Excretion

• Body can get rid of co2,urea,o2
• Plants can get rid of o2
• Carbon dioxide, urea, oxygen, lactic acids, are all metabolic waste products
• Carbon is a metabolic waste product/excretory product
• What do metabolic reaction/metabolism involve?

  It involves the chemical reaction taking place inside the living cell
• urea is a metabolic waste product/excretory product
• Oxygen is a metabolic waste product/excretory product
• egestion is the removal of undigested food out of the body in form of feces
• What is Egestion?

  it is the removal of undigested food out of the body in form of feces
• What is excretion?


  Removal of toxic metabolic waste products such as urea/co2 or substances found

  in excess out of the body.
• What is the glamorous?

  A taft of capillaries, providing high blood pressure
• What is bladder?

  The organ that stores urine
• Renal artery

  Blood vessels with the highest concentration of urea
• Renal vein

  Blood vessel with the lowest concentration of area
• Ureter

  Tube that carries urine out of the kidney
• Urethra

  Tube that carries urine out of the body
• Homeostasis

  Maintaining the internal environment of the body constant
• Process of urine formation/Role of kidney in excretion

  Filtration of blood

  where ultrafiltration occurs in the glamorous

  reabsorption of useful substances, such as glucose

  Removing urea and substances found in excess
• There are 3 stages

  Ultrafiltration

  Selective reabsorption

  Collecting duct
• Ultrafiltration

  Blood filtered out under high pressure where small molecules such as glucose, water, urea,

  salts, oxygen and amino acids are forced out of the blood through capillary pores in

  glomerulus to be collected in bowman's capsule
• Selective reabsorption

  Reabsorption of useful substances such as glucose/salts by active transport, most water by

  osmosis back to blood.
• Collecting duct

  More water reabsorbed by osmosis into blood, urea and excess salts dissolved in excess water

  form urine to be excreted.
• Osmoregulation

  so water

  Controls the amount of water excreted in urine.

  Depending on how much water our body needs.
• Hot weather/Exercise

  • Alot of water is lost as sweat.

  • So less in urine.

  • Urine will be dark yellow.

  • Since there is more urea than water.

  • Small volume of urine produced.

  • To prevent dehydration.

  • Keeping water in blood constant.
• Cold weather/Drink a lot of water

  • More water lost in urine.

  • Urine is diluted.

  • Large in volume.

  • To help you get rid of excess water
• Role of kidney in homeostasis

  • Maintain amount of urea and water in blood

  • Water through reabsorption back to blood by osmosis.

  • Urea through filtration and diffusion then excreted in urine.
• Glomerulus structure

  • Network of capillaries.

  • Ball shape.

  • Has pores.
• Role of glomerulus

  • Provides blood at high pressure.

  • Provides large surface area.

  • For ultrafiltration to occur.

  • Small molecules can pass through capillary pores.

  • Large molecules cannot pass as they are large and stay in glomerulus.
• How is urea formed

  By deamination

  Breakdown of Access amino acids

  Removal of nitrogen containing part

  In the liver

  Producing area