Chapter 12 - Nervous Tissue

a. regulating / controlling peripheral structures and system

b. providing sensation of the internal / external environments

c. coordinating voluntary and involuntary activities

The CNS includes the ____________ and _______________.

Which nervous system controls skeletal muscles?

Which nervous system controls smooth muscles of the visceral organs?

Which cells are the supporting cells of the nervous system? However these cells do not get involved in information processing.

a. secretion of CSF

b. BBB: isolation of neurons

c. Defense: phagocytosis

d. providing support of the neuron (myelin sheath formation)

Only the _____________ is responsible for information processing. NEUROGLIA IS NOT.

a. astrocytes

b. oligodendrocytes

c. ependymal cells

d. microglia

What are the two types of neuroglia in the PNS?

a. maintaining BBB (blood-brain barrier)

b. guiding neuron development

c. repairing damaged tissue

d. controlling the interstitial environment surrounding neurons

What do the oligodendrocytes do?

Cell that myelinated several parts of several axons

Which cells for myelin sheets on the PNS

Myelinates a single axon

___________________ increases the speed of the conduction of a nerve impulse

Damage to which cell would result in decreased speed of action potential?

A disease in which myelin sheet is abnormal due to autoimmune antibodies = demyelination

Which cells produce CSF (cerebral spinal fluid)?

Which cells are small phagocytes?

Which cells are the largest and most numerous of the glia cells in the CNS?

Which cells have the least number of neuroglia in the CNS?

_________________ is the cytoplasm surrounding the nucleus of the neuron.

Aggregations of fixed and free ribosomes in neurons.

An area that the axon connects to the soma (cell body).

The actual site of information processing in the nervous system...

Branches that sometimes occur along the length of an axon.

Terminal end of an axon that contains a series of fine extensions.

Where are the neurotransmitters released from?

A series of fine extensions at the axon terminal...

The site of intercellular communication between neurons.

Cellular materials move from axon terminal to the cell body to be degraded or recycled.

rabies, herpes, and polio viruses can travel to the CNS via this means.

neuron in which dendrites and axon are continuous and the cell body (SOMA) lies OFF to one side.

neurons have ONE axon and ONE dendrite

i. neurons have several dendrites and ONE SINGLE axon

ii. multipolar neurons are the most common type of neuron in the nervous system

Where is the axon of the unipolar neuron found?

Where is the cell body of the unipolar neuron found?

Where is the axon of the multipolar neuron found?

Where is the cell body of the motor neuron found?

a. by diffusion of potassium out of the cell (easy)

b. by diffusion of sodium ions into the cell (difficult)

c. by an excess of negatively charges protein molecules in the interior of the cell membrane of the neuron (neurilemma)

What are membrane channels that are always OPEN called?

Which type of channels can OPEN or CLOSE in response to binding of particular substance with specific receptors?

A stimulus that opens the GATED CHANNELS produces a ___________________.

OPENING of chemically-gate SODIUM channel results in what?

CLOSING of SODIUM channels and opening of POTASSIUM channels in the membrane of a neuron results in what?

At the end-phase of an action potential, additional POTASSIUM IONA exit from the cell membrane of a neuron results in what?

a. chemical and electrical forces push SODIUMS into the cell

b. chemical forces tend to drive POTASSIUM ions out of the cells

c. potassium ions are attracted to negative charges inside the cell (electric gradient)

SODIUM IONS (Na+) ____________ the cell membrane

exit or enter

POTASSIUM IONS (K+) ___________ the cell membrane

exit or enter

CALCIUM IONS (Ca+) _____________ the cell membrane to trigger the releasing of neurotransmitter (such as acetylcholine or epinephrine/norepinephrine)

exit or enter

Where can VOLTAGE-REGULATED SODIUM CHANNELS be found?

The SODIUM-POTASSIUM exchange pump requires ____________ to operate.

The process involves in exchange 3 intracellular SODIUM IONS for 2 extracellular POTASSIUM IONS.

When cholinergic receptors are stimulated, SODIUM IONS ____________ the postsynaptic neuron.

enter or exit

What contributes to maintaining the resting membrane potential (-70mV)

Which principle states that all stimuli GREAT enough to bring the membrane to the THRESHOLD will produce INDENTICAL action potentials?

____________ potential includes depolarization, depolarization and hyperpolarization.

GRADED POTENTIAL ____________ spread across the membrane surface (local only). The potential becomes weaker and weaker and finally disappears (detrimental effect)

can or cannot

The refractory period would be _____________ if voltage sodium channels failed to become inactivated.

longer or shorter

During which phase do local currents depolarize adjacent areas of membrane so that action potentials continue to be generated along the membrane...

During which phase do action potential occur at SUCCESSIVE NODES along the length of the stimulated axon?

Neurons ____________ regenerate because of LACK OF CENTRIOLES.

can or cannot

a. presence or absence of myelin sheath (faster spend with myelin sheath)

b. length of axon (the shorter, the faster the speed)

c. diameter of the axon (the larger the axon, the faster the speed)

Which type of fiber is the largest, myelinated fiber, and therefore it conducts the greatest rate of impulse?

Which type of fiber is responsible for relaying SENSORY information concerning touch, position and balance?

Which ion is needed to initiate the release of acetylcholine in the synaptic cleft of the NEURON?

______________ synapse is a synapse in which acetylcholine (Ach) is released at the synaptic cleft.

_______________ synapse is a synapse in which epinephrine or nor-epinephrine (e/ne) is released at the synaptic cleft.

The effect that a neurotransmitter has on the postsynaptic membrane depends on the ____________________________, not a nature or characteristic of the neurotransmitters.

__________________ or ______________ is usually and EXCITATORY neurotransmitter (EPSP).

_________________ may be and EXCITATORY or and INHIBITORY receptor depending on what kind of receptor at the synapse

Resting membrane potential is _______________ in muscle fibers

lower or greater

speed of conduction is ______________ in the muscle fibers

lower or greater

action potentials last _________________ in the muscle fibers (long duration)

shorter or longer

Muscle fibers ONLY conduct action potential via __________________ conduction.

What type of conduction do neurons use to conduct action potential?

The minimum amount of stimulus required to depolarize and excitable membrane and generate AP

The period of time which an excitable membrane CAN respond again, BUT ONLY if the stimulus is GREATER than the initial stimulus

The period of time during which an excitable membrane CANNOT respond again, regardless the intensity of the stimulus

The action potential traveling along an axon is called what?

EPSP's occur when sodium channels open, resulting in?

IPSP's occur when potassium channels open, resulting in?

___________________ occurs when a second EPSP arrives at a single synapse before the effects of the first have disappeared

_____________________ is the addition of stimuli arriving at DIFFERENT LOCATIONS on the same time to produce and AP

Neurons normally derive ATP solely through what?

a. synthesis of neurotransmitters

b. releasing of neurotransmitters

c. movement of material to and from SOMA via axoplasmic flow

d. recovery from an action potential

e. recycling of neurotransmitters

f. stimulating sodium-potassium pump

deteriorating changes at the distal segment of an axon as a result of a break between it and the soma (cell body)

These cell participate in the repair of damages nerves by FORMING A CELLULAR TUBE OR CHANNEL that can direct the growth of new axons.

________________ is a process in which the Nissl bodies break up into fine granular masses.

________________________ occurs when the release of SEROTONIN activates chemically gated CALCIUM channels in the presynaptic neuron membrane. The calcium channel opens longer. Therefore the postsynaptic neurons become more and more excited (EPSP).

_____________________ occurs when the release of GABA inactivates chemically gated CALCIUM channels open the postsynaptic neurons become more and more inhibited (IPSP).

a. glutamate and aspartate are excitatory neurotransmitters in the CNS

b. GABA and glycine are inhibitory neurotransmitter in the CNS

_________________ is different from other neurotransmitters because it is not synthesized in advance and packaged into synaptic vesicles. Rather, it is formed on demand and acts immediately.