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CH3041
THE CHEMICALS
• A xenobiotic substance is one which is
foreign to a living system.
foreign to a living system.
• An endogenous substance is one which
occurs naturally in a living organism.
occurs naturally in a living organism.
• Endogenous chemicals may show a bell
shaped curve rather than an S curve.
shaped curve rather than an S curve.
Detrimental effects
Lethal effects
Physiological conditions
• These curves
occur for
the various essential
nutrients Ca, P, K, Na..
the various essential
nutrients Ca, P, K, Na..
• Some biological
cmpds
are biosynthesized as toxins
which give the familiar S-shaped curves.
are biosynthesized as toxins
which give the familiar S-shaped curves.
