radi 660 gateway 5: urinary system

functions of urinary system

remove waste material, regulate fluid volume/BP, maintain electrolyte concentration, control blood pH, secrete erythropoietin (produces RBCs), secrete renin (BP reg.)

indentation where the renal artery, renal vein, and ureter enter the kidney

hilus

consists of renal corpuscle and renal tubule

nephron

renal corpuscle contains…

glomerulus and bowman’s capsule

renal tubule contains…

proximal convoluted tubule, loop of Henle (descending and ascending limbs), distal convoluted tubule

urine passes from the _ into _ and then _

nephrons; collecting ducts; minor calyces

the _ is located in the glomerulus and has modified cells where it is close to the loop of Henle; secretes renin when BP is low, increases BP because kidneys need sufficient pressure to filter

juxtaglomerular apparatus

_ are continuous with the renal pelvis and descend along the posterior abdominal wall; retroperitoneal

ureters

ureters enter the bladder on the _ and _ surface

posterior, inferior

term for expelling urine

micturition

posterior to the pubic symphysis and below the parietal peritoneum in the pelvic cavity

urinary bladder

lining is mucous membrane with rugae for expansion/collapsing; smooth muscle wall is the detrusor muscle

urinary bladder

floor of the bladder outlined by the two ureters and the internal urethral orifice

trigone

transports urine from the bladder to the exterior; controlled by two sphincters

urethra

where urethra leaves the bladder (smooth muscle)

internal sphincter

where urethra penetrates the pelvic floor (skeletal muscle)

external sphincter

the 3 steps to urine formation are:

glomerular filtration, tubular reabsorption, tubular secretion

which process of urine formation removes things from the blood?

glomerular filtration

tubular reabsorption

which process of urine formation takes things from the filtrate and puts them back into blood?

everything in blood gets filtered out except for…

blood cells and large proteins

what is the only component of the nephron that does filtration?

renal corpuscle

where does tubular reabsorption primarily happen?

proximal convoluted tubule (some in loop of henle and distal CT)

plasma components cross the filtration membrane in the glomerulus into bowman’s capsule

glomerular filtration

moves substances in the filtrate into the blood; reduces urine volume; water moves by osmosis except in the ascending loop

tubular reabsorption

tubular secretion happens mainly in the…

distal convoluted tubule

from blood into filtrate; adds substances to the urine such as H+ ions, K, creatinine, histamine, and some drugs

tubular secretion

what is considered the final product/urine?

substances filtered in the renal corpuscle MINUS substances reabsorbed in the tubules PLUS substances added by tubular secretion

net filtration rate = ?

blood pressure in the glomerulus (60) minus hydrostatic pressure in the capsule (15) plus osmotic pressure in the blood (28) = around 17 mm Hg

blood pressure in the glomerulus is usually around ?

60 mm Hg

hydrostatic pressure in the capsule is usually around ?

15 mm Hg

osmotic pressure in the blood is usually around ?

28 mm Hg

push-out pressure; increasing push out pressure increases filtration

hydrostatic pressure

hold-in pressure; keeps things out of the blood; decreasing _ pressure increases filtration

osmotic pressure

what affects how much gets filtered out of the blood?

what is pushed out versus what is kept in versus what can’t leave

hydrostatic pressure in bowman’s capsule is what kind of pressure?

push-back

obstructions cause urine/filtrate to back up, increasing the pressure in bowman’s capsule, creating push-back pressure in the glomerulus, making it harder for things to leave the blood/get filtered out

good to know

glomerular filtration rate is _ proportional to the net filtration pressure, so a fluctuation in any of the three pressures will change the GFR

directly

prolonged changes in normal GFR will cause either ?

too much or too little water and solutes to be removed from the blood

the total amount of filtrate formed by all the renal corpuscles in both kidneys per minute

glomerular filtration rate (GFR)

normal kidneys produce how much filtrate per minute?

125 milliliters of filtrate/minute, about 180 liters in 24 hours; 99% of this volume is reabsorbed, otherwise we would constantly be peeing

loss of albumin causes a _ in osmotic pressure; fluid will leak into the interstitial spaces and edema results; eventually there will be a low circulatory volume and possibly shock

decrease

loss of blood clotting proteins can cause ?

uncontrolled bleeding; clotting issues for renal patients

loss of globulins and complement proteins make an individual ?

prone to infection; pts with chronic renal disease may have bleeding issues, edema, BP issues, and prone to infection depending on what is wrong and if they’re losing proteins

why do we get too much of some substances in the urine?

some substances like glucose are transported via facilitated diffusion which is limited by carrier molecules; if the solute concentration exceeds the threshold, it will show up in the urine

you can affect blood concentration, volume, and pressure by altering ?

the concentration and volume of urine

aldosterone does what?

increases sodium reabsorption in the tubules, causing increased sodium retention and thus increased water retention because solvent follows solute, increasing blood pressure

antidiuretic hormone (ADH) does what?

increases water reabsorption in the tubules, causing decreased urine volume, thus adding to the body fluid/blood volume and increasing blood pressure

role of renin

in juxtaglomerular cells, promotes the production of angiotensin II from angiotensin I

role of angiotensin II

is a vasoconstrictor, increases BP through peripheral resistance; stimulates release of aldosterone, increasing sodium retention, thus increasing water retention/blood volume, raising blood pressure

normal blood pH range

7.35 - 7.45

how does high blood pH (alkaline) relate to urine being alkaline?

if your blood pH is high (too basic), you want to retain more hydrogen ions/excrete less hydrogen ions, making your urine less acidic/more basic/alkaline

pH range of normal urine

between 4.6 and 8.0; higher range to compensate for changes in blood pH

normal urine is _% water and _% solutes

95% water and 5% solutes

what substances would you find in abnormal urine?

albumin (proteins should be filtered out at renal corpuscle), glucose, blood cells (indicates infection, stone, or tumor), ketone bodies (indicates uncontrolled diabetes), microbes, WBCs if infection is present

how does aging impact urination?

bladder and urethral changes (can’t control urine = incontinence), decreased filtration (keeping waste products in circulation, nephrons worn out), increased risk of dehydration, unable to compensate/handle as well for glucose, electrolytes, drugs (renal function needed to take certain drugs or else too much will be in the system), pH changes

renin is secreted by ?

juxtaglomerular cells when blood flow into the glomerulus is decreased

list some causes of RBCs in urine:

urinary stones, urinary tract infections, glomerulonephritis, anticoagulant drugs, trauma and urinary tract tumors

inflammation of the bladder, most commonly caused by a bacterial urinary tract infection (UTI); bladder wall and urethra inflamed, red,

swollen, and potentially ulcerated; irritated hyperreactive bladder wall with reduced bladder capacity

cystitis

typically an STI but can result from injury or chemical irritant; categorized as gonorrhea caused -gonococcal - or not - nongonococcal

urethritis

list causes of cystitis

Bacterial Infection, Reaction to Certain Drugs, Radiation Therapy, Potential Irritants such as feminine hygiene products, spermicides, or long term catheter use

common manifestations of cystitis

Due to inflammation of bladder wall because of urine irritation; mild and may be unnoticed but include Pain in lower abdomen, Dysuria (painful urination), Urgent need to void, Short intervals between voiding, Nocturia (need to urinate during sleep period)

systemic signs of infection/cystitis:

Fever, Malaise, Nausea, and Leukocytosis

additional signs of cystitis:

Reactive Arthritis resulting in swollen, painful joints, Conjunctivitis - eye infection, Cloudy, foul smelling, discolored urine, Urinalysis indicates bacteria in urine, pyuria - pus in urine, microscopic hematuria

complications of cystitis:

Prostatitis - inflammation of the prostate; PID (Pelvic Inflammatory Disease) - lower UTI migrates from the urinary tract to ascend to the uterus, ovaries, or fallopian tubes which triggers PID; Cervicitis - inflammation of the cervix; infertility

infection of the kidney

Pyelonephritis

causes of pyelonephritis

bacteria ascending from the bladder to the kidneys, commonly from e. coli; infxn extends from the ureter into the kidney, involving the renal pelvis and medullary tissue (tubules and interstitial tissue); purulent exudate fills the kidney pelvis and calyces and the medulla is inflamed, blocking flow of blood and urine; abscesses and necrosis can be seen in the medulla and may extend through the cortex to the surface of the capsule

manifestations of pyelonephritis

signs of cystitis are present since infxn is present in both kidneys and bladder including dysuria, painful urination, frequent urges, and cloudy or bloody urine; dull aching pain in the lower back or flank due to inflammation that stretches the renal capsule; systemic signs more obvious in pyelonephritis including high fever, chills, possible nausea and vomiting

complications of pyelonephritis

if the infxn is severe, exudate can compress renal artery and vein, obstructing urine flow to the ureter; bilateral obstruction can result in acute renal failure; recurrent infxn can lead to fibrous scar tissue forming over a calyx, leading to a loss of tubule function and hydronephrosis; if severe and bilateral, can cause renal failure

infection of the kidney specifically within the renal cortex; a group of kidney diseases that involve inflammation or damage to the glomeruli; functional glomeruli filter waste and excess fluid from the blood

glomerulonephritis

causes of glomerulonephritis

follows a streptococcal infxn (usually originating from an upper respiratory infxn); certain strains of staphylococcus could initiate an immune response in the kidney; antistreptococcal antibodies formed from the infxn create an antigen-antibody complex that lodges in the glomerular capillaries, activating the complement system that then causes an inflammatory response in the glomeruli of both kidneys

manifestations of glomerulonephritis

urine becomes dark and cloudy (smoky or coffee-colored) because proteins and RBCs have leaked into it; facial and periorbital edema from fluid retention, then becomes generalized edema as osmotic pressure drops because sodium and water are retained; flank or back pain because the kidney tissue swells and stretches the capsule; general signs of inflammation like malaise, fatigue, headache, anorexia, nausea; oliguria (decreased urine output because GFR declines)

complications of glomerulonephritis

acute renal failure if blood flow is sufficiently impaired, severe prolonged inflammation could cause kidney tissue scarring; decreased blood flow will trigger increased renin secretion, leading to sodium and water retention that may cause hypertension and edema

Function of the Kidneys

Adjust how much water and how many electrolytes are kept or removed in urine, filter blood, and remove waste products… ultimately forming urine

Reasons Kidneys Cause Hypertension

inadequate excretion of sodium, excess renin release, Damage to kidney tissue (EX: CKD, diabetes) because Damaged nephrons cannot properly regulate sodium and water, Renal artery disease because narrowed renal arteries reduce blood flow to the kidneys, triggering renin release and increasing blood pressure

how do the kidneys compensate for hypertension

ANP (Atrial Natriuretic Peptide) Turns on when too much blood volume stretches the heart → heart will send signals to the kidneys to excrete more sodium and water → blood volume and pressure will decrease; Natriuresis: Kidneys decrease sodium reabsorption/increase sodium excretion; diuresis: kidneys excrete more water; Chronic hypertension damages and narrows the arteries supplying the kidneys, less blood reaches the nephrons, perceived as low blood volume, kidneys trigger RAAS system which makes it worse

effects of long term hypertension of the kidneys

vessel damage Due to persistent high blood pressure, renal blood vessels thicken, weaken and scar so peripheral resistance increases; increased pressure damages glomerular capillaries, so filtration barrier becomes damaged and proteinuria happens (proteins like albumin abnormally appear in the urine); function reduction because nephrons become damaged, waste isn’t filtered out properly, sodium/water content isn’t regulated properly, toxins and waste accumulate in the blood

treatments for hypertension

testing (test serum renin levels), renin-blocking drugs like lopressor and propranolol, ACE inhibitors like vasotec, quinapril, diuretics like lasix and aldactone, combination of medications, treat the underlying cause of hypertension

hypertension can lead to ?

kidney diseases; Over time, high blood pressure damages renal blood vessels and nephrons, reducing the kidneys' ability to filter blood and regulate fluid balance

Chronic high blood pressure causes thickening and narrowing of renal blood vessels, reducing blood flow to kidney tissue.

Nephrosclerosis

Progressive damage to nephrons reduces the kidneys’ ability to filter wastes and maintain fluid and electrolyte balance

Chronic Kidney Disease (CKD)

Severe long-term kidney damage can eventually lead to loss of kidney function, sometimes requiring dialysis or transplant.

Renal Failure / ESRD (end stage renal disease)

what is nephrotic syndrome

abnormality in glomerular capillaries due to damage to glomerular filtration barrier; increased capillary permeability caused by filtration barrier damage; large amounts of plasma protein/albumin escapes into filtrate, leads to hypoalbuminemia and decreased plasma osmotic pressure which causes generalized edema; Blood pressure may remain low or normal in many cases because of hypovolemia or it may be elevated depending on angiotensin II levels; decreased blood volume leads to increased aldosterone secretion and more severe edema; high levels of cholesterol in blood and lipoproteins in urine, the cause is not totally clear, although it appears to be related to the response of the liver to heavy protein loss

signs and symptoms of nephrotic syndrome

proteinuria due to increased capillary permeability, frothy urine, massive edema (anascara), swollen legs and feet because gravity increases pressure in lower limbs and decreases patient mobility/physical activity, weight gain from massive edema, loss of appetite/anorexia, ascites due to decreased capillary osmotic pressure (hypoalbuminemia), pleural effusion from fluid leakage from capillaries into lungs, skin breakdown and infxn because swelling impairs arterial flow and compromises capillary exchange, making skin vulnerable to breakdown and infxn, marked pallor

causes of obstruction

In men, prostatic cancer or enlargement can cause urinary obstruction; Other causes in both genders include stones, scarring, tumors, stenosis, and birth defects

signs and symptoms of obstruction *depends on the location and severity

Urinary hesitancy: difficulty starting urination; Weak urine stream: reduced force of urine flow; dribbling; urinary frequency, nocturia, urinary retention: inability to empty the bladder completely; flank or back pain may occur with kidney involvement or stones; hematuria (may occur with stones); decreased urine output may occur with severe obstruction

Stones in the kidney or bladder are frequently _, unless frequent infections lead to investigation. Sometimes flank pain occurs because of distention of the renal capsule.

asymptomatic

Obstruction of the ureter causes an attack of “renal colic,” consisting of…

intense spasms of pain in the flank area radiating into the groin that last until the stone passes or is removed. This pain is caused by vigorous contractions of the ureter in an effort to force the stone out. The severe pain may be accompanied by nausea and vomiting, cool moist skin, and rapid pulse

Effects of obstruction of the urinary tract

whether due to a tumor, scar tissue, enlarged prostate, or stones, can cause hydronephrosis (dilation of the kidneys collecting system due to a backup of urine) as a secondary complication; Continued backup of urine can eventually Cause necrosis of the tissue due to pressure On blood vessels. It can also lead to chronic Renal failure; mostly asymptomatic unless it is causing Infection

Treatment of stones in the urinary tract

depends on size and amount of stones; smaller stones can be passed through normal urination although painful, and drugs could be used to dissolve smaller stones; larger stones can be broken into smaller stones to be passed through urination, shockwave lithotripsy uses soundwaves to break up stones, laser lithotripsy uses a laser and ureteroscope to break up stones; invasive procedures such as percutaneous nephrolithotomy could be done to remove stones surgically

Urinalysis indicates ?

bacteriuria (more than 100,000 organisms per milliliter of urine), pyuria, and microscopic hematuria

Urinalysis results of pyelonephritis are similar to those for cystitis except that…

urinary casts, consisting of leukocytes or renal epithelial cells, are present, reflecting the involvement of the renal tubules

The significant sign of nephrosis/nephrotic syndrome is ?

massive edema (anasarca) associated with weight gain and pallor; excessive fluid throughout all tissues impairs appetite (ascites), breathing (pleural

effusion), and activity (swollen legs and feet)

What is Kidney Cancer?

Most common form is renal cell carcinoma; Cancer cells grow in the tubule epithelium, more often in renal cortex; common in men aged 60-80 and smokers; Tends to be asymptomatic in the early stage and often has metastasized to liver, lungs, bone, or CNS at the time of diagnosis

risk factors for kidney cancer

genetic predisposition, certain conditions and medications, smoking, high blood pressure, and obesity

Young children ages are 3-4 more likely to develop ?

wilms tumor

risk factors for wilms tumor

genetic predisposition/family history, being Black, having other conditions like hemihypertrophy (one side of the body is larger) or Aniridia (the iris is not fully colored in)

signs and symptoms of wilms tumor

palpable mass in stomach area, pain and swelling around stomach, high blood pressure, and fever; Symptoms can also include general cancer symptoms, most noticeably bleeding causing hematuria as well as anemia

signs and symptoms of kidney cancer

initial sign is usually painless hematuria, either gross or microscopic; dull, aching flank pain; a palpable mass; unexplained weight loss; anemia or erythrocytosis (depending on the tumor's effects on erythropoietin secretion); hypercalcemia (increased parathyroid hormone) or Cushing's syndrome (increased adrenocorticotropic hormone); this tumor tends to be silent, so diagnosis is made in 1/3 of cases after metastasis to lungs, liver, or bone has already occurred; diagnosed via blood and urine tests, x-ray, ct, mri, biopsy

Treatment of Kidney Cancer

If cancer has not metastasized, surgery is often used to remove the tumor or the entire kidney (nephrectomy); radiation therapy, chemotherapy, cryoablation (cold substance such as argon gas or liquid nitrogen is injected into site of cancer to freeze cancer cells, more common for those with increased risk from surgery); palliative care relieves symptoms and provides mental and emotional support

What is Bladder Cancer?

Often forms from the transitional epithelium of the bladder as multiple tumors with high recurrence rate; Transitional epithelium (urothelium) is the tissue that stretches/contracts with fluid volume changes in urinary tract; Can spread invasively through the wall to adjacent structures and metastasize through blood to pelvic lymph nodes, the liver, and bone