9. Urinary System Flashcards
Where are the kidneys located?
On either side of the vertebral column; the right kidney is slightly lower due to the liver.
What is the kidney’s main role?
To maintain homeostasis by regulating blood ion composition, volume, pressure, pH, and removing waste.
Why is the kidney considered retroperitoneal?
Because it lies behind the peritoneal cavity, against the posterior abdominal wall.
How much blood flows through the kidneys per minute?
About 1200 ml or one-fourth of the systemic cardiac output.
What structures make up the urinary system?
Kidneys, ureters, urinary bladder, and urethra.
What is the functional unit of the kidney?
The nephron, which performs filtration, reabsorption, and secretion.
What are the three processes of urine formation?
Glomerular filtration, tubular reabsorption, tubular secretion.
What causes glomerular filtration?
Blood pressure that forces water and solutes from plasma into the glomerular capsule.
What percentage of filtered water is reabsorbed?
Approximately 99% of filtered water is reabsorbed.
What substances are secreted during tubular secretion?
Hydrogen ions, potassium ions, ammonia, creatinine, and some drugs.
What happens in the proximal convoluted tubule?
Reabsorption of glucose, amino acids, ions, and most water; secretion of H+, toxins, and drugs.
What is reabsorbed in the descending loop of Henle?
15% of water by osmosis.
What is reabsorbed in the ascending loop of Henle?
Chloride ions actively; sodium ions passively.
What happens in the distal convoluted tubule?
Reabsorption of Na+, Cl-, and Ca2+; water follows; secretion of K+ and H+.
How does the collecting duct affect urine?
Reabsorbs Na+ and water (influenced by ADH and aldosterone); secretes K+ and H+.
What is the composition of normal urine?
95% water and 5% solutes, including urea, uric acid, creatinine, and ions.
What is the normal urine volume per day?
1 to 2 liters per day.
What is specific gravity of urine?
A measure of solute concentration; ranges from 1.008 to 1.030.
What is the normal pH range of urine?
Between 5.0 and 7.8, slightly acidic.
What does glycosuria indicate?
Presence of glucose in urine, often due to diabetes mellitus.
What does hematuria indicate?
Blood in urine; possible causes include kidney stones or infection.
What is albuminuria?
Presence of albumin in urine, indicating possible renal disease.
What is polyuria?
Excessive urine output, seen in diabetes.
What is oliguria?
Scanty urine output, may indicate renal failure or dehydration.
What is dysuria?
Painful urination, often due to UTI or kidney stones.
What stimulates ADH release?
Increased blood osmolarity or decreased blood volume.
What is the effect of ADH?
Increases water reabsorption by increasing aquaporins in DCT and collecting duct.
What stimulates aldosterone?
Low plasma sodium, high potassium, or low blood volume.
What does aldosterone do?
Stimulates Na+ reabsorption and K+/H+ secretion in DCT and collecting duct.
What is the micturition reflex?
A spinal reflex that causes contraction of bladder and relaxation of internal sphincter.
What is cystitis?
Inflammation of the urinary bladder.
What are the three main kidney replacement therapies?
Hemodialysis, peritoneal dialysis, and kidney transplant.
