EXCRETORY SYSTEM

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• EXCRETORY SYSTEM

• Karen Lancour Patty
  Palmietto
• National Bio Rules National Event
• Committee Chairman Supervisor AP

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Excretory System

• Humans produce waste products that must be
  removed from their body.
• Most animals have a system that deals with
  nitrogen-rich wastes from the breakdown of
  proteins and nucleic acids.
• Ammonia (NH3) is toxic.
• it helps maintain homeostasis balancing osmotic
  action and pH.

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Excretory System

• Functions
• Excrete toxins and nitrogenous waste
• Regulate levels of many chemicals in blood
• Maintain water balance
• Helps regulate blood pressure

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Organs of Excretory System

• Kidney filters blood
• and forms urine
• Ureter carries urine to
• bladder
• Bladder stores urine
• Urethra releases urine

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URINARY BLADDER
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KIDNEY STRUCTURE
human kidney
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Kidney

• Filtration
• Reabsorption
• Secretion

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Nephron
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The nephron
4 STAGES OF URINE FORMATION

• Glomerular filtration into Bowmans Capsule
• 2. Solute Reabsorption
• from proximal tubule to capillary
• Water Reabsorption
• from proximal tubule and Loop of Henle to
  capillary
• 4. Tubular Secretion from capillary to distal
  tubule

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Blood vessels in the glomerulus
Bottleneck Effect The blood enters the Bowmans
capsule by the afferent arteriole and leaves by
the efferent arteriole. The diameter of afferent
arteriole is greater than that of the efferent
arteriole. Therefore, when the blood enters the
efferent arteriole, it is under high pressure as
it tries to force its way out of the smaller
efferent arteriole.
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Nephron
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URINE FORMATION

• Glomerular Filtration
• substances move from blood in glomerulus to the
  Bowmans capsule

• Tubular Reabsorption
• substances move from renal tubules into blood of
  peritubular capillaries
• glucose, water, urea, proteins, creatine
• amino, lactic, citric, and uric acids
• phosphate, sulfate, calcium, potassium, and
  sodium ions

• Tubular Secretion
• substances move from blood of peritubular
  capillaries into renal tubules
• drugs and ions

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Composition of Urine
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HYDRATION
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Glomerular Filtration Rate

• GFR amount of filtrate formed per minute in all
  nephrons of both kidneys
• The amount of fluid filtered from the glomeruli
  into Bowman's space per unit of time. 
• Renal capillaries are much more permeable than
  others.
• The flow rate is 180 L/day (125 ml/min) compared
  to 4 L/day in the other capillaries.
• The entire plasma volume is filtered about 60
  times a day! Most is reabsorbed!
• GFR UV Urine concentration x Rate of
  Urine Flow g/ml x ml/min ml/min
• P Blood Plasma
  Concentration
  g

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Excretory System Problems

• Kidney stones crystalized mineral salts and
  uric acid salts in the urine. Stones block flow
  of urine and cause excrutiating pain.
• Kidney failure - can be caused by long-term
  diabetes, infections, physical injuries, chemical
  poisoning. Causes toxic materials to build up to
  lethal levels.
• Dialysis or kidney transplant is the treatment.

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Diseases of Excretory System

• Obstructive Disorders
• Urinary tract infections (UTI)
• Glomerular Disorders
• Renal Failure
• Acute
• Chronic
• Treatment for Renal Failure
• Incontinence, Prostatitis, BPH (national)