Exam 3 Flashcards
The sensory division of the PNS is further subdivided into the ______ sensory division, which carries signals from receptors in the skin, muscles, bones, and joints, and the ______ sensory division, which carries signals from organs of the thoracic and abdominal cavities.
somatic, visceral
Afferent neurons are what type of neurons?
sensory
The soma of a neuron gives rise to branch-like processes called what? They are the primary sites for receiving signals from other neurons.
dendrites
The autonomic nervous system is subdivided into the ______ division which tends to arouse the body for action and the ______ division which tends to have a calming effect.
sympathetic, parasympathetic
Which correctly describes axonal transport?
It involves the transport of proteins within the axon (i.e. synaptic knob enzymes or proteins that maintain the axolemma).
It is bidirectional (retrograde and anterograde transport).
______ cells protect the neurons and help them function.
glial
Which terms refers to the part of the PNS that carries signals from various receptors to the CNS?
sensory division
Which types of glial cells are found in the central nervous system?
Ependymal cells
Oligodendrocytes
Astrocytes
Microglia
Which glial cell insulates nerve fibers from extracellular fluids and speeds up signal conduction in the brain?
Oligodendrocyte
Unmyelinated nerve fibers (axons) in the PNS are enveloped in Schwann cells.
True
Which of the following contributes to the development of the resting membrane potential in neurons?
K+ is more concentrated in the ICF than in the ECF.
Which type of glial cell aids in the regeneration of damaged peripheral nerve fibers by forming a regeneration tube to help reestablish the former connection?
Schwann cells
Characteristics of local potentials.
Decremental
Graded
All that are properties of action potentials.
Self-propagating
Nondecremental (signal maintains amplitude)
All or none
In order for local potentials to trigger an action potential, the membrane must depolarize up to a level called which of the following?
Threshold
Which ion has the greatest influence on the resting membrane potential of most neurons?
Potassium (K)
The refractory period in which it is possible to trigger a new action potential, but only with an unusually strong stimulus is the ______ refractory period.
Relative
Action potentials occur only where there are voltage-gated ion channels.
True
Which best describes signal conduction in unmyelinated axons?
A wave of depolarization opens more voltage-gated channels immediately distal to the action potential.
The all-or-none law of action potentials states which of the following?
A neuron will fire at maximum voltage if a stimulus depolarizes it to threshold.
Which term refers to the period of time after a nerve cell has responded to a stimulus in which it cannot be excited by a threshold stimulus?
Refractory period
Which best describes an electrical potential?
A form of potential energy that can produce current
Which term is used to describe signal conduction along a myelinated axon?
Saltatory
Choose all of the following statements that are true about signal conduction along unmyelinated fibers.
A zone of depolarization excites voltage-gated channels immediately distal to the action potential.
Unmyelinated fibers have voltage-gated channels along their entire length.