UNIT 2 (CH 3/5) Flashcards
(122 cards)
a nerve cell; the basic building block of the nervous system
neuron
neurons that carry incoming information from the sensory reseptors to the brain and spinal cord
sensory neuron (afferent neuron)
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands
motor neurons (efferent neuron)
neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs
interneurons
the bushy, braching extentions of a neuron that receive messages and conduct impulses toward the cell body
dendrite
the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to the muscles or glands
axon
a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impluses as the impulse hops from one node to the next
myelin sheath
a neural impulse; a brief electrical charge that travels down an axon
action potential
the level of stimulation required to trigger a neural impulse
threshold
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft
synapse
chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to reseptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse
neurotransmitters
a neurotransmitter’s reabsorption by the sending neuron
reuptake
morphine within - natural . opiatelike neurotransmitters linked to pain control and to pleasure
endorphins
the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems
nervous system
the brain and spinal cord
central nervous system (CNS)
the sensory and motor neurons that connect the central nervous system to the rest of the body
peripheral nervous system (PNS)
bundled axons that form neural “cables” connecting the central nervous system with muscles, glands, and sense organs
nerves
the division of the peripheral nervous system that controls the body’s skeletal muscles.
somatic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.
autonomic nervous system (ANS)
the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations
sympathetic nervous system
the division of the autonomic nervous system that calms the body, conserving its energy
Parasympathetic nervous system
In neural processing, a brief resting pause that occurs after a neuron has fired; subsequent action potential cannot occur until the axon returns to its resting state
Refractory period
a simple, automatic response to a sensory stimulus, such as the knee-jerk response
reflex
the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream
endocrine system