NEUROSCIENCE AND BEHAVIOR

Chapter 2

Structure of a Neuron

Neuron 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 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 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 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

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

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