Drugs and Addiction

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Drugs and Addiction

• (Chapter 14)

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Drugs and addiction

• Drug addiction is a condition characterized by
  compulsive drug intake, craving and seeking,
  despite negative consequences associated with
  drug use.
• The activity of any drug varies with dose
• The amount of the drug taken over time
• The amount of a drug taken to be toxic or lethal
  depends upon the chemical structure of the drug
• Also body size and other physiological variables

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Drugs and addiction

• Although being addicted implies drug dependence,
  it is possible to be dependent on a drug without
  being addicted.
• People that take drugs to treat diseases and
  disorders, which interfere with their ability to
  function, may experience improvement of their
  condition.

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Drugs and addiction

• There is an growing consensus that drug addiction
  is a form of disfunctional learning.
• Drugs of abuse take over the neuronal circuitry
  involved in motivation and reward, leading to
  aberrant engagement of learning processes.
• Because of this, drug-associated cues can trigger
  cravings as well as unconcious or compulsive
  drug-seeking behavior, with the sense that
  voluntary control over drug use is lost.

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How drugs enter the body

• The way in which a drug enters the body often
  affects its resulting concentration in body
  tissues.
• Example Cocaine
• A product of the coca plant grows in the high
  Andes
• Cocaine exists in many forms that differ in both
  conc of the drug and its molecular form.
• Coca leaves are chewed by South American Indians
• Concentrations absorbed by the gut are low

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How drugs enter the body

• By contrast, when cocaine is purified into a
  powder and sniffed the rate and concentration of
  absorption is increased many times.
• Cocaine is sometimes further purified into crack
• Whether cocaine is sniffed or smoked, it is
  inhaled not as a gas, but as small particles
• For these chemicals to be absorbed they must
  first adhere to lung tissue

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How drugs enter the body

• Chemicals can be highly concentrated within a
  particle
• Thus these particles cause substantial damage to
  lung tissue
• Sniffing cocaine powder also causes substantial
  damage to cells in the nasal passage and rot a
  person nose
• Can also eat away at the roof of the mouth

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How drugs enter the body

• Other drugs are injected into the body.
• Can be injected into veins, or under the skin
• Continued uses always leads to infection and
  amputation of damaged tissue

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How drugs enter the body

• In the US, most drugs are inhaled and quickly
  enter the blood system and affect the brain.
• However, it is important to remember that the
  most popular drug in the US is caffeine!
• The second is alcohol!
• It is important to remember what is a drug!

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So what is the biology of the Respiratory System?
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The Respiratory System

• During inspiration or inhalation, air is
  conducted toward the lungs.
• During expiration or exhalation, air is conducted
  away from the lungs.
• Works in conjunction with the cardiovascular
  system for RESPIRATION to occur
• Breathing air in and out of lungs
• External respiration exchange of gasses between
  air blood
• Internal respiration exchange between blood
  tissue fluid
• Cellular respiration production of ATP in cells

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The Respiratory System

• Two parts
• Upper Respiratory Tract
• Nasal Cavities
• Filter, warm and moisten air
• Pharynx
• Connection to surrounding regions
• Glottis
• Passage of air into larynx
• Larynx
• Sound production

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The Respiratory System

• Lower Respiratory Tract
• Trachea
• Passage of air to Bronchi
• Bronchi
• Passage of air to lungs
• Bronchioles
• Passage of air to each alveolus
• Lungs
• Gas Exchange

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The Respiratory System

• As air moves towards the lungs it is cleansed,
  warmed, and moistened.
• As air moves out during expiration, it cools and
  deposits moisture on the lining of the trachea
  and the nose

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The Larynx

• This serves as a passageway for air between the
  pharynx and the trachea.
• The larynx houses the vocal cords
• Mucosal folds suspended by elastic filaments
  stretched across the glottis.
• Air moves through glottis vibration - sounds
• The trachea is a tube connecting the larynx to
  the primary bronchi.

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The Trachea

• Windpipe connects larynx to primary bronchi.
• Held open by cartilage
• Goblet cell
• Makes mucus
• Mucosa contains layer of pseudostratified
  ciliated epithelium
• Sweep dirt and excess mucus upwards

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The Bronchial Tree

• The trachea divides into L R primary bronchi
• eventually branch into secondary bronchi and then
  into bronchioles.
• Each bronchiole leads to an elongated space
  enclosed by alveoli.

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The Lungs

• These lie on either side of the heart within the
  thoracic cavity.
• Total cross-sectional area of 50 70 meter
  squared (1 ½ Tennis courts)
• Right lung has three lobes and the left lung has
  two lobes.
• This allows room for the heart
• Each lobe is divided into lobules, further
  divided into bronchioles serving many alveoli.

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Alveoli

• There are 300 m alveoli per set of lungs.
• Each one is made up of squamous epithelium and
  blood capillaries.
• Gas exchange occurs O2 diffuses across the
  alveolar wall and enters blood CO2 goes in
  other direction
• Lined with lipoprotein lowers surface tension
  and prevents them from closing.

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Mechanism of Breathing

• Respiratory Volumes
• Tidal volume is the amount of air that moves in
  and out with each breath.
• Vital capacity is the maximum amount of air that
  can be moved out in a single breath.
• Inspiration can be increased by expanding the
  chest (inspiratory reserve volume).
• Residual volume is the air remaining in the lungs
  after deep exhalation

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Gas Exchanges in the Body

• External respiration refers to gas exchange
  between air in the alveoli and blood in the
  pulmonary capillaries.
• Blood entering the pulmonary capillaries has a
  HIGHER partial pressure of CO2 than atmospheric
  air.
• CO2 diffuses out of the blood into the lungs.
• Carried in blood plasma as bicarbonate ions (HC03
  ions)
• Blood entering the pulmonary capillaries has a
  LOWER partial pressure of O2 than the avlvoli.
• O2 diffuses into plasma and then red blood cells
• Binds with hemoglobin forms oxyhemoglobin

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Internal Respiration

• Internal respiration - gas exchange between the
  blood in systemic capillaries and the tissue
  fluid.
• O2 diffuses out of the blood into the tissue
  because the partial pressure of O2 in tissue
  fluid is LOWER than that of blood.
• O2 leaves hemoglobin and enters tissue fluid
• CO2 diffuses into the blood from the tissue
  because the partial pressure of CO2 in tissue
  fluid is HIGHER than that of blood

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• Internal Respiration occurs at systemic
  capillaries that is in the major organs.
• External Respiration occurs at pulmonary
  capillaries that is in the lungs ONLY

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Addiction

• Addiction has been defined as
• Compulsive physiological and psychological need
  for a substance
• This implies there is both a biological basis and
  a mental basis for addiction.
• However, as all brain function is biochemically
  based, the distinction between physiological and
  psychological addiction is becoming blurred.

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Addiction

• Ventral tegmental area (VTA)
• Thought to be positive enforcement area (pleasure
  center).
• Experiments on rats and rhesus monkeys have show
  that both would rather electrically stimulate
  this area of the brain than eat even if near
  to starvation
• Nucleus accumbens (NA)
• joined to the VTA by synaptic connections
• Interprets the stimulation signal from the VTA

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Addiction

• Frontal cortex (FC)
• Play a part in impulse control, judgment,
  language production, working memory, motor
  function, problem solving, sexual behavior,
  socialization and spontaneity.
• Assist in planning, coordinating, controlling and
  executing behavior.
• This is why behavioral changes occur which are
  hard to break

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Addiction

• So these positive reinforcement areas are
  affected by drugs
• Amphetamines indirectly stimulate the neurons of
  the VTA
• Used as a treatment for depression
• Cocaine acts on the brain cells of the VTA that
  secrete dopamine
• Produces euphoria

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Addiction

• Opiates, marijuana, caffeine, and alcohol all
  produce VTA self-reinforcing effects.
• Drugs of abuse take over the neuronal circuitry
  involved in motivation and reward, leading to
  altered engagement of learning processes.
• Because of this, drug-associated cues can trigger
  cravings as well as unconcious or compulsive
  drug-seeking behavior, with the sense that
  voluntary control over drug use is lost

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Addiction

• The stages of problematic use could be defined as
  Pre-occupation/anticipation, binge/intoxication
  withdrawal/negative effect
• As drugs activate neuronal pathways in the brain
  we effectivly learn to use them, these pathways
  in the brain not only get 'laid down' stronger
  and stronger with sucessive use but also activate
  faster
• the quicker the effect or 'high' the stronger
  this dysfunctional learning

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Addiction

• Objects, people or places also seem to to be
  strongly associated with the drug experience,
  making them 'Triggers' to 'Cravings'
• increase the chances of further use.
• Animal studies have shown drug availabilty over
  and above the actual effects of the substance)
  are associated with stimuli, exposure to objects
  associated with use trigger the release of
  adrenaline (Fight or flight)
• this excitation can be perceived as a 'need' to
  use

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Addiction

• Users in addictive drugs in the US in 1991
• The top three are widely not considered drugs by
  most of the population
• All of these three produce addictive behavior.

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METH

• Methamphetamine or Meth, a derivative of
  amphetamine is an extremely powerful stimulant
  that affects the central nervous system.
• Developed in 1919 by Japanese pharmacologist. 
  Although its initial uses were for medical
  purposes, its ability to increase energy and to
  enable users to function without sleep made it
  attractive for military purposes during World War
  II.

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METH

• Meth has undergone both legal and illegal uses in
  the United States. 
• As early as the 1930s it was used therapeutically
  to treat asthma and epileptic seizures
• In the 1950s it was given to housewives to cope
  with bordem and depression
• During the 1970s meth was a primary appetite
  suppressant in prescription diet pills. 
• The illicit demand for meth resulted in forged
  prescriptions, theft and a black market. 

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METH labs

• How is Meth Made?
• ephedrine reduction. 
• In this process, ephedrine or psuedoephedrine are
  chemically extract from over the counter cold
  medicines. 
• Red phosphorous (match tips), iodine (table
  salt), acetone (nail varnish remover), and
  sulphuric acid (car battery) are all that is
  required

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METH labs

• Lastly, drain cleaner, camping fuel and paint
  thinner are used to dry out the drug into a
  powder
• Clandestine labs are often simple, crude and
  consist of common household items. 
• Meth can be cooked in basements, old buildings,
  motel rooms, camping trailers and moving vehicles

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How to tell if Someone is on or has been using
Meth

• Meth affects nerve endings throughout a user's
  body.
• Many people feel a sensation of small bugs, known
  as "Meth Mites", moving right under their skin.
• They scratch, pick and dig the spots, trying to
  relieve the itching.
• The Meth Mites and the scratching result in sores
  and serious infections

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How to tell if Someone is on or has been using
Meth

• The heated substance, when fully aspirated,
  swirls through the users' teeth and gums,
  inevitably leading to sores which never heal
  -Meth Mouth
• Tooth enamel wears away quickly as entire rows of
  teeth dissolve to the gum line.
• Collects in the nasal passages which drain in the
  back of the throat, effectively corroding your
  entire face.

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How to tell if Someone is on or has been using
Meth

• Chronic meth users are typically gaunt, maintain
  poor hygiene.
• Lose interesting in eating
• Digestive system shuts down due to chemicals used
  to make meth
• Kidney and liver shut down
• Due to all the toxic chemicals
• Skin scratched off, infections
• Blindness

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Environmental Damage

• Each pound of meth produced leaves behind
  five-seven pounds of toxic waste.
• Toxic byproduct is often poured down drains or
  directly into the ground, creating long term
  hazards.
• Mobile labs and meth lab dump-sites are found
  threaten our states natural resources.
• Clean-up costs range from 5,000 to
  50,0005,000-50,000

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The End.

• Any Questions?