Exam 2 Terms Flashcards
Picks up sound waves in the environment
Outer ear
Convey and amplify sound waves
Middle ear
Translate sound waves into nerve impulses
Inner ear
Psychological aspect of sound related to magnitude
Loudness
Psychological aspect of sound related to fundamental frequency
Pitch
Magnitude of displacement of a sound pressure wave
Amplitude
Number of times per second that a pattern of pressure change repeats
Frequency
Denoting a substance that stimulates the growth of microorganisms, especially those with beneficial properties (such as those of the intestinal flora)
Probiotic
Frontal lobe area specialized in the production of language
Broca’s Area
Temporal lobe area that mediates language comprehension
Wernicke’s Area
Difficulty comprehending language due to damage to these areas (or others)
Aphasia
Inability to name objects
Agnosia
Ordered projection of axons from one region of the nervous system to another, by which the organization of the body (or some function) is reflected in the organization of the nervous system
Map
Topographic mapping of frequency across the surface of a structure, which originates in the cochlea and is preserved in ascending auditory structures
Tonotopic map
Cortical or subcortical arrangements of sensory pathways that reflect the organization of the body
Somatotopic map
Two dimensional representation of the retinal image in the neurons of the primary visual cortex
Retinotopic map
Part of the temporal lobe involved in consolidation of short-term memories into long-term memories (cortex)
Hippocampus
Integral membrane proteins possessing pores that allow certain ions to diffuse across cell membranes, thereby conferring selective ionic permeability
Ion channel
Electrical signal conducted along axons (or muscle fibers) by which information is conveyed from one place to another in the nervous system
Action potential
Atom or molecule with a net electrical charge
Ion
Acquisition of novel behavior through experience
Learning
Faculty by which the mind stores and remembers information
Memory
Strengthening or weakening of synapses
Molecular basis of memory
Altering the interconnections between neurons
Cellular basis of memory
A swelling specialized for the release of neurotransmitter that occurs at the end (or along) an axon – pre-synaptic (before the synaptic cleft)
- Also known as an axon terminal or terminal boutons
Synaptic bouton
Proteins on the post-synaptic membrane that sense the neurotransmitter
Receptors
Receptors in which the ion channel is an integral part of the receptor molecule (as of course is the ligand binding site)
- Ionotropic receptors are also called ligand gated ion channels
Ionotropic receptor
Large group of neurotransmitter receptors that combine receptor and ion channel functions into a single molecule
- Presence of the ligand allows ion flow – “gating” (controlling the passage of)
Ligand gated ion channel
Molecule that binds to another (usually large) molecule
Ligand
Receptors in which the ligand binding site is an integral part of the receptor molecule but the receptor is only indirectly linked to an ion channel
- Also known as G-protein-coupled receptors – the intracellular signaling pathways use G-proteins
- Also known as 7 transmembrane receptors
Metabotropic receptor
Direct effect on ion flow, effects fast and brief
- Ions flow through the receptor
- Most fast receptors are of this type
Ionotropic
Indirect effects on ion flow; conformational change transmits information across the membrane
- Often involve biochemical cascades that can affect many processes
- Can be longer lasting
Metabotropic
Allows ion flow in response to membrane depolarization
Voltage sensitive sodium channel
Periodic gaps in the myelin of axons where action potentials are generated
Node of Ranvier
Mechanism of action potential propagation in myelinated axons
- So named because action potentials “jump” from one node of Ranvier to the next due to generation of action potentials only at these sites
Saltatory conduction
Influx of Ca++ at synapse causes vesicles to fuse with the membrane and release neurotransmitter
Voltage Gated Ca++ channel
Substance that binds to a receptor and activates it
Agonist
Substance that binds to a receptor and prevents its activation
Antagonist
Neurotransmitter typically binds to an ionotropic receptor on the post-synaptic membrane activating a single neuron
- Glutamate is a key example in the brain
- Glutamate synapses can be readily strengthened or weakened
- Acetylcholine is used at the neuromuscular junction
Fast excitatory
Rapidly inhibit target neurons via ion channels
- GABA is the main brain inhibitor, glycine in the spinal cord
- Sedatives typically enhance GABA signaling
Fast inhibitory
Typically small proteins acting via GPCRs that change neural activity for longer periods, often in multiple neurons
- Dopamine, serotonin, epinephine (adrenaline)
Slow neuromodulators
Electrical difference across the cell membrane of -70 milli Volts that results from the action of the Na+/K+ pump
- The cell is polarized: there is an electrical difference across the cell membrane
Resting Potential
Displacement of the cell’s membrane potential to a less negative value
Depolarization
Displacement of the cell’s membrane potential to a more negative value
Hyperpolarization
Activation by ligand binding such as a neurotransmitter allows ion flow across the membrane
Ligand gated channel
Activated by changes in membrane potential allowing ion flow across the membrane
Voltage gated channel
Swelling at the junction of the neuronal cell body (soma) and the start of the axon
- Starting point for action potentials
Axon hillock
1) Self regenerating
2) All or none change in voltage
3) Propagates from axon hillock (cell body)
4) Induces synaptic transmission
Action potential characteristics
Depolarizes target neuron
- Glutamate allows Na+ and Ca++ influx
Excitatory neurotransmitter
Hyperpolarizes target neuron
- GABA allows Cl- ion influx
Inhibitory neurotransmitter
Away from the synapse
Diffusion
Neurotransmitter re-enters presynaptic axon terminal
- Enzymatic destruction inside terminal cytosol or synaptic cleft
Reuptake
Alkaloid neurotoxin, produced by certain puffer fish, tropical frogs, and salamanders, that selectively blocks voltage-sensitive Na+ channels
Tetrodotoxin
Small molecule excitatory neurotransmitter that acts at motor neuron synapses
- Also acts in the autonomic nervous system (unconscious functions such as breathing, digestion) and modulates synapses in the brain (important in Alzheimer’s disease)
Acetylcholine (ACh)
Amino acid that is the predominant excitatory neurotransmitter in the brain
Glutamate
Major inhibitory neurotransmitter in the brain (technically an amino acid)
GABA
Cell death resulting from the toxic actions of excitatory amino acids such as glutamate
- Progression of hyperexcitability, excitotoxicity, cell death
- Elevated calcium levels trigger cell death enzymes
Excitotoxicity
Support cells associated with neurons, providing support and protection
Glia
Star shaped glial cell, closely associated with neuronal synapses, which regulates the ionic environment of the neurons and sometimes neurotransmitter reuptake
- Most abundant cells of the human brain
Astrocyte
Glial cell in the central nervous system that elaborates myelin
Oligodendrocyte
Glial cell in the peripheral nervous system that elaborates myelin
Schwann cell
Glia cell concerned primarily with repairing damage following neural injury
- Macrophages – immune cells responsible for engulfing foreign particles and cellular debris including dead cells
Microglia
Method in which the combination of genetic manipulation and optical stimulation can be used to elicit either gain or loss of function events in specific cells
- Expression of algal ion channels that are activated by specific wavelengths of light – can depolarize or hyperpolarize neurons
Optogenetics
Genetically encoded Calcium indicator that emits (green) fluorescent light when calcium is present
- Indicates synaptic activity in living organisms
GCaMP
Study of the electrical properties of neurons (and cells in general)
Electrophysiology
Measures action potentials, tip located near the cell
- Can be used to stimulate the neuron by passing current
Extracellular electrode
Record electrical activity inside the cell
Intracellular electrode
Maintains the voltage at a given level allowing the ionic current flow across the membrane to be measured
- Important as voltage sensitive channels are only open at certain voltages
Voltage clamp
Control the current flow to allow measurement of the membrane potential (voltage)
- Can stimulate action potentials by passing current
Current clamp
Extraordinarily sensitive voltage clamp method that permits the measurement of ionic currents flowing through individual ion channels
Patch clamp
Wave of activation (depolarization) followed by inactivation
- Causes release of substances that irritates pain neurons
One theory of migraines
