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Chapter 6: Body and Behavior

Introduction to Psychology

  • Psychology is the study of the nervous system and its interactions with the environment.

  • Behaviors such as thoughts, emotions, and creativity are rooted in biological processes within and between cells.

Understanding the Nervous System

Main Idea

  • The nervous system sends messages to and from the brain, influencing behavior and bodily functions.

Key Vocabulary

  • Central Nervous System (CNS): Comprises the brain and spinal cord.

  • Peripheral Nervous System (PNS): Nerves branching from the spinal cord to the rest of the body.

  • Neurons: The basic units of the nervous system that transmit messages.

  • Synapse: The gap between neurons where neurotransmitters are released.

  • Neurotransmitters: Chemicals that transmit signals across synapses.

  • Somatic Nervous System (SNS): Controls voluntary muscle movements.

  • Autonomic Nervous System (ANS): Controls involuntary functions (e.g. heart rate).

Objectives of Chapter

  • Identify parts and functions of the nervous system.

Structure of the Nervous System

  • CNS: Processes information; consists of the brain and spinal cord.

  • PNS: Connects the CNS to limbs and organs; transmits sensory and motor information.

  • Divisions of the PNS:

    • Somatic Nervous System: Voluntary muscle control.

    • Autonomic Nervous System: Involuntary muscle control; further divided into:

      • Sympathetic Nervous System: Prepares body for stress (e.g. increased heart rate).

      • Parasympathetic Nervous System: Conserves energy and returns the body to rest after stress.

Neurons – The Building Blocks of the Nervous System

Neuron Structure

  • Basic parts include:

    • Dendrites: Receive signals from other neurons.

    • Cell Body: Contains the nucleus.

    • Axon: Sends signals away from the cell body.

    • Axon Terminals: Release neurotransmitters to communicate with other neurons.

  • Myelin Sheath: Insulates axons to speed up signal transmission.

The All-or-None Principle

  • Neurons either fire completely or not at all, based on whether they reach a threshold of stimulation.

Synaptic Transmission

  • The synapse is where neurotransmitters facilitate communication between neurons by either exciting or inhibiting them.

  • Different neurotransmitters (e.g., dopamine, serotonin) have distinct roles in mood and behavior.

Brain Anatomy

The Three Parts of the Brain

  • Hindbrain: Regulates basic life functions (e.g. medulla controls breathing).

  • Midbrain: Integrates sensory information and relays it.

  • Forebrain: Involves higher cognitive functions, emotions, and memory.

    • Contains structures like the thalamus (sensory relay) and hypothalamus (controls homeostasis).

Cerebral Cortex and Lobes

  • The cortex is divided into two hemispheres connected by the corpus callosum.

  • Lobes:

    • Occipital Lobe: Visual processing.

    • Parietal Lobe: Sensory information from the body.

    • Temporal Lobe: Involves hearing, memory, and emotions.

    • Frontal Lobe: Responsible for reasoning, planning, and movement.

Methods of Studying the Brain

  • EEG (Electroencephalograph): Measures electrical activity of the brain.

  • CT (Computed Tomography): Creates detailed images of brain structures.

  • PET (Positron Emission Tomography): Shows active areas during tasks.

  • MRI (Magnetic Resonance Imaging): Provides images of brain structure and activity.

The Endocrine System

Overview

  • The endocrine system releases hormones that influence growth, behavior, and emotional responses.

Key Components

  • Pituitary Gland: Master gland controlling other glands' hormone release.

  • Thyroid Gland: Regulates metabolism.

  • Adrenal Glands: Produce adrenaline in stress response.

  • Sex Glands: Ovaries and testes regulate sexual development and reproduction.

Nature vs. Nurture

  • Heredity: Genetic transmission of traits from parents to offspring.

  • Environment: External factors influencing behavior and development.

  • The interaction between heredity and environment shapes individual behavior and abilities.

Conclusion

  • Understanding the nervous and endocrine systems provides insight into the biological foundations of behavior and psychological processes.