physiology quizzz 2

Ion channels that open in response to depolarization are called A. ion-gated channels. B. voltage-gated channels. C. stimulation-gated channels. D. potential-gated channels.

B. voltage-gated channels.

During an action potential A. Na+ efflux causes depolarization. B. K+ influx causes repolarization. C. Na+ influx causes depolarization. D. K+ influx causes after-hyperpolarization.

C. Na+ influx causes depolarization.

What process is needed to return a membrane to its resting membrane potential with all ions in the correct locations? A. after-hyperpolarization B. all-or-none-law C. Na+/K+ pump D. refractory period

C. Na+/K+ pump

Action potentials would be conducted most rapidly by A. a 10 mm diameter myelinated axon. B. a 10 mm diameter unmyelinated axon. C. a 40 mm diameter myelinated axon. D. a 40 mm diameter unmyelinated axon.

C. a 40 mm diameter myelinated axon.

The blood-brain barrier results mostly from the action of __________, a type of glial cell. A. ependymal cells B. microglia C. astrocytes D. oligodendrocytes

C. astrocytes

Local anesthetics block conduction of action potentials in sensory neurons by A. inhibiting the release of acetylcholine. B. binding to potassium channels. C. binding to sodium channels. D. binding to calcium channels.

C. binding to sodium channels.

Local anesthetics block conduction of action potentials in sensory neurons by A. inhibiting the release of acetylcholine. B. binding to potassium channels. C. binding to sodium channels. D. binding to calcium channels.

C. binding to sodium channels.

In a myelinated axon, Na+ channels are A. along the whole length of the axon. B. every 5 mm. C. concentrated at the nodes of Ranvier. D. less numerous at the nodes of Ranvier.

C. concentrated at the nodes of Ranvier.

What type of neural pathway involves one neuron forming synapses with several postsynaptic neurons? A. convergent B. oscillating C. divergent D. plastic

C. divergent

What coding system do neurons use to get a greater response? A. greater amplitude of stimuli B. greater Na+ concentration gradient C. increased frequency of stimuli D. more active Na+/K+ pump

C. increased frequency of stimuli

What coding system do neurons use to get a greater response? A. greater amplitude of stimuli B. greater Na+ concentration gradient C. increased frequency of stimuli D. more active Na+/K+ pump

C. increased frequency of stimuli

Which of the following is NOT a functional classification of neurons? A. motor or efferent B. interneuron or association C. multipolar D. sensory or afferent

C. multipolar

Which ion's movements is responsible for repolarization? A. influx of K+ B. influx of Na+ C. outward diffusion of K+ D. outward diffusion of Na+

C. outward diffusion of K+

The ability of a neuron to transmit charge through its cytoplasm is called cable properties and is very A. good. B. strong. C. poor. D. easy.

C. poor.

The membrane of resting nerve cells is more permeable to ____________ ions than ____________ ions. A. sodium, potassium B. calcium, potassium C. potassium, sodium D. chloride, potassium

C. potassium, sodium

As the intensity of a stimulus increases, more axons will become activated. This process is called A. threshold. B. refraction. C. recruitment. D. None apply.

C. recruitment.

What is NOT true of conduction through dendrites and cell bodies of neurons? A. they are EPSPs B. they are spread by cable properties C. they can summate to reach threshold D. they are action potentials

D. they are action potentials

The average resting membrane potential of an axon is A. -70mV. B. -85mV. C. 0 mV D. +30mV.

A. -70mV.

An axon will depolarize only if the membrane potential reaches between -70mV and -55mV. This follows the A. All-or-none law. B. recruitment law. C. graduated law. D. threshold law.

A. All-or-none law.

______ synapses occur between axons of presynaptic cells and dendrites of postynaptic cells. A. Axodendritic B. Axosomatic C. Myoneural D. Axoaxonic

A. Axodendritic

What is NOT true of the relative refractory period? A. Na+ channels are inactivated B. many Na+ channels are returning to a closed state C. K+ is moving out of the axon through its open channels D. a strong stimulus could cause a depolarization

A. Na+ channels are inactivated

The myelin sheaths of PNS neurons are produced by A. Schwann cells. B. oligodendrocytes. C. ependymal cells. D. leukocytes.

A. Schwann cells.

What type of proteins are present in gap junctions that form water-filled channels between neurons? A. connexins B. myelin C. terminal boutons D. cell adhesion molecules (CAMs)

A. connexins

Which of the following is NOT a structural classification of neurons? A. motor neuron B. bipolar neuron C. multipolar neuron D. pseudounipolar neuron

A. motor neuron

The mesolimbic dopamine neurons arise in the midbrain and terminate in the A. nucleus accumbens. B. corpus striatum. C. basal nuclei. D. corpus callosum.

A. nucleus accumbens.

What neurotransmitter is used by neurons with cell bodies in the raphe nuclei along the midline of the brainstem? A. serotonin B. dopamine C. glycine D. GABA

A. serotonin

Sensory neurons A. are multipolar and carry impulses toward the CNS. B. are pseudounipolar and carry impulses toward the CNS. C. are bipolar and carry impulses away from the CNS. D. are multipolar and carry impulses away from the CNS.

B. are pseudounipolar and carry impulses toward the CNS.

Gliotransmitters A. include calcium ions. B. can stimulate neurons. C. form the blood-brain barrier. D. break down ATP.

B. can stimulate neurons.

Synaptic plasticity involves structural changes in neurons such as A. formation of axillary branches B. formation of dendritic spines C. formation of more axon terminals D. mitosis of neurons

B. formation of dendritic spines

What process occurs when glutamate-releasing presynaptic neurons stimulate postsynaptic release of endocannabinoids that acts as retrograde neurotransmitters? A. long-term potentiation B. long-term depression C. depolarization-induced suppression of inhibition D. All apply.

B. long-term depression

Repolarization is accomplished through a A. positive feedback loop. B. negative feedback loop. C. relative refractory loop. D. sodium equilibrium potential.

B. negative feedback loop.

The myelin sheaths of CNS neurons are produced by A. Schwann cells. B. oligodendrocytes. C. ependymal cells. D. leukocytes.

B. oligodendrocytes.

The mechanism that allows many Na+ ions to move into the axon is A. negative feedback. B. positive feedback. C. equilibrium feedback. D. None of the choices are correct.

B. positive feedback.

Conduction of an action potential in a myelinated axon is called A. point to point conduction. B. saltatory conduction. C. refractory conduction. D. cable conduction.

B. saltatory conduction.

The minimum depolarization needed to open Na+ gates is called the A. repolarization. B. threshold. C. refractory period. D. All-or-none law.

B. threshold

Blocking ____________ channels would prevent neuron depolarization. A. K+ B. Cl- C. Na+ D. Mg2+

C. Na+

The period of time when Na+ channels are recovering from their inactive state and K+ channels are still open is the A. repolarization. B. absolute refractory period. C. relative refractory period. D. Repolarization and relative refractory period are correct.

D. Repolarization and relative refractory period are correct.

Degeneration of spinal motor neurons in adults may be due to a lack of ____________ factor. A. brain-derived neurotrophic (BDNF) B. neurotrophin-3 C. nerve growth (NGF) D. glial-derived neurotrophic (GDNF)

D. glial-derived neurotrophic (GDNF)

Which of the following is NOT a function of neurotrophins? A. maintaining sympathetic ganglion B. sustaining neurons that use the NT dopamine C. embryonic development of neurons D. regeneration of injured motor neurons

D. regeneration of injured motor neurons