Kidneys and the Urinary Systemwww.contemporaryissues.tcu.edu/.../13-

kidneys-urinary-system.ppt

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

Based on: Mader, S., Inquiry Into Life, McGraw-Hill

Protein

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

Urinary System

Based on: Mader, S., Inquiry Into Life, McGraw-Hill

Anatomy of the Kidney

Based on: Mader, S., Inquiry Into Life, McGraw-Hill

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

Nephron

Based on: Mader, S., Inquiry Into Life, McGraw-Hill

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

Nephron

Based on: Mader, S., Inquiry Into Life, McGraw-Hill

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

Kidney Disease and EthnicityKidney disease 26 million

Americans

African Americans five times likely to require dialysis or kidney transplant

Possible reasonsLack of health careGenetic componentDiabetesHypertension