Chapter 1 Flashcards by Candice Hopkins

Why does the brain need thiamine

To enable it to metabolize glucose

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The endoplasmic reticulum is a

Network of then tubes that transport newly synthesized proteins

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_____ In the brain and spinal cord and _____ in the periphery are specialized tubes of glia that build the myelin sheath that surround neurons

Oligodendrocytes; Schwann cells

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Which type of glia remove waste material in the nervous system

Astrocytes

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What type of glia helps to synchronize the activity of axons

Astrocytes

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Korsakoffs syndrome _____

Is marked by severe memory impairments

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Why do neurons rely so heavily on glucose as their source of nutrition

Other fuels do not readily cross the blood brain barrier

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The major disadvantage of a blood brain barrier is that

Certain required chemicals must be actively transported

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Glucose enters the brain via which type of transport

Active transport

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Chemicals are released by axons

Into the junction between neurons

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The insulating material that covers many vertebrate axons is called the

Myelin sheath

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If you were to accidentally touch a hot stove with your hand you would quickly pull your hand away. the information Carried to the muscles in your arm to make them contract was carried by

Efferent neurons

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Neurons differ most strongly from other body cells in their

shape

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Ribosomes are the part of the cell that

Synthesizes new proteins

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Dendrites

Are branching fibers that getting narrower near their ends

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Water oxygen and ______ most freely flow across a cell membrane

Carbon dioxide

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If all of the neurons dendrites or axons were contained within the spinal cord it would be considered an ______ neuron

Intrinsic

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Which type of glia release chemicals that modify the activity of neighboring neurons

Astrocytes

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An axon has many branches each of which swells edits tip these are known as

Presynaptic terminal’s

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Nodes of Ranvier are

Gaps in the Myelin of axons

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A presynaptic terminal is also known as

And and bulb

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Glial cells whose function most closely resembles that of the immune system are called

Microglia

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Small charged molecules can cross the cell membrane through

Protein channels

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Glial cells

Are smaller but more numerous than neurons in the human brain

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What is the approximate resting potential of the inside of the neurons membrane relative to the outside

-70 mV

The virus that manages to cross the blood brain barrier and enter the brain

It remains there and may cause negative affects several years later

Which type of glia build myelin and sheath around axons in the periphery of the body

Schwann cells

Neurons typically have one _____ but many _____

Axon, dendrites

What type of neurons in the pons receive information only from other cells in the pons and send information only to other cells in the pons

Intrinsic

Radial glia

Guide the migration of neurons during embryonic development

As compared to dendrites axons usually

Are covered with Myelin

The surface of the dendrite is lined with specialized junctions through which the dendrite receives information from other neurons what are these junctions called

Synaptic receptors

Molecules that can cross the blood brain barrier are usually

Molecules that can dissolve and the fact of the capillary walls

As a general rule axons convey information

Away from their own cell body

What do neurons have the other cells do not

Large branching extensions

The structure that contains the cells chromosomes is called the

Nucleus

The two basic kinds of cells in the nervous system are

Neurons and Glia

Many dendrites contain short outgrowths called spine that

Increase the surface area available for synapses

The membrane of a neuron is composed of ____ with _____ embedded in them

Fat molecules proteins

What mechanism events or slow some chemicals from entering the brain while allowing others to enter

The blood brain barrier

The cell membrane is composed of two layers of

Fat

What leads to Korsakoff syndrome

thiamine deficiency due to chronic alcoholism

What is the main source of nutrition for vertebrate neurons

Glucose

The branching fibers that form the information receiving pole of the nerve cells are called

Dendrites

What structure is composed of two layers of fat molecules that are free to flower around one another

The membrane

What type of glial cells Myelinate axons in the brain and spinal cord

Oligodendrocytes

The idea that a neurons membrane is polarized refers to a difference in electrical potential between

The inside and the outside of the membrane

The net effect of each cycle of the sodium potassium pump is to

Decrease the number of positively charged ions within the cell

Which of the following is the advantage of having a resting potential

The cell is prepared to respond quickly to a stimulus

The function of a myelin sheath is too

Increase the velocity of transmission along an axon

In the normal course of an action potential

Sodium remains much more concentrated outside than inside the neuron

Electrical gradient lead to the

Movement of ions to areas heavy opposite electrical charges

Which of the following describes the transmission of information in a local neuron

The signal decreases in strength as it travels

What term describes the difference in voltage that typically exist between the inside and the outside of the neuron

Resting potential

When a neuron is at rest what is primarily responsible for moving potassium ions into the cell

Both the sodium potassium pump and electrical gradient

Which event will increase the concentration gradient of sodium

Increasing activity of the sodium potassium pump

The speed of an action potential done and on myelinated axon is best described as

Faster in thick axons then in thin one

Voltage activated channels are channel for which I change in the voltage across the membrane alters there

Permeability

What occurs when a stimulus shifts the potential inside a neuron from the resting potential doing more negative potential

Hyperpolarization

The resting potential is mainly the result of

Negatively charged proteins inside the cell

When I neurons membrane is at rest the concentration gradient tends to move sodium ______ the cell and the electrical gradient tends to move it _____ the cell

Into into

The primary feature of a neuron that prevents the action potential from traveling back from where it just passed is the

Refractory period

At what point do the sodium gates begin to close shutting out further entry of sodium into the cell

At the peak of the action potential

A drug that blocks the sodium gates of a neuron's membrane will

Block the action potential

The concentration gradient refers to the

Difference in distribution for various ions between the inside and out side of the membrane

At the peak of the action potential the electrical gradient of potassium

Pushes potassium out of the cell

What causes potassium ions to leave the axon just after the peak of the action potential

Continuing concentration gradient in the opening of the potassium gates

What is one major cause for the resting potential of a neuron's membrane

The sodium potassium pump

What occurs when depolarization is less than the cells threshold

Sodium crosses the membrane only slightly more than usual

Local anesthetic drugs attached to the sodium channels of the membrane which

Prevents sodium ions from entering and stopping action potential

The neuron will produce an action potential only if the depolarization exceeds the

Threshold of excitation

Under which conditions were the sodium potassium pump likely be far less if active in creating a concentration gradient

If selective permeability of the membrane did not exist

The action potential of a neuron depends mostly on what movement of ions

Sodium ions entering the cell

Ordinarily stimulation of a neuron takes place

At the synapse

When the neuronal membrane is it rest the potassium leak channels

Permit potassium ions to pass slowly

After the peak of an action potential with prevent sodium ions from continuing to enter the cell

The sodium gates in the membrane close

The resting potential of a neuron refers to the

Net negative charge of the inside of the neuron

When the neuronal membrane is it rest the sodium channels

Are closed so there's almost no flow of sodium

According to the all or non-law

Once an axon reaches threshold the amplitude and velocity of an action potential are nearly equal each time

Which action with depolarize a neuron

Increasing membrane permeability to sodium

The all or none law states that

A neuron produces an action potential of maximal strength or not at all

When I neurons membrane is at rest the concentration gradient tends to move potassium ____ the cell and the electrical gradient tends to move it ______ the cell

Out of, into

When I membrane is at rest what attracts sodium ions to the inside of the cell

Both an electrical gradient and a concentration gradient

Which of the following describes selective permeability

Only certain molecules are allowed to cross the membrane freely

What action tends to open the sodium gates across a neuron's membrane

Depolarization of the membrane