urinary system Flashcards
Struct. and func of urinary syst
Upper
2 kidneys –> form urine
2 ureters –> drain urine
Lower
Bladder –> stores urine
Urethra –> urine leaves body
Main and side funcs of Urinary syst
Main: regulate ECF and excrete waste
Other: BP, EPO, vit D, acid base
Kidney macrostructure
R lower than left
Retroperitoneal: T12 to L3
surrounded by fat and CT
Capsule of fibrous membrane
arteries, nerves, veins, ureters at hilus
Cortex = outer layer
Medulla = pyramids
Papillae = apices of pyramids
Calyces = funnel of urine to pelvis
Ureter = urine from pelvis to bladder
Kidneys microstructure (UNNECESSARY)
nephron = func unit
-glomerulus
-bowman’s capsule
-tubular syst: proximal convoluted tubule, loop of Hele, collecting tubules
Cortex = glomerulus, Bowman’s capsule, proximal tubule
Medulla = loop of Henle and collecting tubules
Kidneys and BLood supply
1200 mL/min (20-25% CO)
Aorta –> renal artery –> afferent arterioles –> glomerulus –> efferent arteriole –> peritubular capillaries –> renal vein –> inferior vena cava
Steps of urine formation NOPE
filtration
reabsorption
secretion
excretion of H2O, electrolytes, and metabolic waste
Glomerular filtrateion NOPE
blood filtered by hydrostatic pressure
passes thru semipermeable membrane into Bowman’s capsule
filtrate passes down tubule (shouldn’t have blood cells, platelets, or big prots)
Normal GFR is 125 mL/min
Tubular func.NOPE
Reabsorption from tubules to capillaries
Secretion from capillaries to tubules
-proximal convoluted tubule (80% electrolytes, 100% glucose, AA and small prots, H+ and creatine)
-Loop of Henle: reabsorbs Na+, Cl-, and H2
-Descending limb: water sodium, urea, others
-ascending limb: Cl and Na
Hormones on Distal convoluted tubule NOPE
ADH
-imp for water balance
regulated by post pit gland
Aldosterone
-reabsorption of Na+ and H2O; K+ secretion
-from adrenal cortex
Acid base balance distal cocvoluted tubule
how does heart help with water balance? NOPE
Bicarb reabsorbed
H+ secreted
Right atrium
-ANP increases Na secretion; inhibits renin, ADH and Angio II; increases GFR
Calcium balance in renal tubules NOPE
PTH increases calcium reabsorption and decreases phosphate reabsorption
vit D needed to absorb Ca from GI tract
RBC production and BP regulation in kidneys
RBC- Erythropoietin is secreted in response to hypoxia and decreased renal bloodflow
BP :
-RAAS increases BP
-prostaglandin synthesis - vasodilation, decreased BP and SVR (systemic vascular resistance)
Ureters: struct and func NOPE
carry urine from pelvis to bladder
-10 to 2” peristaltic, one-way flow
Joins renal pelvis at the ureteropelvic junction (UPI) and bladder at uretovesical junction (UVI)
Narrowed at junctions - obstruction –> renal colic
Reflux can occur with incomplete UI closure
Bladder
what is normal urine output?
how much urine to stretch bladder?
structural features of bladder
Serves as reservoir for urine; doesn’t absorb; ureoepithelium stretches
Normal adult urine output: 1500 mL/day (0.5 cc/kg/hr)
200-250 = mil distention and urge to urinate
400600 = moderate distention (uncomfy)
600-1000 = capacity
trigone = 2 ureteral openings and bladder neck
bladder muscle = detrusor
Urachus = attachment to abdominal wall
urination, micturition, voiding
Urethra
from bladder neck to external meatus
controls voiding
conduit for urine during voiding
Length:
M = 8-10 in
F = 1-2 in
Urethrovesical unit NOPE
Formed by bladder, urethra, and pelvic floor muscles
Voluntary control = continence
-distention of bladder stimulates stretch receptors
-impulses sent from brain to T11-L2 and S2-S4
-Not time to void - inhibitor impulses stimulated
-Time to void - impulses from spinal cord causes relaxation and contraction of bladder neck, sphincter, and pelvc floor muscles
Anatomic changes of old ppl’s urinary system
Bt ages 30-90 size and weight of kidneys decreases by 20-30%
By 7th decade, loss of 50% of functioning glomeruli
Atherosclerosis speeds decrease of size
continues to maintain fluid homeostasisi though
Physiologic changes of old ppl’s kidneys, urethra, and bladder
Kidney
-less renal blood flow slows GFR
-altered hormones result in less concentrated urine and more excretion of water, Na, K and acid
Urethra and bladder:
F: less elasticity and muscle = infections and incontinence
M: enlarged prostate = dif urinary patterns
Imp subjective data when assessing urinary syst
Health history: diseases or other probs
Meds: OTC shit, Nephrotoxic stuff
Surgery/treatments (including radiation or chemo)
Health perception
Nutritional/metabolic pattern
Elimination pattern (edema, pain, pattrn, color)
Activity level
sleep
cognition
self perception
role
sexuality
Objective data when assessing urinary syst NOPE
Physical examination
-inspect skin, mouth, face, extremeties, abdomen, weight, general state of health
-palpate costovertebral angle (CVA), R kidney lower pole, and bladder (L kidney can’t be felt)
-percussion: kidney punch and bladder
-auscultation for bowel sounds
Genetic risks NOPE
polycystic kidney disease and congenital uritary tract abnormalities
normal physical asessment of urinary system NOPE
no costovertebral angle tenderness
nonpalpable kidney and bladder
no palpable masses
Radiologic studies of urinary system
bowel prep
-magnesium citrate and fleet enema (except with kidney failure)
-iodine based contrast can cause contrast-induced kidney injury (CIN) and allergic reacions —> maintain hydration and administer N-acetylcysteine to deduce CIN)
-NPO - avoid dehydration; insulin adjustment for diabetics
Urine studies
urinalysis = first morning void –> examine within an hour
Creatine clearance = best indicator of renal func
-collect 24 hr urine and blood specimen
-creatine clearance approximates GFR
Urodynamic studies
- Cystometrogram = catheter inserts saline into bladder to check capacity to contract and expel urine
- RNC Radionuclide cystography = detects and grades vesicoureteral contractions –> VCUG-ish stuff with radioisotope instilled into bladder
- sphincter electromyography (EMG) = Recording of electrical activity created when nervous system stimulates muscle tissue
- Urine flow study = normal for men = 20-25 mL/s —> women = 25-30 mL/s
- Videourodynamics
- Voiding pressure study = combo of 1, 3, and 4
- Whitaker study = measures pressure differential bt renal pelvis and bladder –> involves instilling fluid into renal pelvis
Renal arteriogram with catheter insertion
urinary system cystoscopy
