Ch. 11 Nervous System Flashcards by Scott Bower

Q

? is really a potential difference between the inside of the cell and the outside of the cell across the membrane.

A

Resting membrane potential

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Q

Diseases such as multiple sclerosis, that damage the myelin sheath of neurons, likely affect which of the following cells?

a) Ependymal
b) Astrocyte
c) Oligodendryte
d) Microglial

A

Oligodendrytes

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Q

Which of the following neuroglia line the central cavities of the brain and spinal cord and provide a fairly permeable barrier between the CSF and nervous tissue?

a) Ependymal
b) Astrocyte
c) Oligodendryte
d) Microglial

A

Ependymal

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Q

Which of the following types of glial cells are the most abundant and versatile and aid in making exchanges between capillaries and neurons?

a) Ependymal
b) Astrocyte
c) Oligodendryte
d) Microglial

A

Astrocytes

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Q

Which of the following types of glial cells line the central cavities of the brain and spinal cord, where they help to circulate the cerebrospinal fluid?

a) Ependymal
b) Astrocyte
c) Oligodendryte
d) Microglial

A

Ependymal

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Q

Which of the following neuroglia is most responsible for helping determine capillary permeability in nervous tissue?

a) Ependymal
b) Astrocyte
c) Oligodendryte
d) Microglial

A

Astrocytes

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Q

Which of these cell types influences neuronal function by “mopping up” leaked potassium ions and by recapturing and recycling released neurotransmitters?

a) Ependymal
b) Astrocyte
c) Oligodendryte
d) Microglial

A

Astrocytes

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Q

Organelles for degradation or recycling are moved through the axon by ?

A

Retrograde movement

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Q

What is the difference between nerves and tracts?

A

Bundles of axons are called tracts in the CNS and nerves in the PNS.

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Q

From where can collaterals emerge on a myelinated nerve?

A

At the myelin sheath gaps (nodes of Ranvier)

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Q

Motor (efferent) neurons are bipolar. True/False?

A

False

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Q

What is a a collection of neuron cell bodies in the CNS?

A

Nucleus

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Q

Which part of the nervous sytem transmits impulses that most directly lead to an increase in heart rate?

a) Autonomic
b) Sensory division
c) CNS
d) Somatic

A

Autonomic

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Q

Which two types of neuroglia form insulating coverings called myelin sheaths?

A

Oligodendrocytes (CNS) and Schwann cells (PNS)

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Q

Which type of neuroglia form epithelial layers within the CNS?

A

Ependymal cells line the brain and spinal cord

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Q

Which structural and functional type of neuron is activated first when you burn your finger?

A

Unipolar & Afferent.

Unipolar neurons carry sensory information from receptors to the CNS along afferent pathways.

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Q

Which parts of a neuron are frequently wrapped by myelin sheaths?

A

Axons

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Q

Which of the following is best described as a conductor?

a) ion channel
b) Na-K pump
c) phospholipid membrane
d) ions

A

Ion channel

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Q

Which event most directly explains the polarity of the resting membrane potential of an unstimulated neuron plasma membrane?

a) leakage of K out of the neuron
b) leakage of K into the neuron
c) leakage of Na out of the neuron
d) leakage of Na into the neuron

A

Leakage of K out of the neuron.

K diffusing out of the cell causes the cell to become more negative inside.

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Q

Graded potentials always result in membrane ?

A

Depolarization (or Hyperpolarization)

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Q

Which neuroglia myelinates the CNS?

A

Oligodendrocytes

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Q

Which neuroglia myelinates the PNS?

A

Schwann cells

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Q

What is the gap in myelin called?

A

Node of Ranvier

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Q

Potential energy generated by separate charges

A

Voltage

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Flow of ions between two points

Current

Hindrance to ion flow

Resistance

Current is directly proportional to ?

Voltage

Current is inversely proportional to ?

Resistance

A signalling chemical that binds specifically to membrane receptors.

Ligand

What are 3 functions of the nervous system?

1. Sense changes through receptors 2. Respond to stimuli 3. Analyze information and make decisions

What are neurons called in the CNS and PNS?

Nuclei in CNS and Ganglia in PNS

Bundles of axons in the CNS are called ?

Tracts

Bundles of axons in the PNS are called ?

Nerves

What are the 4 neuroglia in the CNS?

1. Oligodendrocytes 2. Astrocytes 3. Ependymal 4. Microglia

What are the 2 neuroglia in the PNS?

Schwann cells and Satellite cells

Which of the following is not part of the CNS? a) brain b) nerve c) spinal cord d) tract

Nerve

? myelinates nerve fibers in the CNS.

Oliodendrocyte

? lines brain cavities.

Ependymal cells

? myelinates nerve fibers in the PNS.

Schwann cells

? is a CNS phagocyte.

Microglial cell

? helps regulate the ionic composition of CNS extracellular fluid.

Astrocytes

Biogenic amine neurotransmitters include all but ? a) norepinephrine b) acetylcholine c) dopamine d) serotonin

Acetylcholine

Inhibition of acetylcholinesterase by poisoning blocks neurotransmission at the neuromuscular junction because ?

ACh is not degraded, so prolonged depolarization is enforced on the postsynaptic cell

What is myelin?

A whitish, fatty, phospholipid insulating material

How does myelination differ in CNS and PNS?

CNS myelin sheaths are formed by oligodendrocytes and lack an outer collar or perinuclear cytoplasm. PNS myelin sheaths are formed by Schwann cells and does have an outer collar.

Since all AP's have the same magnitude, how does the CNS know if a signal is strong or weak?

Frequency, or rate

Briefly describe the three stages of neuron development.

1. Neurons proliferate 2. Neurons migrate to position 3. Neurons connects to other neurons

Which type of ion channel opens when a neurotransmitter binds to it?

Chemically gated (ligand-gated) channels

An autoimmune disease that leads to destruction of the myelin sheaths in the CNS is ?

Multiple sclerosis

What describes a change of membrane potential from -70mV to -75mV?

Hyperpolarization

The resting membrane potential of neurons is determined by ?

The distribution, across the cell membrane, of large anionic cytoplasmic proteins, Na+, K+, and Cl-

What could cause a graded depolarization?

Na+ entering the cell through chemically gated channels

A stimulus that fails to generate an action potential is called a ?

A sub-threshold stimulus

The sodium-potassium ion pump will pump ___ Na ions out for every ___ K ions in.

3 Na; 2 K

What period begins with the opening of the Na+ channels and ends when the Na+ channels begin to reset to their original resting state?

Absolute refractory period

What is the most common neuron type in humans?

Multipolar

The sensory, or afferent, division of the peripheral nervous system transmits information from the ? to the CNS.

Skin

Relative to extracellular fluid, the interior of a neuron has a negative charge because ___.

Potassium diffuses out of the cell

The Nissl bodies in the neuron cell body are otherwise known as which cellular organelle(s)?

Rough endoplasmic reticulum

What best describes the resting membrane state in the neuron?

All of the voltage-gated Na+ and K+ channels are closed.

? cells provide a fairly permeable barrier between the CSF and nervous tissue of the CNS.

Ependymal

Ions only flow directly from cell to cell in an ? synapse.

Electrical

Only ? use voltage-gated channels that rely on a threshold.

Action potentials

The larger the diameter of the axon, the ? it conducts impulses.

Faster

During which phase of an action potential are voltage-gated K+ channels open, while voltage-gated Na+ channels are closed?

Repolarization

? act as naturally occurring opiates and reduce the perception of pain under certain stressful conditions.

Endorphins

Spatial summation occurs when _____.

Multiple local potentials occur at different places on the same cell at the same time

What neurogila covers capillaries in central neural tissue.

Astrocytes

What kind of neurons are generally associated with the special senses.

Bipolar

Organelles in the axon that need to be degraded or recycled move back to the neuron cell body by ? movement.

Retrograde

? neurons are found in the head and are always part of an afferent pathway.

Bipolar

A synapse between an axon terminal and a neuron cell body is called ?

Axosomatic

In an earthquake, which type of sensory receptor is most likely to sound the first alarm?

Mechanoreceptor

Which autonomic division typically has long preganglionic and short postganglionic fibers?

Parasympathetic

Which autonomic division is enhanced by direct stimulation of a hormonal mechanism?

Sympathetic

Hypoactivity of this autonomic division would lead to a decrease in metabolic rate.

Sympathetic

Which autonomic division sets the tone for the heart?

Parasympathetic

Sensory neurons respond to an appropriate sensory stimulus with a change in membrane potential that is ?

Graded with the stimulus intensity

If the depolarization that reaches the axon is large and suprathreshold, the result in the axon is ?

Action potentials at higher frequencies

At the axon terminal, each action potential causes the release of a neurotransmitter. This neurotransmitter diffuses to the receiving end of an interneuron, where it binds to receptors and causes ?

Ion channels to open, so that the receiving end of the interneuron depolarizes

Interneurons respond to chemical stimulation with a change in membrane potential that is ?

Graded with the stimulus intensity

What directly determines the amount of neurotransmitter released at the axon terminal of the sensory neuron?

The amount of calcium that enters the sensory receptor

Action Potential (AP) threshold is ? mV?

-55 to -50 mV

What are pain sensitive neurons called?

Nociceptors

The rough ER in neuron cell bodies is also called ?

Nissl bodies

What receptor type would be activated by a soft caress?

Meissner (tactile) corpuscle

What receptor type would be activated by a pinch?

Pacinian (lamellated) corpuscle

What is a neuron serving as part of the conduction pathway between sensory and motor neurons?

Interneuron

Sensory receptors found in muscle that detect their degree of stretch are called ?

Proprioceptors