Chapter 1 Flashcards
Why does the brain need thiamine
To enable it to metabolize glucose
The endoplasmic reticulum is a
Network of then tubes that transport newly synthesized proteins
_____ 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
Which type of glia remove waste material in the nervous system
Astrocytes
What type of glia helps to synchronize the activity of axons
Astrocytes
Korsakoffs syndrome _____
Is marked by severe memory impairments
Why do neurons rely so heavily on glucose as their source of nutrition
Other fuels do not readily cross the blood brain barrier
The major disadvantage of a blood brain barrier is that
Certain required chemicals must be actively transported
Glucose enters the brain via which type of transport
Active transport
Chemicals are released by axons
Into the junction between neurons
The insulating material that covers many vertebrate axons is called the
Myelin sheath
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
Neurons differ most strongly from other body cells in their
shape
Ribosomes are the part of the cell that
Synthesizes new proteins
Dendrites
Are branching fibers that getting narrower near their ends
Water oxygen and ______ most freely flow across a cell membrane
Carbon dioxide
If all of the neurons dendrites or axons were contained within the spinal cord it would be considered an ______ neuron
Intrinsic
Which type of glia release chemicals that modify the activity of neighboring neurons
Astrocytes
An axon has many branches each of which swells edits tip these are known as
Presynaptic terminal’s
Nodes of Ranvier are
Gaps in the Myelin of axons
A presynaptic terminal is also known as
And and bulb
Glial cells whose function most closely resembles that of the immune system are called
Microglia
Small charged molecules can cross the cell membrane through
Protein channels
Glial cells
Are smaller but more numerous than neurons in the human brain
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
