Ch2 The Brain and Behavior The biological perspective The nervous system Neurons Structures of the brain and functions Endocrine system Brain damage plasticity and repair Overview of The Nervous System Nervous System an extensive network of specialized cells that carry information to and from all parts of the body examines the structure and the function of the nervous system interested in the relation of the nervous system to behavior and learning aka biopsychology how does this biology work together to make a whole that can think eat sleep etc THINK COMMUNICATION Neuroscience Behavioral Neuroscience Characteristics Complexity billions of cells involved automatic and controlled simultaneously Integration different levels and different parts power from working and knowing together the whole is more than the sum of the parts something so incredible but still such a mystery Adaptability responsive to changing environment leans Plasticity capacity for change survival value a nervous system that cannot adapt will fail to survive Electrochemical transmission portions of it that work electrically and some that are dependent on chemical reactions primary divisions organization of NS on blackboard Neurons basic cell in the nervous system does the processing receives THE NEURON and sends messages minority cell but primary cell of the nervous system maybe as many as a trillion neurons in the body Mature neurons don t divide but they can get new jobs called NEUROPLASTICITY when a neuron takes on a new job or function i e a blind peron s neurons can relocate and switch to giving this person more language skills because they are not needed for vision Neurogenesis PARTS OF THE NEURON We can make some new neurons Start deep in the brain and migrate connect How do we access this process Dendrites receives the message detects Soma cell body maintains life of the cell Soma in the Center Axon long tube like structure carries message to other cells sends detects carries information from senses to the CNS central nervous system aka AFFERENT neuron figure 2 2 the neuron blackboard Three Types of Neurons 1 Sensory Neuron 2 Motor Neuron carries messages from CNS to muscles aka EFFERENT neuron 3 Interneuron found in CNS middleman receive info from sensory neuron and sends commands to muscles motor neurons connect and coordinate allow A E to talk can be multiple between neural networks most common neuron in brain involved in spinal cord reflex Other Types of Brain Cells Glial Cells cells that support 90 1 provide support for neurons to grow on around 2 deliver nutrients to neurons 3 clean up waste products and dead neurons 4 help repair damage 5 some produce myelin a fatty substance that coats axons to insulate protect and speed up impulse The message passes dendrite cell body axon detect center away The function of myelin speed transmission of message More neurons or more glial cells in brain glial cells I bring info from the senses to the brain afferent neuron Generating the Message Neural Impulse Sending message WITHIN the neuron from dendrite to axon Electrical moving charge difference All or none fires completely or not at all always the same strength How are different strength responses indicated a Change the rate of firing Can fire more or less often how quickly I fire again b The number of neurons firing Sending message BETWEEN cells from axon to dendrite Chemical Neurotransmitter NT chemical used to pass message to next cell Sending the Message to Other Cells Synapse synaptic gap Microscopic space between neurons NEURONS DON T TOUCH Receptor sites Holes in the surface of the dendrites or muscle or gland cells shaped to fit only certain NT figure 2 5 how synapses and transmitters work blackboard Neurotransmitters are Chemical messengers Neuron Communication Chemical substances can affect neuronal communication i e increasing or decreasing what happens in the synapse with communication Agonists mimic or enhance effect of NT i e black widow venom increasing the effect of acetylcholine muscle movement can cause muscles to go into convolution Antagonists block or reduce response to NTs i e curare blocks acetylcholine from working fits receptor cell gets in the way of anything else getting in the receptor leads to paralysis betablockers controlling blood pressure block reaction to some stress hormones CLEANING UP THE SYNAPES Reuptake NTs taken back into sending cell most common within milliseconds Diffusion NTs drift away Enzyme a protein made by cells breaks down NT Even Faster than Reuptake used for acetylcholine Most common way to prepare the synapse for the next massage REUPTAKE If I enhance the effect of a NT I am AGONIST CENTRAL NERVOUS SYSTEM brain and the spinal cord CNS Spinal Cord bundle of neurons 1 carries messages b w body and brain 2 responsible for very fast lifesaving reflexes spinal cord reflex on blackboard THE PERIPHERAL NERVOUS SYSTEM all nerves and neurons not in CNS 2 main divisions SOMATIC NERVOUS SYSTEM carries sensory info controls skeletal muscles 1 Sensory pathway sensory afferent neurons from senses to CNS 2 Motor pathway motor efferent neurons from CNS to voluntary muscles ALS Lou Gehrig s Disease progressive detiriation of these motor neurons AUTONOMIC NERVOUS SYSTEM controls involuntary muscles organs and glands Keeps you alive 1 Sympathetic Division reacts to stressful events when a crisis happens you sympathize direct resouces to short term survival called fight or flight 2 Parasympathetic Division restores body to normal functioning heal and grow health issues if not enough if too much stress can elicit through yoga meditation How to study the brain See what happens when we lose it See what happens when we use it Brain Imaging Techniques X ray 2D images CT or CAT scan 3D images PET scan metabolic changes sugar MRI brain structure f MRI brain function oxygen Three Sections HINDBRAIN MIDBRAIN FOREBRAIN The Hindbrain medulla pons cerebellum Medulla life sustaining functions controls breathe Dys f death or swallowing heart rate blood pressure life support Pons plays role in sleep and arousal Cerebellum motor coordination and conditioned reflexes Dys f problems Dys f lead to a Coma To automatic motor behaviors balance Brain Stem includes most of the hindbrain and midbrain not cerebellum determines alertness regulates basic functions Midbrain reticular formation Forebrain involved in walking and sleeping arousal filter and relay station damage can lead to irreversible coma
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