Chapter 2 The Biology of Mind and Behavior The Brain in Action electrochemical describe the biological basis of behavior receives signals from neurons or sense organs dendrites processes signals cell body determines to either turn on or turn off send signals to other neurons muscles and organs axon THE NEURON receive integrate transmit signals basic unit of the nervous system brain contains 100 billion neurons main parts of a neuron dendrites tree cell body processes and integrates axon terminal buttons long cable like structure transmits information has many dendrites but only one axon THE NEURON TYPES sensory neuron repsond to simuli input from the outside world transform that into electrochemical signals send that to brain motor neuron take signals and commands from brain and sent out to body to control movement more positively charged ions outside than inside action potential NEURAL IMPULSES resting potential neuron at rest negative when charge in neuron switches from negative to positive axon fires action inside of neuron has a negative charge outside of neuron has a positive charge threshold exceeded flow of ions through channels potential draws in positively charged ions send wave of electric signal down axon once an action potential starts it cannot stop all neurons fire action potential at the same strength layer of fatty tissue that surrounds the axon speeds up the electrical impulse keeps electrical impulse from jumping from axon to other areas like the insulation around electrical cord multiple sclerosis MS deteriorated myelin myelin NEUROTRANSMITTERS synapse tiny space connecting all neurons neurotransmitters chemicals used by neurons to communicate with each no 2 neurons actually touch each other other receptors area of a dendrite that receives chemical signals many different types of neurotransmitters have different functions neurotransmitters from other axons lock and key system neurotransmitter has a special shape like a key that will only fit in a certain receptor like a lock for every specialized type of neurotransmitter there is a specialized type of receptor to receive it excitatory tells neuron to fire an action potential inhibitory tells neuron to stay at rest one it receives more of will occur neuron will receive multiple excitatory and inhibitory signals whichever function controls memory and muscle control linked to Alzheimer s disease NEUROTRANSMITTER TYPES acetylcholine dopamine serotonin function controls motivation and reward and arousal linked to excess schizophrenia deficit Parkinson s disease function pain emotions master neurotransmitter linked to depression antidepressant most common drug 1 2 million people DRUGS AND THE BRAIN agonists increases the activity of a neurotransmitters antagonists decreases or halts activity of a neurotransmitter Propanolol Naltrexone neurotoxins LSD cocaine methamphetamine THE NERVOUS SYSTEM peripheral nervous system 1 2 3 all of the nerves outside the brain and spinal cord controls everything in your body other than your head autonomic nervous system controls non voluntary functions tied with psychological disorders 1 2 4 central nervous system sympathetic nervous system fight or flight speeds us up overactive anxiety disorder parasympathetic nervous system slows things down relaxes sensory somatic nervous system controls all voluntary motor behavior 1 2 1 3 4 1 2 3 4 5 spinal cord controls reflexes extension of the brain reflexes reflex to something before you cognitively realize it jerking back from touching a hot stove cerebral hemisphere 2 halves of the brain separate from one another lobes each hemisphere divided into 4 lobes occipital lobe devoted to vision back of the brain temporal lobe controls hearing and memory below temples in front of ears parietal lobe sense of touch and motor behavior frontal lobe planning memory communicant emotion upper rear portion intelligence what makes up human behind the forehead corpus callosum thick bundle of nerve fibers that connect the 2 hemispheres cerebral cortex largest most complex part of the brain outer layer 6 1 7 1 Split brain patient 2 hemisphere cannot communicate uniquely human controls higher thinking functions subcortical structures brain structures beneath cerebral cortex controls basic functions SUBCORTICAL BRAIN AREAS thalamus sensory switchboard hypothalamus controls biological instincts hippocampus memory filing program amygdala involved in learning through fear brain stem arousal medulla heart rate breathing metabolism pons connect different parts cerebellum controls balance motor activity psychopaths politicians first affected by alcohol how relates to hormones and brain hormones pituitary gland brain lesion studies phineas gage EEG CT scan MRI PET Mendelian vs complex inheritance genetic research methods