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Excretory System - Coggle Diagram

- - - - Nephrons are the filtering units in the kidney
      - They clean and rebalance the blood to produce urine
      - Parts
        
        Glomerulus and Bowman's Capsule
        
        Renal artery splits into numerous arterioles, each feeding a nephron
        
        Afferent arteriole feeds the glomerulus
        
        It is enclosed by the Bowman's Capsule
        
        Efferent arterioles leave the glomerulus
        
        The glomerulus it a knot of capillaries from by the arteriole
        
        The afferent arteriole leading into the glomerulus is wider than the efferent arteriole leading out because of higher blood pressure in the capillaries
        
        This pressure forces plasma out of the blood by filtration
        
        Small molecules are squeezed out of the blood to form a filtrate in the Bowman's capsule
        
        Only blood cells and larger proteins remain in the blood
        
        Filtration
        
        Small molecules diffuse out of the
        blood creating a filtrate consisting of:
        
        Water
        
        Electrolytes
        
        Amino acids
        
        Glucose
        
        Urea
        
        Proximal Convoluted Tubule
        
        80% of the filtrate is reabsorbed here
        by the tissue fluid and then into the blood
        
        This ensures that the 'useful' materials
        that were filtered out are put back in the blood
        
        Loop of Henle Descending Limb
        
        Some water leaves the filtrate through osmosis because the medulla surrounding the loop is very salty
        
        The filtrate gets more concentrated as it descends due to the water leaving
        
        Loop if Henle Ascending Limb
        
        Makes the tissue fluid hypertonic (Concentrated with solutes) compared to the filtrate in the nephron
        
        The purpose of this is to make more water be absorbed in the descending limb
        
        Na and Cl are actively transported out of the ascending limb
        
        Water would follow via osmosis, but the ascending limb is impermeable to water
        
        Distal Convoluted tubule
        
        Certain substances are actively transported (Secreted) from the blood into the filtrate
        
        Include H+ (for pH homeostasis), K+ (for salt homeostasis), ethanol, toxins, drugs and other 'foreign' substances
        
        This secretion is regulated by hormones, so this is the homeostatic part of the kidney
        
        Collecting Duct
        
        The collecting duct passes through the salty medulla, so water can be regulated
        
        This concentrates urine and conserves water
        
        Water leaves via special water channels in the cell membrane that can be controlled by ADH (Anti-Diuretic Hormone)
        
        Allows the amount of water in the urine to be controlled
        
        More ADH opens the channels, so more water is conserved in the body, and more concentrated urine is produced
- - - - Is when waste and indigestible material
        is removed from the body
        
        Solid waste from the digestive system in the form of faeces
    - - Is the removal of metabolic wastes - produced by chemical reactions like respiration, hydrolysis, synthesis and neutralization
        
        e.g. Water, Carbon Dioxide, Salts, Urea