Ch 12 - Nervous System EXAM *** McGraw

one axon and many dendrites.

A neuron may have

dendrite.

A neuron process that receives impulses from receptors or another neuron is a/an

sensory or afferent neuron.

A neuron that conducts pain sensations to the central nervous system would be classified as a(n)

an all-or-none response.

A stimulus either causes an action potential or it doesn't. This is called

Neuromodulator

A substance released from neurons that can influence the production of action potentials in the postsynaptic cell is called a(an)

-they are released into the bloodstream before reaching the postsynaptic cell.

not a characteristics of neurotransmitters

sympathetic

the ___ division tends to prepare the body for action.

visceral motor division.

the autonomic nervous system is also called the

multiple sclerosis.

the disease ______________ is characterized by destruction of CNS myelin sheaths and the formation of hardened scars.

ganglia

Clusters of neuron cell bodies in the PNS are called _____.

Nuclei

Collections of gray matter in the CNS are called

Nerve tracts

Collections of myelinated axons in the CNS are called

large myelinated fiber.

Conduction speed of a nerve fiber would be the fastest in a

a cell body

Every neuron has

nodes of Ranvier.

Gaps or interruptions in the myelin sheath are called

hyperpolarized.

If a resting potential becomes more negative, the membrane is

concentrated at the nodes of Ranvier.

In a myelinated axon, Na+ channels are

the soma and at least some neurilemma intact.

In order for a peripheral nerve fiber to regenerate it must have

hyperpolarization of the cell membrane.

Inhibitory postsynaptic potentials (IPSPs) are associated with

lipids.

Most of the myelin sheath is composed of

False

Most synapses in the body are electrical.

oligodendrocyte

Multiple sclerosis is a neurological disorder in which myelin sheaths in the CNS are destroyed. Which of the following neuroglial cells is being damaged in multiple sclerosis?

Schwann cells form a myelin sheath around a portion of only one axon, while oligodendrocytes can surround portions of several axons.

Schwann cells differ from oligodendrocytes in which of the following ways?

visceral motor division.

The autonomic nervous system is also called the

Central nervous system (CNS)

The brain and spinal cord make up the

Hyperpolarization

The continued movement of potassium ions out of the cell through open voltage-gated K+ channels is called

dendrites.

The cytoplasmic extensions that, together with the cell body, provide the main receptive surfaces for neurons are

Calcium

What ion is necessary for the release of neurotransmitter from synaptic vesicles?

Sodium-potassium pump

What is the primary method of maintaining the difference in sodium and potassium ions across the plasma membrane?

Nissl substance

What part of the neuron is the primary site of protein synthesis?

Na+/K+ pump

What process is needed to return a membrane to its resting membrane potential with all ions in the correct locations?

Voltage-gated ion channels

What type of membrane channels open and close in response to changes in membrane potential?

satellite cells

What type of neuroglial cells provide support and nutrition to sensory ganglia in the PNS?

Oligodendrocytes

Which cells produce myelin in the brain and spinal cord?

outward diffusion of K+

Which ion's movements is responsible for repolarization?

Astrocytes

Which neuroglial cells are the most abundant in the CNS?

association

about 90% of the neurons in the nervous system are ___ neurons.

Myelin

consists of layers of lipids and proteins that wrap around an axon.

sodium ions.

depolarization of the nerve cell membrane occurs when there is a rapid influx (inflow) of

Na+

locking _____ channels would prevent neuronal depolarization.

nerves

A bundle of axons and their connective tissue sheaths are called

Neurotransmitters

A chemical synapse uses _______ to continue the action potential.

from node to node on a myelinated axon.

Action potentials are conducted more rapidly when transmission is

-they are synthesized by a presynaptic neuron. -they are released in response to stimulation. -they bind to specific receptors on the postsynaptic cell. -they alter the physiology of the postsynaptic cell.

All of the following are typical characteristics of neurotransmitters

EPSPs overpower IPSPs.

An action potential is triggered if

Schwann cells

Can conduct an impulse

repolarization

During an action potential, the closing of voltage-gated sodium channels begins a phase called:

potassium ions are leaving the cell.

During hyperpolarization (or afterpotential)

no stimulus of any strength will trigger a new action potential.

During the absolute refractory period

-on unmyelinated axons -only on axons with a small diameter -only on axons with a large diameter

Saltatory conduction occurs:

-Are called inhibitory neurons -Cause hyperpolarization -Decrease the likelihood of producing action potentials

Neurons that release neurotransmitters that cause IPSPs

blocking Ca2+ influx in the axon terminal.

Neurotransmitter release would be inhibited by

Presynaptic terminals

Neurotransmitters are found in the

areas of rough endoplasmic reticulum.

Nissl bodies are

1. Large cells; wrap around CNS axons forming a myelin sheath - Oligodendocytes 2. Also called Schwann cells; myelinate PNS axons - 2 Neurolemmocytes 3. Small cells; wander through the CNS in response to infection - 3 Microglial cells 4. Cuboidal epithelial cells; line internal cavities of the brain - ependymal cells 5. Flattened cells in the PNS; around neuronal cell bodies in ganglia - Satellite cells 6. Have a starlike shape; most abundant glial cells in the CNS -Astrocytes

Please match the type of glial cell with its description. 1. Large cells; wrap around CNS axons forming a myelin sheath 2. Also called Schwann cells; myelinate PNS axons 3. Small cells; wander through the CNS in response to infection 4. Cuboidal epithelial cells; line internal cavities of the brain 5. Flattened cells in the PNS; around neuronal cell bodies in ganglia 6. Have a starlike shape; most abundant glial cells in the CNS

exocytosis.

Presynaptic neurons release neurotransmitters by ______________.

cell bodies or soma.

Protein synthesis in neurons occurs in

afferent; efferent

Some ___ neurons are specialized to detect stimuli, whereas ____ neurons send signals to the effectors of the nervous system.

presynaptic terminals.

Synaptic vesicles contain neurotransmitters and are present in the

12, 31

The are ____ pairs of cranial nerves and ____ pairs of spinal nerves.

axon hillock

The area of the neuron that generates the action potential is the

Digestive system

The enteric nervous system involves the

depolarization

The figure illustrates the Action Potential. What does "B" represent?

synapse.

The junction of a neuron with another cell is a/an

potassium, sodium

The membrane of resting nerve cells is more permeable to ____________ ions than ____________ ions.

threshold.

The minimum depolarization needed to open Na+ gates is called the

all muscle types and glands.

The motor division of the PNS carries action potentials from the CNS to

is an example of a positive feedback cycle.

The opening of more and more Na+ ion channels during depolarization is

cranial nerves spinal nerves ganglia

The peripheral nervous system includes the

cranial nerves.

The peripheral nervous system includes the

hyperpolarization of the membrane

This image shows an action potential. What does "6" represent?

Can conduct an impulse

Which of the following is NOT characteristic of neuroglia?

K+

Which of the following is NOT found in high concentration outside a nerve cell?

Connexons

Which of the following is NOT part of a chemical synapse?

It is an equilibrium based on sodium ion diffusion

Which of the following is NOT true about the resting membrane potential?

Release neurotransmitters that cause hyperpolarization

Which of the following is NOT true of excitatory neurons?

Form the myelin sheath around neuron cell bodies

Which of the following is NOT true of satellite cells?

A stimulus causes ion channels to open which changes membrane permeability

Which of the following is TRUE of a graded potential?

Neuroglia

Which of the following is not part of a neuron?

Parasympathetic

Which subdivision of the autonomic nervous system regulates resting or vegetative functions?

Ependymal cells

Which type of neuroglial cells help to produce and circulate cerebrospinal fluid?

Microglia

Which type of neuroglial cells respond to inflammation and are phagocytotic?

Visceral motor

___ division carries signals to the smooth muscle in the large intestine.

Potassium

___ has the greatest influence on the resting membrane potential.

Astrocytes

___________ form the blood - brain barrier and act to provide structural support for nerve cells in the CNS.

Leak ion channels:

are always open

Microglia

are phagocytic cells in the CNS.

oltage-gated calcium channel

he figure is a process figure of the chemical synapse. What does "A" represent?

The blood-brain barrier

protects neurons from toxic substances in the blood.