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:star: Excretion In Humans (:fountain_pen: The Human Urinary System ((5)…

- - - - Human kidney contains 12-16 renal pyramids
      - Numerous kidney tubules = nephrons (urine is formed here)
    - - Outer dark red region, covered and protected by a fibrous capsule
    - - Enlarged portion of the ureter inside the kidney
    - - Renal pyramids are located here
      - Inner pale red region
  - - - (5) Collecting Duct
      - (3) Loop of Henle
      - (2) Proximal Convulated Tubule
      - (1) Bowman's Capsule
      - (4) Distal Convulated Tubule
    - - (2) Each arteriole further branches into a mass of blood capillaries (glomerulus), glomerulus + bowman's capsule = Renal Corpuscle
      - (3) Blood then enters blood capillaries surrounding the nephron
      - (1) Blood enters the kidney by the renal artery, which branches into arterioles
      - (4) Blood capillaries then unite to form venules, which in turn forms a branch or the renal vein
  - - - Alcohol abuse
      - Severe accidents that physically damage the kidney
      - Diabetes
      - Complications from undergoing major surgery
      - High blood pressure
    - - Kidney Transplant
      - Dialysis Machine
        
        Features of a dialysis machine
        
        The dialysis fluid does not contain metabolic waste products
        
        Sets up concentration gradient = waste products are removed from the blood
        
        The tubing in the machine is narrow, coiled and long
        
        Increases surface area to volume ratio = speeds up rate pf exchange of substances
        
        Dialysis fluid contains the same concentration of essential substances as healthy food
        
        Ensures that essential substances do not diffuse out, if blood plasma lacks these substances, substances can diffuse into the blood from the fluid,
        
        The direction of the blood flow is opposite to the flow of the dialysis fluid
        
        Maintains concentration gradient for the removal of waste products
        
        How does it work?
        
        Blood drawn from patient and is pumped through the machine
        
        Small molecules (urea, other metabolic waste products) diffuse out the tubing (partially permeable) into dialysis fluid
        Blood cells, platelets and large molecules remain in tubing
- - - - Some water reabsorbed
    - - Some water reabsorbed
      - Mineral salts reabsorbed
    - - Glucose and Amino Acids reabsorbed (diffusion and active transport)
      - Most water reabsorbed (osmosis)
    - - Excess water reaborbed
      - Excess salts and metabolic waste products reabsorbed (as urine to renal pelvis)