Final Flashcards
(164 cards)
a network of cells that sense and respond to stimuli in ways that maintain homeostasis
the nervous system
What two cell types are neural tissue composed of?
Neurons and neuroglia
specialized cells that read to physical and chemical changes in their surroundings
neurons
small cellular processes (arms) that receive input; typicaly highly branched, providing receptive surfaces with which processes from other neurons communicate
dendrites
contains granular cytoplasm, mitochondria, lysosomes, glory apparatus, microtubules; also neurofilaments ad chromatophilic substance
cell body
longer process (arm) or nerve fiber that carries information away from the cell in the form of impulses
axon
a bioelectric signal or action potential which allows the neuron to communicate with other neurons and with cells outside the nervous system
impulse
What are bundles of axons called in the PNS?
Nerves
What are bundles of axons called in the CNS?
Tracts (brain and spinal cord)
nourish neurons; send and receive chemical messages; fill spaces and surround or support neurons; create blood-brain barrier and forms the capillaries
neuroglia
the small space between a neuron and the cells with which it communicates
synapse
biological messenger molecules that convey electrochemical messages
neurotransmitter
3 general functions of the nervous system
receiving information, deciding what to do, and acting on decisions
structures at the ends of neurons in the PNS that provide the sensory function of the nervous system gather information by detecting changes side and outside the body; convert information into impulses -> PNS -> CNS
sensory receptors
communicate voluntary (conscious) instructions originating in the CNS to skeletal muscles, causing contraction
somatic nervous system
communicates instructions from the CNS that control viscera, which are involuntary subconscious actions
autonomic nervous system
neurons that conduct impulses from the NS to these responsive structures that carry out motor functions of the nervous system; muscles and/or glands
effectors
Two systems that are part of the motor portion of the PNS
somatic and autonomic nervous system
a network of fine threads that extends into the axon and supports it
neurofilaments
(Nissl bodies) many membranous packets which consists mainly of touch E.R.
chromatophilic substance
the place from which the axon arises from the cell boy as a cone-shaped thickening
axon hillock
space between axon terminal (synaptic knob and receptive surface of another cell
synaptic cleft
neuroglia that encase the large axons of peripheral neurons in lipid-rich sheaths
Schwann cells
a specialized end of an axon that has many fine extensions that ends as a synaptic knob
axon terminal