Neuroscience and Behavior Chapter 2

Structure of a Neuron Neuron Dendrites Axons Myelin Sheath Consists of a cell body and branching fibers Dendrites Receive information from sensory receptors or other neurons Axons Pass that information to other neurons Myelin Sheath Insulates fibers of some neurons and helps speed impulses

Con’t A neural impulse fires when stimulated Pressure, heat, light, or messages from other neurons Received signals trigger only if the signals exceed the minimum intensity (threshold)

Con’t The impulse (action potential) is a electrical charge that travels down axon Interior carries negatively charged atoms Exterior carries posititvely charged atoms

Neural Communication When electrical impulses reach axon terminal, they release neurotransmitters These cross the junction of neurons called the synapse

Neurotransmitters Acetylcholine Endorphines Location: Junction between motor neuron and skeletal muscle Function: Causes muscles to contract Endorphines What: Natural Opiates Function: Released in response to pain and exercise Example: Runners High

Opiate Drugs Heroine/Morphine Therapeutic drugs Simulated opiates that flood the brain Withdraw results in pain until the brain is able to kick start natural opiates Therapeutic drugs Agonists: mimic natural neurotransmitters Antagonist: block neurotranstmitter effects

The Nervous System The communication of neurons with our primary system make sup the nervous system Central Nervous System (CNS) Brain and spinal cord Peripheral Nervous System (PNS) Links CNS to body’s sense receptors, muscles, and glands

Con’t Sensory Neurons Interneurons Motor Neurons Reflexes Send info to the brain Interneurons Process the information Motor Neurons Carry info from brain from CNS to body Reflexes Our automatic response to stimuli

The Brain The Brainstem Medulla Reticular Formation Thamlamus Controls heartbeat and breathing Reticular Formation Controls arousal Thamlamus Recieves sensory information (except smellI Sends it to correct places in brain Cerebellum Coordinates muscle movement

The Brain Limbic System: Linked to memory, emotions, and drives Hippocampus Processes memory for storage Amygdala Influences aggression and fear Hypothalamus Bodily maintenance and pleasurable rewards Major link to nervous and endocrine systems via pituitary gland

The Brain Cerebral Cortex thin sheet of cells composed of billions of nerve cells Glial Cell Support and nourish nerve cells The brain is divided into two hemispheres with four geographic lobes Frontal, parietal, occipital, and temporal

The Brain Cortexes Motor Cortex Sensory Cortex Occipital Lobes Rear of frontal lobes Controls voluntary muscle movement Sensory Cortex Front of parietal lobes Process body sensations Occipital Lobes Back of head Receive info from eyes Temporal Lobes Auditory area Recieves info from ears