PSY 101: CHAPTER 3

Chapter Overview

• Chapter 3: Biological Bases of Behavior

  • Key areas covered:

    • Communication in the Nervous System

    • Organization of the Nervous System

    • The Brain and Behavior

    • The Endocrine System

    • Heredity and Behavior

    • Evolutionary Bases of Behavior

Nervous System Structure

• Divisions of the Nervous System:

  • Central Nervous System (CNS):

    • Composed of the brain and spinal cord.

  • Peripheral Nervous System (PNS):

    • Somatic—controls voluntary movements.

    • Autonomic—regulates involuntary functions.

      • Divided into sympathetic and parasympathetic systems.

Organization of the CNS

• Main Components:

  • Brain:

    • Forebrain: Contains thalamus, hypothalamus, limbic system.

    • Midbrain: Central core of brainstem.

    • Hindbrain: Contains cerebellum, medulla, pons.

  • Spinal Cord: Connects brain to PNS.

Brain Structures

• Forebrain: Largest region; responsible for higher cognitive functions.

• Midbrain: Involved in sensory processing.

• Hindbrain: Controls basic life functions.

Cerebral Hemispheres

• The brain is divided into two hemispheres:

  • Left Hemisphere: Language, analytical thought.

  • Right Hemisphere: Creative functions, spatial abilities.

• Corpus Callosum: Connects the two hemispheres.

The Cerebral Cortex

• Divided into four lobes:

  • Frontal Lobe: Primary motor cortex; involved in reasoning, planning.

  • Parietal Lobe: Primary somatosensory cortex; processes touch information.

  • Occipital Lobe: Primary visual cortex; processes visual information.

  • Temporal Lobe: Primary auditory cortex; processes sound information.

Split-Brain Research

• **Corpus Callosum Surgery: **

  • Severed to treat epilepsy.

  • Allows for study of independent hemisphere function.

• Processing Differences:

  • Left: Verbal processing.

  • Right: Nonverbal processing.

Language Processing Areas

• Broca's Area:

  • Responsible for speech production.

  • Aphasia symptoms: Poor grammar, difficulty forming sentences.

• Wernicke's Area:

  • Responsible for language comprehension.

  • Wernicke's Aphasia symptoms: Nonsensical speech, creating non-words.

Quick Recap of Nervous System

• Nervous System Divisions:

  • CNS and PNS.

• CNS Subdivisions:

  • Brain (hindbrain, midbrain, forebrain) and spinal cord.

• Brain Lobes: Frontal, Parietal, Temporal, Occipital.

Peripheral Nervous System

• Divided into:

  • Somatic Nervous System: Voluntary control.

  • Autonomic Nervous System: Involuntary control, further divided into:

    • Sympathetic Division: Activates fight-or-flight response.

    • Parasympathetic Division: Calms the body, conserves energy.

Parasympathetic vs. Sympathetic Systems

• Responses:

  • Sympathetic: Increased heart rate, dilation of pupils.

  • Parasympathetic: Decreased heart rate, constriction of pupils.

Neurons and Glial Cells

• Major Types of Cells:

  • Neurons: Basic units of the nervous system, responsible for sending and receiving messages.

  • Glial Cells: Support neurons and maintain homeostasis.

• Neuron Structure:

  • Soma, axon, myelin sheath, dendrites.

The Neural Impulse

• Resting Potential:

  • Neurons maintain a stable, negative charge when inactive (-70 mV).

• Action Potential:

  • Occurs when a neuron is stimulated; rapid change in charge from negative to positive.

Synaptic Transmission

• Neural Impulse: Signaling between neurons at synapses.

• Neurotransmitters: Chemicals released to communicate across synapses.

• Reuptake Process: Unused neurotransmitters are reabsorbed for recycling.

Neurotransmitters and Behavior

• Key Neurotransmitters and Associated Disorders:

  • Acetylcholine (ACh): Regulation of attention and muscle movement. Associated with Alzheimer's disease.

  • Dopamine (DA): Involved in movement control and reward. Related to Parkinson's, schizophrenia.

  • Norepinephrine (NE): Modulates mood. Linked to depressive disorders.

  • Serotonin: Involved in mood and sleep regulation. Affected in anxiety and depressive disorders.

  • GABA: Inhibitory neurotransmitter; involved in anxiety regulation.

  • Endorphins: Pain relief and stress response regulation.

Final Recap of Neurons

• Two major cells: Glial cells and Neurons.

• Neurons have a common structure and operate on an all-or-none basis regarding firing impulses.

• Information communication via neurotransmitters at synaptic junctions.