Chapter 2 - Neuroscience and Behavior Flashcards
neuron
a nerve cell, basic building block of nervous system
dendrite
bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body
axon
extension of 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 segment ally encasing the fibers of many neurons, enables vastly greater transmission speed of neural impulses as the impulse hips from one node to the next
action potential
a neural impulse, a brief electrical charge that travels down an axon. the action potential is generated by the movement of positively charged atoms in and out of channels in the axons membrane
threshold
level of stimulation required to trigger a neural impulse
synapse
junction between axon tip of sending neuron and the dendrite or cell body of the receiving neuron. tiny gap at this junction is called the synaptic gap or cleft
neurotransmitters
chemical messengers that traverse the synaptic gaps between neurons. when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse
acetylcholine
a neurotransmitter that enables learning and memory and also triggers muscle contraction
endorphins
“morphine within” - natural, opiatelike neurotransmitters linked to pain control and to pleasure
nervous system
the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems
central nervous system (CNS)
the brain and spinal cord
peripheral nervous system
the sensory and motor neurons that connect the central nervous system to the rest of the body
nerves
neural “cables” containing many axons. these bundled axons, which are part of the peripheral nervous system, connect the central nervous system with muscles, glands, and sense organs
sensory neurons
neurons that carry incoming information from the sense receptors to the central nervous system
motor neurons
neurons that carry outgoing information from the central nervous system to the muscles and glands
interneurons
central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs
somatic nervous system
division of the peripheral nervous system that controls the body’s skeletal muscles. also called skeletal nervous system
autonomic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). it’s sympathetic division arouses; it’s parasympathetic division calms.
sympathetic nervous system
division if the autonomic nervous system that arouses the body, mobilizing it’s energy in stressful situations
parasympathetic nervous system
the division of the autonomic nervous system that calms the body, conserving it’s energy
reflex
simple, automatic, inborn response to a sensory stimulus, such as the knee-jerk response