click below
click below
Normal Size Small Size show me how
Ch 11
Fundamentals of the Nervous System and Nervous Tissue
Question | Answer |
---|---|
Neurons can be classified structurally by the number of processes extending from their cell bodies. Which of the following is the most common neuron type in humans? | multipolar |
The sensory, or afferent, division of the peripheral nervous system transmits information from the __________ to the CNS. | skin |
Relative to extracellular fluid, the interior of a neuron has a negative charge because __________. | potassium diffuses out of the cell |
The Nissl bodies in the neuron cell body are otherwise known as which cellular organelle(s)? | rough endoplasmic reticulum |
Which of the following statements best describes the resting membrane state in the neurons? | All of the voltage-gated Na+ and K+ channels are closed. |
Which cells line the central cavities of the brain and spinal cord and provide a fairly permeable barrier between the CSF and nervous tissue? | ependymal cells |
Which of the following characteristics is NOT associated with a myelinated nerve fiber? | slow conduction of nerve impulses |
Which of the following events occurs at an electrical synapse? | Ions flow directly from one neuron to the next. |
Which of the following electrical events occurs when a certain threshold is reached? | action potential |
Which of the following factors is associated with increased conduction velocity in an axon? | large diameter |
n a neuron, a membrane potential of –90 mV is considered __________. | hyperpolarized |
During which phase of an action potential are voltage-gated K+ channels open, while voltage-gated Na+ channels are closed? | repolarized |
Which of the following neurotransmitters act(s) as a natural opiate? | endorphins |
The CNS can discriminate between strong and weak stimuli as strong stimuli __________. | increase the frequency of action potentials |
Spatial summation occurs when __________. | multiple local potentials occur at different places on the same cell at the same time |
Which of the following statements concerning inhibitory synapses (IPSPs) is correct? | The postsynaptic membrane becomes more permeable to potassium and chloride. |
Which of the following is NOT a biogenic amine neurotransmitter? | acetylcholine |
Which of the following neuroglia are most responsible for helping determine capillary permeability in the central nervous tissue? | astrocytes |
Which of the following is a rare type of sensory neuron that is found in special sensory structures such as the retina of the eye? | bipolar |
Which of the following defines integration? | processing and interpreting sensory input and determining what should be done at each moment in the body |
Which of the following divisions of the nervous system is also known as the involuntary nervous system? | the autonomic nervous system |
Organelles slated for degradation or recycling are moved through the axon by ___________. | retrograde movement |
From where can collaterals emerge on a myelinated nerve? | the nodes of Ranvier |
Which of the following membrane ion channels in the neuron are always open? | leakage channels |
Which of the following is characteristic of an action potential? | voltage-gated ion channels |
The sodium-potassium ion pump will | pump three sodium ions out of the cell for every two ions of potassium it brings into the cell |
Which of the following explains the inability of a neuron to respond to a second stimulus of equal strength to the first stimulus to which it has already responded? | The neuron is in the absolute refractory period |
Which of the following conditions would cause synaptic potentiation? | influx of Ca++ |
In a __________ circuit, multiple presynaptic neurons innervate a single postsynaptic neuron. | converging |
Which of the following substances is NOT a neurotransmitter? | acetylcholinesterase |
Which of the following best describes the nervous system function of integration? | The nervous system processes and interprets sensory input and decides what should be done at each moment. |
What is the primary difference between the somatic nervous system and the autonomic nervous system? | som, nervous system allows us to consciously control our skeletal muscles, and the autonomic nervous system controls activity that humans cannot consciously control, such as the pumping of the heart and the movement of food through the digestive tract. |
Which of the following types of glial cells line the central cavities of the brain and spinal cord, where they help to circulate the cerebrospinal fluid? | ependymal cells |
Which of the following types of glial cells are the most abundant and versatile, and aid in making exchanges between capillaries and neurons? | astrocytes |
Which of the following is NOT a characteristic of neurons? | Neurons are relatively small, simple-structured cells. |
What is the difference between the clusters of cell bodies called nuclei and those known as ganglia? | Nuclei exist in the CNS, ganglia in the PNS. |
Dendrites and axons are both armlike processes that extend from neuron cell bodies. | True |
Which of the following are the main receptive or input regions found in neurons? | dendrites |
Which of the following is NOT a function of the myelin sheath? | to recapture and recycle released neurotransmitters |
What is the difference between nerves and tracts? | Bundles of neuron processes are called tracts in the CNS and nerves in the PNS. |
Which criterion is used to structurally classify neurons? | the number of processes extending from their cell body |
Which of the following is NOT a structural classification of neurons? | sensory |
Which of the following is FALSE regarding motor (efferent) neurons? | Motor (efferent) neurons are bipolar. |
Which of the following membrane ion channels open and close in response to changes in the membrane potential? | voltage-gated channels |
An action potential is a phenomenon that either happens completely or doesn't happen at all. | True |
Which of the following diseases is directly related to demyelination? | multiple sclerosis |
Which of the following is FALSE regarding chemical synapses? | They transmit nerve impulses directly from one neuron to another. |
Which of the following is NOT a functional classification of neurotransmitters? | chemical |
Which of the following circuit types is exemplified by impulses that travel from a single neuron of the brain, activate one hundred or more motor neurons in the spinal cord, and excite thousands of skeletal muscle fibers? | diverging circuit |
Which type of ion channel opens when a chemical binds to it? | chemically gated (ligand-gated) channel |
he movement of which ion out of the cell through leakage channels establishes the negative membrane potential? | potassium |
Which part of the action potential occurs when the voltage-gated Na+ channels are inactivating and voltage-gated K+ channels open? | repolarization |