Chapter 46: Organization of the Nervous System... Flashcards
T/F: Most neuronal synaptic signal normally passes in the forward direction
T
Most activities of the nervous system are initiated by __________ experiences
Sensory experiences that excite sensory receptors
The most important eventual role of the nervous system is to control:
motor functions of the effectors
These are actual anatomical structures that perform the functions directed by the nerve signals
effectors
Which regions of the CNS are concerned primarily with automatic, instantaneous muscle responses to sensory stimuli?
Lower regions
Which regions of the CNS are concerned with the deliberate complex muscle movements controlled by the thought process of the brain?
Higher regions
This is the channeling and processing of information of the central nervous system
integrative function of the CNS
These determine the directions that the nervous signals will spread through the nervous system
synapses
Where in the nervous system does most storage of information occurs?
cerebral cortex
Each time certain types of sensory signals pass through sequences of synapses, these synapses become more capable of transmitting the same type of signal the next time, a process calle:
facilitation
This is the part of the nervous system for the subconscious control of arterial pressure and respiration
medulla and pons
Control of equilibrium is a combined function of:
older portions of the cerebellum (archicerebellum) and reticular substance of the brainstem
Which major level of the central nervous system initiate wakefulness in the cerebral cortex?
lower brain centers
Information is transmitted in the central nervous system mainly in the form of nerve action potentials, called:
nerve impulse
Most of the synapses used for signal transmission in the central nervous system of the human being are:
chemical synapses
This is the chemical substance secreted by the neuron at its nerve ending synapse
neurotransmitter or transmitter substance
These are clusters of ion channels that allow free movement of ions from the interior of one cell to the interior of the next cell
gap junctions
True or False:
Electrical synapses have bidirectional transmission
True
Which type of synapse that always transmit signals in one direction?
chemical synapse
*principle of one-way conduction
Electron microscopic studies of the presynaptic terminals show that they have varied anatomical forms, but most of them resemble small round or oval knobs and therefore are sometimes called
terminal knobs, boutons, end-feet, synaptic knobs
How wide is a synaptic cleft?
200-300 angstroms
These are the two important internal structures at the synaptic terminal for excitatory and inhibitory functions of the neuron
transmitter vesicles and mitochondria
What protein channels found in the presynaptic membrane opens when an action potential depolarizes the membrane?
voltage-gated calcium channels
To which special proteins in the presynaptic membrane do calcium ions bind causing them to open through the membrane, and allowing a few transmitter vesicles to release their transmitter into the cleft after each single action potential
release sites
What are the two components of receptor proteins in post-synaptic neurons?
Binding component and intracellular component
This is a molecule that protrudes into the cell cytoplasm and activates one or more substances inside the postsynaptic neuron
second messenger
These are neurotransmitter neurons that directly gate ion channels
ionotropic receptors
These are neurotransmitters that act through second messenger systems
metabotropic receptors
Between cation and anion channels, which channel is known to be excitatory?
cation channels (entry of sodium)
Prolonged postsynaptic neuronal excitation or inhibition is achieved by activating a ___________ system inside the postsynaptic neuronal cell, and then it is this that causes the prolonged changes in neurons after the initial transmitter substance is gone
second messenger chemical system
Which component of the G protein in the activator component?
alpha component
What is the most widely used means of excitation of postsynaptic receptors?
Opening of sodium channels to allow large numbers of positive electrical charges to flow to the interior of the postsynaptic cell