AP Psychology Unit 1 Summary: Biological Basis of Behavior

Introduction

• Focus: How biological systems impact physical and mental actions/responses.
• Key Question: Nature vs. Nurture (outdated, now considered as nature and nurture).

Nature vs. Nurture

• Nature: Heredity, passing traits gen to gen.
• Nurture: Environmental factors (family, social groups, etc).
• Evolutionary Approach: Leans nature, uses Darwin's evolution theory.
  • Natural Selection: Traits beneficial to a species are passed on.
  • Eugenics Misuse: Discriminatory practices based on selective breeding.
• Epigenetics: Study of how environment affects gene expression.
  • Identical Twins: Often develop different traits.

Nervous System

• Central Nervous System (CNS): Brain & spinal cord.
• Peripheral Nervous System (PNS): Connects CNS to body organs/muscles.
  • Afferent Neurons: Sensory neurons, send signals to CNS.
  • Efferent Neurons: Motor neurons, send signals from CNS.

Divisions of PNS

• Somatic Nervous System: Controls voluntary movements and senses.
• Autonomic Nervous System: Controls involuntary functions (heartbeat, digestion).
  • Sympathetic Division: Activates fight or flight.
  • Parasympathetic Division: Promotes rest and digest.

Neurons and Neural Transmission

• Glial Cells: Structure, insulation, waste transport, support neurons.
• Neurons: Basic unit of nervous system, communicate via electrical impulses.
  • Reflex Arc: Sensory, motor, and interneurons act without brain involvement.
• Action Potential: Neuron firing, all or nothing; requires depolarization.
• Synapse: Space between neurons, site of neurotransmitter exchange.

Neurotransmitters

• Types:
  • Acetylcholine: Muscle action, learning, memory.
  • Substance P: Pain signal transmission.
  • Dopamine: Movement, learning, emotion.
  • Serotonin: Hunger, sleep, mood.
  • Endorphins: Pain control.
  • Epinephrine/Norepinephrine: Emotional response, alertness.
  • Glutamate: Memory, learning.
  • GABA: Sleep, movement.

Brain Structure & Functions

• Regions:
  • Hindbrain: Medulla, pons, cerebellum (coordination, autonomic functions).
  • Midbrain: Sensory information processing.
  • Forebrain: Cerebrum, complex thoughts.
• Lobes:
  • Frontal Lobe: Higher thinking, motor control.
  • Parietal Lobe: Sensory input processing.
  • Temporal Lobe: Auditory processing, memory.
  • Occipital Lobe: Visual processing.

Hormones

• Adrenaline: Fight or flight response.
• Leptin/Ghrelin: Energy balance, hunger signals.
• Melatonin: Sleep regulation.
• Oxytocin: Bonding, affection.

Psychoactive Drugs

• Agonists: Increase neurotransmitter effectiveness (e.g. Prozac).
• Antagonists: Decrease neurotransmitter effectiveness (e.g. schizophrenia meds).

Sleep

• Stages:
  • Non-REM: Stages 1 (light) to 3 (deep sleep).
  • REM: Dreaming, brain active but body relaxed.
• Sleep Theories:
  • Activation-Synthesis: Dreams from random neural activity.
  • Consolidation Theory: Strengthen memories.

Sensation & Perception

• Sensation: Detecting information.
• Visual System: Light perception, rods/cones, color theories.
• Auditory System: Sound waves, pitch theories.

Balance and Movement

• Vestibular Sense: Balance, fluid in semicircular canals.
• Kinesthesis: Body part position and movement.

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• Study Resources: Ultimate Review Packet for quizzes, videos, and practice questions.