-70 mv -the minus sign indicates that the ______ of the membrane is ________ charged and the ______ of the membrane is _______ charged.
action potentials, depolarization
_________ may arise if the ______ is strong enough. If the threshold is reached (-55 mv).
inhibitory, excitatory, both
Neurotransmitters can be __________, or __________, or ___________.
Most axons are surrounded by a __________.
When a stimulus causes the membrane potential to be "more negative", the membrane is being _____________.
nonessential, inhibited, digestion
Physiological adj. in sympathetic division. All __________ activities are _________. An example would be: ___________
presynaptic, calcium, calcium
Step 1 of a chemical synapse: depolarization of _________ neuron results in the opening of _________ channels, which allows ______ to flow into the cell.
exocytosis, synaptic vesicles, neurotransmitters
Step 2 of a chemical synapse: Ca causes __________ of the neurotransmitter filled synaptic vessicles. When the _______ fuse with the plasma membrane, the __________ are released into the synaptic cleft.
Step 3 of a chemical synapse: __________ bind receptors located on the ______ membrane.
excitatory (causes a response), inhibitory (stops a response)
Step 4 of a chemical synapse: This causes either an ___________ or an _____________ response.
neurotransmitters, synaptic cleft
CHEMICAL SYNAPSE Once a response has been brought about the ______ must be removed from the ________.
diffusion- move from an area of high concentration to an area of low conc. away from the cleft; degraded by enzymes-broken down; taken back into presynaptic neuron;
What are the three ways that a response can be removed from tghe synaptic cleft.
myelin, demyelinating, multiple sclerosis, central nervous system, sclerosis
The importance of ___________ to nerve transmission is painfully clear to those with ______ diseases such as ________. In this disease, myelin sheaths in the _______ are gradually destroyed, reduced to nonfunctional hardened lesions called ________.
The loss of ______ causes such substantial shunting & short circuiting of the current that successive _____ are excigted more & more ______ and eventually _____ ceases. However, the ______ themselves are not damaged and growing numbers of ________ channels appear spontaneously in the _______. This may account for the remarkably variable cycles of _________ and __________.
Glial cells and Neurons
Two major categories of nervous cells.
controls non-stressful situated "rest & digest"
somatic nervous system, autonomic nervous system
The peripheral nervous system is divided into 2 other systems; They are:
pheripheral nervous system
Regeneration of nervous tissue: If the soma of the neruon is intact, the neurons can be repaired.
Neurons that have axons that are not covered with myelin are called: ___________.
central nervous system
In the ____________, myelin is produced by oligodendrocytes.
efferent cell process
This cell process carries away from the cell body.
Senses changes (stimuli) n the internal and external environment.
Responds to the stimuli after decisionis made.
This neurotransmitter is a powerful exitatory.
myelinated, white, white matter, fast
Regions of the central nervous system that consist mainly of _______ axons are _______ in color and referred to as _______. Conduction is very ________.
afferent cell process
This cell process carry toward the cell body.
The somatic nervous system is usually composed of ___________ pairs of spinal nerves and ______ pairs of cranial nerves.
Myelin insulates the _____ and _____ the conduction of a nervous impulse.
The all or none principle
__________ is if depolarization reaches threshold the action potential will occur at a constant strength, whether or not the stimulus continues. However, if the # of Na entering the cell is too low to achieve threshold no AP will occur.
action potentials (AP)
_________ is a "nervous impulse".
_________ is that point, usually (-55 mV), when a neuron is stimulated to produce AP.
GABA and Glycine
This neurotransmitter is a powerful inhibitory.
resting membrane potential
________________ is the electrical voltage difference across the membrane of a neuron at rest. (-70 mV)
repolarization, negative (-70 mV)
___________ is when sodium channels close and Potassium channels open. K rushes out of the cell making the membrane potential more _________ again.
The inflow of sodium (Na) further _______ the membrane (30 MV).
central nervous system, peripheral nervous system
Neurotransmitters are found in both the _____________ and ____________.
central nervous system (CNS), peripheral nervous system (PNS)
Name 2 organizations of the nervous system.
______ are the chemical messengers of the nervous system.
Analyzes the changes and makes decisions on what should happen.
Motor (efferent) neurons
______ conduct nervous impulses away from the central nervous system to muscles and glands.
These conduct nervous impulses from one prt of the body to another *Partially electric
sensory (afferent) neurons, motor (efferent) neurons
What are the 2 functional classifications of neurons?
When a stimulus causes the membrane potential to be less negative the membrane is being _________.
Nodes of Ranvier, sodium channels
The spaces between Schwann cells are called ___________. These containe buches of ____________________.
sensory function, integrative function, motor function
What are the three basic functions of the nervous tissue?
Clusters of cell bodies in the peripheral nervous system are _________.
central nervous system
Regeneration of nervous tissue: currently there is no chance of repair.