Anatomy exam 3 connect hw

A single process

unipolar neurons

An action potential arriving at the presynaptic terminal causes what to occur?

voltage gated calcium ion channels open and calcium diffuses into the cell

Graded potentials are produced within the _______________________ segment of a neuron.

receptive

The antagonists will be inhibited. This is an example of what

reciprocal inhibition.

Near the site of injury, the basal lamina and the neurilemma form a BLANK tube.

regeneration

The depolarization causes a BLANK that excites the entire membrane.

repetition

Reflex marked by removal of the body segment from injurious elements

flexor reflex

The visceral motor division of the PNS is also called the autonomic division. Which of the following are functions of this division? Select all that apply.

-Controlling gland secretion -Accelerating or decreasing heartbeat -Stimulating or inhibiting digestion

Which of the following cause a postsynaptic transmission to stop? Check all that apply.

-Diffusion of the neurotransmitter into the nearby extra-cellular fluid -Reuptake of the neurotransmitter by endocytosis -Degradation of the neurotransmitter in the synaptic clef

Why is myelin important? Check all that apply.

-It speeds up signal conduction in the nerve fiber.It speeds up signal conduction in the nerve fiber. -It is formed to assist in the regeneration of damaged fibers.It is formed to assist in the regeneration of damaged fibers. -It insulates the nerve fiber.It insulates the nerve fiber.

What are the three general classes of neurons that correspond to the three major aspects of nervous system function? Check all that apply.

-Motor neurons that send signals predominantly to muscle and gland cells -Interneurons that lie between, and interconnect the incoming sensory pathways and the outgoing motor pathways of the CNS -Sensory neurons that are specialized to detect stimuli such as light, heat, pressure, and chemicals and transmit information about them to the CNS

If acetylcholinesterase became mutated and nonfunctional, what would be the immediate result?

Acetylcholine would build up in the synaptic cleft.

most abundant glial cells in the CNS and is a multi-functioning cell involved with neurogenesis scar formation

Astrocytes

In an adult, the spinal cord ends at which vertebra?

Between L1 and L2

One axon; one dendrite

Bipolar nuerons

If a drug was developed that interfered with the proper functioning of the microtubules found within the axons of neurons, how would you expect this to impact axonal transport processes?

Both anterograde and retrograde transport processes would cease

Where is cervical plexus

C1-C5

Where is brachial plexus

C5-T1

The enzyme choline acetyltransferase catalyzes the reaction between acetyl-CoA and choline resulting in the formation of the neurotransmitter acetylcholine. This enzyme is produced within the cell body of neurons, but the synthesis of acetylcholine occurs within the axon terminals. Which statement best describes the axonal transport mechanism associated with this process?

Choline acetyltransferase is transported in the anterograde direction.

marked by actions to stabilize the limb opposite of injurious agents, is contralateral and is marked by actions that stabilize the contralateral limb

Crossed-extensor reflex

the most superficial covering of the spinal cord

Dura mater (dural sheath)

The presynaptic membrane releases (via exocytosis) acetylcholine (ACh) into the

ECF of the synaptic cleft.

What is the loose connective tissue surrounding an individual nerve fiber called?

Endoneurium

Cilliated cells resembling epithelium in the CNS

Ependymal cells

T or F: Acetylcholine is actively transported from the presynaptic membrane to the postsynaptic membrane. Group starts

False

The movement of positive charges to the BLANK causes the relative charge across the membrane to become positive on the inner surface.

ICF

When voltage-gated sodium channels are open, sodium flows _____________ the neuron, making the inside of the cell more _______________.

Into; positive

Choose the correct statement about myelin.

It is best not to give children under two years of age a low-fat diet because myelin formation requires lipids

Wheres lumbar plexus

L1-L4

Where is sacral plexus

L4,L5 and S1-S4

Macrophages of CNS

Microglia

One axon; multiple dendrites

Multipolar nuerons

Assume in a laboratory you were able to isolate a neuron and remove the Acetylcholine receptors from the postsynaptic membrane. The substance _________________ would no longer cause facilitation of this neuron.

Nicotine

Forms the myelin sheath in the CNS

Oligodendrocytes

Which spinal nerve roots carry sensory nerve signals?

Posterior

_______________ the time between signals sent from the same presynaptic terminal increases the strength of the graded potential. This is an example of ________________ summation.

Reducing; temporal

The following information best describes the _____________ phase of an action potential. • A membrane potential reading of +10 mV• Inactivated voltage-gated sodium channels• Open voltage-gated potassium channels

Repolarization

Suppose that a new virus is discovered that specifically infects motor neurons. Assume that this virus enters neurons in conjunction with choline molecules. Once inside the cell, the virus enters the nucleus and replicates. Which direction describes the axonal transport route taken by this virus?

Retrograde transport

surround and insulate cells of the PNS and found around the somas

Satellite cells

form myelin sheath in PNS, and insulted neurons and enhances the rate of transmission in the pos

Schwann cells

A reflex hammer striking the tendon is the Blank that triggers the Blank

Stimulus, receptor

The reflex that results in quick contraction of the same muscle stimulated is called

Stretch reflex

reflex that is monosynaptic, initiated by an increase in muscle length and has muscle spindles as the receptor

Stretch reflex

What happens as a result of ion flow at a presynaptic terminal?

Synaptic vesicles migrate to the plasma membrane and release acetylcholine

Which of the following describes a reverberating circuit?

There is a prolonged or repetitive effect that lasts until one or more neurons in the circuit fail to fire or until an inhibitory signal from another source stops one of them from firing. Neurons stimulate each other in a linear sequence such as A→B→C→D, but neuron C sends an axon collateral back to A.

If demyelination occurs, why don't action potentials occur at regions of the axon that were previously myelinated?

These regions lack the appropriate concentration of voltage-gated sodium channels.

T or F: If the postsynaptic membrane potential reaches threshold level, an action potential will be produced.

True

T or F: Reflexes have four important properties: they require stimulation, they are quick, they are involuntary, and they are stereotyped.

True

Indicate the summative effect that brings the initial segment closest to threshold.

Two EPSPs in proximity to each other

Which term describes all neurons that carry signals towards the CNS?

afferent

What causes sodium to diffuse into the cell

an action potential at the trigger zone

No axon; multiple dendrites

anaxonic neurons

Which of the following are made of gray matter?

anterior, posterior and lateral horns

middle layer of the meninges

arachnoid mater

The excitation of the entire membrane ends when the signal reaches the end of the

axon

At the synaptic knob, voltage-gated ______________ channels open, thereby stimulating the synaptic vesicles to release their neurotransmitters by exocytosis.

calcium

When a nerve fiber is cut, the fiber distal to the injury BLANK survive.

cannot

Substances that cause facilitation of a neuron ____________________________.

cause the neuron to fire that may not fire under the same circumstances in the absence of the facilitator

A resting membrane potential of -70 mV indicates that the ________________.

charges lining the inside of the plasma membrane are negative compared to the charges lining the outside

Demyelinating diseases cause a(n) ______________ in the conduction velocity of action potentials.

decrease

sodium diffusing out of the cell results in membrane

depolarization

If we are using the patellar ligament as the example, the quadriceps muscles are the

effectors

The afferent neuron synapses with the Blank in the integrating center.

efferent neuron

Action potentials occur ____________________________.

in the unmyelinated regions of an axon

All reflexes utilize a

integrating center

The afferent neuron synapses with a(n) BLANK which then synapses with the efferent neuron.

interneuron

Which portion of a reflex arc is located entirely within the central nervous system?

interneuron

An unmyelinated fiber has voltage-gated ion gates along its entire

length

Graded potentials result from the opening of ________________.

ligand-gated channels

Acetylcholine has which effect on the postsynaptic neuron?

ligand-gated sodium ion channels open and sodium diffuses in

The ACh diffuses across the cleft and binds to the

ligand-regulated sodium channels.

In somatic neurons, an action potential arrives at the synapse causing synaptic vesicles to fuse with the

presynaptic membrane.

A damaged BlANK nerve fiber may regenerate if its soma is intact and some neurilemma remains.

peripheral

the innermost covering of the spinal cord

pia mater

Prior to the arrival of a signal from a presynaptic input, the post-synaptic membrane is polar with a greater relative BLANK in the ECF.

positive charge

An inhibitory postsynaptic potential results from the opening of____________________.

potassium and/or chloride channels

Normally, sodium and potassium leakage channels differ because ___________________.

sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell

When contact is established, the BLANK shrinks, and reinnervated muscle fibers regrow.

soma

The tube guides the growing sprout back to the original target cells, reestablishing what

synaptic contact

inhibits excessive muscle contractions and tendon organs are the receptors.

tendon reflex