Flashcards in Ch 7 Urinary Function Deck (155):
what are the functions of the urinary function?
regulates fluid volume, blood pressure, metabolic waste and drug excretion, vitamin D conversion, pH regulation, and hormone synthesis
where are the kidneys located?
in the retroperitoneal space
connective tissue surrounding the kidneys
the area directly beneath the renal capsule that contains the functional units of the kidney, the nephrons
supplies the kidney with blood
the opening in the kidney through which the renal artery and nerves enter and the renal vein and ureter exit
what the central portions of the renal sinus enlarge to form. urin drains into the renal pelvis through tubes called calyces
what do calyces drain urine into?
what do ureters do?
transport urine to the bladder using peristaltic actions
what are the functions of the kidneys?
eliminate waste from the blood; help regulate body water concentration; help regulate blood pressure; help maintain a constant blood pH
what is the function of the urinary bladder?
stores urine; contracts to eliminate stored urine
what is the function of the urethra?
transports urine to the outside of the body from the urinary bladder
what gives us the urge to urinate?
as the volume of urine in the bladder increases, the urine exerts pressure on the two bladder sphincters and stretch receptors of the bladder. a pressure of 200-300 mL on the sphincters and receptors sends messages to the brain, triggering the urge to urinate
what occurs when urination is initiated?
the bladder contracts and the external sphincter relaxes, forcing urine out through the urethra
how long is the urethra in females? how long is it in males?
approximately 1.5 inches long in women and about 6-8 inches long in men
what things make a woman more susceptible to urinary tract infections than men?
shorter urethra, in combination with sitting for urination
similar to a funnel with a long stem. contains multiple sections and each section is responsible for excreting or reabsorbing specific substances
how many nephrons are in one kidney?
the proximal convoluted tubule enlarges into a double membrane chamber called...
Bowman's capsule surrounds a cluster of capillaries called...
this determines the amount of urine made and is necessary for healthy renal function
the blood supply to the glomerulus
what is the glomerular filtration rate (GFR)
the speed at which blood moves through the glomerulus
what is normal GFR and normal urine output?
urine output ~1500mL/day
what are the three most significant metabolic wastes that the kidneys manage?
ammonia, uric acid, and urea
a highly toxic chemical that results from the breakdown of amino acids in the liver
why does amino acid breakdown generally occur?
in the presence of excess protein or deficient carbs in the diet
when amino acids are broken down and the amino groups are stripped from the molecules
how is urea formed?
amino acids are broken down and the amino groups are stripped from the molecules, these amino groups are converted to ammonia following deamination and then most of this ammonia is converted to urea in the liver
how does liver disease affect urea production?
it can impair the production of urea because it makes urea from ammonia, so liver disease can lead to high levels of ammonia in the blood
what does uric acid production result from? what is it a by-product of? and what can excess levels lead to?
the breakdown of nucleotides. by-product of metabolism in the liver. excess levels can lead to gout, which results in uric acid crystal deposits in the joints
aside from ammonia, urea, and uric acid, what are other elements normally found in the urine?
sodium, potassium, and small amounts of protein and bacteria
the kidneys are responsible for converting which vitamin to its active form?
what does vitamin D do when it is in its active form?
aids in calcium and phosphorus absorption
how do the kidneys regulate pH?
by secreting bicarbonate and excreting hydrogen
what do the kidneys release in response to hypoxia? what does this do?
release erythropoietin. this stimulates the bone marrow to produce more red blood cells. if iron levels are adequate, an increase in red blood cells increases oxygen-carrying capacity, thus decreases hypoxia
what can happen when the aging individual experiences less filtration capability?
this may lead to waste accumulation and loss of homeostatic regulation
why may an aging person require an alternative medicine dose?
they may need a smaller dose, or doses spaced further apart to prevent drug toxicity because of impaired filtration
what affect does increased ADH levels have on the kidney?
collecting ducts and distal convoluted tubules become permeable to water; water moves out of the ducts and into the blood
what affect does decreased ADH levels have on the kidneys?
collecting ducts become impermeable to water; water is not reabsorbed from the filtrate and is excreted
what affect does increased aldosterone levels have on the kidneys?
tubules increase reabsorption of sodium from the filtrate and decrease reabsorption of potassium; water and sodium thus move from filtrate into the blood, and excess potassium is excreted
what affect do decreased levels of aldosterone have on the kidney?
tubular absorption of sodium and potassium is normal; water is not reabsorbed from the filtrate and is excreted
conditions that alter urination may include what two things?
structural barriers or problems with the act of urination
conditions that impair renal function include what disorders?
those that prevent the kidney from regulating fluid and electrolytes as well as excreting waste products or other substances
what things does the act of urination require?
a functioning bladder with stretch receptors to sense the filling of urine, an intact parasympathetic pelvic nerve to transmit the signal, and working detrusor muscles to initiate bladder contractions to expel the urine
what things prevent inappropriate urination?
sympathetic innervations to the detrusor muscle and the internal sphincter
how can upper motor impulses delay voiding?
by tightening the urethral sphincter
what will happen if the urge to void is ignored too long?
bladder contractions take over the neural delaying mechanism and involuntary urination occurs
any infections that begin in the urinary tract
urinary tract infections
what part of the urinary tract is the most frequent site for infection?
the lower urinary tract - bladder and urethra
what are UTI caused by? what is the most frequent cause?
they are caused by a direct invasion of the urinary tract by bacteria. most commonly caused by bacteria from the digestive tract - E. coli
why is urine an excellent medium for microorganism growth?
because of its protein content
what mechanisms does the urinary system have to prevent infection?
one-way valves where the ureters attach to the bladder; urination, which washes microbes out of the body; prostate secretions that slow bacterial growth in men; and the immune system
what are the two ways that bacteria can invade the urinary system?
through the urethra, ascending into the urinary tract. but occasionally it can invade the kidneys through the blood
why are women more vulnerable to UTIs than men?
they have shorter urethras so the microorganism has a shorter distance to travel, women usually urinate in a sitting position which prevents full emptying of the bladder, women may experience increased perineal tissue irritation from sexual activity, bubble baths, bathing suits, tight-fitting clothing, and deoderants, as well as nylong, lace, and thong underwear
why are men likely to have a recurrent UTI?
bacteria can hide deep inside the prostate tissue
what are some risk factors for developing UTI?
being a woman, benign prostatic hypertrophy, congenital urinary tract abnormalities, immobility, urinary or bowel incontinence, renal calculi, decreased cognition, pregnancy, impaired immune response, impaired nerve innervations, urinary cathetarization, improper personal hygiene, using a diaphragm or spermicide for birth control, using unlubricated condoms
how does benign prostatic hypertrophy contribute to causing a UTI?
causes urinary retention
how does congenital urinary tract abnormalities cause UTIs?
alter urinary flow
how does immobility cause a UTI
prevents complete bladder emptying, leading to urinary stasis
how does urinary or bowel incontenence contribute to the developement of a UTI?
can increase the potential for contamination of the urinary meatus
how do renal calculi contribute to the development of a UTI?
obstruct urine output, leading to urinary stasis
how does decreased cognition cause UTI?
increases the risk for incontenence and toileting issues
how does pregnancy cause UTI?
the growing uterus puts pressure on the bladder, impairing urinary flow
how does urinary catheterization lead to UTI?
breaks the first line of defense, the most common source of nosocomial infection
how does using a spermicide or diaphragm for birth control increase risk for UTI?
increases bacterial growth
how does using an unlubricated condom increase risk for UTI?
when present, what are the clinical manifestations of UTIs?
urgency, dysuria, frequency, hematuria, bacteriuria, cloudy foul-smelling urine, symptoms of infection
inflammation of the bladder
what happens during cystitis?
inflammatory response in which the walls of the bladder and urethra become red and swollen. it is usually initiated my infection, but irritants can occasionally activate the inflammatory response.
what are the clinical manifestations of cystitis?
in addition to the manifestations of UTI, they also have abdominal pain and pelvic pressure
an infection that has reached one or both kidneys.
how can the infection reach the kidney in pyelonephritis?
usually it ascends from the lower urinary tract, but it can also gain access from the blood stream
what are some risk factors for the development of pyelonephritis?
same as UTI, people who require frequent medical attention, experience recurrent UTIs, or have contracted an antibiotic resistance bacterial strain.
what happens to the kidneys in pyelonephritis? what can this lead to, and what can result?
they become grossly edematous and structures fill with exudate, compressing the renal artery. abscesses and necrosis can develop, imapairing renal function and causing permanent damage.
what are the manifestations of pyelonephritis?
usually UTI manifestations, but are more severe and include flank pain and increased blood pressure (hypertension)
blockage in the urinary tract that keeps the flow of urine from progresssing, however the kidneys keep producing urine and so the urine keeps backing up
urinary tract obstructions
what are the results of urinary tract obstructions?
hydroureter and hydronephrosis
when urine accumulates in the ureters
when urine is backed up into the renal pelvis of the kidney
what can hydronephrosis cause?
distention of the renal pelvis, and can cause damage to the kidney
what are the manifestations of urinary tract obstructions?
flank pain, may develop UTI, pyelonephritis (specifically if the obstruction is in the kidney)
the presence of renal calculi
hard masses of crystals composed of minerals that the kidneys normally excrete
the most common cause of urinary obstruction
how large are renal calculi?
they can vary in size from as small as a grain of sand to as large as a golf ball
who are calculi more common in?
males and caucasians
where do calculi usually form?
renal pelvis, ureters, and bladder
what are the normal characteristics of calculi?
they can be either smooth or jagged, and are usually yellow or brown
what things have to happen to form a calculi?
have to have too much of a substance (supersaturization) and it must precipitate out, crystalize, and start to go
in the healthy individual, these are chemicals contained in the urine that prevent crystals from forming
what could be a reason the south is the 'kidney stone belt'
high humdity and high temperatures cause sweat which decreases the urine volume, stuff stays and precipitates out of the urine
what are conditions that increase the likelihood of calculi forming?
pH changes, excessive concentration of insoluble salts in the urine, and urinary stasis. family history, obesity, hypertension, high protein high sodium or low calcium diet
what is a good way to prevent the formation of kidney stones?
stay adequately hydrated
why should you push fluids on a person with kidney stones?
the ureters will dilate and help push the stones out
what are the types of kidney stones and how common are each?
calcium is the most common 70-80%, struvite stone may occur during an infection 15%, uric acid may be caused by gout 7%, cystine stone is rare and has to do with alterations in patients metabolism - less than 1%
what are the manifestations of kidney stones?
renal colic - flank pain and costovertebral angle tenderness, nausea/vomiting due to pain, hematuria, dysuria, frequency, fever/chills due to infection; blood, cloudy, or foul smelling urine; genital discharge
when do manifestations of kidney stones present?
when they obstruct urinary flow
moderate to severe pain that occurs in periods of 20-60 mins
how do you assess for costovertebral angle tenderness?
take 12th rib and spinal column and that makes an angle that puts you over the kidney. percuss over the kidney and if it is inflammed, the percussion hurts
what is the most common type of tumor in the urinary system?
malignant, benign tumors are rare
rare kidney cancer that primarily affects children. usually grows as a solitary mass that can become quite large. a second tumor may appear in the remaining kidney later.
Wilm's tumor or nephroblastoma
what is the peak incidence of Wilm's tumor?
around 3-4 years
what is thought to be the cause of Wilm's tumor?
exact cause is unknown, but it is though to arise in utero when the cells that normally form the kidneys fail to develop properly. Most commonly it has been associated to genetic mutations on chromosome 11 and the X chromosome
how can Wilm's tumor occur?
spontaneously or as the result of genetic changes
what does wilm's tumor often occur in conjunction with?
several congenital defects: aniridia, hemihypertrophy, and urinary tract abnormailities
what are the risk factors for the development of Wilm's tumor?
tends to run in families, higher in females and African Americans
what are the clinical manifestations of wilm's tumor?
asymptomatic abdominal mass, high blood pressure, hemihypertrophy, hematuria, UTI, abdominal pain, nausea and vomiting, anorexia, bowel pattern changes, weight loss, fatigue, vague abdominal pain
the most frequently occurring kidney cancer in adults. a primary tumor arising from the renal tubule
renal cell carcinoma
what are risk factors for the development of renal cell carcinoma?
being male, dialysis, family history, hypertension, other kidney disease, and smoking, and african american
metastasis to what organs is common with the diagnosis of renal cell carcinoma?
liver, lungs, bone, or nervous system
what are the manifestations of renal cell carcinoma?
it is usually asymptomatic in its early stages; painless hematuria (gross or microscopic), abnormal urine color, dull achy flank pain, urinary retention, palpable mass over affected kidney, unexplained weight loss, anemia, polycythemia (tumor could secrete erythropoietin or a substance like it), hypertension, paraneoplastic syndromes such as hypercalcemia or Cushing's syndrome, fever
what is bladder cancer? what are most bladder cancers?
bladder cancer is any cancer that forms in the tissue of the bladder. there are many types, but most are transitional cell carcinomas
what are risk factors for the development of bladder cancer?
smoking, occupational exposure (those who work with chemicals), chronic bladder irritation/infection, age (older patients), males, caucasians, family history or personal history of bladder cancer, excessive use of analgesics, experience recurrent UTIs, long-term catheter placement, recieved chemotherapy or radiation
is bladder cancer considered recurrent?
what are the manifestations of bladder cancer?
painless hematuria - gross or microscopic, abnormal urine color - dark, rusty, or brown, frequency, dysuria, urge incontinence, UTIs, back or abdominal pain (flank pain)
with bladder cancer, metastasis is common to what organs?
pelvic lymph nodes, liver, and bone
common, nonmalignant enlargement of the prostate gland that occurs as men age, usually appearing by age 50
benign prostatic hyperplasia/hypertrophy (BPH)
what causes BPH?
the exact cause is unknown, but it is though to be caused by declining testosterone and increasing estrogen levels that care thought to cause prostatic stromal cell proliferation. a second theory is that stem cells in the prostate do not mature and die as programmed (apoptosis)
why can BPH become a problem?
as the prostate expands, it presses against the urethra like a clamp on a hose and this obstructs urinary flow, leading to urinary stasis and UTIs. the bladder wall becomes thick and irritated as urine overfills and the bladder begins to contract with even small amounts of urine, and over time loses its ability to empty completely
what do the severity of the symptoms of BPH have to do with?
the size of the prostate
what are the manifestations of BPH?
frequency, urgency, urinary retention, difficulty initiating urination, weak urinary stream, dribbling urine, nocturia, bladder distention, overflow incontinence, erectile dysfunction (usually related to medications and treatments)
inherited disorder characterized by numerous, grape-like clusters of fluid-filled cysts in both kidneys. these cysts enlarge the kidneys while compressing and eventually replacing functional kidney tissue. the exact trigger for this disease is unknown
polycystic kidney disease (PKD)
type of PKD that occurs in children and adults, but is much more common in adults. its symptoms often do not emerge until middle age, and it has been linked to the short arm of chromosomes 16 and 4
autosomal dominant PKD
how is autosomal dominant PKD usually discovered?
on accident during another exam
type of PKD that appears in infancy or childhood, tends to be extremely serious and progresses rapidly, ending in renal failure and generally causing death in infancy or childhood. Less common of the two.
autosomal recessive PKD
what do the manifestations of PKD depend on?
persons age and type of PKD they have
pronounced epicanthic folds, pointed nose, small chil, and floppy low-set ears
what are the manifestations of PKD in neonates?
potter facies, large bilateral symmetrical masses on the flanks, respiratory distress, uremia
what are the manifestations of PKD in adults?
hypertension, lumbar pain, increased abdominal girth, swollen tender abdomen, grossly enlarged palpable kidney
what are the manifestations for both neonates and adults with PKD?
hematuria (due to impiared glomerular filtration), nocturia (related to an inability to concentrate urine), drowsiness (because of waste accumulation)
what are the manifestations of glomerular disease?
proteinuria, hematuria, reduced GFR, hypoprotinemia, edema
why does edema occur with glomerular disease?
the glomerulus allows more things to be filtered out into the urine and lower than normal levels of protein in their blood makes it difficult for fluid to stay in the vessels and allows it to push out into the tissues
what is a good way to detect proteinuria?
lots of bubbles in the urine that stay there
bilateral inflammatory disorder of the glomeruli that typically follow a streptococcal infection. these inflammatory changes impair the kidneys ability to excrete waste and excess fluid. can be acute or chronic
what are risk factors for developing glomerulonephritis?
being male, immunodeficiency, the presence of chronic inflammatory conditions
this is a leading cause of chronic kidney disease in the US
what things can cause glomerulonephritis?
immunlogic abnormalities, systemic and vascular diseases, durgs and toxins
the kidney's inability to function adequately, classified as either acute or chronic
sudden loss of renal function that is generally reversible and more common in critically ill, hospitalized patients
acute renal failure (ARF)
how quickly can ARF develop?
48 hours to weeks
what are some causes of ARF? what is each?
prerenal conditions - there is something going on in the body before the kdieny. usually has to do with blood flow
itrarenal conditions - something is going wrong inside the kidney itself. inflammation.
postrenal conditions - conditions that interfere with urination
what are things that can cause prerenal conditions?
extremely low blood pressure or volume (hemorrhage, sepsis, shock, traumatic injury)
heart dysfunction (myocardial infarction and heart failure)
what are some things that can cause intrarenal conditions?
reduced blood supply within the kidneys - atherosclerosis
hemolytic uremic syndrome
what are things that can cuase postrenal conditions?
ureter obstructions and bladder obstruction or dysfunction
what are risk factors for the development of ARF?
advanced age, autoimmune disease, liver disease
how many phases does ARF progress through? what are they?
asymptomatic phase - patient has no symptoms
oliguric phase - less than 400 mL of urine a day (about 60/hour) dialy urine output decreases and waste products accumulate in the body
diuretic phase - daily urine output reaches about 5L
recovery phase - glomerular filtration returns to normal
what are the clinicla manifestations of the oliguric phase of ARF?
decreased urine output, electrolyte disturbances, fluid volume excess, azotemia, metabolic acidosis
what are the manifestations of the diuretic phase of ARF?
increased urine output, electrolyte disturbances, dehydration, hypotension
gradual loss of renal function that is irreversible, nonoperational scar tissue replaces injured nephrons
chronic renal failure (CRF)
what conditions can initiate the slow progressive destruction of the nephrons with CKD?
diabetes mellitus (leading cause in US), hypertension, urine obstructions, renal diseases, renal artery stenosis, ongoing exposure to toxins, sickle cell disease, SLE, smoking, aging
how many stages are there in CKD? what is the GFR with each stage?
Stage I - kidney damage present, GFR normal or high (+90)
Stage II - 60-89
Stage III - 30-59
Stage IV - 15-29
Stage V - renal failure when the GFR drops to below 15, or the patient begins dialysis
when do clinical manifestations begin to appear with CKD?
slowly, when renal function declines by 50%
why can the kidneys remain functioning normally for so long, even with decreased GFR?
the surviving nephrons hypertrophy and increase their rate of filtration, reabsorption, and secretion.
what happens with CKD? what abilities does the kidney lose?
waste products begin to accumulate and eventually the kidneys lose the baility to concentrate the urine, maintain blood pressure control, and secrete erythropoietin. multiple systems are affect as those changes develop. these complications worsen as the renal function declines