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PSYC 101 Study Guide - Exam 2

Vitreous Humor

  • The clear gel-like substance that fills the space between the lens and the retina of the eye.

  • Supports shape of the eyeball and provides a pathway for light to reach the retina.

Main Components of the Eye

  1. Fovea

    • The central focal point in the retina, where visual acuity is highest.

    • Contains a high density of cones and is crucial for seeing fine detail.

  2. Pupil

    • The adjustable opening in the center of the eye through which light enters.

    • Controlled by the iris, changes size in response to light levels.

  3. Cornea

    • The transparent front part of the eye that covers the iris and pupil.

    • Provides most of the eye's optical power and helps focus light.

Drugs and Behavior

  • Mechanism of Action (MOA)

    • Describes the specific biochemical interaction through which a drug substance produces its effect.

    • There are three primary types of MOA: competitive agonists, non-competitive agonists, and antagonists.

Continued Drug Use/Substance Use Disorders

  • Defining Features

    • Criteria for diagnosing include the presence of symptoms for a specified duration, such as tolerance and withdrawal.

  • Length of Time of Symptoms

    • Clinically significant impairment or distress must persist for at least 12 months.

Major Drug Types

  1. Stimulants

    • Drugs that increase the activity of the nervous system.

    • Examples:

      • Nicotine: Found in tobacco; stimulates the release of neurotransmitters such as dopamine.

      • Caffeine: Increases energy and alertness by blocking adenosine receptors.

      • Cocaine: A powerful stimulant that acts by inhibiting the reuptake of dopamine, norepinephrine, and serotonin.

      • Amphetamine: Increases the release of catecholamines, leading to heightened alertness and energy.

    • Mechanism of Action (MOA) and Behavioral Effects:

      • Typically increase heart rate, blood pressure, and energy levels.

  2. Depressants

    • Drugs that reduce the activity of the nervous system.

    • Examples:

      • Alcohol: Affects various neurotransmitter systems including GABA and glutamate, leading to sedation.

      • Benzodiazepines: Enhance the effect of the neurotransmitter GABA, producing a calming effect.

      • Opioids: Bind to opioid receptors in the brain, decreasing the perception of pain and producing euphoria.

    • Mechanism of Action (MOA) and Behavioral Effects:

      • Examples of effects include muscle relaxation, decreased anxiety, impaired motor function, and respiratory depression.

  3. Hallucinogens

    • Drugs that alter perception, mood, and various cognitive processes.

    • Examples:

      • Psilocybin: Found in magic mushrooms, acts mainly on serotonin receptors to induce visual and auditory hallucinations.

      • Lysergic Acid Diethylamide (LSD): Similar effects to psilocybin, with very potent effects at low doses.

      • Cannabis (Marijuana): Contains THC which acts on cannabinoid receptors in the brain.

    • Mechanism of Action (MOA) and Behavioral Effects:

      • May include altered sensory perception, euphoria, and altered thought processes.

      • Set and Setting: Refers to the environment and mindset in which the drug is consumed, strongly influencing the experience.

Sleep

  • Circadian Rhythm

    • The body's internal clock regulating sleep-wake cycles, influenced by external cues like light.

    • The Suprachiasmatic Nucleus (SCN) in the hypothalamus plays a crucial role.

Importance of Light

  • Light is vital for regulating the circadian rhythm.

  • Exposure to natural light helps synchronize biological cycles, affecting mood, sleep patterns, and overall health.

Stages of Sleep and Sleep Cycles

  • Sleep is divided into four stages, each with specific characteristics.

  • A complete sleep cycle through these stages typically lasts 90 minutes and repeat several times throughout the night.

1. Stage 1

  • Transitional phase from wakefulness to sleep.

  • Features:

    • Hypnic Imagery: Brief visual, auditory, or other sensory impressions.

    • Hypnic Jerks: Sudden muscle contractions occurring during this stage.

    • EEG Activity: Characterized by a mix of alpha and theta waves.

2. Stage 2

  • Represents a deeper sleep phase.

  • Features:

    • Sleep Spindles: Sudden bursts of brainwave activity.

    • K-Complexes: Sudden spikes in brain activity in response to external stimuli.

    • Typical length: Approximately 20 minutes.

3. Stage 3 (Slow-Wave Sleep)

  • The deepest stage of sleep, also termed delta sleep due to the presence of delta waves.

  • Features:

    • Associated with restorative processes in the body, such as tissue growth and repair.

4. Rapid Eye Movement (REM) Sleep

  • Occurs after about 90 minutes of sleep and recurs multiple times throughout the night.

  • Features:

    • Brain Activity: Resembles wakefulness, but the body is typically paralyzed.

    • Length of Time: Initially short, lengthening with each cycle, with longer episodes in the latter part of the night.

    • REM Rebound: It occurs when an individual loses REM sleep due to sleep deprivation and then experiences longer REM periods when sleep resumes.

    • Dreaming: Most vivid dreams occur during this stage.

Sleep Disorders

  1. Parasomnias

    • Abnormal behaviors or movements occurring during sleep that may include sleepwalking, night terrors, and sleep talking.

  2. Dyssomnias

    • Disorders characterized by difficulties in sleeping, including insomnia, hypersomnia, and sleep apnea.

    • When Are They Seen?: Often related to lifestyle factors, physiological problems, or psychological conditions.

Sensation & Perception

  • Transduction

    • The process of converting physical stimuli into neural signals.

  • Sensory adaptation

    • Diminished sensitivity to a constant stimulus over time when exposed continuously; allows the organism to focus on change instead of unimportant background information.

Vision

  • Eye Anatomy

    • Comprises various structures essential for light transmission and processing.

    • Common issues include refractive errors (myopia, hyperopia, astigmatism).

Rods and Cones

  • Two types of photoreceptor cells in the retina.

    • Rods: Responsible for vision in low light conditions; do not detect color.

    • Cones: Responsible for color vision and high acuity; concentrated in the fovea.

Color Perception

  • Three major theories explain color vision:

    1. Trichromatic Theory: Proposes that the human eye has three types of cones sensitive to red, green, and blue light.

    2. Opponent Process Theory: Suggests that color is perceived in terms of opposing pairs: red-green, blue-yellow, and black-white.

    3. Retinex Theory: Posits that the brain accounts for color perception by comparing the intensity of light reflected from objects in a scene.

Audition

  • The Properties of the Stimulus

    • Includes loudness (determined by amplitude), pitch (determined by frequency), and timbre (quality of sound).

  • Anatomy and Structures of the Ear

    • Comprises three main parts:

      • Outer Ear: Captures sound waves and directs them to the eardrum.

      • Middle Ear: Contains ossicles that amplify sound vibrations.

      • Inner Ear: Houses the cochlea, which converts sound vibrations into neural signals.

    • Functions of each part are crucial for effective hearing and balance.