PSYCH 115 MIDTERM 2024 EXAM
UCLA~ QUESTIONS AND DETAILED
CORRECT ANSWERS A+ GRADE
What's the difference between the two anatomical pathway
labeling techniques? Correct Answer Anterograde Labeling
(Forward): Uses radioactive molecules taken up by the cell and
then transported to the axon termi...
PSYCH 115 MIDTERM 2024 EXAM UCLA~ QUESTIONS AND DETAILED CORRECT ANSWERS A+ GRADE What's the difference between the two anatomical pathway labeling techniques? Correct Answer Anterograde Labeling (Forward): Uses radioactive molecules taken up by the cell and then transported to the axon terminals, trace where the neuron is going. Retrograde Labeling (Backwards): It is taken up in the axon terminals and transported to the cell bodies, then visualized through chemical reactions, traces where the neuron came from What are the three layers of protective layer called? Correct Answer Meninges - Dura Mater (thick outer layer) - Arachnoid (Spongy middle layer) - Pia Mater (thin inner layer) What is the organ that constantly manufactures the CSF? Correct Answer choroid plexus, which resides in hollow tubes and cavities called ventricles Where does the action potential originate? Correct Answer Integration zone (or active zone) What are the three types of neurons? Correct Answer Multipolar - with multiple dendrites coming off the soma Bipolar - just 2 processes sticking off soma Unipolar - just one extension form soma that branches off into two How do excitatory, inhibitory, and modulatory neurotransmitters differ? Correct Answer excitatory - depolarize post synapt ic neuron and increases likelihood of post synaptic action potential inhibitory - hyperpolarize post synaptic neuron and decreases likelihood of AP modulatory - has multiple effects on post synaptic target What is the difference between efferent and affer ent? Correct Answer efferent - output afferent - input What is the potential equation for a voltmeter? Correct Answer V = C+ - C- What is the driving force on a molecule and when is it zero? Correct Answer - Sum of both electrical force (determined by charge of membrane & ion) & chemical force (determined by concentration gradient) acting on ion - its zero either when both forces are zero OR when they are equal and opposite What are the approximate equilibriums for each molecule? Correct Answer Ek = -80mV ENa = +60 mV ECl = - 90 mV ECa = +120 mV How do IPSPs work? Correct Answer Inhibitory Post -Synaptic Potential - when an inhibitory transmitter such as GABA is released from synapse and binds to receptors such as ligand gated chloride channels which make membrane potential more negative which leads to hyperpolarization of membrane preventing it from making an action potential How do EPSPs work? Correct Answer Excitatory Post Synaptic Potentials - when the excitatory neurotransmitter (glutamate or acetylc holine) is released & binds to ligand gated sodium ion channels which depolarizes cells and makes it more likely to fire AP What is the passive propagation of the EPSP? Correct Answer When the EPSP gets smaller as it travels from the synapse to the axon h illock (integration zone) How can spatial summation and temporal summation help with the passive propagation of the EPSP? Correct Answer Spatial summation - if two presynaptic neurons fire simultaneously the two EPSPs will sum to create a larger EPSP Temp oral Summation - creation of large EPSP from two smaller EPSPs occurring in rapid succession at a single synapse Why is an AP called an "all or none" phenomenon? Correct Answer As soon as membrane is depolarized above spike threshold, an AP will occur. - This is because opening voltage gated sodium channels will allow sodium to enter and depolarize membrane, which opens ever more channels (positive feedback cycle) How do the 4 protein subunits that make up the voltage gated sodium channel influence its 3 different states? Correct Answer Physical configurations of subunits change for each state Closed - Na+ cannot pass through pore, when cell is hyperpolarized Open - Na+ ions can flow freely, happens when depolarization occurs, but quickly switches to inact ive after millisecond Inactive - Na+ cannot pass through pore, channel cannot be opened even if depolarized, must go back to closed state through hyperpolarization before another AP What is the role of the delayed rectifier channels? Correct Answer Open a t -45mV to help potassium ions get out faster, they open slowly to allow spike to reach its peak -only has 2 states, open (when membrane depolarized above delayed rectifier threshold) and closed (when below threshold) After sodium moves into cell and pota ssium moves out because of the AP, how do they go back to equilibrium? Correct Answer Na-K ATPase Pump which ejects 3 sodium ions for each 2 potassium ions imported, which repolarizes membrane at the end of AP What is the difference between active and pas sive transport? Correct Answer Active - required ATP an pushes ions in the direction it wants REGARDLESS OF DRIVING FORCES Passive - ion channels open or close to allow ions to flow according to electrochemical gradient in direction of driving force Which factors contribute to the ending of the action potential Correct Answer - Na-K ATPase Pump -Delayed Rectifier K+ channel - Inactivation of Sodium channels - Leak K+ channels What is the difference between the central and peripheral nervous systems? Corre ct Answer Central Nervous System - includes brain and spinal cord, group of neurons in CNS called nucleus Peripheral Nervous System - includes spinal and cranial nerves that relay sensory & motor info to & from CNS, group or cluster of neurons on PNS calle d ganglion What is the role of the Dorsal root ganglion? Correct Answer DRG unipolar neurons in PNS whose job is relay somatosensory information from skin to spinal cord How do local anesthetic drugs work? Correct Answer They block somatosensation by blo cking active zone sodium channels in skin What does active propagation look like? And where does it occur? Correct Answer IT happens in unmyelinated axons and they have sodium and delated rectifier channels all the way
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