ch. 12 anatomy and physiology
Which of the following are characteristics of neurons?
secretion, excitability, extreme longevity, amitotic, conductivity
The somatic division of the nervous system that receives information from the eyes, ears, and skin is the somatic ______division
sensory
Glial cells are ______ than neurons
smaller
The flow of ______ ion is the most common cause of depolarization.
sodium
Which of the following membrane transporters are present throughout the membrane of a neuron?
sodium leak channels, Na+/K+ pumps, potassium leak channels
Which nerves extend from the spinal cord?
spinal nerves only
Neurons integrate multiple synaptic inputs by the process of _____
summation
______ are found in mixed nerves.
Sensory and motor axons
______ are essential for the generation of an action potential.
Voltage-gated channels
______ are unique channels in that they have three states; resting, activation, and inactivation.
Voltage-gated channels
A substance synthesized at the cell body must undergo ______ transport to reach the synaptic knobs.
anterograde
The myelin sheath covers _____
axon
The central nervous system is made of the _____and_______ spinal
brain , spinal cord
The main activity of the ______ is the propagation of an action potential along the axolemma
conductive segment
Which terms are used for the structural classification of nerves?
cranial , spinal
A positive change in the membrane potential is called _____
depolarization
Glial cells ______ transmit electrical impulses
do not
Creating and transmitting ______ currents is central to the function of neuron physiology.
electrical
A difference in the number of charged particles between two sides of the membrane forms a(n) _____
electrical gradient
True or false: Ion channels use the energy of ATP to maintain concentration gradients across neuron membranes
false
The peripheral nervous system is made of nerves and _____
ganglia
A(n)______ is a cluster of neuron cell bodies within the peripheral nervous system.
ganglion
Negatively charged proteins and other large organic molecules are found in ______
greater amounts inside a neuron
The myelin sheath is made of a high percentage of ____
lipids
The resting membrane potential is measured in ______
millivolts
Most named nerves are ______ nerves.
mixed
The brain interprets the increased frequency of nerve signals as a ______ stimulus
more intense
The autonomic division of the nervous system is part of the ______ nervous system.
motor
If a neuron has many dendrites and a single axon, it is called a(n) ______ neuron.
multipolar
Most motor neurons are _____
multipolar
The components of nervous tissue that conduct electrical impulses are _____
neurons
_____ are released from neurons in response to conductive activity.
Neurotransmitters
______ are released from neurons in response to conductive activity
Neurotransmitters
_____ is a type of membrane transport protein that increases the potential energy across a membrane
a pump
Action potentials are always propagated along an axon at the same ______ but ______ can vary depending on the strength of the stimulus
amplitude; frequency
Cytoplasm within an axon is called _____
axoplasm
The presence of ______ ions causes the synaptic vesicles to bind to the membrane, allowing neurotransmitters to be released.
calcium
Most synapses in the human body are ______ synapses
chemical
Synapses are classified as _____
chemical synapses and electrical synapses
The total length of the axon is called the segment.
conductive
The electrical gradient in a resting neuron is such that the ________ of the cell is negative relative to the _____
inside , outside
A cablelike bundle of axons in the peripheral nervous system is called a _____
nerve
What is the primary tissue of the nervous system?
nervous tissue
A nerve is part of the ______ nervous system.
peripheral
The function of a neuron is dependent on _____
resting membrane potentials changing
Na+ and K+ leak channels and Na+/K+ pumps on the neuron are responsible for establishing and maintaining the ________membrane__________
resting, potential
The process by which postsynaptic potentials are added together at the initial segment is known as _____
summation
In retrograde transport, substances are moved ______ the cell body.
toward
True or false: Graded potentials vary in size depending on the stimulus
true
True or false: Most voltage-gated ion channels are closed until the electrical potential across a membrane changes
true