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Techniques for studying the brain
EEG (Electroencephalograph); PET (Positron Emission Tomography); MRI (Magnetic Resonance Imaging); fMRI (Functional MRI)
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EEG (Electroencephalograph)
multiple electrodes placed on scalp; shows general electrical activity of the brain; represented as a line on a graph or screen
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PET (Positron Emission Tomography) Technique
Positrons and photons emitted by radioactive substances; indicate specific changes in neuronal activity; brain structure
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MRI (Magnetic Resonance Imaging) Technique
Exposes the brain to a magnetic field; shows high resolution image of brain; does not indicate functions as the
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Functional MRI (fMRI)
combines the advantages of the PET and MRI; detects changes in cerebral blood flow and oxygen; shows areas of the brain that appear activated during a task (brain function)
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major neurortransmitters
a chemical messenger in nervous system; housed in synaptic vesicles; they transmit a message; at least 100 identified neurotransmitters
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Acetylcholine (ACh)
one of the first (neurotransmitter) to be identified; stimulates skeletal muscles (contract); role in memory, arousal and attention; underproduction can lead to Alzheimer's, overproduction causes convulsions
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Norepinephrine
Involved in learning, memory, wakefulness and eating; also arousal and mood; underproduction leads to depression, overproduction leads to stress and panic
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Serotonin
affects sleep, arousal, appetite and mood; underproduction leads to depression, sleeping and eating problems (low levels often found in suicide victims), over productions leads to obsessive compulsive disorder (OCD)
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Dopamine
involved in emotional arousal (sensations of pleasure) and movement; underproduction leads to Parkinson's disease and depression, overproduction leads to Schizophrenia
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Endocrine System
hormone - secreting glands distributed throughout the body; "ductless" gland
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hormones
chemical messages secreted directly into the bloodstream; slower, more widespread messages
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glands
pituitary, pineal, thyroid, parathyroid, pancreas, adrenal, and gonads
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pituitary gland
pea-shaped organ located in brain, regulates growth; regulates water and salt metabolism; causes the uterus to contract during childbirth; causes milk production for nursing; "Master" gland
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pineal gland
located in brain directly above brainstem; secreates melatonin; regulates the sleep-wake cycle
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thyroid gland
located in the neck; secretes thyroxin; controls the metabolic rate: alert and energetic; fat or thin; embedded in thyroid glands are parathyroids
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parathyroids
embedded in thyroid gland; regulate calcium and phosphate levels in body; influences excitability
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pancreas
curve between the stomach and small intestines; regulates blood sugar levels with two hormones; insulin, glucagon; underproduction of insulin leads to diabetes mellitus
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adrenal glands
twin structures or glands located just above kidneys; adrenal cortex - outer layer, adrenal medulla - the inner core; produce and secrete about 50 different hormones; best known is adrenaline (epinephrine); norepinephrine (also a neurotransmitter) involved in body's response to stress arousal when physically threatened; "fight or flight"
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gonads
sex glands; testes in males, ovaries in females; secrete two hormones: androgen - masculine, estrogen - feminine; primary and secondary sex characteristics (females - larger breasts/hips, males - pubic/facial hair, adams apple, muscles)
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testosterone
needs to be present during prenatal development (3-4 months); fetus to develop as male; link to aggressive behavior
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