Excretory System

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Excretory System

• Metabolic Waste Removal

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Organs of Excretory System

• Lungs CO2 and water
• Skin - Sweat
• Kidneys Urine
• Liver detoxification of blood
• These organs work with other body systems to keep
  the body in homeostasis.

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Excretion

• Excretion is the process by which waste and
  excess substances are removed from the body.
• If wastes from metabolism (metabolic wastes) are
  not removed from the body, the body will die.
• Metabolic wastes come from chemical reactions in
  the cells of the human body

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Major Metabolic Wastes

• Carbon Dioxide
• Nitrogen compounds
• Ammonia
• Urea
• Uric acid
• Mineral Salts
• Sodium chloride
• Potassium sulfate
• All of these wastes are poisonous to the body in
  high concentrations

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Nitrogen wastes

• Nitrogen wastes are a by product of protein
  metabolism.
• Amino groups are turned into ammonia, which in
  turn is converted to urea, dumped into the blood
  and filtered out by the kidneys.
• Ammonia is converted to urea, a compound the body
  can tolerate at higher concentrations than
  ammonia.

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Role of the Liver

• Removes harmful substances such as bacteria,
  certain drugs, and nitrogenous wastes from the
  blood
• In the liver the substances are changed into
  inactive or less poisonous forms
• Inactive substances (urea) are returned to the
  blood stream and filtered and excreted by the
  kidneys.

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The Skin

• The skin performs a number of different functions
  one of them is excretion of wastes.
• In sweat there is a small amount of urea and
  salts.
• Sweat 99 water 1 Urea and Salts

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Lungs

• Excrete CO2 and Water
• The end products of cellular respiration

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Urinary System

• Waste is filtered from the blood and collected as
  urine in each kidney.
• Urine leaves the kidneys by ureters, and collects
  in the bladder.
• The bladder can distend to store urine that
  eventually leaves through the urethra
• The urinary system
• Kidneys
• Ureters
• Bladder
• urethra

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Urinary tract
Kidneys
Ureters
Bladder
Urethra
Prostate
Male
Female
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Kidneys

• Bean shaped organs that are about 10cm long
• Main Functions
• Remove wastes of cellular metabolism (metabolic
  waste)
• Regulate the concentrations of the substances in
  the blood

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Kidneys (1)
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Kidneys (2)
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Structure of the Kidneys

• Kidney is made up of 3 parts
• Cortex outer part
• Medulla middle part
• Pelvis inner part
• Blood is filtered in the cortex
• Collecting ducts extend through the medulla
• The filtered substances, called the filtrate,
  collect in the pelvis which are connected to the
  ureter

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Cross Section of Kidney
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Nephrons

• MOST important job of the kidney is to filter
  waste from blood
• The filtering is done by the nephron.
• There are about 1.25 million nephrons in each
  kidney

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Components of The Nephron

• Glomerulus Arteriole blood is filtered under
  high pressure.
• Bowman's Capsule surrounds the glomerulus and
  collects the filtrate

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Bowman capsule
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Component of Nephrons Continued

• Proximal Convoluted Tubule
• Loop of Henle
• Distal Convoluted Tubule
• All of these nephron structures aid in the
  reabsorption of materials needed for the body.

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Nephron (1)
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The Nephron Function

• The nephron consists of a ball of blood
  capillaries called the glomerulus
• Blood flows into the kidney through the renal
  artery, which branches into capillaries
  associated with the glomerulus.

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The Nephron Function Continued

• Arterial pressure causes water and solutes from
  the blood to filter into the Bowmans Capsule
  which surrounds the glomerulus
• The Filtrate flows through the proximal
  convoluted tubule, loop of Henle, and then into
  the distal convoluted tubule.
• The distal tubule empties into a collecting duct.
  Which carries urine to the pelvis of the Kidney

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The nephron has three functions

• Glomerular filtration of water and solutes from
  the blood.
• Tubular reabsorption of water and conserved
  molecules back into the blood.
• Excretion of urine from collecting tubes

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WOW thats a big filter

• Nephrons filter 125 ml of body fluid per minute
  filtering the entire body fluid component 16
  times each day.
• In a 24 hour period nephrons produce 180 liters
  of filtrate, of which 178.5 (99) liters are
  reabsorbed.
• The remaining 1.5 liters forms urine.

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Disruption of Kidney Function

• Infection, environmental toxins such as mercury,
  and genetic disease can have devastating results
  by causing disruption of kidney function. Many
  kidney problems can be treated by dialysis, where
  a machine acts as a kidney. Kidney transplants
  are an alternative to dialysis.