Urinary System

Question 1

Urinary System

Answer 1

Removes metabolic wastes
Removes hormones from the body
Removes drugs other foreign material from body
Regulates water, electrolyte, acid-base balance
Secretes erythropoietin
Activates vitamin D
Regulate blood pressure through the renin-angiotensin-aldosterone system

Question 2

Urinary System Anatomy

Answer 2

Kidneys
↓
Ureters
↓
Urinary bladder
↓
Urethra

Question 3

Nephrons

Answer 3

functional units of the kidneys
Each kidney has over a million nephrons.

Question 4

Renal corpuscles
↓
Glomerulus
Bowman capsule

Answer 4

filtration units of the kidneys that filter blood and create urine:

Question 5

Bowman capsule

Answer 5

a cup-shaped sac in the kidney that surrounds the glomerulus and performs the first step in filtering blood to form urine

Question 6

Glomerulus

Answer 6

to filter plasma to produce glomerular filtrate, which passes down the length of the nephron tubule to form urine.

Question 7

Renal tubules
↓
Proximal convoluted tubules
Loop of Henle
Distal convoluted tubules
Collecting duct

Answer 7

One of millions of tiny tubes in the kidneys that returns nutrients, fluids, and other substances that have been filtered from the blood, but the body needs, back to the blood.

Question 8

Filtration (Formation Of Urine)

Answer 8

In renal corpuscles
Large volume of fluid passes from glomerular capillaries into the tubule (Bowman capsule)
Wastes, nutrients, electrolytes, other dissolved substances
Cells and protein remain in the blood.

Question 9

Reabsorption (Formation Of Urine)

Answer 9

Reabsorption of essential nutrients, water, and electrolytes into the peritubular capillaries
Control of pH and electrolytes

Question 10

Transport mechanisms for reabsorption

Answer 10

Active transport
Co-transport
Osmosis—water

Question 11

Proximal convoluted tubules

Answer 11

Most of water reabsorption
Glucose reabsorption
Nutrients and electrolytes to maintain homeostasis

Question 12

Hormones Involved in Reabsorption

Answer 12

Antidiuretic hormone (ADH)
Secreted by the posterior pituitary
Reabsorption of water in distal convoluted tubules and collecting ducts

Aldosterone
Secreted by adrenal cortex
Sodium reabsorption in exchange for potassium or hydrogen

Atrial natriuretic hormone
Hormone from the heart
Reduces sodium and fluid reabsorption

Question 13

Blood Flow through the Kidney

Answer 13

Specialized pattern:
Renal artery → interlobar artery → arcuate
artery → interlobular artery → afferent arteriole
→ glomerular capillaries → efferent arteriole →
peritubular capillaries → interlobular vein →
arcuate vein → interlobar vein → renal vein

Question 14

Glomerular Filtration Rate

Answer 14

Control of arteriolar constriction by three
factors:
Autoregulation
Local adjustment in diameter of arterioles
Made in response to changes in blood flow in kidneys
Sympathetic nervous system
Increases vasoconstriction in both arterioles
Renin
Secreted by juxtaglomerular cells when blood flow to afferent arteriole is reduced
Renin-angiotensin mechanism

Question 15

Incontinence and Retention

Answer 15

Incontinence
Loss of voluntary control of the bladder
Enuresis
Involuntary urination by child age older than 4 years
Often related to developmental delay, sleep pattern, psychosocial aspect
Stress incontinence (more common in women)
Increased intra-abdominal pressure forces urine through sphincter.
Coughing, lifting, laughing
Multiple pregnancies

Question 16

Incontinence and Retention
(2 of 3)

Answer 16

Overflow incontinence
Incompetent bladder sphincter
Older adults
Weakened detrusor muscle may prevent complete emptying of bladder—frequency and incontinence
Spinal cord injuries or brain damage
Neurogenic bladder—may be spastic or flaccid
Interference with CNS and ANS voluntary controls of the bladder

Question 17

Incontinence and Retention
(3 of 3)

Answer 17

Retention
Inability to empty bladder
May be accompanied by overflow incontinence
Spinal cord injury at sacral level blocks micturition reflex
May follow anesthesia (general or spinal)

Question 18

Urinalysis: Appearance of Urine

Answer 18

Straw colored with mild odor
Normal urine, specific gravity 1.010 to 1.050

Cloudy
May indicate the presence of large amounts of protein, blood, bacteria, and pus

Dark color
May indicate hematuria, excessive bilirubin, or highly concentrated urine

Unpleasant or unusual odor
Infection or result from certain dietary components or medication

Question 19

Urinalysis: Urinary Infection

Answer 19

Heavy purulence and presence of gram-negative and gram-positive organisms

Question 20

Urinalysis: Abnormal Constituents of Urine (1 of 2)

Answer 20

Blood (hematuria)
Small amounts
Infection, inflammation, or tumors in urinary tract

Large amounts
Increased glomerular permeability or hemorrhage

Elevated protein level (proteinuria, albuminuria)
Leakage of albumin or mixed plasma proteins into filtrate

Bacteria (bacteriuria)
Infection in urinary tract

Question 21

Urinary casts

Answer 21

Indicate inflammation of kidney tubules

Question 22

Specific gravity

Answer 22

Indicates ability of tubules to concentrate urine
Low specific gravity—dilute urine (with normal hydration)

High specific gravity—concentrated urine (with normal hydration)
Related to renal failure

Question 23

Glucose and ketones(Urine)

Answer 23

Found when diabetes mellitus is not well controlled

Question 24

Elevated serum urea and serum creatinine levels

Answer 24

Indicate failure to excrete nitrogen wastes
Caused by decreased GFR

Question 25

Metabolic acidosis*

Answer 25

Indicates decreased GFR Failure of tubules to control acid-base balance

Question 26

Anemia*

Answer 26

Indicates decreased erythropoietin secretion and/or bone marrow depression

Question 27

Blood Tests

Answer 27

Electrolytes Depend on related fluid balance Antibody level Antistreptolysin O or antistreptokinase titers Used for diagnosis of poststreptococcal glomerulonephritis Elevated renin levels Indicate kidney as a cause of hypertension

Question 28

Other Tests (1 of 2)

Answer 28

Culture and sensitivity studies on urine specimens Identification of causative organism of infection Help select appropriate drug treatment Radiologic tests Radionuclide imaging, angiography, ultrasound, CT, MRI, intravenous pyelography Used to visualize structures and possible abnormalities, flow patterns, and filtration rates

Question 29

Other Tests (2 of 2)

Answer 29

Clearance tests Examples: creatinine or inulin clearance Used to assess GFR Cystoscopy Visualizes lower urinary tract May be used to perform biopsy or remove kidney stones Biopsy Used to acquire tissue specimens

Question 30

Diuretic Drugs

Answer 30

Used to remove excess sodium ions and water from the body Increased excretion of water though the kidneys Reduces fluid volume in tissues and blood Prescribed for many disorders Renal disease, hypertension, edema, congestive heart failure, liver disease, pulmonary edema Several different mechanisms to increase urine volume based on specific drug Some drugs are potassium-wasting and some are potassium-sparing.

Question 31

Dialysis

Answer 31

Provides filtration and reabsorption Two forms Hemodialysis Peritoneal dialysis Sustains life during kidney failure Used to treat patients with acute kidney failure Until primary problem reversed For patients in end-stage renal failure Until kidney transplant becomes available and is successful

Question 32

Hemodialysis (1 of 2)

Answer 32

In hospital, dialysis center, or home with special equipment and training Patient’s blood moves from an implanted shunt or catheter in an artery to machine Exchange of wastes, fluids, and electrolytes Semipermeable membrane between blood and dialysis fluid (dialysate) Blood cells and proteins remain in blood. After exchange is completed, blood returned to patient’s vein

Question 33

Hemodialysis (2 of 2)

Answer 33

Usually required three times a week Each lasts about 3 to 4 hours. Potential complications Shunt may become infected. Blood clots may form. Blood vessels involved in shunt may become sclerosed or damaged. Patient has an increased risk of infection with hepatitis B, hepatitis C, or HIV if Standard Precautions are not followed.

Question 34

Peritoneal Dialysis (1 of 2)

Answer 34

Usually done on outpatient basis May be done at night (during sleep) or while patient is ambulatory Peritoneal membrane serves as the semipermeable membrane. Catheter with entry and exit points is implanted into the peritoneal cavity Dialyzing fluid is instilled into cavity Dialysate is drained from cavity via gravity into container

Question 35

Peritoneal Dialysis (2 of 2)

Answer 35

Takes more time than hemodialysis Requires loose clothing to accommodate bag of fluid Major complication Infection resulting in peritonitis With both types of dialysis Prophylactic antibiotics with either form of dialysis Any additional problem occurring in patient such as infection may alter dialysis requirements Caution is required with many drugs because toxic level buildup can occur.