www.contemporaryissues.tcu.edu/.../13-kidneys- urinary-system.ppt
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Major Parts of the Machinefood, water intake oxygen intake
elimination of carbon dioxide
Digestive System Respiratory System
Circulatory SystemUrinary System
elimination of excess watersalts, wastes
rapid transportto and from allliving cells
eliminationof foodresidues
nutrients,water,salts
carbondioxide
watersolutes
oxygen
Based on: Starr, C., Biology: Concepts and Applications, Brooks/Cole
Overview of LessonFormation of urine Urinary systemWater balance and alcoholProblems of the urinary
tract
When protein is broken down in the body, it results in nitrogenous waste that must be eliminated from the body
All 20 amino acids have a nitrogen group (NH2). When broken down for energy, the nitrogen group is converted to ammonia (NH3).
Examples of Amino Acids
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Ammonia is converted into urea by the liver. Urea is then transported in the blood to the kidneys where the urea is removed from the blood.
Circulatory System
Based on: Mader, S., Inquiry Into Life
Urea is less toxic than ammonia and can be transported in the blood to the kidney
H2N - C - NH2
urea
O
Formation of UrineAmino acids in protein are broken
down, resulting in production of ammonia
Ammonia is converted to urea in liver
Urea travels in blood to kidneys, where removed from blood and incorporated
into urine
Overview of LessonAmino acids, ammonia and urea
Urinary systemWater balance and alcoholProblems of the urinary
tract
Urine Formation by NephronBlood pressure forces water, glucose, amino acids
and urea from capillaries into nephron
Glucose and amino acids are reabsorbed into blood from nephron
Some water is reabsorbed into blood
Urine is urea and salt concentrated in water
Urine moves from the collecting ducts through the kidney pelvis to the ureter
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Urine moves from the kidneys, through the ureters to the bladder and finally through the urethra
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Overview of LessonAmino acids, ammonia and urea
Urinary systemWater balance and alcoholProblems of the urinary
tract
Regulation of Water BalanceBrain monitors water content of blood
If low water content, pituitary releases ADH (antidiuretic hormone)
ADH travels in blood to nephron
ADH causes more water to move from urine back into blood
Alcohol consumption suppresses the production of ADH by the pituitary. Why would this result in dehydration and a hangover?
Write on back of sheetDescribe how the following chemicals and/or cells
affect the production of urine:Osmoreceptors- cells in hypothalamus
responsible for sensing water pressure in plasma (blood) = control urine output
Aldosterone- hormone in adrenal cortex that reabsorbs sodium ions (salt); this causes water to be reabsorbed as well = decreases urine output
Renin- hormone in kidneys that simulates aldosterone (see above) = decreases urine output
ADH- in nephron causes water to be reabsorbed into bloodstream = decreases urine output
Salt- causes cells to retain water = decreases urine output
Water- increases water output (under normal conditions)
Caffeine- acts as a diuretic = increases urine output
Alcohol- surprreses ADH = increases urine output
Overview of LessonAmino acids, ammonia and urea
Urinary systemWater balance and alcoholProblems of the urinary
tract
Incontinence (urine leakage)More than 10 million Americans experience
incontinence
Most do not seek treatment
Treatment can improve or eliminate the problem 90% of the time
Causes of Incontinence
Stress incontinence: leaking small amounts of urine when coughing, lifting, or exercising
Urge incontinence: the bladder suddenly and unexpectedly contracts and expels urine
Overflow incontinence: bladder cannot completely empty so urine dribbles
Treatments for Incontinence Kegel exercises to strengthen the urinary
sphincterMedicines that increase the sphincter’s ability
to contractSurgery to strengthen the pelvic muscles or to
lift the bladderRetrain the bladder to increase its storage
capacity (allowing 3-4 hours between urinating)
Drugs to prevent urge incontinenceSurgery to remove part of prostate gland if
responsible for overflow incontinence
Kidney stones form in the kidney pelvis. There are 4 types of stones.
Calcium stones (most common)
Uric acid stonesBacteria caused stonesCystein stones
Based on Mayo Clinic Health Letter
Kidney stones cause pain when they pass down the ureters to the bladder and urethra
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
Treatments for Kidney Stones Small stones may pass with no painLarger stones may pass but cause
extreme of pain, requiring a lot of pain medication
Stones that are too large to pass may require surgical treatment
Surgical treatment including:
using a ureteroscope to go up and snare the stone
using a nephroscope to crush the stone and retrieve it
using shock wave lithotripsy where a person is submerged in water containing shock waves to pulverize the stones
Urinary Tract Infection (UTI)
Second most common infection following respiratory infections
UTI occur when bacteria (E. coli) from the digestive tract get into the opening of the urinary tract and multiply
Bacteria first infect the urethra, then move to the bladder and finally to the kidneys
UTI tend to occur more in women than men
Women may have more UTIs than men because:
1) they have a shorter urethra, allowing quicker access to the bladder
2) the urethral opening is nearer the anus3) intercourse may result in UTIs in women
Based on: Harvard Medical School Family Health Guide
Symptoms of UTIs
Urge to urinate but only small amount of urine produced
Pain and burning sensation in bladderFever Blood in urine
Diagnosis and TreatmentDoctors check urine for white and
red blood cells and bacteriaBacteria grown in culture to
determine which antibiotic will work the best
UTIs are treated with antibiotics and are often cured within 1 or 2 days