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89 Cards in this Set

  • Front
  • Back
What is a ganglion?
A collection of neuron cell bodies
Where are ganglions located?
Outside of the CNS
An extensive network of axons and, in some

cases, neuron cell bodies are called a....

Plexus

Where is the plexus located?

Outside the CNS

Large numbers of intermediate filaments


(neurofilaments) and microtubules form what?

Bundles that organize the cytoplasm into


different regions.



What separates abundant rough ER (also called Nissl Bodies)?

Neurofilaments

Where are nissl bodies primarily located?

In the cell body and dendrites

Nissl bodies are the primary site of?

Protein synthesis in neurons

Helps regulate the extracellular composition of the brain.

Astrocytes

How does astrocytes regulate the extracellular


composition of the brain?

By releasing chemicals that promote the


formation of tight junctions between the


endothelial cells of capillaries.

The endothelial cells with their tight junctions form what?

blood-brain barriers

What does blood-brain barriers determine?

What substances can pass from the blood into the nervous tissue of the brain and spinal cord.

Whats does the blood-brain barriers protect?

Neurons from toxic substances in the blood

What does blood-brain barriers allows the


exchange of?

Nutrients and waste products between neurons and the blood

What does blood-brain barriers prevent?

Fluctuations in the blood composition from


affecting brain functions

What are microglia?

Neuroglia in the CNS that become mobile and phagocytic.

Why does microglia become mobile and


phagocytic?

In response to inflammation

True or False? Microglia phagocytize necrotic


tissue, microorganisms, and other foreign


substances that invade the CNS.

True

Numerous microglia migrate to areas damaged by what?

infection, trauma, or stroke

True or False? Microglia perform phagocytosis.

True

How can pathologist identify damaged areas in the CNS during autopsy?

Large numbers of microglia are found in them

The ______________ pump uses ATP to pump _____


against its concentration gradient and keep it in high concentration _____ the cell and to pump


_____ against its concentration gradient and keep it in high concentration ______ the cell.

sodium-potassium


K+


inside


Na+


outside



Dealing with the sodium-potassium pump, how many Na+ are transported out of the cell for each ATP molecule used?

Three

Dealing with the sodium-potassium pump, how many K+ are transported into the cell for each ATP molecule used?

Two

What is the resting potential of neurons in mV?

approx. -70 mV

What is the resting membrane potential of skeletal muscle fibers?

approx. -90mV

Why is it that by convention, the potential


difference is reported as a negative number?

The inside of the plasma membrane is negative compared with the outside.

True or False? The greater the charge difference across the plasma membrane, the LESSER the potential difference.

False....it is the greater the charge difference across the plasma membrane, the GREATER the potential difference.

A cell with a resting membrane potential of -90 mV has a ________ charge difference between the inside of the cell membrane and the outside of the cell membrane than a cell with a resting membrane potential of ______.

greater




-70 mV

When the membrane potential becomes more POSITIVE and is the movement of the membrane potential CLOSER to zero it is.....

Depolarization

When the membrane potential becomes more NEGATIVE and is the movement of the


membrane potential FURTHER AWAY from zero it is.....

Hyperpolarization

What takes place because negatively charged molecules CANNOT follow the positively charged K+?

A small negative charge develops inside the


plasma membrane.

The negative charge inside of the cell attracts...

positively charged K+

When is an equilibrium established?

When the negative charge inside the cell is great enough to prevent additional K+ form diffusing out of the cell through the plasma membrane.



After the repolarization phase, the plasma membrane may be slightly hyperpolarized for a short period called......

Afterpotential

The second part of the refractory period and it follows the absolute refectory period....

relative refractory period

Act as a layer of insulation, forcing the local

currents to flow from one node of Ranvier to the next


the lipids within the membrane of the myelin sheath

Voltage-gated Na+ channels are highly


concentrated at the _______ of ______.

Nodes




Ranvier

The local current quickly flows to a node and ________ the voltage-gated Na+ channels to _____, resulting in the production of an ______ _______.

stimulates




open




action potential

Medium-diameter, lightly myelinated axons that conduct action potentials at 3-15 m/s


Type B fibers

Small-diameter, unmyelinated axons that


conduct action potentials at 2 m/s or less

Type C fibers

Which fiber types are primarily part of the ANS?

Type B and C

Which internal organs are stimulated by Type B and C fibers?

the stomach, intestines, and heart

The responses necessary to maintain internal homeostasis....

digestion

True or False? The responses necessary to


maintain internal homeostasis , need not be as rapid as responses to the external environment.

True

Limits the length of time the neurotransmitter molecules remain bound to their receptors.

Diffusion of neurotransmitter molecules away from the synapse and into the extracellular fluid

It is taken up primarily by liver and kidney cells

Norepinephrine in the circulation

Which two enzymes convert norepinephrine into inactive metabolites?

Monoamine oxidase and




catechol-o-methyltransferase

Which drug increases the release and block the reuptake of norepinephrine?

Cocaine and amphetamines

what results if the release is increased and the reuptake of norepinephrine is blocked?

It results in overstimulation of postsynaptic neurons & deleterious effects on the body.

Particularly effective at treating depression and behavioral disorders.

Drugs that block serotonin reuptake

Results when two or more action potentials


arrive in very close succession at a single


presynaptic terminal.

Temporal summation

In a chemical synapse......

Action potentials in the presynaptic terminal cause voltage-gated Ca2+




Neurotransmitters can cause ligand-gated Na+ channels to open

In a chemical synapse

-action potentials in the presynaptic terminal cause voltage gated Ca2+ channels to open


-neurotransmitters can cause ligand-gated Na+ channels to open


-neurotransmitters can be broken down by enzymes


-neurotransmitters can be taken up by the presynaptic terminal

An inhibitory presynaptic neuron can affect a postsynaptic neuron by...

-Producing an IPSP in the postsynaptic neuron


-Hyperpolarizing the plasma membrane of the -postsynaptic neuron


-Causing K+ to diffuse out of the postsynaptic neuron


-Causing C1- to diffuse into the postsynaptic neuron.

Causing Cl- to diffuse into the postsynaptic


neuron is an inhibitory presynaptic neuron that can affect a postsynaptic neuron




True or False?

True

what are sensory receptors? (Pg 362)

the endings of neurons, or separate, specialized cells.

what do they detect?
they detect temperature, pain, touch, pressure, light, sound, odor, and other stimuli.

where are sensory receptors located?

in the skin, muscles, joints, internal organs, & specialized sensory organs, such as the eyes and ears.

a bundle of nerve fibers, called axons, and their sheaths.

Nerve

what does a nerve connect?

It connects the CNS to sensory receptors, muscles, and glands.

How many pairs of cranial nerves are there?

12

Where do the cranial nerves originate?

from the brain

how many pairs of spinal nerves are there?

31

where do the spinal nerves originate?

the spinal cord

what are the 2 functional subdivisions of the PNS?


The sensory, or afferent ("toward") division


The motor, or efferent (away) division

The sensory division

transmits action potentials from the sensory receptors to the CNS

where are the cell bodies of sensory neurons located? (2)

in the dorsal root ganglia near the spinal cord or in ganglia near the origin of certain cranial nerves.

The motor division

transmit action potentials from the CNS to effector organs, such as muscles and glands.

What are the 2 subdivisions of the motor division? (364)


Somatic nervous system (voluntary)


Autonomic nervous system (ANS) (involuntary)

The somatic nervous system

allows us to consciously control movements of our skeletal muscles through action potentials that originate in the CNS & are transmitted by the somatic nervous system to the same skeletal muscles.

The cell bodies of somatic motor neurons are located within the ______ & their axons extend through _____ to form connections w/________.


CNS


Nerves


skeletal muscle cells.

A synapse is

the junction of a neuron with another cell

neurons can also form synapses with

other neurons, smooth muscle cells, cardiac muscle cells, and gland cells

The ANS is subdivided into the (2)

sympathetic and parasympathetic divisions

the sympathetic division

is most active during physical activity

the parasympathetic division

regulates resting functions, such as digesting food or emptying the urinary bladder.

consists of plexuses within the wall of the digestive tract

Enteric nervous system (ENS)

what is a unique feature of the enteric neurons?

They monitor & control the digestive tract independently from the CNS through local reflexes.

How can the CNS override enteric functions?

via the parasympathetic and sympathetic actions

The ENS is an independent subdivision of the _____ that is integrated w/the ______.

PNS, ANS

What forms the choroid plexuses? (pg 367)

Specialized ependymal cells & blood vessels

Where are choroid plexuses located?

within certain regions of the ventricles

What do choroid plexuses secrete?

Cerebral spinal fluid that flows through the ventricles of the brain.

Neurons expend energy to maintain what?


(pg. 371)

an uneven distribution of ions across the plasma membrane.

After repolarization, the plasma membrane may be slightly hyperpolarized for a short period. This is called..... (pg. 376)

afterpotential

The 2nd part of the refractory period, called the _______, follows the absolute refractory period.

Relative refractory period

when can another action potential during the relative refractory period be initiated?

when there is a stronger than threshold stimulus, but only before the relative refractory period is completed.

temporal summation results when

another action potential initiates another graded depolarization before the depolarization caused by the previous action potential returns to its resting value.