Element B1 / 3 Target Organs and Systems

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Nathaniel Morrison
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1 / 3 Target Organs and Systems

2 Target Organs / Target Systems (Specified toxic substance exerts its effects) Target organs Liver Lungs Kidneys Brain Skin Bladder Eyes

3 Target Organs / Target Systems Substances that have target effect Coal dust Lungs pneumoconiosis Mineral oils Skin Benzidine Bladder Leptospirosis Liver and kidneys

4 Target Organs / Target Systems Target systems Nervous system Circulatory system Reproductive system Substances and effects Alcohol and solvents CNS Lead and Mercury CNS

5 Target Organs / Target Systems Chemical Entry and Target Organs Once chems have entered bloodstream distribute at a rate which depends on: Rate of blood flow Structure of capillary wall Affinity of tissue for the chemical

6 Target Organs / Target Systems Chemicals are stored or metabolised by the organs Eg. Lead Replaces calcium in long bones Structural weakness Later released into bloodstream Toxic effects Chlorinated hydrocarbons (i.e. pesticides) Accumulate in body fats

7 Target Organs / Target Systems Primary metabolising organ is liver Largest internal organ 500 metabolic functions, including detox of poisons Ability to regenerate after toxic damage But chronic exposure = cirrhosis Detox To make absorbed chems more water soluble Render harmless and aid secretion from body

8 Target Organs / Target Systems Liver Responds to substances in different ways Exposure to nickel expelled in urine Exposure to styrene converted to mandelic acid and expelled in urine Exposure to trichloroethylene converted to trichloroacetic acid and expelled in urine Sometimes by product can be toxic bioactivation

9 Excretion Kidneys Predominant route for excretion Pass urine through bladder urethra Digestive tract Bile and faeces Lungs and Body Fluid Minor routes

10 Excretion Liver / Kidneys / Bladder Long contact time = high concentration

11 Local Effects Chem causes harm at first contact E.g. substance inhaled to lungs

12 Systemic Effects Chem enters via a route and has effect elsewhere E.g. CO2 inhaled no direct effect on lungs Systemic effect replaced oxygen in blood

13 Main Routes of Entry Eyes and ears Inhalation Ingestion Skin pervasion Injection

14 Main Routes of Entry Eyes Water soluble substances Conjunctiva absorbs Passes through eye destroys tissue Virus / bacteria

15 Main Routes of Entry Inhalation Most significant route of entry 90% industrial poisons through lungs Particle size important Micron = 1 millionth of a metre Larger particles = >10 microns Travel as far as nose Smaller particles = 5 to 10 microns Enter bronchi and bronchioles Smaller again = < 5 microns As far as alveoli Smallest = < 0.3 microns Exhaled without settling in alveoli

16 Main Routes of Entry Ingestion Through digestive tract (mouth to anus) Eating, drinking, smoking, in contaminated areas Touching mouth, licking lips Chemicals can be ejected spitting Swallowing stomach vomiting (imm. Response) Or absorbed through lining Intestine liver bloodstream - colon

17 Main Routes of Entry Skin pervasion Skin = semi permeable membrane Substances absorbed Via cuts / abrasions Thin membranes eye or ear Transferred by blood to target organs / systems Injection Sharp objects - contaminated

18 Common symptoms of attack Lungs Wheezing, short of breath Coughing Allergic asthma Skin Reddening, cracking, blisters Dermatitis = chronic effect Nose / eyes Increased mucus Swelling / reddening Digestive tract Nausea / vomiting

19 Physical form of substances Contributing factor to it s potential harm How easily it gains entry into body Solids More harmful when finely divided / airborne and inhaled Dusts Solid airborne particles Grinding, crushing, milling, sanding, demolition Particle size is important

20 Physical form of substances Fibres May be so small inhaled into alveoli Fumes Solid particles formed by condensation from the gaseous state Welding fumes number of gases with variety of particles suspended in it Liquids Ingestion or skin Mists finely dispersed spray, foam, etc Vapours solvents release vapours

21 Physical form of substances Gases Formless fluids produced by chemical process A gas will normally seek to fill the space completely into which it is liberated

22 Properties Main process of entry of chemicals is by absorbtion Site of absorbtion = not always the process of entry E.g inhaled into the alveoli and onto the bloodstream. Process is influenced by chemicals properties

23 The Body s Defensive Responses Innate Immune Response Immediate defence against infection Eg white blood cells remove substances from organs, tissue, blood Adaptive Immune Response Provides immune system with cells (lymphocytes) that have ability to mount stronger attacks each time pathogen encountered Modification of DNA recognise and remember

24 The Body s Defensive Responses Superficial Defense Mechanisms Nose trapped by nasal hairs Resp tract reflexes coughing, sneezing expels Mouth taste spits out Stomach acid vomiting Skin Limited by physical characteristics Outer layer oily surface substances have to overcome this Dead skin cells sacrificed to preserve new ones Blister protects cells underneath

Lecture 2 Chemical and Biological Agents

Lecture 2 Chemical and Biological Agents In the Chemical ad Biological section, Routes of exposure we will be covering: Forms of Chemical agents Examples of chemical agents Forms of Biological agents Classifications