Chapter 3 Biological Psychology Biological Psychology Study of the physical or biological nature of psychological processes Immune system genetics hormones the brain nervous system Neuroscience the study of the structure and function of the nervous system and how it relates to behavior and mental processes The Nervous System The body s communication system information transmitted by electrical and chemical signals everything we experience and do is the result of communication within the nervous system two systems work together central nervous system peripheral nervous system central nervous brain spinal cord peripheral nervous cranial nerves spinal nerves sensory organs eyes nose tongue ears and skin Stimuli from the environment can be processed quickly reflexes peripheral nervous system transmits information to and from the central nervous system somatic somatic controls voluntary muscle movement sensory pathway signals from the senses to CNS motor pathway signals from CNS to muscles autonomic nervous system control the involuntary muscles organs and glands divided into sympathetic activates body activates body during time of stress fight or flight system arouses the body mobilizes energy parasympathetic nervous system calms body back down to rest rest and digest conserves energy CNS spinal cord pathway connecting the brain to PNS sensory neurons receive signals from senses motor neurons sends signals to muscles can direct simple reflexes without going to the bran Brain interprets and stores information and sends commands to muscles glands and organs most complex part of the nervous system allows richest information processing Structure of the nervous system Spanish scientist Santiago Ram n y cajal 1852 1934 discovered that nervous system is made up of individual cells not continuous structure building blocks of the nervous system two types of cells neurons specialized cells within the nervous system that receives and sends messages within that system Glial cells supports structure of the nervous systems Anatomy of a neuron dendrite bushy branching extensions of a neuron that receive messages from other neurons and carry them to the soma cell body soma main body of a neuron where nucleus is responsible for life of the cell genetic material axon tail of a neuron long tube like structure that carries the neural message to be sent to other neurons action potential travels down the axon to the axon terminals speed of impulse myelin fatty coating on axons insulates protects and speeds up the neural impulse more myelin more speed within a single neuron necessary for swift communication damage results in impaired movement cognition and sensation axon terminals end of the axon and beginning of the junctions with other cells where messages are transferred via chemicals called neurotransmitters terminal button rounded areas on the end of axon terminals that contain synaptic vesicles synaptic vesicles sac like structures found inside the terminal that contain the chemical NTs synapse tiny gap NTs travel from the axons terminals to the next neurons dendrites axon terminal electrical signal from axon triggers a chemical release from the axon terminals neurotransmitters chemicals that transmit the message on to the next neuron Neural communication receptor sites ports in the surface of the dendrites of the receiving cells shaped to fit a specific NT receptor site is like a lock NT is like a key Cell resting potential cells are usually polarized more negative on the inside Action potentials add a little bit of excitement and a little more Depolarization channel lets in positive Dendrites get input information from dendrites go to cell body depolarization of cell when a threshold is reached action potential occurs action potential goes down axon to the terminal neurotransmitters are released into the synapse to bind to the next neuron 2 refractory period cells can t fire cells restore electrochemical Negative in positive out The action potential resting potential negatively charged state of the neuron when NOT firing a neural impulse action potential positively charged state during the neural impulse the electrical message FIRE refractory period during return to resting potential the neuron cannot fire all or none like a firing gun the neuron either fires completely or it does not fire at all does NOT vary in strength or intensity travels down the axon about 100 ft sec The Brain Brain Stem medulla vital functions blood pressure heart rate breathing reflexes cough swallow sneeze vomit pons literally bridge between lower brain regions to higher midbrain and cerebral hemispheres autonomic functions play a key role in sleeping and dreaming Cerebellum Little brain functions movement balance coordination and fine motor skills cognitive functions learning and language affected by stroke alcohol poor coordination balance slurred speech Midbrain integrates sensory input with voluntary muscle movement Parkinson s disease loss of neurons in midbrain that use dopamine so they shake uncontrollably Subcortex thalamus receives sensory input from ears eyes skin taste buds and relays that information to the cerebral cortex sensory relation station one exception is smell olfactory bulb has direct connection to limbic structures emotion and memory centers of brain Subcortex Basal ganglia surrounding thalamus involved in voluntary motor control often considered part of the limbic system Subcortex hypothalamus neural structure lying below the thalamus regulates how strongly we feel motivational emotions body temperature hunger thirst fight or flight sexual behavior Subcortex hippocampus memory patient H M sensory information enters hippocampus sometimes creating lasting memories 3 Subcortex amygdala connected to hypothalamus hippocampus thalamus and cerebral cortex evaluates emotional significance of sensory input Amygdala when electrically stimulated in cats makes them exhibit fear response when removed in aggressive monkeys they became tame and non aggressive also fearless approach rather than fleeing dangerous snakes The Brainstem Medulla automatic life support heartbeat breathing Cerebral cortex anatomical areas frontal lobe temporal lobe parietal lobe occipital lobe functional areas sensory motor association frontal lobe involved in attention holding things in mind while solving problems working memory planning abstract thinking controlling impulses creativity and social awareness home of the motor cortex
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