Final Exam Review

  • All skeletal muscles are directly innervated by the:

    • Lower motor neurons of the somatic sensory system

  • The image the detailed structure of white matter you could use ___ and to image regions to brain active during a task you could use ___

    • Diffusion tensor imaging (DTI), functional magnetic resonance imaging (fMRI)

  • Which neuron is properly paired with a characteristic

    • Soma: Cell body, synthesizes proteins

    • Axon: Sends/amplifies signals

    • Dendrites: Receives signals

    • Axon terminal: Create synaptic connections with other neurons to transmit signals via chemical neurotransmitter

    • Oligodendrocyte: Coat axons in the CNS with myelin to speed up transduction

    • Schwann cell: Coat axons in the PNS with myelin to speed up transduction

    • Node of Ranvier: A gap in myelination, creates saltatory conduction

  • In which area of the nervous system will cell bodies of motor neurons be found

    • In grey matter of the ventral horn of the spinal cord

  • What are ganglia?

    • Collection of cell bodies in the CNS (nuclei in PNS)

  • Which statement about astrocytes is true?

    • They maintain appropriate chemical environments for neurons, form the blood brain barrier (BBB), facilitate transport between neurons and blood, take up some neurotransmitters, secrete signaling molecules to promote new synapses, provide scaffolding for migrating neurons in development, form scar tissue (by laying down ECM) due to injuries and signal molecules that interfere with axon regrowth to stop preventing growth. Only in the CNS, look star-like. Within the BBB, they have many feet which connect out, which allows them to transport materials from blood

  • Extracellular, intracellular, and single unit recordings all record the electrical activity of neurons. Which one is properly paired with a situation in which it would be useful

    • Extracellular: An electrode is inserted into the spinal cord near involved neurons, after a given action is performed/observed an action potential can be recorded/visualized on a computer screen, each slash representing an action potential. More frequent signals indicate greater signal intensity

    • Intracellular: The electrode is directly inserted into the neuron which will damage it, but it can detect smaller changes than extracellular recordings. Can reveal precise timing of electrical signaling, measures both action potentials and graded potentials

    • Single unit recording: The electrode is inserted into the brain to record activity of a single neuron, or extracellularly action potentials. Determines the relationship between peripheral sensory and cortical neurons, determines the receptive field of a given sensory neuron, physical stimulation of different areas changes how the neuron will activate, mapping receptive fields

  • Golgi staining (silver staining) of nervous system tissue is preferable to staining with a fluorescent antibody if:

    • Morphology needs to be understood for individual neurons, as it is high contrast

  • An elderly person has been experiencing severe watery diarrhea and vomiting for 2 days, causing their plasma K+ to decrease from a normal value of 4 mEq/L to 2 mEq/L. Which set of changes best descries the RMP and the K+ equilibrium potential in a neuron compared to before the onset of the diarrhea

    • More negative (RMP), More negative (K+ equilibrium potential)

  • If the permeability of a resting neuron increases above the resting permeability, what effect will this have on the transmembrane potential? (Goldman equation)

    • The membrane potential will shift toward that ion’s equilibrium potential

  • The resting membrane potential is not exactly equal the the Nernst potential for potassium because

    • There are other ions with permeabilities that contribute to RMP like Na+ making RMP more positive than EK, even though K drives RMP

  • The classic voltage clamp technique would be suitable for which application

    • Changing the membrane potential and observing current changes. Doesn’t allow for ion determination, tells about changes in permeability

  • Which of the following nerve fibers will have the greatest increase in conduction velocity compared to an unmyelinated nerve fiver in the PNS with conduction velocity .35 m/sec?

    • Myelinated nerve fiber in the CNS with a larger diameter

  • Which of the following expressed the relationship between voltage (V), current (I), resistant (R), and/or conductance (g)

    • R = V * I

  • What is true of ion channels?

    • They all have a water filled pore

  • Which statement is a common, defining feature of membrane-bound active ion transporters?

    • All are able to move at least one ion against its concentration gradient

  • Choose the pair of items that correctly indicates the gating of the voltage-gated channels responsible for the action potential (about functions of K+ and Na+ gates)

    • Na+ activation gate - opened during the rising phase

  • Which technique would you use to study the effects of intracellular signaling (missed the end of the question, about patch clamping)

    • Patch clamping: A technique used to study current flow through ion channels, uses refinement of voltage clamps. Uses a glass micropipette to form a tight seal with a small area of the cell membrane, ideally isolating a single channel. This pipette serves as the recording electrode and the current injecting electrode Current flowing through the channel is measured by the pipette, has the ability to clamp voltage

      • Cell-attached recording: The cell is intact, it can measure current through channels under physiological conditions, with intracellular signaling paths intact. It measures spontaneous activity, ideally just one channel

      • Whole-cell recording: The pipette suction disrupts membrane/cytoplasm, so that the cytoplasm is continuous with the micropipette electrolyte solution, allowing it to measure whole cell currents or membrane potentials in response to extracellular signals or signals introduced by the micropipette. Will alter the cytoplasmic contents after several minutes of exposure

      • Inside-out recording: The micropipette extracts part of the whole cell and detaches it before retracting, allowing manipulation of the internal surface and studying of intracellular signaling molecules and their roles (like cyclic nucleotides). Best for detecting impacts of intracellular signals on a single channel

      • Outside-out recording: Most difficult subtype as there are many points of potential failure, requires strong suction to generate free ends when breaking the membrane in two (like with inside out recording, but split), free ends join together, so that the membrane is shaped like an upright U inside the micropipette, used to examine effects of multiple external conditions (like with a dose-response curve)

  • A ___ synapse would be useful for coordinating action potential in many neurons and a __ synapse (options are chemical and electrical)

    • Electrical, chemical

  • Gap junctions may exhibit all of the following features except (they allow currents and small ions)

    • The ability to amplify small incoming electrical signals into large regenerative potentials

  • Assume a hypothetical postsynaptic neuron has thee presynaptic inputs X, Y, Z. When presynaptic neuron X and Y are stimulated simultaneously, the postsynaptic neuron reaches threshold and undergoes an AP, yet when the presynaptic neuron X and Z are simultaneously stimulated there is no change in potential of the post synaptic neuron, If the response to each neuron in similar in absolute magnitude, what can you tell about the presynaptic neurons Y and Z?

    • Presynaptic neuron Y is excitatory, presynaptic neuron Z is inhibitory

  • The data in these graphs were collected using voltage clamping to explore what was leading to depolarization in muscle fibers at a from neuromuscular junction in response to ACh release by a motor neuron. What can be concluded

    • Voltage clamp method: Determined the molecular basis of the AP. Allows researchers to set the voltage for an axon (the clamped voltage), which was a change in voltage from the RMP, based on the current that is injected

    • Reversal potential: The membrane potential at which current reverses direction. For a single ion X, this is Ex

  • Which property best explains why biogenic amines typically generate relatively slow synaptic responses?

    • They utilize metabotropic GPCRs and cause secondary messenger cascades

  • A neurotransmitter is synthesized in the soma, processed through the Golgi and released with other signaling molecules from the same precursor. Which class does this describe?

    • Neuropeptide

  • Which characteristic is NOT an accepted criteria of for classifying a molecule as an neurotransmitter?

    • It must be packaged in vesicles (Nitric oxide isn’t)

  • Acetylcholine can be both an inhibitory and an excitatory transmitter because

    • The effect of a neurotransmitter is due to properties of the receptor, not the neurotransmitter

  • In addition to binding of a ligand to a receptor, what else is necessary to activate a trimeric G protein?

    • Replacement of GDP with GTP

  • Stimulation of the metabotropic receptors cannot

    • Open ion pores in the G-protein structure

  • Which of the following is the slowest chemical signaling process?

    • Initiation of transcription

  • Historically, which class of neurotransmitters has been the primary focus for treatment of depression?

    • Biogenic amines, including serotonin and norepinephrine

  • Cholera toxin locks the Go so that GTP is bound and cannot be hydrolyzed back to GDP to turn off the subunit. What effect will cholera toxin have in the cell?

    • Activated adenylyl cyclase will lead to decreased cyclic AMP levels

  • How would an increase in external Ca2+ concentration affect synaptic depression elicited by sustained stimulation? It would ___

    • Increased neurotransmitter release and increase the rate of depression

  • Which protein is necessary for the late phase of LTP but not the early phase?

    • CREB

  • What is the mechanism of LTP expression (what change underlies the enhanced EPSP)?

    • Increase in the number of postsynaptic AMPA receptors

  • After firing a short burse of action potentials in an axon, researchers observe a larger EPSP in the postsynaptic cell, and this effect seems to last a few tends of milliseconds, This is most likely due to the presynaptic terminal having

    • Extra calcium

  • Activation of CREB requires (the one step which is absolutely necessary)?

    • Phosphorylation

  • The conversion of stimuli into action potentials is called

    • Transduction

  • During brain surgery, the lateral portion of the left primary somatosensory cortex of a patient ins stimulated. This patient is most likely to

    • Feel something on his right cheek

  • Which sensory deficits below the level of the lesion would result from a lesion confined to the right side of the spinal cord at the waist?

    • Loss of discriminative touch on the right side and crude touch on the left side of the body

  • Rapidly adapting fibers associated with the somatosensory receptors are most likely to provide information about the ___ of a stimulus

    • Movement or changes

  • The ability to localize the position of body parts is called

    • Proprioception

  • What do nociceptor neurons and proprioceptive neurons form the body have in common?

    • They have cell bodies in dorsal root ganglia

  • The main pathway for fine discriminative touch information from the foot to the cerebral cortex includes:

    • Group A-beta axons → fasciculus gracilis → gracile nucleus → decussation → medial lemniscus → VPL nucleus → postcentral gyrus

  • Which of the following lists the correct order of structures a ray of light encounters as it enters and travels trough the human eye?

    • Cornea, aqueous humor, pupil, lens, vitreous humor, retina

  • A researcher interested in studying how the brain adapts to complete loss of the right visual field should lesion which region to create and animal model of this anopsia?

    • Left optic tract

  • A device that monitors the activity of the photoreceptor cells of the eye indicates that there is a constant flow of neurotransmitter being released by the photoreceptors cells. tis information implies that the subject is

    • In a dark room

  • Which of the following would occur when rod cells are stimulated by light?

    • cGMP levels decline

  • A photoreceptor cell is exposed to a flash of light. How does the membrane potential of this photoreceptor (center receptive field), its Off-center bipolar and OFF center ganglion cells change?

    • photoreceptor hyperpolarize, bipolar hyperpolarize, ganglion cell hyperpolarize

  • Which ion and direction of flow is responsible for depolarization pf inner hair cells in organ of Corti?

    • Potassium into the cell

  • Detection of the frequency of a sound above 5 kHz is based on:

    • The location along the cochlea of the most intensely stimulated hair cells

  • The primary auditory cortex lies primarily in which lobe of the cerebral cortex?

    • Temporal lobe

  • This is a list of the steps that occur in the production of an auditory sensation. What is the proper sequence?

    • Movement of the tympanic membrane → Movement of the malleus causes movement of the incus and stapes → Movement of the oval window establishes pressure waves in the perilymph of the vestibular duct → The pressure wave distorts the basilar membrane on its way to the round window → Distortion of the basilar membrane causes movement of air cell tips → Displacement of the stereocilia stimulates sensory neurons of the cochlear nerve

  • A human’s perception of pitch correspond to the ___ of a sound wave, perception of loudness correspond to the ___ of a sound wave

    • frequency, amplitude

  • Which of the following would be a symptom of nonfunctional otoconia?

    • Detection rotational movements in head tilts only

  • The vestibular ocular reflex is a mechanism for

    • Stabilizing gaze during head movement

  • The most effective stimulus for excitation of the right horizontal semicircular canal hair cell is:

    • Rotary acceleration of the head to the right