Exam 2 Study Guide
Exam 2 Study Guide PGY 451LEC
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This 8 page Study Guide was uploaded by UBnotetaker on Thursday October 15, 2015. The Study Guide belongs to PGY 451LEC at University at Buffalo taught by Baizer, J S in Fall 2015. Since its upload, it has received 68 views. For similar materials see Human Physiology I in Physiology at University at Buffalo.
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Date Created: 10/15/15
Cellular Neurology Membrane Potentials 1 10 11 12 To which electrical gradient does the membrane potential lay Why a Potassium Its weighted conductance is much higher than Chloride s and Sodium s Sodium Channels open to changing charge What causes them to close When do they reopen a Response to transmembrane voltage They are permitted to reopen once the Vm is brought near its resting potential What would happen if Sodium channels of a particular segment of neuron were all activated but in a very slow fashion a There would be no spike because the net sum of activations were not great enough to cause an AP To what extent is a neuron s sodium and potassium stores used in the generation of membrane potential a A relatively low amount of the cell s potassium and sodium go into the generationalteration of membrane potential Can an AP be fired during the refractory period a Yes and No During Absolute Refractory while a large portion of Na channels are still inactivated no AP can be formed However during the Relative Refractory period while some sodium channels are beginning to become ready for new APs and K channels are still active an AP can be generated if the stimulus is large enough What membrane proteins are responsible for active ion transport a The NaK ion pumps How does the Vm of a neuron differ from that of a blood cell A muscle cell a A neuron s Vm is significantly lower than that of a blood cells but still slightly higher than that of a muscle cell s What two membrane proteins are responsible for passive ion transportation a Voltagegated ion channels lingand gated ion channels The components of Aux for Na K C1 and Glucose can be described how a Na K and C1 have both electrical and concentration gradients but Glucose only has a concentration gradient Describe the concentration and electrical gradients for Na K and C1 a Inward concentration and inward electrical for Na Outward concentration and inward electrical for K Inward concentration and outward electrical for C1 If for a particular neuron the absolute refractory is 2ms and relative refractory is an additional 2ms what is the number of APs produced a 250APs A drug is designed to block Sodium channels what would the effect be a No AP could be generated because no Sodium ions can be transmitted to start it this could be used as an anesthetic if the effect is only upon nociceptors but as a poison if on something like cardiac muscle or the neurons supporting the diaphragm 13 Is RMP measured from the insideout or outsidein What directional measurement is indicative of 70 mV a RMP is normally measure from the insideout which measures 70 mV Should the value be 70 mV that would indicate an outsidein measurement 14 What two main factors determine what value a RMP is a The concentration of ions and the relative permeability to those ions 15 What is the evolutionary relationship between Na K and Ca2 voltage gated channels What proves this a They belong to the same family as shown by the same basic structure in terms of 0tsubunits with additional subunits providing selectivity Action Potentials 1 Where does an axon s threshold for AF generation normally lay a 1520 mV above RMP 2 What main three 3 events occur in terms of ion channel activation for an AP a Na channels activate Na channels deactivate K channels activate 3 Why do unmyelinated axons with larger diameters have higher conduction velocities Smaller diameters and lower conduction velocities a The larger diameters lead to a larger length constant meaning signals dissipate much slower A slower dissipation means that the neuron fires APs less frequently and can have a higher CV Likewise a small diameter axon has a slower conduction velocity because its length constant is much shorter so it needs to fire APs more frequently to keep the signal alive 4 By which fundamental principle of CV are Myelinated Axons allowed to have an exceedingly fast CV a The myelin increases the membrane s resistance thus arti cially increasing the Length Constant This increase in Length constant means APs are fired less frequently and can have a higher CV The APs jump between nodes of Ranvier 5 What are the main ergonomic benefits of myelinating axons a There is less of a need to fire APs so energy is preserved Additionally the rate of AP transfer is much quicker because there is fast local transfer of charge between nodes 6 What strength of stimulus will begin to affect AP amplitude a None stimuli strength is encoded in AP frequency 7 What is the main limitation on the frequency of APs a The refractory period However there can be APs generated after the absolute refractory period if the stimulus is strong enough 8 If there are many excitatory stimuli will an AP be generated a If the cumulative effect of the stimuli are greater than the threshold NeuroMuscular Iunctions 1 The neuron synapses on the muscle where specific location and relative location on muscle cell a On the muscle end plate more often near the middle of the cell A powerful FF fast twitch fiber has how many NMJs compared to a much weaker S slow twitch fiber a The same one What is the main neurotransmitter between 0t neurons and muscle cells What does the cause in the receptors of the muscle cells a Ach and it causes an increase in membrane permeability for both Na and K How does the membrane potential of a muscle differ from a neuron when activated by a neurotransmitter a It is a graded potential meaning it depends on the amount of Ach released not all or nothing What is the reliability of the NMJ a There is a very large synaptic potential that is always suprathreshold in a healthy individual Acetylcholine is produce where and from what building blocks How is it sequestered a It is produced in the cytosol and by Cholineacetyltransferase that combines the acetyl group from AcetylCoA to a choline It is sequestered by specialized pumps that utilize a proton gradient within vesicles to pump Ach inside Where does Ach bind on the receptor a Two per receptor and to each of the OL subunits Vesicles that hold Ach can best be described as having what kind of pH Why a Low the excess of protons are used to power secondary pumps for building up Ach in the lumen of the vesicle An animal is given a dose of Curare what is the result a The animal cannot produce viable muscle contractions because the AchR s are blocked from receiving signals from the neurons Synaptic Transmission 1 2 3 Vesicles are held to the membrane via what proteins a TSNARE and VSNARE TSNARES on vesicles VSNARES on membrane What are the main Excitatory Neurotransmitters of the nervous system a Glutamate and Acetylcholine nicotinic What are the main Inhibitory Neurotransmitters of the nervous system a GABA and Glycine What are the main Modulatory Neurotransmitters of the nervous system a GABAB Acetylcholine muscarinic monoamines and glutamate What two main types of channels control ion ow a Ligangated fast neurotransmitters And Modulate slow Neurotransmitters An EPSP is most likely to be caused by which NTs How does this affect Vm a Nicotinic Ach Glutamate Causes an increase in Vm to be closer to an AP An IPSP is most likely to be caused by which NTs a GABA Causes a decrease in Vm to be farther away from an AP 8 Which ion is the primary mover in an EPSP Why a Sodium It is the farthest away from its EX 9 Which ion is the primary mover in an IPSP Why Can it be affected by other ions a Chloride It freely moves with its concentration gradient to hyperpolarize the membrane Potassium can also contribute to an IPSP 10 What two types of information does a neuron use about stimuli to determine whether or not to convert it to an AP What is the difference a Its spatial summation the summation of stimuli strengths from different areas that arrive that the axon hillock at the same time to a suprathreshold event and its temporal summation the summation of stimuli strengths from the same synapse that are in rapid succession 11 A neuron is bombarded with 5 IPSPs and 1 EPSP at the same time will it generate an AP a If the summation of IPSPs and the EPSP is greater than the threshold 12 What three methods does the Nervous system use fore NT clearance a Reuptake by neuron or Galial Degradation via enzyme and diffusion 13 What are the three classes of NTs Where is each synthesized a Small molecule axon terminal peptide neuron soma and gaseous axon terminal via enzymes 14 What is the difference between Ionotropic and Metabotropic receptors a Ionotropic are general ligand gated transmitters metabotropic receptors are GPCRs that cause signal amplification 15 Glutamate ionotropic receptors are interesting in that they require what in order to open a The simultaneous addition of glutamate and an altered membrane potential to cause Mg2 to vacate the channel 16 How is GABA formed a From Glutamate which is formed from Glutamine 17 How is Dopamine formed a From L DOPA which is formed from Tyrosine Signal Transduction 1 A muscle of the eye will have what type of innervation pattern compared to the arm a There will be much less innervation per neuron in order to facilitate more accurate control 2 How do type Ia Interfusal fibers respond to stimuli How is this read in the brain a They re in rapid succession for increasing tension and don t re at all for decreasing tension This provides the brain with dynamic information on muscle stretch 3 What is the firing pattern for type II interfusal fibers What information does this provide the brain a Constant firing with a slightly faster rate for increasing stretch Gives the brain static information on the muscles 4 What three components compose a re ex arc a A afferent limb sensory receptors provide info a central component info processing and a efferent limb motor output 5 How do thermoceptors covert temperature into APs 10 11 12 13 14 15 16 17 18 a Ambient temperature causes activation of TRIP receptors How do surface proteins on hair cell convert sound to APs a Mechanical vibrations of the membrane causes channel proteins to open and close allowing Ca2 through How do sensory neurons in the DRG differentiate between types of stimuli a Certain fibers fire for different effects skin displacement velocity of displacement acceleration What types of mechanoreceptor endings are present in Type 1 fibers Where are they a Meissner s corpuscles Pacinian corpuscles Merkel s disk Ruffmi endings In shallow skin What types of mechanoreceptors endings are present in Type 2 fibers Where are they a Hair and free nerve endings Deep in the skin How do slow adapting mechanoreceptor fibers differ from fast adapting ones What is the effect of this on sensation a The fast adapting ones fire only under stimuli change But slow adapting fire constantly There are drastically smaller receptive fields for Type 1 fibers but much larger ones for type 2 How do cone cells differ from rod cells a They are fewer in number lower in sensitivity and are mostly located in one area fovea What type of chemical pathway is responsible for the transduction of light How do photoreceptors differ from other neurological cells a Modulatory activation of Gprotein complexes for chain reactions Photoreceptors exist in a resting state of depolarization and are only hyperpolarized after rhodopsin is activated by light causing Na channels to be closed by a deficit in cGMP Where is the majority of tasting transduced a Nasal passageways the tongue does a certain amount but the real differences in taste perception are accomplished via olfaction The taste of Umami is activated by what chemical What substance is this associated with a Monosodium Glutamante meat How does each chemical associated with one of the basic tastes lead to an AP a Salty and Acidic compounds can directly affect Vm therefore create APs However Sweet bitter and umami require Gprotein receptors to be activated and lead to a messenger system that causes APs to be produced What is special about olfactory receptor cells which is different from other neurons a They are able to undergo adult neurogenesis and are replaced every 60 days How is a specific smell transduced by olfactory receptor cells a Anything with an odor produces a number of molecules that act upon the nose Each olfactory receptor cell only senses one type of molecule however the net sum of these excitations leads to APs that travel to the brain and are decoded as being a particular smell The odor molecules bind to Gprotein receptors that lead to various changes within the cell which ultimately cause APs The activation of G protein receptors in olfactory receptor cells changes membrane potential in what unique way a Gprotein receptors cause NaCa cationic channels to open and cause a in ux of those ions Ca2 ions cause Chloride channels to become activated and an exodus of those ions leading into further depolarization of the membrane Autonomic Nervous System 1 Which types of muscles would the Autonomic nervous system be most likely to control a Smooth and cardiac 2 How do the Sympathetic Parasympathetic and Enteric Nervous Systems differ a Though both the sympathetic and parasympathetic both innervate smooth muscle cardiac muscles and glands they differ in the extent of neuron divergence sympathetic diverges 110 parasympathetic 13 Separately the Enteric NS innervates only the digestive tract 3 What are the two man types of neurons in the Autonomic NS How are they different a Pre and PostGanglionic Neurons PreGanglionic neurons utilize acetylcholine exclusively for communication PostGanglionic neurons can utilize both acetylcholine in the parasympathetic NS and Norepinephrine in the sympathetic NS 4 How do postganglionic fibers differ in length between Nervous systems Why a The Sympathetic NS has very long postganglionic fibers because they diverge fairly quickly and extensively Parasympathetic NS has very short postganglionic bers because they don t innervate as many organs therefore don t need to diverge as soon 5 What is the collective goal of the sympathetic NS and parasympathetic NS How do they each contribute a Both are designed to maintain a level of homeostasis but the sympathetic NS deals more with system activations and the parasympathetic NS deals with deactivations 6 Contraction in a smooth muscle cell is activated by what three mechanisms a Ionotropic channel activation in turn activating Ca channels metabotropic receptors activate 2O messengers release Ca stores and Y1 receptors cause Ca release by an unknown mechanism 7 Smooth muscles can be caused to relax by what two main mechanisms a NO release causes cGMP formation and Vasoactive intestinal peptide VIP binds to a receptor causing Ca to decrease in the muscle cell Poisons amp Diseases 0 TetrodotoxinSaxitoxin blocks Na channels in neurons and skeletal muscle cells 0 Cocaine Analogs block the Na channels in nociceptors thus preventing APs from being generated 0 Multiple Sclerosis partial demyelination of axons causing errors in signal transmittance o Myasthenia Gravis Autoimmune disorder where antibodies bind to AchR s and cause them to be deactivated Additionally they target the muscle cells for destruction by the immune system Treated with steroids or Thymus removal 0 K channel blockers prevents repolarization thus new APs from forming Ach release Blockers prevents signals from leaving neurons to go to muscles Achesterase blockers prevents Ach breakdown outside of cells AchR blockers prevent muscles from receiving signals from neurons Skeletal muscle Na blockers prevents membrane depolarization for EPPs or muscle APs Axonal Ca2 channel blockers prevents the vesicle from fusing W membrane to relay message Neuronal Na blockers prevents membrane depolarization for APs Pentobarbitol enhances effect of IPSPs Shingles reactivation of Herpes Zoster virus in Dorsal Root Ganglion causes asymmetrically rashes on body that correlate to area innervated by one DRG Function SUBTYPE SPECIFIC FUNCTION WWM internurons of reflex circuit Widely present opens non selective cationic channels in combo w Vm change Primary excitatory NT mm Acetylcholine Nicotinic Muscarinic NMJ Autonomic NS N directly opens ion channels M aids in metabotropic pathways transmitts signal btwn prepost ganglionic cells WM AolrenalineNoraolrenaline M W Inhibitory M Widely present main NS inhibitor W m ll A l will will m Hi In loll l Pentameric l my NH H W My H I VGABA lvwmayprese in N5 inhlbitor I wilulli ilil will quotlei XMetabotropic Glutamate widely ent main NS e xci tor VAK M increases oloen NaCa ion channels for AP generation K xxw M receives photons to initiate conformational changes that transudce light gustation Parasympathetic NS blocks K channels to help depolarize membrane in order to open Ca channels participates in signal receipt from neuron v v MM ChAT Cholineacetvltransferase M produces Ach from AcetvlCoA anol Choline vv Alltl t ll ulli39 quotillliilll39il39llilli open pentameric catio han will ltll PSPs chlor entry llil i llu MA 394 ll il39i llu l L r ill l illl
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