Chapter: Physiological Processes

Topic: Physiological Processes – Notes

* The nervous system, glands, and muscles control human and animal

responses.

- All cells in the nervous system share two attributes: irritability and

conductivity.

Neurons

* The neuron is the basic cell of the nervous system.

The firing process in the neuron completely exhausts its resources:

- Absolute refractory period: the short time period during which a cell

cannot fire again no matter how stimulated.

- Relative refractory period: the time period during which the neuron needs

stronger stimulation than usual in order to fire (follows the absolute

refractory period).

- Neurons fire according to an all-or-none principle. If the stimulation is

severe, they fire more rapidly.

- The firing of a neuron greatly changes the electrical potential within the

cell; the process of neuron-to-neuron conduction is a complex

electrochemical reaction:

- Neurotransmitter: chemical that must be released and cross the synapse

separating one cell from the other in order to stimulate another neuron.

Nerves

* A nerve is composed of many neurons, and the nervous system is a

complex communications network of neurons, activated by receptors.

- Afferent neurons carry messages toward higher levels in the central

nervous system.

- Internuncial (associative) neurons carry information within the

system at any given level.

- Efferent neurons conduct messages away from the central nervous system

toward the effectors, which are muscles or glands.

Organization in the Nervous System

Nervous System

/ \

Central Nervous System (CNS) Peripheral Nervous System

/ \ / \

Brain Spinal Cord Somatic Nerv. Sys. Autonomic Nerv. Sys.

(voluntary muscles) / \

Sympathetic Parasympathetic

Nerv. Sys. Nerv. Sys.

/ \

expends body stores body

resources resources

Central Nervous System

* Responses controlled at each higher level in the central nervous system

become more and more complex, less fully automatic, and involve larger

amounts of coordinated, voluntary muscle activity.

- Spinal cord: controls the simplest reflexes, but serves mainly as a

message carrier between the peripheral nervous system and the brain.

Brain

/ \ \

Hindbrain Midbrain Forebrain

/ \ \

Thalamus Limbic Cortex

System / \

Left Right

Hemisphere Hemisphere

- Most complex sensory-motor reactions are controlled by the cortex, which

is also the seat of thought, memory, and language.

- The cortex is split into two hemispheres, with each hemisphere controlling

responses on the opposite side of the body. The halves can work together on

complex activities because connections are made through the corpus

callosum and through other lower-level connections.

Glands

- In addition to the nervous system, a system of glands influences how we

behave.

- Eight endocrine (ductless) glands produce hormones which influence

other glands and organs of the body.

Natural Changes in Consciousness

We can alter our conscious awareness in at least four natural ways:

1) Sleep

2) Biofeedback

3) Meditation

4) Hypnosis

Artificial Changes in Consciousness

Basic body processes can also be altered through the use of drugs such as

depressants, stimulants, or hallucinogens.

Topic: The Nervous System – Notes

*All of the physiological processes within our bodies are coordinated

by our nervous system -- it organizes and coordinates all we think and do.

- We exhibit a huge variety of responses that are ultimately explained in

terms of our neurons, our nerves, the organization of our nervous

system, our spinal cord, and our brain.

- Our brain is composed of the hindbrain and midbrain and the forebrain.

Neurons: the basic cells of the nervous system

Nerves: groups of neurons

Glands: introduce various hormones into our blood stream

We can use our nervous system to create both natural and artificial

changes in our consciousness: sleep, biofeedback, meditation, and hypnosis,

as well as the use of drugs.

Neurons

- Simplest part of the nervous system

- Vary greatly in size:

-> The smallest neurons, probably located in the brain, are less

than a millimeter in size.

-> The largest neurons in the system, connecting the brain with the

lower legs, may be more than a meter in length.

- All neurons have two features in common: irritability and conductivity

- These two processes, irritability and conductivity, are the basic life

processes that all neurons share

- In response to the proper ''stimulation,'' all neurons will fire

Neuronal Firing

- Firing is a process by which ions such as sodium (Na+), potassium (K+), and

calcium (Ca++) are allowed inside the cell boundaries. Likewise, ions

normally kept within the cell are allowed to escape

- The result: the normal electrical charge (called a resting potential) of the

neuron is greatly changed for a moment

- Once a neuron fires, that complex change sweeps rapidly from the point of

stimulation to the farthest ends of the neuron

- The firing impulse (called an action potential) is conducted in one direction

only, from that end to the far end

Topic: Neurons – Notes

Neurons are the most basic components of our nervous system and are

organized into nerves.

NEURON'S FIRING PROCESS

- Firing completely exhausts the neuron's resources

- Before a neuron can fire again it must at least partially restore the resting

potential

- A neuron, when stimulated, either fires or does not fire. That is, it fires

according to the all-or-none principle -- completely, or not at all

- As long as the negative electrical charge stays below the neuron's

threshold, the cell does not fire

- Signals in the nervous system are electrical within the neuron and

chemical between neurons. Thus, a signal transmitted between neurons along

a nerve is described as an electrochemical message

- Synapse: junction through which impulses pass between any two neurons

- Neurons form many synaptic connections to adjacent neurons and

transmitting a message across the synaptic gap is the slowest part of the

entire conduction process.

- When a neuron fires, the impulse usually starts in the dendrites of the cell

and passes from there through the cell body and then out along a single

extension present in each neuron called the axon. When the impulse arrives at

the end of the axon, it releases a chemical, called a neurotransmitter, which

floods into the synapse. That chemical crosses the synapse and reaches the

dendrite of the next neuron.

EFFECTS OF NEUROTRANSMITTERS

* Any one neuron emits only one kind of chemical

* The effect of that chemical on the next cell depends on which chemical has

been released:

1) Stimulating (e.g. Acetylcholine would stimulate the next cell)

- OR -

2) Inhibitory

- Any of a number of other chemicals would inhibit the next cell, making it

harder for other neurons to fire it.

* Drugs may influence the nervous system at the synapse -- helping or

hindering it.

TIMING SEQUENCE OF A NEURON FIRING

- During the absolute refractory period the cell cannot fire again, regardless

of how strongly it is stimulated

- After the absolute refractory period, the recently fired neuron enters a

longer phase called the relative refractory period

- During the relative refractory period the cell will fire again if stimulated,

but it takes mroe than the usual level of stimulation to fire it

- When the cell has fully recovered it will fire again when given the same

level of stimulation as it received originally

- The recently fired neuron recovers fully after only a few thousandths of a

second

- The job of the sodium pump is to assure that certain ions must be outside,

others inside, which causes a slight electrical charge to be reestablished

between the outside and the inside

***The nerves are organized into our nervous system, the director of

which is the brain supplemented by influences of our glands. ***

- The nervous system can cause a variety of changes in consciousness, both by

natural and artificial means.

Topic: Nerves - Notes

Nerves: formed by tracts of clustered neurons

ACTIVITY WITHIN NERVES

- Individual neurons still fire on an all-or-none basis.

- Because each neuron has a different threshold (level of stimulation above

which it will fire), when the impulses in one nerve are combined, much more

information about the stimulus is passed on than in the firing or nonfiring of

a single neuron.

- More severe stimulation means more neurons within the nerve are firing

and each one more frequently.

- The more severe the stimulation, the greater the total activity within a

specific nerve.

*** The nervous system reflects the intensity of stimulation through the

firing rate of individual neurons and/or through the number of neurons firing.

PROCEDURES FOR STUDYING NERVES

1) Electrical Stimulation

- Inserting an electrode into the brain, then applying a very, very slight

electrical charge and thus stimulating a certain area of the brain

2) Chemical Stimulation

- Implanting a chemtrode

- chemtrode: hollow tube anchored to the skull that permits very small

amounts of a chemical to be delivered to a precise point in the brain

- allows study of the precise role of chemicals in the nervous system and

body chemistry

3) Lesioning

- a portion of the nervous system is cut or somehow destroyed

- such research is not usually conducted on humans, but we can study humans

who have somehow damaged their brains (war injuries or accidents)

- helps psychologists determine what portions of the brain and nervous

system control normal responses

***These three techniques -- electrical stimulation, chemical stimulation,

and lesioning -- all involve actively altering the nervous system in some

manner. The electrical and chemical techniques of stimulation involve very

little, if any, damage to the nervous system as a whole. Except for the direct

result of the extra stimulation, the normal behavior of the human or animal

isn't changed. Lesioning is a more severe method.***

4) Electroencephalogram (EEG)

- based on the electrical nature of neuronal activity: electrical impulses

occur in regular patterns that change according to the state of the organism

- requires no alterations to the nervous system

- EEG measures the normal electrical activity of the nervous system

Topic: Organization in the Nervous System – Notes

Nervous system: a complex communications network controlling the body's

internal environment as well as its responses to the world around it.

The nervous system is controlled by the brain.

The processes of our nervous system are set in motion by stimuli from

the receptors.

Receptors: a variety of cells that react to certain aspects of the physical

environment.

Effectors: muscles or glands to which the nervous system connects that

allow control of the body.

- Glands secrete hormones that influence the body's internal environment.

- Muscles usually respond by action.

The nervous system is a network of neurons connecting the receptors with the

effectors.

Three types of neurons are involved in the process of transmitting messages

from the receptors to effectors:

(1) Afferent cells: conduct nerve impulses from the receptors toward the

brain or spinal cord. These are the points in the body where a decision

(voluntary or involuntary) is made as to what the response should be.

(2) Internuncial (associative) neurons: carry information within the system

(3) Efferent cells: conduct nerve impulses away from the decision points to

the effectors.

The central nervous system includes the brain and spinal cord, which are the

decision-makers.

PERIPHERAL NERVOUS SYSTEM

The peripheral nervous system is a relay system that includes all afferent

nerves bringing messages in to the spinal cord from the receptors as well as

the efferent nerves leaving the spinal cord for various organs or muscle

groups.

The peripheral system can also be divided into two groups of nerves on the

basis of the function they serve: somatic and autonomic nervous system.

Somatic nervous system: controls voluntary muscles and movement.

Autonomic nervous system: controls the glands and organs of the body and is

divided into the sympathetic and parasympathetic nervous system.

Sympathetic Nervous System

- focused on using body resources, this system becomes active when you are

in danger or are about to engage in something like an athletic contest.

- physical changes: heart beat increases, digestive processes slow down, and

blood flow is increased to the muscles.

- prepares you for extreme physical exertion

Parasympathetic Nervous System

- physical changes: slows the heartbeat, increases the digestive processes,

and diverts blood from the muscles toward the stomach and intestines.

- restores body resources in preparation for the next event.

*** Activity of each of these nervous systems has essentially opposite

effects. However, together the parasympathetic and sympathetic nervous

systems precisely control the organs and chemical balance in the body.***

Topic: The Brain – Notes

Nervous system: organized to process and deliver neural messages.

Peripheral nervous system: message delivery system.

Spinal cord and brain: decision making apparatus.

Brain: governing portion of the nervous system divided into

three main sections: the hindbrain and midbrain and the forebrain.

Sensory Messages are usually relayed to the spinal cord and up to the brain,

where active processing is involved before any action takes place.

Localization of Function:

Phrenology: Study of lumps on the head to identify unusual ability in skills

controlled by the area of the brain under the lump. This controversial

approach was popular in the 1800s.

*** Evidence shows that certain body functions are controlled by specific

areas of the brain in both humans and animals.***

The human brain is a large group of neurons (some 10 billion) and nerves in

one part of the body. The brain can be divided into a number of areas that are

easy to identify, and each controls different responses of the total organism.

Topic: The Hindbrain and Midbrain – Notes

Brain: controlling portion of the nervous system composed of three

principal sections: hindbrain, midbrain, and forebrain.

Hindbrain: closest part to the spinal cord.

- performs a number of reflex actions

- brain stem and the cerebellum are parts of the hindbrain

Brain stem: located at the top of the spinal cord. Lower part of the brain

stem is located in the hindbrain, the upper part of the brain stem is located

in the midbrain.

-some of the most basic processes of the body, such as breathing and heart

rate, are controlled in the brain stem.

- relays afferent messages from many of the sensory organs to higher levels

in the brain. It also relays efferent messages from those levels to the

effectors.

Cerebellum:

- controls posture, balance, and the muscle tone of voluntary muscles all

over the body.

Control of the most basic processes of life occur at the lowest levels of the

brain. As you move upward through the brain, increasingly complex process

are found.

Midbrain: located just above the hindbrain forms the upper part of the brain

stem.

- serves to relay both afferent and efferent messages.

- performs some of the same kind of reflex responses that are controlled by

the hindbrain.

- also controls more complex responses such as walking

Forebrain:

- third principle part of the brain in addition to the hindbrain and midbrain

- primarily responsible for controlling glands and producing a variety of

natural changes in consciousness

- an act of imagination occurs in the forebrain

Topic: The Forebrain – Notes

In addition to the hindbrain and midbrain, the brain also contains the

forebrain: the most complex and the biggest part of the human brain.

The forebrain is often divided into into two components according to their

functions -- the old or classic part of the forebrain and the new portion, the

neocortex or cortex.

CLASSIC PART OF THE FOREBRAIN

In the classic part of the forebrain, there are three parts:

1) The thalamus: last relay station through which afferent messages will

pass.

It serves as a major ''switching point.'' Messages from all the senses except

that of smell are relayed from here directly to a specific area of the highest

part of the forebrain, the cortex.

2) The limbic system

3) The hypothalamus

- found to be involved in a huge variety of complex human processes

- many of its activities are unconscious and automatic

- reacts to the state of the body by monitoring the blood

- controls eating, drinking, and certain sexual activities as well as more fully

automatic adjustments such as temperature.

- controls the operation of the body's organs through the autonomic nervous

system.

*** Electrical stimulation of the hypothalamus can cause a hungry animal to

stop eating, a full animal to continue eating, and a variety of other surprising

responses.

CORTEX (NEOCORTEX)

* The most complex part of the forebrain is the cortex itself.

- Areas within the cortex are called lobes; there are four lobes, three of

which are separated by deep valleys, or fissures.

1) frontal lobe: located at the front of the brain.

- the back of the frontal lobe contains the motor cortex, which is concerned

primarily with regulating voluntary movements

- the sides of the frontal lobe are the areas of the brain controlling speech

- the front of the frontal lobe seems to be used mainly for abstract mental

activity

2) occipital lobe: center for vision located at the back of the cortex

3) temporal lobe: mainly concerned with hearing, this lobe is located

to the side of the brain and separated from the rest by a fissure

4) parietal lobe: primary receiving area for the skin senses located across the

back top of the brain

The human brain is composed of two apparently equal halves called

hemispheres:

- Events that occur to the left side of the body stimulate the right cortex;

similarly events on the right side stimulate the left cortex.

- The corpus callosum connects the two hemispheres thus ensuring that each

hemisphere is informed of the other.

Topic: Glands – Notes

The functions of the glands represent another set of physiological

processes that also affect our behavior.

Two kinds of glands:

1) Exocrine (ducted):

- secrete through the wall of the digestive pipe to the outside (sweat) or

inside (saliva)

- produces many different products including sweat, saliva, tears, sperm and

eggs

- products are secreted into a duct which carries it either to the skin or to

an internal cavity

- they glands are altered by behavior but do no alter behavior

2) Endocrine (ductless):

- secrete into the circulatory system with the wall of the digestive pipe

- produce hormones which are secreted directly into the bloodstream

- they may affect an organ or another endocrine gland, or they may directly

influence behavior.

- these glands secrete hormones upon being stimulated by other hormones or

by the nervous system

There are eight endocrine glands, two of which (pituitary and adrenal) have

two parts. All the other endocrine glands are controlled by the pituitary,

often called the master gland.

PITUITARY GLAND

- controlled to some extent by chemicals released by the hypothalamus

- secretes a number of hormones that influence the glands and organs

* Control of the pituitary gland by the hypothalamus makes good sense,

since the hypothalamus itself responds to chemicals within the blood

stream.

- By monitoring the blood chemistry, the hypothalamus can directly

stimulate the pituitary gland through neural connections and hormonal

influence.

- The pituitary stimulates the other glands.

Men and women have all these glands in common save one pair collectively

know as the gonads. Men have testes and women have ovaries. Each produces

hormones related to male and female sexual characteristics respectively.

Both these glands respond to gonadotropin, a hormone released by the

pituitary gland.

Three systems are the major factors responsible for the ways humans and

animals behave: 1) the nervous system, 2) the glands, and 3)the muscles.

* Psychologists usually do not study the muscles since they are

simply effectors responding to the nervous system. Understanding the

nervous system and glands is enough to explain the physiological bases of

behavior.

Topic: Natural Changes in Consciousness – Notes

- Changes in our immediate levels of consciousness can be brought about in

two different ways: naturally and artificially.

-> Natural changes in consciousness resulting from alterations of nervous

system activity include:

1) sleep

2) biofeedback

3) meditation

4) hypnosis

These effects require voluntary cooperation of the person.

-> Artificial changes in consciousness (including those brought on by drugs) at

first involve the active cooperation of the person. However, once the process

is underway, the person may lose some or all control over what is taking

place

Topic: Sleep – Notes

Sleep is one of the most fascinating of all natural changes in consciousness,

especially considering the fact that the average human is actively engaged in

sleep for 20 to 25 years of his or her total lifetime.

* Sleep research attempts to relate nervous system activity to what happens

during sleep.

- The EEG, or electroencephalograph guides our understanding of sleep. By

attaching the EEG electrodes to the human scalp it is possible to record the

electrical activity of a large number of neurons in the brain beneath.

- These EEG recordings reveal that cells tend to fire more or less together in

the alert, awake human.

- The electrical activity appears as ''waves'' of activity, or cycles of

increasing and then decreasing neuronal firings.

STAGES OF SLEEP

- Regular 90 minute cycle of electrical activity exists throughout the night.

- Four stages through which we all pass, and a fifth we enter when soundly

asleep after 90 minutes or so.

- We drop fairly rapidly to Stage Four, the stage of deepest sleep.

- The Fifth stage, called paradoxical sleep or Emergent Stage One is a

modified version of Stage One sleep.

1) The EEG record in paradoxical sleep appears as though the participants

were awake, yet they are as difficult to awaken as someone whose EEG

record indicates they are in Stage Four sleep.

2) Rapid eye movements (REMs) occur in this stage.

3) If an individual whose EEG records indicate they are in this paradoxical

sleep, about 70 percent of the time they will report that they have been

dreaming.

DREAMING

1) Does everyone dream?

- Yes, just about everyone dreams. Typically, those who report they never

dream have a problem remembering that they dreamed. If such people are

awakened when they are showing REMs, they too will usually report that they

have been dreaming.

2) How important is dreaming?

- People who are deprived of REM sleep become more short-tempered, more

distractable, and less able to concentrate on their everyday responsibilities.

- Rebound effect: people deprived of this sleep engage in much more REM

sleep than usual when no longer awakened.

3) Is sleeping really a quiet state?

- The evidence says no. What seems to happen is that incoming stimuli are

blocked instead of being relayed to alert higher centers of the brain. The

brain remains active, but simply does not respond to incoming stimuli.

Topic: Biofeedback – Notes

One of the most controversial natural changes in consciousness is biofeedback.

Biofeedback refers to the use of electronic instruments to show the

participant the activity of one or more of his or her bodily processes -- heart

beat, respiration, or what have you.

For many years psychology divided all human behavior into voluntary and

involuntary responses. Voluntary responses included, as you might expect,

any responses that involved active control of muscles. Involuntary responses

included heart beat, blood pressure, and EEG wave patterns.

It had long been assumed that humans could not control, except in a very

limited way, involuntary responses. However, biofeedback allowed

participants to observe their ''involuntary'' behavior, such as brain waves, on

an oscilloscope. By watching their EEG, people were able, by a conscious

effort, to make the alpha waves appear!

Scientists' early enthusiasm for biofeedback cooled somewhat during the 70s

since results were not always easily duplicated. However, the rapid growth

of behavioral medicine reaffirms the growing number of successful results

in using biofeedback to treat even such severe problems as loss of blood

pressure in paralyzed hospital patients.

* Biofeedback offers hope for increasing our life span by reducing internal

body stress.

Topic: Meditation – Notes

Consciousness is defined by many as an awareness of ourselves and our

ability to think and experience.

Meditation: a type of deep, concentrated thought, which functions as a means

to ''expand'' consciousness.

Kinds of Meditation:

1) Zen meditation: one question (called a koan) serves as a point of focused

concentration, sometimes over a period of years.

2) Yoga uses one word (called the mantra), which is said time and again in

the early stages of meditation. This word has or gains great personal

meaning.

3) A third kind of meditation has the participant direct his or her attention

to an object (called a mandala).

* It is not easy to define when a meditative state of ''higher consciousness''

is achieved.

* All approaches use the same method: they limit the awareness of

body feeling and the environment to a single object or concept.

- Meditation is an altered state of consciousness exactly because of this

narrowed attention. It is a naturally altered state requiring nothing more

than the will to achieve it.

EEG Patterns During Meditation:

In our study of the EEG wave patterns we learn that the alpha wave pattern

occurs when the participant is awake, but resting calmly with eyes closed.

- People in meditation often show the alpha wave pattern with their eyes

open or shut. This is impossible for the nonmeditator to achieve.

Meditation is of much interest to modern-day psychologists.

Benefits of Meditation:

- Allows a person to be aware of stressful situations, yet to control their

damaging impact on the body.

- It also increases the apparent ability of people to nonrelevant perceptions.

Controversy:

During the 1980s some psychologists began to dispute earlier findings,

suggesting it was possible to replicate the findings related to meditation by

asking people to relax -- not sleep, but relax -- in a quiet environment for 30

minutes or more. Now, some argue meditiation is simply the result of

relaxation, others view it as a more complex, elevated state of focused

concentration.

Topic: Hypnosis – Notes

Hypnosis: natural means of altering the normal state of consciousness.

- Experiments have shown that hypnosis works equally well with men or

women and that even a five-year-old can be hypnotized.

- People vary widely in the ease with which they can be put under. People

with unusually high powers of concentration are easiest to hypnotize.

*Some psychologists doubt that the hypnotic state really exists.

- Some explain it as resulting from the ''suggestibility'' of some people.

- Others investigate differences in personal attributes, such as the ability to

attend to only a limited number of stimuli.

- Still other attempts to explain it have focused on differences in the

social environment. The phys

*More research is required to determine which explanation is appropriate.

- Superhuman feats cannot be performed either during or following

hypnosis.

Post-hypnotic suggestion: people behave as though they have actually

forgotten a fact, or cannot hear a certain word or see a certain action.

* People cannot be hypnotized against their will; a person must work

actively to place conscious processes under the hypnotist's control.

Two important traits in the participant to be hypnotized are 1) being very

open to suggestions and 2) having a strong ''capacity for total attention.''

Hypnosis is a natural change in consciousness some -- but not

all -- can achieve. Other such changes include sleep, responses to

biofeedback, and meditation

Topic: Artificial Changes in Consciousness – Notes

Changes in our basic physiological processes caused by our nervous

system fall into two broad categories: natural and artificial changes in

consciousness.

Natural changes in consciousness involve nothing other than conscious control being

exercised over voluntary and involuntary behavior. For example, sleep,

biofeedback, meditation, and hypnosis are natural methods for altering basic

body processes.

The nervous system can also be influenced by artificial means. Once these

artificial techniques have been applied, the nervous system typically cannot

control their effects. Various types of drugs that influence our behavior

include depressants and stimulants as well as hallucinogens.

How drugs influence the body:

- The most basic function of the nervous system is the electrochemical

process called neuronal firing. So one of the most direct ways to influence

the body is to introduce chemicals which hinder or help the nervous system.

MAJOR DRUG GROUPS

Stimulants: any drug that increases activity in the nervous system or

in any function of the body.

Depressants: any drug that reduces activity in the nervous system or slows

down some body function.

Hallucinogenic drugs: produce changes in the normal senses (hallucination),

sometimes without altering the person's awareness (or consciousness) of

those changes. Produce both stimulating and depressing effects.

*** The nervous system that controls us is very complex. If control of a

function is located at a particular point in the central nervous system, then

stimulant or depressant drugs that act at that point will affect that

function. ***

Topic: USING PSYCHOLOGY: The Effects of Depressants and Stimulants – Notes

- Artificial changes in consciousness are often sought either through the use

of depressants or stimulants or through the use of hallucinogens.

DEPRESSANTS

Alcohol is the most widely used (and abused) depressant.

- The percentage of alcohol in the blood determines the extent of its effects.

- Main effects of alcohol are registered on the brain:

-> As the percentage of alcohol in the blood rises, the highest levels of

the brain become depressed. Higher mental processes (thinking,

feeling, & problem solving) are first to be lost. As more alcohol is

consumed, lower areas in the midbrain become affected. Soon a

person is increasingly unable to talk and reason clearly.

- The person feels relaxed and acts with fewer restraints as the cortex is

increasingly depressed by the alcohol.

- As lower brain centers are affected, even the sense of balance is in time

lost.

Narcotics represent the more extreme depressants (ranging from opium and

morphine to codeine) that affect the central nervous system.

- They depress the functions of the sensory cortex and the thalamus

and thus provide a false sense of well-being and relief from anxiety and pain.

- As the effects spread, the person may become increasingly drowsy and

finally fall asleep.

- Too large a dose may depress the automatic activities normally controlled

by the brain stem, and death can result from respiratory failure.

STIMULANTS

Amphetamines

- cause the heartbeat to increase

- cause the pupils of the eyes to dilate

- cause the organism in general to feel flushed, active, alert and ''high''

- the digestive processes are slowed down

- with too large a dosage, the person may hover between sleep and

unconsciousness as the body attempts to restore its chemical balance

Topic: USING PSYCHOLOGY: The Effects of Hallucinogens – Notes

* Artificial changes in consciousness may be created through using

stimulants or depressants or through the use of hallucinogens. The

hallucinogenic drugs are very difficult to classify as depressant or

activating as they may be a little of both.

Effects of Hallucinogens

* One of the most obvious processes impacted by hallucinogens is our ability

to achieve normal sensation and perception.

- In small dosages there is little doubt that the hallucinogens produce mild

stimulation of the central nervous system.

- Generally, a person under the influence of one of these drugs is more

excitable and alert.

- Despite the increased activity, the person is less able to receive and

interpret sensory stimuli.

* This combination of increased activity and decreased sensitivity to

external stimulation lends increased importance to prior thoughts and

experiences stored in memory.

- The person may indulge in flights of fancy

- The person may become immune to outside stimulation and more or less

totally at the will of internal thoughts.

Marijuana

One of the most widely recognized and used drugs in this group is marijuana.

Because of the isolation from external stimuli experienced by marijuana

users, the mood or environment in which they originally take marijuana may

affect how they will experience it.

LSD

- This drug is extremely powerful and controlling the effects of the drug is

very difficult.

- Slight variations in the amount consumed leads to a wide range of effects.

- Many sites that are affected by LSD:

- Pupils dilate

- Heartbeat increases

- Synapses in the CNS are affected

- Sensory cortex is stimulated, but restraints are lost

- Information from the senses gains in importance

* The drug does produce response patterns very similar to some aspects of

abnormal human behavior.

*** Drug usage can and usually does have profound effects on the body, many

of which are unpredictable and possibly dangerous. Any altering of the

function of the nervous system by drugs will produce detectable or even

dramatic changes in behavior. The effects of drug use depend mainly on the

type of drug involved and the primary site of action of that drug within the

nervous system. ***