Homework Review Test 1 Flashcards
___ are one of the cell types composing the nervous system
neurons
___ neurons control movements and actions of organs
motor
The most important supporting cells of the brain are the
glial cells
The dendrites of a neuron…
transmit info to the cell body
The part of a neuron that contains the nucleus is called the
soma
___ can be long enough to provide a direct connection b/t the spinal cord and the toes of a giraffe.
axons
In motor neurons, the axon and the dendrites branch out from the soma in many directions, giving this type of neuron the designation of a ___ neuron
multipolar
Many business deals involve a “middle man” who communicates b/t buyer and seller. The middle man b/t a sensory neuron and a motor neuron is a…
interneuron
The fact that the cell membrane is highly permeable to some substances and much less so to others is one variable underlying the cell being…
polarized
One function of the specialized protein channels in a cell membrane is to…
selectively allow substances to enter or leave a cell
The cells that produce myelin in the CNS are called…
Oligodendrocytes
The cells that produce myelin in the PNS are called…
Schwann cells
The gaps in the myelin sheaths on axons are known as
Nodes of Ranvier
Glial cells…
Guide new neurons in fetal development,
Stimulate the development of synapses,
Clean up cellular debris
A disease that destroys myelin is…
Multiple sclerosis
Where are vesicles stored?
The axon terminals
The resting membrane potential is…
The difference in electrical charge inside and outside the inactive neuron.
Sodium ions are most concentrated in the ___ fluid.
extracellular
The force by which high concentrations of ions disperse away from each other and thus spread evenly through a solution is called…
Force of diffusion
When depolarization of the cell membrane reaches threshold, which occurs?
Opening of sodium ion channels
What ionic movement is responsible for pulling the membrane potential back to a negative voltage during an action potential?
Potassium ions move out of the cell.
The action potential spreads through an axon by…
Depolarizing adjacent membrane to threshold, triggering another action potential.
Absolute refractory period is when…
The neuron cannot fire again because the sodium channels are unable to open.
The conduction speed of neurons is largely a function of…
axon diameter and myelination
