unit 2

• axon


  the extention of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands
• myelin sheath


  a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next
• action potential


  a neural impulse; a breif electrical charge that travels down an axon
• threshold


  the level of stimulation required to trigger a neural impulse
• synapse


  the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
• neurotransmitters


  chemical messengers that traverse the synaptic gap between neurons
• acetylcholine


  muscle action, learning, associated with alzheimer
• endorphins


  linked to pain control and pleasure
• electroencephalogram (EEG)


  an amplified recording of the waves of electrical activity that sweep across the brain&surface
• CT (computed tomography) scan


  a series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body
• PET (positron emission tomography) scan


  a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task
• MRI (magnetic resonance imaging)


  uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue
• brainstem


  the oldest part and central of the brain, beginning where the spinal cord swells as it enters the skull; responsible for automatic survival functions
• medulla


  the base of the brainstem; controls heartbeat and breathing
• reticular formation


  a nerve network in the brainstem that plays an important role in controlling arousal
• thalamus


  the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla
• cerebellum


  helps coordinate voluntary movement and balance
• limbic system


  associated with emotions such as fear and agression and drives such as those for food and sex
• amygdala


  two almond-shaped neural clusters that are components of the limbic system and are linked to emotion
• hypothalamus


  emotion, sexual, pleasure, drinking, eating, body temporature
• cerebral cortex


  the body's ultimate control and information-processing center
• frontal lobes


  invloved in speaking and muscle movements and in making plans and judgments
• parietal lobes


  senses except vision, body position
• occipital lobes


  includes the visual areas
• temporal lobes


  hearing, storing and learning memories
• plasticity


  the brain's capacity for modification, as evident in brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development
• corpus callosum


  the large band of neural fibers connecting the two brain hemispheres and carrying messages between them
• split brain


  a condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them
• hormones


  chemical messengers, mostly those manufactured by the endocrine system, that are produced in one tissue and affect another
• adrenal glands


  secrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stress
• pituitary gland


  under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands
• dendrite


  recieves messages and conduct impulse toward cell body
• agonist


  speed up
• antagonist


  slow down, botox
• dopamine


  influence movement, learning, attention, and emotion. Lead to schizophrenia, parkinson, depression ex: cocaine, alcohol
• serotonin


  affects mood, hunger, sleep, &arousal. Prozac, OCD
• norepinephrine


  helps control alertness&arousal
• GABA


  major inhibitory nt, seizures, tremors, &insomnia, Huntington disease
• Glutamate


  excitatory nt, involves memory. migraines/seizures, avoid MSG, Lou Gherigs's