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.