Chapter 12 - Nervous System: Nervous Tissue

Ganglia are clusters of nerve cell bodies located within the CNS

False, ganglia are in the PNS

What nerves always relay information to the CNS?

Sensory nerves

What channel is needed for the generation of an action potential? a. voltage gated channels b. chloride leak channels c. chemically gated channels

a

Which of the following ions have leak channels on the plasma membrane? a. Na+ b. Ca2+ c. H+ d. K+

a & d

The _____________ refractory period is when a membrane cannot respond to another stimulus, no matter how strong.

absolute

Pain receptors in the skin send signals to the CNS for processing. These pain receptors are an example of afferent/efferent neurons.

afferent

The refractory period occurs immediately _________ an action potential.

after

When threshold is reached, depolarization occurs with the same amplitude of potential change. This is known as the

all-or-none principle

________ channels allow ungated flow of specific ions from regions of high concentration to regions of low concentration.

leak

Which terms are used for structural classification of nerves?

spinal and cranial

Neurotransmitters are removed from a synapse from degradation and reuptake

true

On a graph of an action potential, the small depolarizations that lead to threshold are from

EPSPs

To enhance the effect acetylcholine has in a particular synapse, a drug may block acetylcholinesterase (AChE) so that

acetylcholine is not destroyed and will remain in the synapse longer

What cells are star shaped?

astrocytes

Which glial cell is star shaped and help forms the blood-brain barrier?

astrocytes

The _________ division of the NS is subdivided into the sympathetic and parasympathetic divisions.

autonomic

Which of the following pumps ca be found in the plasma membrane? a. H+ b. Ca2+ c. Na+/K+ d. CI-

b & c

Acetylcholinesterase

catalyzes hydrolysis of ACh to remove it from the synaptic cleft.

Satellite cells are found surrounding

cell bodies

Ependymal cells help produce

cerebrospinal fluid

When a neurotransmitter binds a protein channel, it opens and lets sodium diffuse down its concentration gradient. This is an example of a

chemically-gated sodium channel

The somatic sensory division detects stimuli that are ________ detected.

consciously

Upon binding of endocannabinoids to their target, there is a(n)

decrease in neurotransmitter release from presynaptic neurons

The tissues that receive nerve impulses from motor neurons are called

effectors

The motor nervous system is also referred to as the ________ division.

efferent

Neurons that carry signals from the CNS to skeletal muscle for contraction would be classified as _____________ neurons.

efferent from motor NS

Synapses are classified as

electrical or chemical synapses

EPSPs and IPSPs have long term effects on a neuron

false

Glial cells help neurons by generating action potentials.

false, glial cells don't generate action potentials

In neurons, protein pumps allow substances to move passively down their concentration gradients.

false, pumps are not involved in passive transport

An axon with a large diameter transmits an impulse ___________ than an axon with a smaller diameter

faster

A(n) ___________ results in a swelling, enlarged portion, along the length of a nerve, which is often large enough to be visible by the naked eye.

ganglion

Negatively charged proteins and other large organic molecules are found in

greater amounts inside the neuron

____________________ occurs when the inside of a cell becomes more negative than the resting membrane potential

hyperpolarization

Neuronal pools are composed of

interneurons

What cells wander through the CNS and replicate in response to infection?

microglia

Which glial cell acts as a phagocyte?

microglial cells

The vagus nerve contains afferent and efferent neurons; therefore it is an example of a(n) ___________ nerve

mixed

What would increase the magnitude of a postsynaptic potential?

more neurotransmitter released from presynaptic neuron, more chemically gated channels open in postsynaptic neuron

Nerve growth factors that stimulate outgrowth of severed axons are secreted by

neurolemmocytes

Nervous tissue is composed of glial cells and

neurons

Bipolar neurons have how many axons and dendrites?

one of each

When sodium chemically enters the neuron, the membrane will depolarize thus becoming more ____________ in charge

positive

The ________ NS transmits information from receptors to the CNS, while the __________ NS transmits information from the CNS to the rest of the body

sensory, motor

As a result of a neurotransmitter opening up chemically gated sodium channels on the postsynaptic membrane,

sodium ions enter the cell

Receptors detect change from the external or internal environment. These changes are called

stimuli

A change in membrane potential insufficient to cause an action potential is called a

subthreshold potential

The process by which postsynaptic potentials are added together at the initial segment is known as

summation

A typical synapse in the CNS consists of a presynaptic neuron and a postsynaptic neuron, separated by a narrow space called the

synaptic cleft

Which part of a neuron contains calcium pumps and channels?

synaptic knobs/bulbs

Fifty presynaptic neurons all briefly release a single burst of excitatory neurotransmitter, generating excitatory postsynaptic potentials (EPSPs) in a postsynaptic neuron. Using this example, select all that apply.

the EPSPs will be summed at the axon hillock

Which of the following characteristics of action potentials can vary?

the frequency of action potentials

The negative value of the RMP means that

the inside of the cell is more negative compared to the outside of the cell

Scorpion agitoxin is a neurotoxin that blocks the activity of voltage-gated potassium channels. In the presence of agitoxin, which will occur during an action potential?

the neuron will remain depolarized and unable to repolarize

An EPSP causes

the postsynaptic neuron's membrane potential to become more positive

A regenerating axon in the PNS is guided by the regeneration tube and grows at a rate of about 5mm per day

true

If extracellular concentrations of potassium are increased dramatically, a neuron may not be able to repolarize during an action potential

true

On a typical neuron, the axon is longer in length than the dendrites

true

The entry of sodium ions into the postsynaptic neuron causes depolarization

true

The enzyme acetylcholinesterase causes acetylcholine to break down into acetate and choline, stopping the stimulation of a postsynaptic cell

true

Postsynaptic neurons can generate both inhibitory and excitatory postsynaptic potentials simultaneously.

true?

Sensory information from the visceral sensory division is _____________ sensed

unconsciously

Most afferent neurons are classified functionally as

unipolar