What describes an atom in which the total number of electrons is not equal to the total
number of protons, giving the atom a net positive or negative electrical charge – Ion
What is the negatively charged particle in an atom? – Electron
What has neutral particles, along with protons, and is found in the nucleus of an atom? –
Neutrons
Which particles of an atom are positively charged? – Protons
What makes up the elements found in all matter? – Atoms
What is the voltage inside the nerve cell membrane in a resting membrane potential? – –
90 to -70mV
What is the major ion outside a cell membrane? – Sodium
What is the major ion inside a cell membrane? – Potassium
What is the physiological term when depolarization occurs it causes a muscle and/or
nerve fiber to either respond to a stimulus completely if it reaches threshold or no
response if the depolarization is insufficient to reach threshold? – All or non response
What describes changing from a resting potential or polarized state to an excited state?
- Depolarization
What causes the inside of the cell to be more positively charged relative to its resting
state? – Depolarization
What describes when nerve cells are changed from an excited state back to a resting
electrical potential or polarized state? – Repolarization
What causes the inside of the cell to be more negatively charged relative to its resting
state? – Hyperpolarization
During the repolarization phase, sodium channels become inactivated and cannot be
opened no matter how much depolarization occurs and no action potential can be
generated no matter how strong the stimulus. What is this? – Absolute refractory period
In the later stages of repolarization, a brief increase in the permeability to potassium
occurs and this results in hyperpolarizing the membrane and returning it slowly to its
resting value during which time an increasing number of sodium channels can be
opened. If you give a strong stimulus, it might be possible for another action potential to
occur. This time is known as the – relative refractory period
Propagation of action potentials along myelinated axons from one Node of Ranvier to
the next Node of Ranvier is called? – Saltatory conduction
What is the name of the cells that are surrounding the axon to form the myelin sheath? –
Schwann Cells
What describes the periodic gaps in the insulating sheath (myelin) on the axon through
which ion channels allow the flow of ions across the nerve membrane? – Nodes of
Ranvier
The length between two nodes of Ranvier is called? – Internodal length
Forcing sodium out of the cell and potassium in is the function of what? – Sodiumpotassium pump
What can increase or decrease the conduction velocity of a nerve? – Diameter of the
axon and degree of myelination
What type of fibers mediate pain, temperature, and autonomic function? – Unmyelinated
fibers
Nerve fiber bundles’ having a common destination describes? – Fascicles
Each individual fascicle is surrounded by connective tissue called? – Perineurium
What is the connective tissue between individual axons called? – Endoneurium
What is the name of the outer supportive layer of connective tissue which surrounds the
whole nerve and binds fascicles to each other? – Epineurium
What types of nerve fibers are myelinated? – Type-A fibers are myelinated fibers of
somatic nerve that can innervate muscle or skin
Type B fibers are myelinated preganglionic fibers
Which type of nerve fiber is not fast and why? – Type C, unmyelinated
Which nerve fiber is fast but not as fast as nerve fiber type A? – Type B – these fibers
are myelinated but not as heavily as type A