitis symptoms, plus febrileii) acute onset of fever, chills, flank or groin pain (test for

costovertebral angle tenderness thru physical assessment)iii) UA/cultureiv) often requires IV antibiotics

25) Nephrotic Syndromea) Increased permeability of the glomerular basement membrane to

proteinb) Collection of Symptoms simply defined with primary symptom

of proteinuria (>3.5 g/day).c) Characteristic of glomerular injury.d) Leads to hypoalbuminemia, hyperlipidemia, edema,

hypercoagulability, altered immunity, lipiduria (fat in urine) (all these symptoms compound are why its called a syndrome)

26) Renal Failurea) Decrease in renal function that is potentially reversibleb) Acute Renal Failure generally reversible

i) Classified by causesa) Prerenal related to decreased renal blood flowb) Post renal related to outflow obstructionc) Intrarenal nephron damage

27) Chronic Renal Failure (need hemodialysis)a) Progressive, predictable loss over months to years not

reversibleb) Final stage ESRD (End Stage Renal Disease)

28) Acute Renal Failurea) Pre renal prevent by keeping well hydrated, maintain BP high

enough, give low dose dopamine to increase renal blood flow and perfuse glomerulus

b) Acute tubular necrosis (damage to inside of nephron) an intrarenal cause i) Few cells actually die but may become non functional for a

whileii) Tubule cells provide a poor barrier between filtrate and

interstitual space and filtered fluid leaks back into interstitumiii) Recovery 2 weeks to up to 12 months (sometimes never

becomes chronic)c) Post renal prevent or treat obstruction

29) Phases of Acute Renal Failurea) Oliguric - urine output < 400 cc/dayb) Diuretic dilute urine (low specific gravity) in normal to > normal

amountsc) Kidneys cant concentrate anymore. What goes in comes out

quick. d) Recovery phase renal function adequate to avoid dialysis, but

not up to normal (renal insufficiency).e) Cr increases, BUN increases in blood (azotemia)f) When azotemia (and other waste products) causes symptoms =

uremia (fatigue, anorexia, N & V, pruritis [urine trying to excrete through skin. Causes itchy. uremic frost], neurologic changes)i) -Chronic condition when someone has higher concentration of

uric acid in bloodii) -Put pt on dietary restricxn. Ie. Less protein so less

nitrogenous wastes.

30) Prevention/ Treatment of ARFa) Increase renal blood flow with:

i) Diuretics such as furosemide (loop diuretics), mannitol (osmotic diuretic. Pulls fluid out of vasculature and out of body. Causes severe dehydration)

ii) Low dose dopamine iii) Natriuretic peptideiv) TEMPORARY DIALYSIS

31) Chronic Renal Failurea) Causes 50% of folks with it, ESRD, is due to 2ndary to diabetes?

b) Stagesi) Decreased renal reserve Cr high end of normal no symptomsii) Renal insufficiency 75% of nephrons damaged, Cr, BUN

elevated but not much, polyuria, nocturia iii) ESRD 90% of nephons destroyed hypervolemia,

hyperkalemia, hyperphosphatemia, metabolic acidosis, uremia, hypocalcemia and osteodystrophy with osteoporosis (due to non-ability to deal with Vit D), anemia

32) Prevention/ Treatment of ESRDa) Tight glucose control in diabetics

i) Use hemoglobin A1C to test below limitsb) Dietary restrictions low protein, usually restrict PO4, K, Na (due

to fluid overload), supplement calcium, vitamin Dc) Transplantation (if young enough)d) Dialysis (if not young enough for transplantation. No end to it.

Once start, its everyday. Go until done, when die quickly)

33) 2 Types of Dialysisa) Hemodialysis AV shunt for access, blood pumped through array

of semipermeable membranes surrounded by dialysateb) Peritoneal Dialysis dialysate placed into abdominal cavity

(peritoneum) and drained out by gravity flow, peritoneal membrane acts as filter. Placed on this when cant handle hemodialysis. Not long term. Dont wan to put in AV shunt if dont have to. Uses peritoneal cavity as filter

34) Complications of ESRD/Dialysisa) Osteodystrophy (defective bone development) stimulation of

Parathyroid Hormone by high PO4 circulation results in activation of osteoclasts, Ca resorption (removal)i) Eventually over time occurs.

b) Anemia loss of erythropoietin, hemodialysis causes RBC damage, now use Epogen, Hematocrit ct in low 30 are routine (adult usually in 40s)

c) Peripheral neuropathiesd) INFECTIONS vascular access or peritonitis. Over time risks

increasee) Anorexia & weight loss diet restrictions + hypermetabolism

35) Review of Bladdera) Sac for urine collection

i) Surrounded by smooth muscle under parasympathetic controlii) Two ureters enter from kidneys, one urethra exits to outside,

urethra has internal sphincteriii) External urethral sphincter is under voluntary control

36) Bladder Disordersa) Bladder Cancer

i) more common in men, ii) hematuria: irritable bladder type issue

b) Voiding Dysfunction (incl. urinary incontinence)i) Common especially in women (20%)

37) 6 Types of Incontinencea) Urge involuntary bladder contractions. Person at rest and then

all of a sudden, have to go. Its a spasm. b) Stress weak pelvic muscle floor. Urethra and sphincter

weakened. Encourage kegel excersizes. c) Mixed combination of urge and stressd) Overflow dribbling. continuous escape of urine caused by

partial obstruction (prostatic hypertrophy)e) Functional diagnosis when others fail. Dont really know reason

but its not psychiatric.f) Reflex no sensory warning or awareness, neuro

38) Treatmentsa) Behavioral often nursingb) Bladder training, pelvic muscle strengthening exercises (Kegel)c) Pharmocologic d) anticholinergic agent, estrogene) Devicesf) Urethreral plugs, Vaginal rings, Padsg) Surgicalh) variety depending on problem