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PSIO |! 201 |! FINAL |! EXAM |! WITH |! PRECISE |!
DETAILED |! ANSWERS
neuronal |! tissue |! (two |! cell |! types): |! - |! Correct |! answer |! ✔a. |! nerve |! cells: |! neurons -involved |! in |! the |! generation |! and |! interpretation |! of |! 'electrical |! signals' b. |! glial |! cells: |! neuroglia -supports |! neuronal |! cell |! activity resting |! membrane |! potential |! is |! the..... |! - |! Correct |! answer |! ✔baseline |! electrical |! condition |! of |! all |! cells distribution |! of |! charges |! in |! resting |! membrane |! potential: |! - |! Correct |! answer |! ✔extracellular |! fluid: |! equal |! number |! of |! + |! and |! - |! charges plasma |! membrane: |! equal |! number |! of |! + |! and |! - |! charges cytosol: |! equal |! number |! of |! + |! and |! - |! charges resting |! membrane |! potential |! has |! what |! two |! parameters? |! - |! Correct |! answer |! ✔- transmembrane |! ion |! gradients |! (Na+ |! and |! K+) -membrane |! permeability transmembrane |! ion |! gradients: |! - |! Correct |! answer |! ✔-Na+ |! leaves |! the |! cell |! while |! K+ |! is |! entering |! the |! cell
-ATPase |! allows |! this |! (ATPase |! develops |! and |! maintains |! steady-state |! ion |! gradients |! for |! ALL |! cells) -K+ |! being |! pulled |! into |! the |! cell |! is |! an |! electrical |! force -K+ |! leak |! channels |! are |! present |! and |! allows |! K+ |! to |! leave |! the |! cell |! (chemical |! force) -K+ |! leak |! channels |! are |! present |! in |! ALL |! cells membrane |! permeability: |! - |! Correct |! answer |! ✔-K+ |! leak |! channel -K+ |! from |! intracellular/cytoplasm |! is |! pushed |! out |! into |! the |! extracellular |! (chemical |! force) -pumping |! creates |! ionic |! gradient |! for |! K+ -K+ |! leaks |! out/down |! its |! concentration |! gradient |! which |! makes |! the |! inside |! of |! the |! cell |! more |! negative |! and |! the |! outside |! of |! the |! cell |! more |! positive -2 |! forces: |! (chemical |! force, |! push |! K+ |! out |! and |! electrical |! force, |! pull |! K+ |! in) in |! a |! typical |! cell |! (including |! neuronal |! cells): |! - |! Correct |! answer |! ✔-chemical |! and |! electrical |! forces |! for |! K+ |! are |! nearly |! in |! balance |! (results: |! inside-negative |! electrical |! potential) the |! electrical |! potential |! difference |! is |! measured |! in: |! - |! Correct |! answer |! ✔volts (typical |! value: |! -0.05 |! volts |! to |! -0.1 |! volts) all |! cells |! at |! rest: |! - |! Correct |! answer |! ✔K+ |! is |! dominated |! and |! has |! an |! inside- negative |! membrane |! potential
-allows |! Ca2+ |! and |! Na+ |! to |! enter |! the |! cell voltage-gated |! channels: |! - |! Correct |! answer |! ✔-voltage-gated |! channel |! opens |! when |! the |! membrane |! potential |! gets |! less |! negative |! (depolarized) -allows |! K+ |! to |! leave |! the |! cell neuronal |! action |! potential: |! - |! Correct |! answer |! ✔a. |! neurons |! are |! excitable |! cells |! (nerve |! and |! muscle) -can |! change |! membrane |! potential |! to |! generate |! an |! electrical |! signal |! b. |! principle |! mechanism |! (voltage-gated |! Na+ |! channel) steps |! for |! the |! generation |! of |! the |! action |! potential: |! - |! Correct |! answer |! ✔1. |! local |! change |! in |! membrane |! potential -hyperpolarizing |! (more |! negative) -depolarizing |! (less |! negative) (an |! action |! potential |! begins |! with |! local |! depolarization)
- |! depolarization |! to |! a |! 'threshold' |! value |! induces |! a |! population |! of |! voltage- gated |! Na-channels |! within |! the |! local |! region |! of |! membrane |! to |! open... (Na+ |! permeability |! --> |! Na+ |! enters |! cells, |! carrying |! a |! positive |! charge |! --> |! inside |! of |! cell |! gets |! more |! positive |! (increasing |! depolarization) |! --> |! more |! Na+ |! channels |! open |! --> |! REPEATED
- |! shortly |! after |! Na-channels |! open |! --> |! they |! spontaneously |! close |! ('inactivation')
- |! depolarization |! opens |! (slower) |! a |! second |! population |! channels: -voltage-gated |! K |! channels |!
- |! conclusion: the |! inactivation |! of |! voltage-gated |! Na |! channels |! combined |! with |! the |! activity |! of |! voltage-gated |! K-channels |! results |! in |! the |! 'repolarization' |! of |! membrane |! potential |! back |! towards |! the |! resting |! value graded |! potentials: |! - |! Correct |! answer |! ✔-occurs |! in |! dendrites |! and |! cell |! body |! of |! neuron -size |! varies |! with |! strength |! of |! stimulus -generated |! by |! chemically |! and |! mechanically |! gated |! channels two |! types:
- |! inhibitory |! post-synaptic |! potentials |! (IPSP)
- |! excitatory |! post-synaptic |! potentials |! (EPSP) refractory |! periods: |! - |! Correct |! answer |! ✔-periods |! during |! which |! it |! is |! difficult |! or |! impossible |! to |! generate |! a |! second |! action |! potential what |! are |! the |! two |! types |! of |! refractory |! periods? |! - |! Correct |! answer |! ✔1. |! absolute |! refractory |! period
-if |! the |! 'new' |! adjacent |! membrane |! is |! depolarized |! to |! 'threshold' |! it |! starts |! a |! new |! cycle |! of |! action |! potential |! in |! this |! 'new' |! new |! region |! of |! the |! membrane... velocity |! of |! propagation: -two |! factors |! - |! Correct |! answer |! ✔1. |! size |! (diameter |! of |! axon): -bigger |! is |! faster -resistance |! to |! current |! flow |! in |! 'axoplasm' |! decreases |! as |! the |! diameter |! increases
- |! myelination: -certain |! glial |! cells |! (oligodendrocytes |! and |! Schwann |! cells) |! form |! insulting |! layer |! (the |! sheath) |! around |! axons saltatory |! conduction: -has |! myelin |! sheath -has |! node |! of |! Ranvier |! - |! Correct |! answer |! ✔1. |! Na |! channels |! at |! node |! open
- |! electrotonic |! conduction
- |! channels |! at |! next |! node |! open
- |! electronic |! conduction |!
- |! next |! node |! begins |! to |! activate |! (channels |! are |! refractory) continuous |! conduction: -no |! myelin |!
-unmeylinated |! axons |! - |! Correct |! answer |! ✔-this |! process |! involves |! the |! sequential |! opening |! of |! voltage |! gated |! Na+ |! and |! K+ |! channels |! located |! within |! the |! axon |! membrane |! along |! the |! entire |! length |! of |! the |! axon |! to |! propagate |! an |! impulse de-myelination: |! - |! Correct |! answer |! ✔-disruption |! of |! myelin |! sheath -in |! the |! absence |! of |! myelin |! 'insulation', |! electronic |! conduction |! fails |! to |! reach |! and |! depolarize |! next |! node. |! this |! causes |! the |! action |! potential |! to |! fails |! (because |! Na |! channels |! are |! restricted) -examples: |! multiple |! sclerosis |! (central) |! and |! guillian-barre |! (peripheral) how |! is |! an |! electrical |! signal |! (action |! potential) |! transmitted |! from |! one |! excitable |! cell |! to |! another: |! - |! Correct |! answer |! ✔synaptic |! transmission synaptic |! transmission: |! - |! Correct |! answer |! ✔in |! pre-synaptic |! neuron:
- |! nerve |! impulse
- |! Ca2+ |! enters |! through |! the |! voltage-gated |! Ca2+ |! channel |!
- |! Ca2+ |! enters |! through |! the |! synaptic |! cleft |! to |! bind |! to |! the |! neurotransmitter |! receptor |! to |! open |! the |! ligand-gated |! channel
- |! Na2+ |! passes |! through |! the |! now |! open |! ligand-gated |! channel
- |! ions |! help |! in |! post-synaptic |! neuron:
- |! Na+ |! enters |! post-synaptic |! potential |! (depolarization)
- |! nerve |! impulse
general |! senses: |! - |! Correct |! answer |! ✔-receptors |! distributed |! throughout |! the |! body |! (particularly |! on |! body |! surfaces) -not |! collected |! within |! specialized |! 'sense |! organs' 4 |! types |! of |! general |! senses: |! - |! Correct |! answer |! ✔1. |! pain |! (nociceptors)
- |! temperature |! (thermoreceptors)
- |! touch, |! pressure, |! body |! position |! (mechanoreceptors)
- |! chemical |! stimuli |! (chemoreceptors, |! -O2, |! CO2) somatic |! senses: |! - |! Correct |! answer |! ✔body |! surface -surface |! temperature -touch -pain |! and |! muscle |! soreness visceral |! senses: |! - |! Correct |! answer |! ✔internal |! organs -stomach |! ache -gut |! cramps special |! senses: |! - |! Correct |! answer |! ✔receptors |! congregated |! in |! specialized |! 'sense |! organs' 5 |! types |! of |! special |! senses: |! - |! Correct |! answer |! ✔1. |! smell |! (olfaction): |! nose
- |! taste |! (gustation): |! tongue |!
- |! sight |! (vision): |! eye
- |! balance/equilibrium: |! ear
- |! sound |! (hearing): |! ear specificity |! of |! sensation: |! - |! Correct |! answer |! ✔-regardless |! of |! stimulus |! 'modality', |! all |! sensation |! is |! read |! in |! the |! CNS |! as |! electrical |! signals -we |! can |! discriminate |! between |! different |! types |! of |! stimuli |! because |! different |! receptor |! types |! respond |! preferentially |! to |! different |! stimuli mechanoreceptor: |! - |! Correct |! answer |! ✔a |! mechanoreceptor |! is |! more |! sensitive |! to |! touch |! than |! to |! light photoreceptor: |! - |! Correct |! answer |! ✔a |! photoreceptor |! is |! more |! sensitive |! to |! light |! than |! to |! touch receptive |! field: |! - |! Correct |! answer |! ✔-discrimination |! between |! 2 |! similar |! stimuli |! (ex: |! two |! points |! on |! the |! body |! surface |! and |! two |! sounds |! of |! similar |! pitch) |! is |! dependent |! on |! the |! number |! of |! receptors |! with |! an |! area |! of |! sensory |! surface |! -stimulation |! anywhere |! WITHIN |! the |! receptive |! field |! results |! in |! a |! signal |! from |! the |! same |! sensory |! afferent |! neuron -smaller |! receptive |! fields |! (increased |! density |! of |! receptors) |! permit |! high |! resolution |! discrimination sensory |! transduction: |! - |! Correct |! answer |! ✔interpretation |! of |! afferent |! (sensory) |! input:
olfactory |! receptor |! cell: |! - |! Correct |! answer |! ✔the |! ordanant |! moves |! from |! mucus |! to |! attach |! to |! the |! G |! protein-coupled |! olfactory |! receptor |! which |! causes |! ATP |! and |! cAMP |! to |! come |! out |! and |! open |! the |! Na-channel |! protein |! allowing |! Na+ |! to |! pass |! through |! into |! the |! cytosol |! which |! causes |! depolarizing |! generator |! potential |! and |! then |! depolarizing |! to |! trigger |! action |! potential optics |! of |! the |! eye: |! - |! Correct |! answer |! ✔-light |! rays |! arrive |! from |! an |! object
- |! focused |! onto |! sensory |! surface |! of |! the |! eye: |! retina
- |! focusing |! involves |! 'bending' |! of |! light |! rays: |! refraction |!
- |! refraction |! occurs |! when |! light |! passes |! from |! one |! medium |! (air) |! into |! another |! (water) where |! does |! refraction |! take |! place: |! - |! Correct |! answer |! ✔cornea -most |! refraction |! occurs |! at |! the |! cornea what |! does |! the |! lens |! do? |! - |! Correct |! answer |! ✔critical |! 'fine |! tuning' what |! regulates |! light |! entry? |! - |! Correct |! answer |! ✔the |! iris what |! happens |! to |! the |! pupil |! during |! bright |! light, |! normal |! light, |! and |! dim |! light? |! - |! Correct |! answer |! ✔bright |! light: -pupil |! constricts |! as |! circular |! muscles |! of |! iris |! contract |! (parasympathetic) normal |! light: -pupil |! stays |! the |! same
dim |! light: -pupil |! dilates |! as |! radial |! muscles |! of |! iris |! contract |! (sympathetic) what |! happens |! when |! the |! image |! is |! out |! of |! focus? |! - |! Correct |! answer |! ✔it |! changes |! the |! shape |! of |! the |! lens -the |! lens |! becomes |! more |! round -the |! entering |! angle |! of |! the |! light |! increases -the |! light |! gets |! more |! refracted |! (bent), |! so |! the |! focused |! image |! now |! falls |! onto |! the |! retina ciliary |! muscles |! keep |! tension |! on |! the.... |! - |! Correct |! answer |! ✔suspensory |! ligaments |! -with |! less |! tension |! on |! the |! lens, |! the |! lens |! will |! round |! up common |! defects: |! presbyopia |! - |! Correct |! answer |! ✔-as |! the |! lens |! ages, |! it |! loses |! elasticity. |! even |! when |! tension |! on |! the |! suspensory |! ligaments |! is |! relieved, |! lens |! retains |! its |! elongated |! shape -failure |! to |! 'round |! up' |! means |! the |! image |! of |! close-up |! objects |! cannot |! be |! focused |! on |! the |! retina -loss |! of |! this |! ability |! to |! accommodate |! means |! the |! 'aged' |! eye |! can't |! focus |! on |! close-up |! objects (need |! reading |! glasses) shape |! of |! the |! eye: |! - |! Correct |! answer |! ✔-normal: |! emmetropia |! (no |! visual |! defects)
-about |! 6 |! million |! -center |! of |! retina -macula |! lutea -no |! rods, |! ALL |! cones -fovea: |! smallest |! receptive |! field -less |! sensitive |! to |! light -can |! discriminate |! between |! different |! wavelengths rod |! photoreceptor |! cell: |! - |! Correct |! answer |! ✔-1000 |! discs, |! each |! disc |! contains |! many |! copies -rhodosin |! (light |! receptor): |! rhodopsin |! consists |! of |! opsin |! and |! retinal |! (a |! light |! sensitive |! molecule |! derived |! from |! vitamin |! A) visual |! receptor |! rod: |! - |! Correct |! answer |! ✔-Na+ |! channels |! in |! outer |! segment |! membrane |! (normally |! open) -contains |! integral |! membrane |! protein |! and |! rhodopsin |! -retinal |! absorbs |! photon |! which |! activates |! opsin -opsin |! breaks |! down |! the |! chemical |! messenger |! that |! is |! required |! to |! keep |! the |! Na+ |! channels |! open what |! causes |! cell |! hyper-polarization? |! - |! Correct |! answer |! ✔rhodopsin |! activation |! closes |! sodium |! channels |! which |! leads |! to |! cell |! hyper-polarization in |! the |! dark: |! - |! Correct |! answer |! ✔Na |! channels |! are |! open |! --> |! Na |! enters |! depolarizing |! cell |! (dark |! current) |! --> |! depolarized |! cell |! releases |!
neurotransmitter |! --> |! neurotransmitter |! influences |! underlying |! sensory |! afferent |! --> |! neurotransmitter |! influences |! underlying |! sensory |! afferent in |! the |! light: |! - |! Correct |! answer |! ✔activated |! rhodopsin |! breaks |! down |! cGMP |! --
|! Na+ |! channels |! close |! --> |! dark |! current |! decreases, |! hyper-polarizing |! cell |! (receptor |! potential) |! --> |! less |! neurotransmitter |! is |! released |! --> |! rate |! of |! action |! potential |! production |! is |! altered rod |! phototransduction: |! - |! Correct |! answer |! ✔1. |! light |! photon |! actives |! rhodopsin |!
- |! this |! activates |! an |! enzyme |! that |! breaks |! down |! cyclic |! CMP |! (cGMP)
- |! cGMP-gated |! sodium |! channels |! close |!
- |! the |! rod |! hyper-polarizes |!
- |! glutamate |! release |! is |! reduced external |! (outer) |! ear: |! - |! Correct |! answer |! ✔-auricle -external |! auditory |! canal -eardrum middle |! ear: |! - |! Correct |! answer |! ✔-auditory |! ossicles |! (maleus, |! incus, |! stapes) -auditory |! tube inner |! ear: |! - |! Correct |! answer |! ✔-semicircular |! ducts |! (equilibrium |! and |! balance) -utricle -saccule |! (gravity |! and |! acceleration)
bending |! stereocilia |! pulls |! open |! the |! gates |! of.... |! - |! Correct |! answer |! ✔ion |! channels summary |! of |! auditory |! transduction: |! - |! Correct |! answer |! ✔1. |! vibration |! of |! basilar |! membrane |! at |! different |! places |! depending |! on |! pitch
- |! movement |! of |! stereocilia |! on |! hair |! cells |!
- |! opening |! of |! mechanically |! gated |! channels |!
- |! movement |! of |! K+ |! into |! hair |! cells |! causes |! depolarization |! (remember, |! endolymph |! outside |! of |! hair |! cells |! is |! high |! in |! K+)
- |! depolarization |! (graded |! receptor |! potential) |! causes |! opening |! of |! Ca++ |! channels |! at |! base |! of |! hair |! cell |!
- |! Ca++ |! triggers |! exocytosis |! of |! neurotransmitter |! and |! depolarization |! of |! underlying |! sensory |! neurons |! in |! VII |! nerve loud |! sound |! damages |! hair |! cells: |! - |! Correct |! answer |! ✔-rustling |! leaves: |! 15 |! dB -whisper: |! 30 |! dB -conversation: |! 60 |! dB -shouting: |! 80 |! dB -US |! workplace |! limit: |! 90 |! dB -headphones: |! > equilibrium/balance: |! - |! Correct |! answer |! ✔semicircular |! ducts |! (within |! canals): -3 |! ducts: |! anterior, |! posterior, |! lateral |! -the |! base |! of |! each |! duct |! is |! enlarged |! to |! form |! a |! compartment: |! ampulla
complex |! 3D |! movements |! of |! head |! can |! be |! coded |! for |! by |! the |! various |! patterns |! of |! action |! potentials |! that |! arise |! from.... |! - |! Correct |! answer |! ✔the |! hair |! cells gravity |! and |! acceleration: |! - |! Correct |! answer |! ✔involve |! patterns |! of |! hair |! cell |! activation |! in |! the |! utricle |! and |! saccule otoliths: |! - |! Correct |! answer |! ✔gravity |! presses |! down |! which |! generates |! receptor |! potentials major |! events |! in |! neurotransmitter |! function: |! - |! Correct |! answer |! ✔1. |! Ach |! released |! from |! synaptic |! vesicle |!
- |! binding |! of |! Ach |! to |! Ach |! receptors |! opens |! cation |! channels
- |! muscle |! action |! potential |! produced
- |! Ach |! is |! broken |! down key |! features |! of |! neuromuscular |! function: |! - |! Correct |! answer |! ✔-action |! potential |! travels |! along |! axon |! of |! motor |! neuron |! to |! the |! pre-synaptic |! terminal |! on |! the |! muscle |! fiber -depolarization |! of |! terminal |! opens |! calcium |! channels |! to |! trigger |! the |! release |! of |! acetylcholine |! (Ach) -Ach |! binds |! to |! nicotinic |! Ach |! receptors |! on |! muscle. |! excess |! is |! destroyed |! by |! acetylcholinesterase -binding |! of |! Ach |! to |! receptors |! opens |! ligand-gated |! sodium |! channel |! to |! cause |! large |! muscle |! depolarization |! (EPSP), |! which |! invariably |! triggers |! muscle |! action |! potential |! in |! a |! healthy |! individual |!
