personal growth paper

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UppersDownersAllArounders-8thEdition-CH2.pptx

2.1 - The nerve cells in the central nervous system use a language that is spelled out in electrical and chemical bits of information. Neurotransmitters cross the synaptic gap and relay messages electrically. There are over 100 billion nerve cells and 100 trillion connections in the body.

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2.2 - The blood brain barrier prevents toxic substances from entering the brain but because the structures of psychoactive drugs are similar to the structures of neurotransmitters they are able to pass through this barrier.

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2.3 - The nervous system is divided into the peripheral and the central nervous systems (CNS). The peripheral nervous system consists of the somatic and autonomic systems. The two parts of the CNS are the brain and spinal cord. Psychoactive drugs primarily affect the central nervous system. They also affect the part of the autonomic system responsible for involuntary functions, e.g., respiration and heartbeat.

The somatic nervous system (SNS) is the portion of the Peripheral Nervous System responsible for voluntary body movement and for sensing external stimuli. All five senses are controlled by the somatic nervous system.

The autonomic nervous system (ANS) is divided into two parts; Sympathetic & Parasympathetic.

The ANS is responsible for regulation of internal organs and glands, which occurs unconsciously.

The sympathetic division typically functions in actions requiring quick responses. It is responsible for activating the fight-or-flight response but it is also constantly active in maintaining homeostasis.

The parasympathetic division functions with actions that do not require immediate reaction. To be specific, the parasympathetic system is responsible for stimulation of "rest-and-digest" or "feed and breed“ activities that occur when the body is at rest, especially after eating, including sexual arousal, salivation, lacrimation (tears), urination, digestion, and defecation (SLUDD). Its action is described as being complementary to that of the sympathetic nervous system

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2.4 - The fossil record of brain evolution demonstrates that our human brain actually consists of two brains. An “older” brain that is present in all mammals and a “newer” brain, the neo cortex, which gives humans more conscious awareness. The old brain is instinctual, more powerful and works faster than the new brain which covers it.

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2.5 - The surface of the lungs are about the size of a football field. The lungs deliver drugs to the brain in 8 seconds; injection is nearly as fast. It takes 30 minutes or longer for a drug to reach the brain when taken orally.

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2.6 – The liver is the primary location where drugs are metabolized and usually deactivated.

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2.7 – There are many different types of brain cells, all of which have a single axon but many dendrites. Purkinje cells can have up to 10,000 dendrites.

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2.8 – All memories are formed as physical protrusions in the brain. Addiction memories are processed in the brain the same as emotional memories which have a more powerful influence on a persons behavior.

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2.9 – The brain’s addiction pathway consists of two major circuits: Survival/Reinforcement circuit in the old brain and the control circuit human neo or new brain.

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2.10 – Craving for drugs in addiction can be visually observed by brain scans. This PET scan reveals activation of the brain’s amygdala when craving occurs in cocaine addicts.

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2.11 – Neurotransmitters, nerve cell chemicals produced by nerve cells, communicate all information between the billions of nerve cells in the brain and body.

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2.12 – All psychoactive drugs have effects in the brain because they act like or disrupt natural brain chemicals known as neurotransmitters.

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2.13 – There are several interactions that can occur when brain cells synapse (communicate with each other).

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2.14 – Down regulation provides one explanation for the development of drug tolerance whereby the brain and/or body becomes resistant to the effects of drugs.

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2.15 - Tolerance can be explained because of the down regulation of neurotransmitters. The more often the cell’s receptor sites are exposed to a drug the more they retreat into the cell wall effectively reducing the number of receptor sites and making it less sensitive to the substance. This causes a need to increase in the amount of the drug to produce the same effect; but will also accelerate down regulation.

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2.16 – Withdrawal symptoms that result from abstinence in addiction are often the opposite effects of the drug’s action when it is used.

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2.17 - These studies of genetic alcohol avoiding and genetic alcoholic mice shows how addiction comes about through different processes.

By continuous exposure to a substance.

Through unavoidable stress plus the availability of a substance.

Through poor nutrition plus the availability of a substance.

Through genetic predisposition to addiction plus exposure to a substance.

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