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Nervous sys& neurons
Term | Definition |
---|---|
Central nervous system | Brain and spinal cord; |
Peripheral nervous system | Made up of smaller branches of nerves that reach other parts of body; transmit info back and forth from organs to cns |
Somatic nervous system | Made up of nerves that control voluntary movements |
Autonomic nervous system | Controls involuntary movements |
Neurons | Cells that make up nerves |
Dendrites | Located at one end of neuron; Receive signals/ info.; stimulate activity by neurotransmitters |
Axon | Pass information through cell from the dendrites; path of electrical impulse (action potential) through neuron |
Myelin sheath | Layer of fatty tissue that insulates axon of neurons; speeds electrical impulse down axon; degenerated by multiple sclerosis |
Axon terminal | End of neuron; releases neurotransmitters into synapse or takes them back up (reuptake) |
Synapse | Gap between dendrites and axon terminals; where neurotransmitters move from axon terminal to dendrites |
Vesicles | Tiny, near spherical packets within axon terminal; contain neurotransmitters; triggers into synapse |
What happens in the synapse | Axon terminal releases neurotransmitters into synapse where they travel to next neuron. |
Neurotransmitter | Chemical messenger of nervous system |
Epinephrine | Functions to speed up body processes; highly arousing; like adrenaline but released by neurons |
Endorphins | “Endogenous morphine” natural opiates that are released in response to pain/ vigorous exercise |
Acetylcholine | learning and memory; messenger between motor neurons and skeletal muscle; allows contraction of muscles |
Serotonin | Mood, hunger, sleep, and arousal; levels raised by antidepressants |
Afferent neurons | Take messages away from SENSORY organs to brain |
Efferent Neurons | take messages from brains to muscles resulting in motor tasks |
Interneurons | Central nervous system neurons that internally communicate and intervene between sensory inputs and motor outputs. |
Dopamine | Movement, learning, attention, and emotion. Excessive activity of these receptors lead to schizophrenia |