Nervous System Flashcards
The nervous system is responsible for controlling most body functions, enabling organisms to ___ and ___ to stimuli from their ___ and ___ environments
receive, respond, external, internal
Signals from the nervous system travel ____, reaching in excess of ______m/s, and in some cases, which results in transmission of information much more rapidly than through the ___ ____
quickly, 100, endocrine system
The nervous system is composed of both ___ and ____. These cells work together to form the major organs of the nervous system, which include the ___ and ___ ____, as well as complex sensory organs such as the ___ and ____. In turn these organs can be grouped into the ____ and ____.
neurons, neuroglia, brain, spinal cord, eye, ear, PNS, CNS
Myelin is produced by glial cells known as ___ in the CNS and by ___ _____ in the PNS.
oligodendrocytes, schwann cells
Maintain the integrity of BBB, regulate nutrient and dissolved gas concentrations, absorb and recycle neurotransmitters
astrocytes
myelinate CNS axons as well as provide structural framework for the CNS
oligodendrocytes
remove cellular debris and pathogens
microglia
line the brain ventricles and aid in the production, circulation and monitoring of CSF
ependymal cells
Surround the neuron cell bodies in the ganglia
satellite cells
enclose axons in the PNS and aid in the myelination of some peripheral axons
schwann cells
The Na/K+ pump pumps ___ Na+ ____ of the cell for every ___ K+ it transports ___ to the cell. This uneven exchange results in a ____ _____ environment. Furthermore, the cell membrane is more permeable to ___ than to ____. This allows some of the K+ that was pumped into the cell to move back out through ___ ___, making the internal environment even more negative
3, out, 2, into, negative, internal, K+, Na+, facilitated diffusion
When depolarization reaches the ____ ___, then ___ ___ __ located into the nerve cell membrane open and an ___ ___ begins when ____ rushes into the cell. This causes the next portion of the ___ toward the terminal to be depolarized and so on until it reaches the ___ ___. At the terminal, a final _____ ____ ____ is opened and __ triggers the ___ of synaptic vesicles containing neurotransmitters
threshold potential, voltage-gated ion channels, action potential, Na+, axon, synaptic terminal, voltage-gated Ca channel, Ca2+, exocytosis
After the signal has been propagated through a segment of the axon, the high voltage there causes ______ ___ ___ to open, allowing K+ to flow ___ of the cell. Meanwhile, the voltage gated Na+ channels _____, and the Na+/K+ pump begins to pump Na+ ___ again. This is called ____.
voltage-gated K+ channels, out, close, out, repolarization
The neuron’s voltage shoots past the ___ __ and becomes even more negative inside than normal due to the K+ still being free to ___ the cell. This is called ______. this results in a ___ ____, where new APs cannot be generated. This period allows the neuron time to _____ ____ and also helps ensure the action potential only moves in the ___ direction, towards the terminal
resting potential, leave, hyperpolarization, refractory period, regenerate neurotransmitter, forward
The action potential itself can be described as an ______ response. The stimulus intensity is coded by the ___ of the action potentials and not by their ____
all-or-none, frequency, magnitude
The greater the ___ of the axon, and the more heavily it is ___, the faster the impulses travel. Myelin increases the __ ___ by insulating segments of the axon such that the membrane is permeable to ___ only in the ___ ___ ___. In this way, the action potential ___ from node to node
diameter, myelinated, conduction velocity, ions, nodes of ranvier, hops
Neurons that communicate with cells in muscles or glands
effector cells
Neurotransmitter can undergo ____ by ______ ____, where it may be reused or degraded, it may be degraded by ___ located in the synapse, or it may simply ____ out of the synapse
reuptake, uptake carriers, enzymes, diffuse
Drug that blocks the postsynaptic nicotinic ACh receptors such as those on muscles, leading to muscle relaxation and paralysis by blocking the ability to constrict muscles
curare
Drug that prevents the release of ACh from the presynaptic membrane and also results in paralysis
botulinum toxin
drugs used as nerve gases and in the insecticide parathion; inhibit the activity of ACh enzyme respomnsible for degrading ACh released in synapse; results in no coordinated muscular contractions
anticholinesterases
neurons that carry sensory information about the external or internal environment to the brain and spinal cord
afferent neurons
neurons that carry motor commands from the brain or spinal cord to various parts of the body
efferent neurons
neurons that participate only in local circuits, linking sensory and motor neurons in the brain and spinal cord; cell bodies and nerve terminals are in the same location
interneurons
bundles of axons covered with connective tissue
nerves
plexus
network of nerve fibers
clusters of neuronal cell bodies in the periphery
ganglia
