Psychology Notes Part Two

Chapter 3

The Biological Basis of Behavior

Be able to recognize and explain the function of the three parts of a neuron.

Dendrite-Parts of the neuron that are specialized to receive information

Cell body or soma-contains the cell nucleus and much of the chemical machinery          common to most cells

Axon-long, thin fiber that transmits signals away from the soma to other neurons            or to muscles or glands

àFrom the many dendrites, information flows into the cell body and then                                              travels away from the soma along the axon

Know the function and importance of the myelin sheath

-Myelin sheath- is insulating material, derived from glial cells, that encases some axons

-Axons are wrapped in cells with a high concentration of white, fatty substance

-Speeds up the transmission of signals that move along axons

àMultiple Sclerosis-due to degeneration of myelin sheaths

Know the function of the Synapse

Synapse- is a junction where information is transmitted from one neuron to another

Summary- Information received at dendrites, is passed through the soma, and along the axon, is transmitted to the dendrites or other cells at meeting points called synapses

Understand and describe the major events in the four, electrical stages of neurotransmission.

Resting potential-its stable, negative charge when the cell is inactive

Action potential-very brief shift in a neuron’s electrical charge that travels along            an axon

Absolute Refractory Period-the minimum length of time after an action           potential during which another action potential cannot begin

• “down time” not very long, 1-2 milliseconds, followed by brief refractory period

Relative Refractory Period-Neuron can fire, but its threshold for firing is        elevated, so more intense stimulation is required to initiate an action potential

Figure 3.2

The Neural Impulse-

The electric charge of a neuron can be measure with a pair of electrodes connected to an oscilloscope. A. At rest, the neuron is like a tiny wet battery with a resting potential of about -70 millivolts B. When a neuron is stimulated, a sharp jump in its electic potential occurs, resulting in a spike on the oscilloscope recording of the neuron’s electrical activity. This change in voltage, called an action potential, travels along the axon. C. Biochemical changes propel the action potential along the axon. An action potential begins when sodium gates in the membrane of an axon open, permitting positively charged sodium ions to flow into the axon D. The potassium gates have opened to let potassium ions flow outward. At the next point along the axon membrane, sodium gates open and the process is repeated thus allowing the action potential to move along the axon E. This blowup of the voltage spike is associated with an action potential depicts how these biochemical changes relate to the electrical activity of the cell

Understand the “All or None Law.”

Neural impulse is an all-or-none proposition.

à Like firing a gun, you can’t half-fire it

-Either neuron fires or it doesn’t, and its action potentials are all the same size

-weaker stimuli do not produce smaller action potentials

-Neurons can convey information about the strength of a stimulus.

-Do so by varying the rate at which they fire action potentials

-Stronger stimulus, cause cell to fire more rapid volley of neural                                                 impulses than weaker stimulus will

-Process of neural transmission only takes a few thousandths of a second

Understand and describe the major events in the five chemical stages of neurotransmission.

Neurotransmitters-Chemicals that transmit information from one neuron to another

1. Synthesis & Storage of neurotransmitter molecules in synaptic vesicles

2. Release of neurotransmitter molecules into synaptic cleft

Synaptic cleft- microscopic gap between the terminal button of one neuron                    and the cell membrane of another neuron

3. Binding of neurotransmitters at receptor sites on postsynaptic membrane

Postsynaptic potential (PSP)-a voltage change at an receptor site on a                           postsynaptic cell membraneà they vary in size and they increase or                                decrease the probability of neural impulse in the receiving cell proportion                                    to the amount of voltage change

4. Inactivation (by enzymes) or removal (drifting away) of neurotransmitters

5. Reuptake of neurotransmitters sponged up by presynaptic neuron

Know the function of following neurotransmitters which are nicely summarized in Table 3.1

Neurotransmitter              Functions and Characteristics

Acetylcholine

(Ach)

Activates motor neurons controlling skeletal muscles

Contributes to the regulation of attention, arousal and memory

Some Ach receptors stimulated by nicotine

Dopamine

(DA)

Contributes to control of voluntary movement; pleasurable emotions

Decreased levels associated with Parkinson’s disease

Overactive at DA synapses associated with schizophrenia

Cocaine and amphetamines elevate activity at DA synapses

Norepinephrine

(NE)

Contributes to modulation of mood and arousal

Cocaine and amphetamines elevate activity at NE synapses

Serotonin

Involved in regulation of sleep and wakefulness, eating, aggression

Abnormal levels may contribute to depression and obsessive-compulsive disorder

Prozac and similar antidepressant drugs affect serotonin circuits

GABA

Serves as widely distributed inhibitory transmitter

Valium and similar anti-anxiety drugs work at GABA synapses

Endorphins

Resemble opiate drugs in structure and effects

Contribute to pain and relief and perhaps to some pleasurable emotions

Understand the ways in which the chemical aspects of neurotransmission may be disrupted and their effect.

Specific neurotransmitters work at specific kinds of synapses.

-Transmitters deliver their messages by binding to receptor sites on the post-     synaptic membrane.

à Transmitter can’t bind to just any site

Binding process; like a key and lock

-Transmitter has to fit into a receptor site for binding to occur

àSpecific transmitters can deliver signals only at certain locations on cell                                   membrane

Know the names, the components, and the function of the various divisions of the human nervous system (summarized in Figures 3.6. 3.7 and 3.8:

Central Nervous System (brain and spinal cord)-consists of brain and the   spinal cord.

• Protected by enclosing sheaths called meninges
• Central nervous system bathed in cerebrospinal fluid
  • Cerebrospinal fluid-nourishes the bran and proves a protective cushion for it
• Brain
  • Hindbrain-Reticular formation, Cerebellum, Pons, Medulla
  • Midbrain-Reticular formation
  • Forebrain-Thalamus, hypothalamus, limbic system, cerebrum
• Spinal Cord- Connects the brain to rest of the body
  • Enclosed by the meninges, and bathed in CSF
    • Houses bundles of axons that carry the brain’s commands to peripheral nerves

Peripheral Nervous System (everything else)-Nerves are bundles of neuron            fibers ( axons) that are routed together in the peripheral nervous system

• Somatic nervous system (voluntary)-Made up of nerves that connect to voluntary skeletal muscles and to sensory receptors
  • These nerves are cables that carry information from receptors in the skin, muscles, and joints to the central nervous system and that carry commands from the CNS to the muscles
  • Afferent ( incoming) nerves-Axons that carry information inward to the central nervous system from the periphery of the body
  • Efferent (outgoing) nerves- Axons that carry information outward from the central nervous system to the periphery of the body
• Autonomic nervous system (involuntary)-Made up of nerves that connect to the heart, blood vessels, smooth muscles, and glands
  • This system is separate, and is ultimately governed by central  nervous system
    • Controls automatic, involuntary, visceral functions that people don’t think about à heart rate, digestion
  • Sympathetic division (mobilizes resources)-is the branch of the autonomic nervous system that mobilizes the body’s resources for emergencies
    • Creates “fight or flight response”
      • Fight-or-flight=organisms generally respond to threat b preparing physiologically for attacking (flight) or fleeing (flight from the enemy
  • Parasympathetic division (conserves resources)-is the branch of the autonomic nervous system that generally conserves bodily resources
    • Allows body to store and save energy

à Nerves slow heart rate, reduce blood                                                     pressure, and promote digestion

Know the three functions of the spinal cord.

Carries sensory input to brain

Carries motor commands from brain to muscles

Mediates spinal reflexes—pulling hand away from hot stove burner

Know the organization, location and function of the following structures of the human brain.

Hindbrain or Brainstem-includes the cerebellum and 2 structures found                                  in the lower part of the brainstem: the medulla and the Pons

Medulla-regulates unconscious functions such as breathing and                                                 circulation

Pons-Involved in sleep and arousal

Cerebellum-Coordinates fine muscles movement, balance

Reticular Formation-contributes to the modulation of muscle                                       reflexes, breathing, and pain perception

• Known for its role in the regulation of sleep and arousal

Midbrain-the segment of the brainstem that lies between the hindbrain                          and the forebrain, contains an area that is concerned with integrating                                  sensory processes, such as vision and hearing

Reticular Formation contributes to the modulation of muscle                                       reflexes, breathing, and pain perception

• Known for its role in the regulation of sleep and arousal

Forebrain-largest and most complex region of the brain, encompassing a                                  variety of structure, including the thalamus, hypothalamus, limbic system,                           and cerebrum

• Thalamus, hypothalamus and limbic system form the core of the forebrainàlocated near the top of the brainstem

Old Structures

Thalamus-structure in the forebrain through which all                                                    sensory information (except smell) must pass to get to the                                                          cerebral cortex

• Relay center for cortex; handles incoming and outgoing signals

Limbic System-is a loosely connected network of                                                                    structures located roughly along the border between the                                                             cerebral cortex and deeper subcortical area

• Involved in the regulation of emotion, memory and motivation

Hypothalamus- structure found near the base of the                                                     forebrain that is involved in the regulation of basic                                                                      biological needs: hunger, thirst, temperature control

Hippocampus-Part of limbic system involved in                                                                        learning and memory

Amygdala-Part of limbic system involved in                                                                  emotion and aggression

Septal Area- involved with producing tranquil,                                                                         peaceful reaction

New Structures

Cerebrum-Responsible for sensing, thinking, learning,                                                   emotion, consciousness, and voluntary movement

Frontal Lobe-Primary motor cortex

Parietal Lobe-Primary somato sensory cortex

Temporal Lobe-Primary auditory cortex

Occipital Lobe-Primary visual cortex

Know what is meant by the term “primitive brain structures.”

Know the differing functions of the left and right hemisphere of the human brain.

Left Hemisphere- Usually handles verbal processing, including language, speech, reading, and writing

Right Hemisphere-Usually handles nonverbal processing, including spatial, musical, and visual recognition tasks

Understand the function of the Endocrine System

Endocrine System- consists of glands that secrete chemicals into the bloodstream that help control bodily functioning

Know the following terms:

Hormones-the chemical substances released by the endocrine glands

• Hormones regulate responses to stress, sexual development, insulin production, metabolic rate

Pituitary Gland-releases a great variety of hormones that fan out across t                                 he body, stimulation actions in the other endocrine glands

• “master gland”

Gonadotrophins-affect the gonads, or sexual glands

Understand the basic nature of genetic transmission:

Be able to define and recognize examples of the following terms:

Chromosome-threadlike strands of DNA that carry genetic information

Genes-DNA segments that are the key functional units in hereditary transmission

DNA-molecules that carry genetic information

Zygote-single cell formed by the union of a sperm and an egg

Homozygous Condition-two genes in a specific pair that are the same

Heterozygous Condition-two genes in a specific pair tat are different

Recessive Gene-paired genes, “masked”

Dominant Gene-paired genes, “expressed”

Genotype-refers to a person’s genetic makeup

Phenotype-refers to a person’s observable characteristics

Family Studies-asses trait resemblance among blood relatives

Twin Studies- compare trait resemblance of identical and fraternal twins

Adoptive Studies- compare adopted children to their adoptive parents and to their       biological parents

Understand and recognize examples of the evolutionary basis of behavior.

Be aware of how evolution has influenced human mating differences in males and females.

-In most species, there are striking disparities between males and females in their parental investment

• “In general, the sex that makes the smaller investment will compete for mating opportunities with the sex that makes the larger investment, and the sex with the larger investment will tend to be more discriminating in selecting its partners”
• Males compete with each other for mating opportunities
• Females- have to invest weeks or months of effort to carry and nourish offspring, thereby limiting the number of offspring they can produce in a breeding season
  • Females have no incentive for breeding with many males

Be aware of differences in male and female preferences in a potential mate.

-Choosing mates that can provide them with better quality genes or material resources that can be invested in offspring

• The typical result when parental investment is high for females and low for males
• Polygyny-a mating system in which each male seeks to mate with multiple females, whereas each female mates with only one male

Know the definition and recognize examples of following evolutionary terminology:

Fitness-refers to the reproductive success of an organism relative          to the population

Natural Selection-heritable characteristics that provide a survival         or reproductive advantage are more likely than alternative characteristics to be passed on to subsequent generations and thus             come to be “selected” over time

Adaptation- is inherited characteristics sculpted through natural             selection because they help solve a problem of survival or    reproduction when they emerged

Inclusive Fitness-is the sum of the individual’s own reproductive         success plus the reproductive success of related others

Parental Investment-refers to what each sex has to invest in time,       energy, and risk to produce and nurture offspring

Chapter 5

Variations in Consciousness

Know what is meant by the term “Circadian Rhythm”

Circadian Rhythm-are the 24-hour biological cycles found in humans and many other species

Know the effect of circadian rhythm on jet.

• Poor Sleep associated with Jet Lag and rotating shift work is due to being out of sync with circadian rhythms

Know the role of melatonin on circadian rhythm

• Melatonin plays a key role in adjusting biological clocks

Know the brain-wave patterns, behaviors and general characteristics of the five stages of sleep (summarized in Table 5.1 and Figure 5.4.

Table 5.1

Correlation between mental states and electrical activity in the brain

• Correlations alone to not establish causation. For example there are strong correlations between drowsiness and particular pattern of cortical activity

Figure 5.4

EEG patterns in sleep and wakefulness

• Characteristic brain waves vary depending on one’s state of consciousness. As people move from an awake state through deeper stages of sleep, their brain waves decrease in frequency and increase in amplitude. However brain waves during REM sleep resemble “wide awake” brain waves

Know the nightly pattern of sleep (Figure 5.5).

Know the effect of sleep deprivation (complete, partial & selective) on human emotions, thoughts and behaviors

Complete-Complete deprivation has negative effects, but these are limited by people’s inability to go very long without sleep

• Negative effects on persons mood and on their performance on both cognitive and perceptual-motor tasks

Partial- is common and can impair alertness and appears to contribute too many accidents

• Much of Am. Chronically suffers from partial sleep deprivation

Know the definition and recognize examples of the following sleep disorders:

Insomnia-Occurs in 3 patterns: Difficulty falling asleep, difficulty remaining        asleep, and persistent early morning awakenings

• Fairly common sleep disorder, has many diverse causes
• Sedative drugs long-term solution

Sleep Apnea-involves frequent, reflexive gasping for air that disrupts sleep

Narcolepsy-is marked by sudden and irresistible onsets of sleep during normal             waking periods

Night Terrors-are abrupt awakenings from the non-REM sleep accompanies b            intense arousal and panic; aka bad bad dreams

Somnambulism-(sleepwalking) occurs when a person wanders about while      remaining asleep

Know the three theories of dreaming summarized Figure 5.12.

• Sigmund Freud asserted that the chief purpose of dreams is wish fulfillment
• Other theorists argue that dreams provide an opportunity to think creatively about person problems
• The activation-synthesis model-proposes that dreams are side effects of the neural activation that produces waking like brain waves during REM sleep

Know about hypnosis, susceptibility and hypnotic phenomenon.

Hypnosis-is a systematic procedure that typically produces a heightened state of suggestibility

Hypnotic susceptibility-how people differ in their response to hypnotic induction. Not everyone can be hypnotized.

• About 10% of population doesn’t respond well to it

Hypnotic phenomenon-interesting affects that can be produced through hypnosis

1. anesthesia
2. Sensory distortions and hallucinations

• May be led to hear or see thing that are not there

1. Disinhibition- can make people do things they wouldn’t normally do
2. Posthypnotic suggestion and amnesia- suggestion may influence a person’s behavior later

• Most common posthypnotic suggestion-“you won’t remember this when you wake up”

Know about the role playing theory of hypnosis and the altered state of consciousness theory.

Hypnosis produces a normal mental state in which suggestible people act out role of hypnotic subject, and behave as they think hypnotized people are supposed to

• It is the subjects’ role expectations that produce hypnotic effects, rather than a special trancelike state of consciousness