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SAT II BIOLOGY > Excretion > Flashcards

Flashcards in Excretion Deck (15):
1

Excretion

Removal of metabolic wastes

2

What organs are involved in excretion in humans?

Kidneys, skin, lungs, liver

3

Skin

Excretes sweat(water&salts), including urea

4

Lungs

Excrete water vapor and CO2 from the Krebs cycle

5

Liver

  • Doesn't excrete anything from the body
  • Site of deamination of amino acids
  • Production of urea

6

Kidneys

  • Excrete excess water and urea
  • Adjusts volume and concentration of urine
  • Filter 1500 liters of blood per day 
  • Produce 1.5 liters of urine

7

Why is the kidney able to respond quickly to changing requirements of the body?

 

  • Under hormonal control
  • Antidiuretic hormone(ADH) targets the collecting tube of the nephrons

8

Antidiuretic Hormone (ADH)

  • Targets the collecting tube of the nephron
  • regulates blood presure by cotnrolling how much water is reabsorbed by the kidneys

9

Nephron

  • Basic functional unit of the kidney
  • Consists of:
    • Glomerulus
    • Bowman's Capsule
    • Loop of Henle
  • Job:
    • Filtration
    • Secretion
    • Reabsorption
    • Excretion

10

Glomerulus

A cluster of capillaries that sits inside the BOwman's capsule

Sieve that only amino acids and glucose can pass through, not blood or proteins

11

Bowman's capsule

Cup-like structure around the glomerulus and forms the starting end of the tubule

12

Filtration

  • Diffusion through the glomerulus to the Bowman's capsule; Passive and nonselective
  • Glucose, salts, vitamins, wastes(rea)
  • Glomerulus --- Bowman's capsule ---- loop of Henle ------ collecting duct/tubule ---- ureter and urinary bladder(temporary storage) ---- urethra --- out of body

13

Secretion

  • Active, selective uptake of molecules that didn't get filtered 
  • Occurs in the tubules of the nephron

14

Reabsorption

  • Most of the water and solutes (glucose, amino acids, vitamins) that entered during filtration are transported back into the capillaries and back to body
  • Occurs in tubule, loop of Henle, collecting tubule
  • Longer the loop of Henle, greater reabsorption of water

15

Aldosterone

  • Produced by adrenal cortex
  • Stimulates reabsorption of Na+ and secretion of K+
  • Leads to a rise in blood volume and blood pressure
  • secreted in response to low extracellular sodium
  • Conserve water and sodium