urine

Examples of urine in the following topics:

• Chemical Composition of Urine

  • There are several conditions that can cause abnormal components to be excreted in urine or present as abnormal characteristics of urine.
  • Some of the more common types of abnormal urine include:
  • Proteinuria—Protein content in urine, often due to leaky or damaged glomeruli.
  • Oliguria—An abnormally small amount of urine, often due to shock or kidney damage.
  • Describe how normal urine consists of water, urea, salts and pigment

• Physical Characteristics of Urine

  • Dark urine may indicate dehydration.
  • Red urine indicates red blood cells within the urine, a sign of kidney damage and disease.
  • Smell: The smell of urine may provide health information.
  • Generally fresh urine has a mild smell but aged urine has a stronger odor similar to that of ammonia.
  • The density of normal urine ranges from 0.001 to 0.035.

• Urinalysis

  • Urinalysis is the process of analyzing urine for target parameters of health and disease.
  • Another method is light microscopy of urine samples.
  • Test strip urinalysis exposes urine to strips that react if the urine contains certain cells or molecules.
  • A urine test strip can identify:
  • White blood cells seen under a microscope from a urine sample.

• Glucosuria

  • Glycosuria or glucosuria is the excretion of glucose into the urine .
  • Ordinarily, urine contains no glucose because the kidneys are able to reclaim all of the filtered glucose back into the bloodstream.
  • Glycosuria leads to excessive water loss into the urine with resultant dehydration, a process called osmotic diuresis.
  • Glucose in urine can be identified by Benedict's qualitative test.
  • A doctor can normally diagnose renal glycosuria when a routine urine test (urinalysis) detects glucose in the urine, while a blood test indicates that the blood glucose level is normal.

• Overview of Urine Transport, Storage, and Elimination

  • Smooth muscle contractions in the walls of the ureters, over time, send the urine in small spurts into the bladder, the organ where urine is stored before it can be eliminated.
  • Circular muscles called sphincters help keep urine from leaking.
  • Nerves in the bladder are stimulated as the bladder fills with urine and becomes larger, which in turn stimulates the need to urinate.
  • When you urinate, the brain signals the bladder muscles to tighten, squeezing urine out of the bladder.
  • When all the signals occur in the correct order, normal urination occurs, removing urine from the body.

• Micturition and the Micturition Reflex

  • Micturition, also known as urination, is the ejection of urine from the urinary bladder through the urethra to the outside of the body.
  • In healthy humans the process of urination is under voluntary control.
  • In males, urine is ejected through the penis, and in females through the urethral opening.
  • The storage phase: A relaxed bladder in which urine slowly fills the bladder.
  • Many males prefer to urinate standing.

• Regulation of Urine Concentration and Volume

  • In a way, urine volume regulation is part of homeostasis, in that it directly regulates blood volume, because greater amounts of urine will reduce the volume of waters in blood.
  • An anti-diruetic is a substance that decreases urine volume, and ADH is the primary example of it within the body.
  • ADH will then act on the nephrons of the kidneys to cause a decrease in plasma osmolarity and an increase in urine osmolarity.
  • This effect causes increased water reabsorption and retention and decreases the volume of urine produced relative to its ion content.
  • A diuretic is any substance that has the opposite effect of ADH— they increase urine volume, decrease urine osmolarity, lead to an increased plasma osmolarity, and often reduced blood volume.

• Urinary Bladder

  • The urinary bladder is a urine storage organ that is a part of the urinary tract.
  • The bladder expands and fills with urine before it is discharged into the urethra during urination.
  • The sphincters must open before the urine can flow into the urethra.
  • The urinary bladder usually holds 300–350 ml of urine.
  • As urine accumulates, the walls of the bladder thin as it stretches, allowing the bladder to store larger amounts of urine without a significant rise in internal pressure of the bladder.

• Diuretics

  • Diuretics alleviate the symptoms of these diseases by causing sodium and water loss through the urine.
  • A diuretic provides a means of forced diuresis which elevates the rate of urination.
  • This results in several effects including bicarbonate retention in the urine, potassium retention in urine and decreased sodium absorption.
  • The reduced concentration of calcium in the urine can lead to an increased rate of calcium in serum.
  • Differentiate among the types of diuretics used to elevate urine excretion

• The Role of the Kidneys in Acid-Base Balance

  • The kidneys help maintain acid-base balance by excreting hydrogen ions into the urine and reabsorbing bicarbonate from the urine.
  • For instance, uncontrolled diabetes results in highly acidic urine.
  • The kidneys have two very important roles in maintaining the acid-base balance: to reabsorb bicarbonate from urine, and to excrete hydrogen ions into urine.