Chapter 12

Axons terminate in a series of fine extensions known as A) telodendria. B) dendrites. C) synapses. D) collaterals

A

Ion channels that are always open are called ________ channels. A) leak B) gated C) local D) regulated

A

Neurons that have several dendrites and a single axon are called: A) multipolar. B) anaxonic. C) unipolar. D) bipolar

A

Opening of sodium channels in the axon membrane causes A) depolarization. B) increased negative charge inside the membrane. C) repolarization. D) hyperpolarization.

A

The equilibrium potential for potassium ion occurs at approximately: A) -90 mV. B) 0 mV. C) +66 mV. D) -70 mV.

A

The most common neuron of the nervous system is the A) interneuron. B) microglial cell. C) bipolar neuron. D) unipolar neuron.

A

The part of the peripheral nervous system that carries sensory information to the CNS is designated: A) afferent. B) somatic. C) motor. D) autonomic.

A

Which of the following is not a function of the nervous system?: A) direct long-term functions, such as growth B) integrate sensory information C) coordinate voluntary and involuntary activities D) control peripheral effectors

A

________ open or close in response to binding specific molecules.: A) Chemically gated channels B) Activated channels C) Voltage-gated channels D) Leak channels

A

The axon is connected to the soma at the A) synaptic terminal. B) axon hillock. C) telodendria. D) collaterals

B

The basic functional unit of the nervous system is the: A) receptor. B) neuron. C) glial cell. D) axon.

B

The sodium-potassium exchange pump stabilizes resting potential of the neuron membrane at about __________.: A) +66 mV B) -70 mV C) -20 mV D) -90 mV

B

The tiny gaps between adjacent Schwann cells are called A) terminals. B) nodes of Ranvier. C) neurillema. D) axolemma.

B

________ carry sensory information to the CNS. A) Interneurons B) Afferent neurons C) Efferent neurons D) Multipolar neurons

B

________ channels open or close in response to physical distortion of the membrane surface. A) Active B) Mechanically gated C) Chemically gated D) Leak

B

A shift of the resting transmembrane potential toward 0 mV is called: A) polarization. B) repolarization. C) depolarization. D) hyperpolarization.

C

Most neurons lack ________ and so are permanently blocked from undergoing cell division.: A) a nucleus B) ribosomes C) centrioles D) endoplasmic reticula

C

The ________ division of the nervous system carries motor commands to muscles and glands.: A) peripheral B) spinal C) efferent D) autonomic

C

The site where EPSPs and IPSPs are integrated is the: A) synaptic terminal B) chemical synapse C) axon hillock D) electrical synapse

C

The sum of the electrical and chemical forces acting on an ion is known as its: A) permeability gradient. B) summation difference. C) electrochemical gradient. D) action potential

C

Voltage-gated channels are present: A) at the motor end plate. B) along the perikaryon of neurons. C) in the membrane that covers axons. D) on the surface of dendrites.

C

________ account for roughly half of the volume of the nervous system. A) Dendrites B) Efferent fibers C) Neuroglia D) Synapses

C

________ neurons are small and have no anatomical features that distinguish dendrites from axons. A) Unipolar B) Bipolar C) Anaxonic D) Sensory

C

Neuron cell bodies in the PNS are clustered together in masses called A) fibers. B) nerves. C) tracts. D) ganglia.

D

Neurons in which dendritic and axonal processes are continuous and the soma lies off to one side are called A) multipolar. B) tripolar. C) bipolar. D) unipolar.

D

Neurons that are rare, small, and lack features that distinguish dendrites from axons are called: A) tripolar. B) multipolar. C) unipolar. D) anaxonic.

D

Neurons that have one axon and one dendrite, with the soma in between, are called A) anaxonic. B) unipolar. C) tripolar. D) bipolar.

D

Raising the potassium ion concentration in the extracellular fluid surrounding a nerve cell will have what effect? A) decrease the magnitude of the potassium equilibrium potential B) increase the magnitude of the potassium equilibrium potential C) hyperpolarize it D) both hyperpolarize it and decrease the magnitude of the potassium equilibrium potential

D

Sensory neurons of the PNS are: A) bipolar. B) multipolar. C) tripolar. D) unipolar

D

The ________ nervous system controls the skeletal muscles. A) autonomic B) parasympathetic C) afferent D) somatic

D

The ________ nervous system provides involuntary regulation of smooth muscle, cardiac muscle, and glandular activity.: A) peripheral B) motor C) afferent D) autonomic

D

The afferent division of the PNS __________. A) controls skeletal muscle B) controls smooth muscle C) carries motor commands D) carries sensory information

D

The most abundant class of neuron in the central nervous system is A) unipolar. B) bipolar. C) anaxonic. D) multipolar.

D

The neuroglial cells that participate in maintaining the blood-brain barrier are the A) ependymal cells. B) Schwann cells. C) microglia. D) astrocytes.

D

The period during which an excitable membrane cannot respond to further stimulation is the _____ period: A) relative refractory B) stationary C) lag D) absolute refractory

D

The plasma membrane of an axon is called the: A) sarcolemma. B)myelin sheath. C) axon terminal. D) axolemma.

D

The site of intercellular communication between a neuron and another cell is the: A) synaptic terminals. B) telodendria. C) collateral. D) synapse

D

The sodium-potassium ion exchange pump: A) transports potassium ions out of the cell during repolarization. B) depends on a hydrogen gradient for energy. C) must reestablish ion concentrations after each action potential. D) moves sodium and potassium opposite to the direction of their electrochemical gradients.

D

________ carry motor information to peripheral effectors.: A)Interneurons B) Multipolar neurons C) Motor neurons D) Efferent neurons

D

________ monitor the digestive, respiratory, cardiovascular, urinary, and reproductive systems. A) Unipolar neurons B) Exteroceptors C) Proprioceptors D) Internoceptors

D

________ monitor the position of skeletal muscles and joints. A) Exteroceptors B) Photoreceptors C) Pressoreceptors D) Proprioceptors

D

________ provide information about the external environment. A) Internoceptors B) Spinal nerves C) Anaxonic neurons D) Exteroceptors

D

the period during which an excitable membrane can respond again, but only if the stimulus is greater than the threshold stimulus is the ____ period: A) Lag B) resting C) absolute refractory D) relative refractory

D