Chapter 11 MyL&M Q's Flashcards
The two structural divisions of the nervous system are ______.
CNS and PNS
Which nervous system is responsible for the integration of sensory information?
CNS
Neurons that relay information within the CNS and are the location of the information processing are called ______.
Interneurons
The conducting region of the neuron is the _____.
Axon
During an action potential, hyperpolarization is caused by _____.
An efflux of K+ ions after returning to resting potential
The channels that open when the axolemma reaches threshold depolarization are the _____.
Voltage-gated Na+ channels
The relative refractory period is caused by ______.
Hyperpolarization
Action potential propagation in unmyelinated axons happens via ______.
Continuous conduction
Depolarization to threshold during action potential propagation in axons is due to ____.
Diffusion of Na+ down to the next segment of the axon
Why is the resting membrane potential negatively charged?
More K+ leaks out of the neuron than move in
The influx of positive charges makes the membrane potential more positive and is known as ______,
Depolarization
The majority of synapses in the nervous system are ______.
Chemical
A neurotransmitter may have an excitatory or inhibitory effect on the postsynaptic cell, based on _____.
The receptor to which it binds
The most important excitatory neurotransmitter in the brain is _____.
Glutamate
A neural circuit pattern in which the signal goes from several neurons to one is called ____.
A converging circuit
What part of the neuron communicates with a target cell and serves as the secretory region of the cell?
Axon terminals
What is the ciliated neuroglial cell that functions to circulate cerebrospinal fluid?
Ependymal cells
What structure found in the PNS promotes regeneration of a damaged axon?
Schwann cells
What neuroglial cells surround and support the cell bodies of neurons and have intertwined processes that link them with other parts of the neuron?
Satellite cells
What characteristic of the myelin sheath makes it such an excellent insulator for axons?
High lipid content
The ANS carries signals to _______.
Glands, smooth muscle, and cardiac muscle
What forms the white matter of the spinal cord?
Myelinated axons
Most sensory neurons, such as ones found in special sense organs, are structurally classified as _____.
Bipolar
The most common type of neuron in the human body is ______.
Multipolar
The majority of neurons are functionally classified as _______.
Interneurons
Regulation of heart rate, blood pressure, and digestive functions are carried out by the _____.
ANS
What structure contains the bulk of the Schwann cell’s cytoplasm and organelles?
Neurolemma
What are clusters of cell bodies within the PNS called?
Ganglia
Which neuroglial cells help form the blood-brain barrier?
Astrocytes
What type of neuron carries info toward the CNS?
Afferent / sensory
What cell type forms the myelin sheath in the CNS?
Oligodendrocytes
Which division of the PNS carries signals from bones, joints, skin, and organs of vision to the CNS?
Somatic Sensory
What is the most metabolically active part of the neuron?
Soma / Cell body
Which neuroglia would be more likely to form a brain tumor because of their ability to rapidly divide following brain injury?
Astrocytes
What neuron structure does not contain protein-making organelles?
Axon
Bundles of axons known as “tracts” are part of the _____, whereas “nerves” are part of the ______?
CNS; PNS
Which effector is controlled by the somatic motor division: smooth muscle, cardiac muscle, skeletal muscle, or glands?
Skeletal muscle
What must be intact for a neuron to regenerate in the PNS?
Cell body
What is the sequence of structures that indicates the direction of an electrical signal carried through a multipolar neuron?
Dendrites –> Cell body –> Axon
What type of channel opens in response to a chemical binding to a receptor on the channel?
Ligand-gated
The influx of positive charges makes the membrane potential more positive and is known as _____.
Depolarization
What is the period during an action potential when a nerve fiber cannot be stimulated to produce an additional action potential no matter how strong the stimulus?
Absolute refractory period
What ion triggers synaptic vesicles to release neurotransmitters into the synaptic cleft?
Calcium
What are the structural components of chemical synapses?
Synaptic vesicles, synaptic cleft, and neurotransmitter receptors (NOT gap juntion)
Where are voltage-gated channels most abundant?
Axolemma
What characteristic is the fundamental process for most functions of the nervous system?
Synaptic transmission
What is the resting membrane potential of a typical neuron?
-70 mV
Influx of which ions can cause an inhibitory postsynaptic potential (IPSP) to be produced?
Chloride ions
What is the process of putting together all the excitatory and inhibitory stimuli that determine whether a neuron will or will not fire an action potential?
Neural integration
The majority of synapses in the nervous system are ____.
Chemical
What type of fiber has the largest diameter?
Type A
Type B fibers are intermediate and Type C fibers are the smallest/slowest
During saltatory conduction, action potentials are generated where?
Only at nodes of Ranvier of myelinated axons
What are the characteristics of local potentials?
they are reversible, also called graded potentials, and decremental in nature (NOT useful for long distances)
What mechanisms terminate the effects of a neurotransmitter?
- Degradation by enzymes in the synaptic cleft
- Reuptake by the presynaptic neuron
- Diffusion away from the synaptic cleft and uptake by glial cells
A series of measurements with a voltmeter show a neuron’s membrane potential becoming more negative, from –70 mV to –85 mV. This neuron is experiencing a _____.
Hyperpolarization phase
Resting membrane potential is maintained by the Na+/K+ ATPase, which brings ______ potassium ions into the cytosol and ______ sodium ions into the extracellular fluid.
2 K+ and 3 Na+
What are the structural types of synapses?
Axodendritic, axoaxonic, and axosomatic
What type of ion channel is always open?
Leak
What type of fiber has the slowest conduction speed?
Type C (smallest & slowest)
What event occurs when EPSPs arrive repidly at a single synapse?
Temporal summation
What channels open in response to changes in membrane potential?
Voltage-gated
How many connections from different presynaptic neurons does an average neuron have?
10,000
What kind of conduction occurs when each section of the axolemma has to be depolarized to threshold in sequence along the entire axolemma for a current to spread down the length of the axon?
Continuous
Which neuron delivers a message to a target cell: presynaptic or postsynaptic?
Presynaptic
What are the three types of catecholamines?
Norepinephrine, epinephrine, and dopamine
Which neuropeptide neurotransmitter is released from fibers transmitting sensory information about pain and temperature?
Substance P
Which neurotransmitter is widely used by the autonomic nervous system (ANS), where it influences functions such as heart rate, blood pressure, and digestion?
Norepinephrine
What is the response of the presynaptic neuron after acetylcholinesterase (AChE) acts?
Reabsorbs choline
What effects occur when neuromodulators bind to metabotropic receptors?
- Increase or decrease in neurotransmitter release from a presynaptic neuron
- Affect the sensitivity of the postsynaptic membrane
- Alter gene transcription
(NOT degenerate synaptic vesicles)
Cholinergic synapses use the neurotransmitter ______.
Acetylcholine
What is thought to be one of the major neurotransmitters involved in mood regulation, motor behaviors, feeding behaviors, and daily rhythms and is a common target in the treatment of depression?
Serotonin
Neuronal pools are located within ______.
The CNS
Which neurotransmitters are strictly inhibitory?
Glycine and GABA
What is considered to be the most important excitatory neurotransmitter in the brain?
Glutamate
How many neurotransmitters operating in the human nervous system have been identified?
Over 100
What type of neurotransmitter receptors elicit much slower changes in the membrane potential of the postsynaptic neuron, but the effects are typically longer lasting and more varied?
Metabotropic receptors
