Urinary Flashcards
Physiology of the Urinary System: Renal function Filtration: Reabsorption: Secretion: Regulation of Urine Volume:
Filtration: of blood into tubules (nonselective: driven by fluid pressure (hydrostatic BP), we lose things we want)
Reabsorption: tubules in the blood (selective: a lot of water, ALL the glucose, Na+ (SODIUM FOLLOWS WATER))
Secretion: blood into tubules (selective: nitrogenous waste- ammonia, H+ (pH), K+)
Regulation of Urine Volume: through ADH, ANH, aldosterone
How much blood is filtered though the kidney?
What is the signif. of this?
20-25% of blood is filtered though the kidney/ min
Shows the importance of a MAP of 60 b/c if it is too high it can cause damage; too low and blood does not get filtered
muscle which forms a layer of the wall of the bladder:? Stimulated by?
Detrusor contraction is triggered by parasympathetic
A triangular area, formed by three openings in the floor of the urinary bladder.
What can occure here?
Trigone: most common place for bladder infection
What is the purpose of pyramids and medulla in the kidney? Renal papilla?
How does dehydration effect this system?
- purpose of pyramids and medulla is to concentrate
urin. Drives the flow of urine
-During dehydration- Fluid becomes more concentrated and thus the more water try to retain in the body
-Renal papilla: where urine flows out of the
pyramids into the cavity
Nephron- The functional unit of the kidney:
Juxtamedullary
Cortical
- Juxtamedullary: long loops of Henle create more concentrated urine more often used during dehydration
- Cortical: shorter loops of Henle
Renal corpuscle consists of what 2 structures?
Glomerulus: ball of filtering tubules
Bowman capsule: surrounds Glomerulus, double membrane
Glomerular filtration membrane (3 layers)
Capillary endothelium
Basement membrane
Capsular epithelium- Filtration Slits
Glomerular filtration membrane: Capillary endothelium Basement membrane Capsular epithelium Filtration Slits
1- Capillary endothelium: outter layer of the capillaries, congruent with basement membrane (innermost of these 3 layers)
2- Basement membrane: inner layer of Bowman’s capsule (the part of the ballooon material touching your fist)
3- Capsular epithelium: Surrounds basement membrane and contains:
-Filtration slits:
(like a colander) collects CELLS which are too large to fit epithelium; and PROTEINS that we do not want to pass into urine. Proteins are small enough to fit through the epithelium but via a shared negative charge they are repealed (like charges repel)
Filtrate passes through the three layers and forms the primary urine
Juxtaglomerular apparatus (JGA): where is it located in the nephron function
Consists of the distal tubule (macula densa cells) and where it touches the afferent arteriole coming out of the glomerulas.
-detects changes in blood flow and pressure to the body system
Macula densa (MD) what that are/ located function
Are cells located in the distal tubule where it touches the afferent and efferent arterioles coming out of the glomerulas.
They detect changes in Pressure (BP) and Na+ (osmotic pressure) from the afferent arteriole.
If BP and Na+ decrease that triggers the activation of JG
Juxtaglomerular (JG) cells
what it is/ located
function
Cells between the afferent arteriole and the MD
Renin secretion (RAAS): which regulates the body’s water balance and BP level
Renal tubules: Proximal tubule Loop of Henle Distal tubule Collecting duct
Proximal tubule: primary site for reabsorption of Na+, 100% glucose, and water
Loop of Henle: reabsorbs the rest of water and Na+ via concentration
Distal tubule: secretion of hormones, gets rid of H+, ammonia, K+
Collecting duct: Water and; ECV regulation…reabsorb H20/Na+
pH regulation …HCO3- and H+
Regulation of Urine Volume (3 hormones)
RAAS
ADH
Natriuretic peptides (ANH)
Function of:
RAAS
ADH
Natriuretic peptides
Renin Aldosterone Angiotensin system (RAAS): works to maintain a low blood volume low BP state in the body.
-starts with the release of renin in kidneys
ADH: pulls water back into blood stream
Natriuretic peptides: promote water and Na+ loss to help lower blood volume and pressure (works opposite from RAAS and ADH)
Function of Filtration
Hint: after afferent, before efferent
Movement of water and protein-free solutes from the blood plasma of the glomerulus (Filtration slits stop cells and proteins from passing into urine)
Across the glomerular capsular membrane into space of Bowman’s capsule
The NFP is determined by the 4 different concentration gradients / pressures that exist in the kidney:
Net Effective Filtration Pressure:
- GHP (glomerular hydrostatic pressure)
- GOP (glomerular onoctic pressure)
- CHP (capsular hydrostatic pressure)
- COP (Capsular Osmotic Pressure)
Equation for:
NFP
NFP = GHP – (Glomerular OP + Capsular HP)
GHP must be > than GOP + CHP (why we need MAP >60)
- GHP (glomerular hydrostatic pressure)
- GOP (glomerular onoctic pressure)
- CHP (capsular hydrostatic pressure)
- COP (Capsular Osmotic Pressure)
- Obstruction
- GHP (glomerular hydrostatic pressure): Systemic blood pressure and resistance in the glomerular capillaries. Pressure that drives out of blood into sac. Decreasing GFR
- GOP (glomerular onoctic pressure): pull of fluid back into glomerular driven by albumin
- CHP (capsular hydrostatic pressure): push of fluid out of capsule
- Capsular Osmotic Pressure: negligible amount (b/c no proteins in the capsule to attract osmotic pressure)
- Obstruction that causes fluid to back up, can cause a reduction of filtration (resulting in kidney stones)
GFR
what it is
what its rate is changd by (2)
Glomerular Filtration Rate (stable)
GFR is the rate of movement of fluid out of the glomerulus and into the capsular space.
GFR is directly proportional to the NFP but can also be changed by:
- Vasodilation / vasoconstriction of the afferent and efferent arterioles
- Changes in Systemic Blood Pressure
We want GFR to be stable over time, but BP is always changing. How is vasoconstriction/ dilation used to maintaine stability?
BP decreases= afferent dilates, efferent constricts
BP increases= afferent constricts, efferent dilates
Reabsorption:
what it is
what is being absorbed
where is absorption happening
Tubular reabsorption is the movement of ions out of various segments of the tubule back into the blood
Water, electrolytes, glucose, amino acids
Via the peritubular blood vessels (travel alongside nephrons allowing reabsorption and secretion between blood and the inner lumen of the nephron)
How does reabsorption take place?
As the filtrate moves through the renal tubule, the concentration of the filtrate changes.
As it moves deeper into the medulla, the osmolarity (concentration) increases, and when it ascends the loop of Henle, it decreases, then once again increases while going down the collecting duct.
This “roller coaster” drives the concentration of urine and the reabsorption of Na+ and water back into blood.
What allows for passive transport of water and Na+?
What is Countercurrent Exchange
The hyperosmotic condition in the medulla (desending loop of Henle)
Hyperosmotic: hyper=“excessive,” and osmos= “push”
Countercurrent Exchange: reabsorption of H2O. Transport of NaCl (without water) in the thin and thick ascending limb of the loop of Henle
Secretion
what it is
what is secreted
Tubular secretion is the movement of substances from the peritubular blood and renal tissues into the renal tubule for removal in urine
Secretion of H+, K+, NH3/NH4+, urea
Concentration and Dilution of Urine (5)
Urea Aldosterone Antidiuretic hormone (ADH) Natriuretic peptides (ANH and others) Diuretics
Urea Aldosterone Antidiuretic hormone Natriuretic peptides Diuretics: increase urine output and thus dilution
1- Urea: nitrogenous waste, ALSO important for regulating urine function
2- Aldosterone: Pulls Na+ and water from urine back into blood. Urine volume goes down, concentration goes up, blood volume goes up, BP increases
3- Antidiuretic hormone (ADH): works in the DCT and CD to pull water out of urine into blood. Urine volume goes down, concentration goes up, blood volume goes up, BP increases, osmotic pressure increases
4- Natriuretic peptides (ANH and others): promote peeing out Na+ and water. Urine volume goes up, urine concentration goes down, blood volume goes down, BP decreases. Blocks the effects of RAAAASTAA
5- Diuretics: increase urine output and thus dilution
RAAS:
what is stands for
what it does
what it is activated by
Renin-Angiotensin-Aldosterone System
- A multi organ system that comes together to help the body have a low blood volume low BP state in the body.
- starts with the release of renin in kidneys
RAAAASTAA
what it stands for
R- Renin A- Angiotensinogen A- Angiotensin I A- Angiotensin Converting Enzyme (ACE) A- Angiotensin II S- Systemic Vasoconstriction* T- Thirst A- ADH A- Aldosterone*
Acidification of urine:
what is the pH range of urine (what about the body)
Hydrogen excretion for acidosis/ alkalosis
Ammonia excretion- its pH is controled by what
4.6-8.0 (body pH: 7.35-7.45)
Acidosis= increase H+ secretion/ decrease HCO3 Alkalotic= decrease H+ secretion/ increase HCO3
Liver converts into urea, taking away pH nature
Renal hormones (4):
Urodilatin (natriuretic peptide)
Vitamin D
Erythropoietin (EPO)
Renin
What do they do? Urodilatin Vitamin D EPO Renin
Urodilatin (natriuretic peptide)
Inhibits sodium and water reabsorption
lower BV/ BP
Vitamin D
Necessary for the absorption of calcium and phosphate
Erythropoietin (EPO)
Released when decreased oxygen to the kidney
Renin
Tests of Renal Function (3)
Clearance and glomerular filtration rate (GFR): filtration and overall kidney function
Plasma (serum) creatinine concentration
Blood urea nitrogen (BUN)
Clearance and glomerular filtration rate (GFR)-
what it is
filtration and overall kidney function
Creatinine: waste product from muscle metabolism, steadily and regularly moved into the blood throughout the day.
The kidney clears creatinine and is used to measure kidney function.
“Creatinine Clearance Test”
How the is the “Creatinine Clearance Test” done
from urine over 24 hours (refrigerated)= true measurement of GFR.
Want Creatinine Clearance to be higher for normal kidney function b/c it is a waste and want it cleared
(most reflective)
Plasma (serum) creatinine concentration:
What are we looking for
we want Creatinine Clearance to be lower for normal kidney function b/c it has not been filtered yet. (typically measure urine AND plasma
Blood urea nitrogen (BUN):
what it is
what we are looking for
what is the problem with this test
urea is a waste product (from the breakdown of ammonia) in the blood: we want BUN to be lower for normal kidney function
Liver also effects the conversion of ammonia to urea (so liver function/ disfunction will effect results).
Urea also comes from protein metabolism and so excessive consumption of protein supplements or excessive exercise can effect BUN levels.
4 Ways the Urinary System Fails
Obstruction: kidney stones (typically unilateral)
Infection: bacterial infection migration into bladder -or worse into the kidney
Glomerular nephritis: damage and inflammation to our filtration structure
Failure: kidney is not filtering and creating urine
Urinary tract obstruction
what is it
anatomic
functional
is an interference with the flow of urine at any site along the urinary tract
The obstruction can be caused by an anatomic (structural: stenosis, reflex, stones etc.)
functional (enlarged prostate) defect
Upper Tract Obstruction occures where
anything out of the kidney and though the ureter
Hydroureter:
what it is
what it causes
Hydronephrosis:
what it is
what it causes
Hydroureter: The build-up in the ureter.
Dilates ureter and fluid backs up into the kidney leads to….
Hydronephrosis: Excess fluid in the kidney (more concerning).
Fluid dilates the open areas of the pyramids and columns causing a disruption or urine production.
Results in a decrease in GFR b/c of the increase in capillary hydrostatic pressure (CHP)
Increased CHP is caused by the backup of urine in the capsule
Compensatory hypertrophy:
caused by a unilateral upper obstruction (beneficial response/ good!). Or if person has only one kidney.
Post-obstructive diuresis:
caused by upper obstruction, that once removed pt. has an increase in urine output. Shows that the obstruction (typically a stone) has passed!
(think of the hole in the dam)
The proper name for kidney stones
Renal Calculi
structurally what are Renal Calculi
How are they classified (3)
Masses of crystals, protein, or other substances that form within and may obstruct the urinary tract
Kidney stones are classified according to the minerals comprising the stones
- Calcium oxalate or calcium phosphate (most common)
- Struvite stones
- Uric acid (pt. w/ Gout are at higher risk. NO relationship with urea!) and cystine stones
How are Renal Calculi formed
what is the cause
how does it grow
Supersaturation of one or more salts that Precipitates a salt from liquid to solid state.
Caused by urine concentration: caused by diet eg: high calcium, high uric acid, dehydration, dropping body temperature, changes in body pH
Growth into a stone via crystallization or aggregation
Uric Acid Foods:
Organmeats: liver, kidney Sweetbreads Red meat Processed seafood Beer and red wine Sugary foods and beverages Vitamin C Coffee
Renal Calculi Manifestations (3)
- Renal colic
- Dysuria
- Hematuria
- Renal colic
- Dysuria
- Hematuria
- Renal colic (recurrent patters): intense recurrent sever flank pain w/ radiating pain b/c of stone obstruction. most common.
- Dysuria: intense pain with peeing. May cause n/v from and pain
- Hematuria: blood in urine
Renal Calculi Treatment (3)
- High fluid intake (create more urine, increasing pressure and helping to pass stones)
- Decreasing dietary intake of stone-forming substances
- Stone removal (ultrasound, surgery)
Lower Tract Obstruction occures where
anywhere from the bladder to the urethera
Neurogenic bladder:
what it is
cause
Obstruction of bladder outlet or urethra
Urethral stricture, prostate enlargement, pelvic organ prolapse (more common in females)
loss of function of the bladder to contract and move urine out of the body
Dyssynergia
Dyssynergia
what it is
what it cuases (2)
Dyssynergia: CNS damage or disfunction (most common). Loss of command to the smooth muscle of the bladder (detrusor)
- Detrusor hyperreflexia
- Detrusor areflexia
Detrusor hyperreflexia:
Detrusor areflexia:
Detrusor hyperreflexia: muscle of bladder are over activated and contract too early- increased frequency of urination, decreased urine volume
Detrusor areflexia: Loss of reflex by the bladder- Decrease in frequency, increase in volume. May fill to the point of sudden contraction and release.
Who is highest risk for urinary tumors
smokers and older males
Renal tumors (2)
Renal adenomas: uncommon, benign
Renal cell carcinoma (RCC): highly malignant and metastatic
Bladder tumors
what it is
s/s
Gross (huge amount), painless hematuria (blood in urine), benign.
Diff. from bladder infection which is painful.
What is a UTI
Acute cystitis
Acute and chronic pyelonephritis
UTI is inflammation of the urinary epithelium primarily caused by bacteria
Acute cystitis: bladder inflammation
Acute and chronic pyelonephritis: kidney inflammation, -pyelo= pelvis, has spread to pelvis
What is the most common pathogen causing a UTI
Who is more predisposed to UTIs
Most common pathogen is Escherichia coli: b/c most UITs come from the external environment.
This predisposes women to be at higher risk due to a shorter distance from anus to vaginal opening PLUS a short urethra
DM pt. are at high risk b/c of year in the urine (bacteria loves sugar)
Acute cystitis:
what is it
Manifestations
Noninfectious cystitis:
Cystitis is an inflammation of the bladder
Manifestations
Frequency, dysuria, urgency, and lower abdominal and/or suprapubic pain
Cloudy urine (main symptom, due to inflammatory exudate), fever, hematuria also can be common
Noninfectious cystitis: due to viral or autoimmune disease (uncommon)
“blood in urine”
hematuria
Pyelonephritis
what it is
A UTI that generally begins in your urethra or bladder and travels to one or both of your kidneys
Acute pyelonephritis
chronic pyelonephritis
Acute pyelonephritis
Acute infection of renal pelvis and/or kidney interstitium
E. coli, Proteus, Pseudomonas
Common causes: renal calculi, ureteral reflux, pregnancy, neurogenic bladder, catheterization
Chronic pyelonephritis
Persistent or recurring episodes of acute pyelonephritis that leads to scarring: impairs kidney function
Risk of chronic pyelonephritis increases in individuals with renal infections and some type of obstructive pathologic condition
Glomerulonephritis
Glomerulonephritis (primary disorder)
Inflammation of the glomerulus
Effects filtration leading to GFR impairment
Primary glomerular injury
Secondary glomerular injury
Acute vs Chronic
Primary glomerular injury
Isolated inflammatory response in kidney
Secondary glomerular injury
Caused by some other systemic disease
Eg: DM, HTN
Acute (short rapid) vs Chronic (slow continuous, systemic disease- DM, HTN)
Glomerulonephritis
Mechanisms of glomerular injury
Causes (3)
inflammation of the glomeruli
Mechanisms of glomerular injury: ALL BILATERAL b/c systemic conditions= more concerning!
Type III (post strep infection), Type II (Lupus), DM/HTN
Glomerulonephritis
3 causes:
ACUTE: Type III
CHRONIC: Type II and nonimmune
1- Deposition of circulating soluble antigen-antibody complexes, often with complement fragments: Type III hypersensitivity
Often from β-hemolytic streptococcal infection (post strep infection)
2- Formation of antibodies against the glomerular basement membrane: Type II hypersensitivity
Ex. Systemic Lupus Erythematosus
3- Nonimmune (metabolic disorders, toxins, ischemia)
Most commonly from diabetes, and prolonged hypertension
Glomular Disorders
4 outcomes to causes
1- hypertension, edema:
2- elevated blood urea nitrogen (BUN) & creatinine, reduced creatinine clearance
3- Nephrotic Syndrome
4- Nephritic syndrome
What does decreased GFR result in
What is the most common protein…
what does this result in
Increased glomerular capillary permeability and loss of negative ionic charge barrier result in passage of plasma proteins into the urine
The most common protein that passes from urine is albumin
Resulting hypoalbuminemia encourages plasma fluid to move into the interstitial spaces (loss of capillary oncotic pressure- COP)
Decreased glomerular filtration rate (GFR):
1- Demonstrate onset of hypertension, edema: b/c…
2- elevated blood urea nitrogen (BUN) & creatinine, reduced creatinine clearance: b/c…
1- Hypertension, edema: b/c of decreased filtration rate and urine production- fluid and Na+ is staying in the body (edema)- increases pressure in the body (HTN).
2- elevated blood urea nitrogen (BUN) & creatinine, reduced creatinine clearance: b/c of decreased filtration rate and urine production- they are not being moved out of the blood.
Loss of filtration slits: 3- Nephrotic Syndrome what is it what is happening s/s
Excretion of 3.5 g or more of protein in the urine per day (should have none!)
The protein excretion is caused by glomerular injury
s/s severe peripheral edema
4- Nephritic syndrome
(less common)
Hematuria with mild proteinuria
Caused by immune attack against glom. causing injury (infection)
2 types of Renal Failure:
Acute Kidney Injury (AKI)
Chronic Renal Failure (CKD)
AKI
what it is, what has happened
Acute Kidney Injury
-Sudden decline of kidney function
CKD
what is it, what has happened
- Chronic Renal Failure
- Irreversible loss of renal function that affects nearly all organ systems, over a period of time (chronic effects)
GFR declines because of the decrease in filtration pressure
2 possible results
Oliguria: production of abnormally small amounts of urine
Anuria: no urine production
hypovolemic
decreased plasma volume
Acute Kidney Injury:
common cause
Less common cause
What happens with GFR
- Most commonly caused by impaired renal blood flow: most likely due to major blood loss or hypovolemic show that decreases blood flow and BP (MAP).
- Others (less common) include inflammation, obstruction or toxins
- GFR declines because of the decrease in filtration pressure, causing oliguria and anuria
Chronic Renal Failure
causes (4)
Outcomes from the cause (6)
End result
Causes: HTN, diabetes, lupus, other kidney diseases
- Proteinuria and uremia
- Creatinine and urea clearance
- Fluid and electrolyte balance
- Acid-base balance
- Anemia
- Hypocalcemia
Pt. has to go on dialysis, supplement EPO, Vit. D, transplant list. w/o tansplant the pt. will die
Chronic Renal Failure: what is occuring with each of there outcomes? -Proteinuria and uremia -Creatinine and urea clearance -Fluid and electrolyte balance -Acid-base balance -Anemia -Hypocalcemia
- Proteinuria and uremia (increased protein in urine and urine in blood= increased BUN)
- Creatinine and urea clearance (Kidneys are not filtering= decreased clearance)
- Fluid and electrolyte balance (not able to eliminate resulting in imbalance)
- Acid-base balance
- Anemia (EPO in made in the kidney= decreased production)
- Hypocalcemia (low vit. D released by the kidney= decreased calcium production)
