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
