Concept Map 07 by Sophie Gregoretti https://padlet.com/gregoretti668/wqj7g13y6sv7as3a en-us 2023-10-18 13:09:58 UTC 2023-11-25 19:01:58 UTC hello@padlet.com ion channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753038187 control excitability of neurons: electrical state]]> 2023-10-18 16:32:20 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753038187 key gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753038388 2023-10-18 16:32:28 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753038388 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753038799 blue = lecture]]> 2023-10-18 16:32:43 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753038799 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753039251 green = textbook]]> 2023-10-18 16:32:59 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753039251 voltage-gated ion channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753081745 - ion channels open and close in response to membrane potential
- production of action potentials]]> 2023-10-18 16:56:57 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753081745 ion channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753084850 - selectively permeable of each major physiological ion (Na, Ca, K, Cl)
- channelopathy: human disorder of mutation in protein of ions]]> 2023-10-18 16:58:36 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753084850 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753092182 - spans plasma membrane
- voltage sensor: one of transmembrane helices in an ion channel that detects changes in electrical potential
- pore loop: 2 helical membrane-spanning structure in a channel
- pore is in the center of the assembled channel that allows the ion through, channel is formed by pore loops]]> 2023-10-18 17:02:54 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753092182 Na+ channel gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753105532 - 10 Na+ genes (SCN genes) (VGSC: voltage gated sodium channel protein)
- Na+ rapidly inactivating during an AP
- Na+ can be persistent --> some Na channels that don't inactivate --> target of local anesthetics
>> alterations: epilepsy, GEFS+, Dravet Syndrome, West Syndrome, familiar hemiplegic migraine, familial autism, febrile seizure, Lennox-Gastaut]]> 2023-10-18 17:11:27 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753105532 VGSC & Dravet syndrome: gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753109032 - intractable epilepsy that begins in infancy
- life long condition
- 1 in 16,000 to 21,000
- children experience seizures, developmental delays, motor impairment
- 20% mortality by the second year of life
- most due to mutation in SCN1A]]> 2023-10-18 17:13:47 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753109032 Ca2+ channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753115848 - Ca2+ channels give rise to AP, similar to Na+ channels
- Ca2+ regulate intracellular Ca2+, controlling signaling pathways
- regulates release of neurotransmitters at presynaptic neuron
- at least 10 Ca2+ channel genes (CACNa genes)]]> 2023-10-18 17:18:13 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753115848 K+ channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753123755 - most diverse type of channel
- 100+ K+ channel genes
- varying rates of inactivation that effect AP
>> alterations: Episodic ataxia, types of seizures]]> 2023-10-18 17:23:11 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753123755 Cl- channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753126975 - in every type of neuron
- contols excitability of the neuron
- regulates pH, volume homeostasis, organic solute transport, cell migration, cell proliferation, and differentiation
- 13 genes for Cl- channels]]> 2023-10-18 17:25:15 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753126975 ligand gated channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753128841 - respond to chemical signal rather than membrane potential
- neurotransmitter bind them
- on cell surface AND organelle membranes
- essential for synaptic transmission and signaling cascades
- sub-class of channels that respond to intercellular ligands]]> 2023-10-18 17:26:20 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753128841 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753144587 2023-10-18 17:34:42 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753144587 stretch and heat channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753148108 - respond to heat or membrane deformation (stretch)]]> 2023-10-18 17:36:52 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753148108 TRP channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753150077 - transient receptor potential
- pain and temperature sensation
- heat channels are specialized to detect specific temperature ranges]]> 2023-10-18 17:38:00 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753150077 stretch receptors gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753151258 - respond to mechanical distortions like at NMJ (neuro muscular junction) or in the ear (hair cells)]]> 2023-10-18 17:38:39 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753151258 ion channel function gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753170485 - ions move through the channel by electrochemical gradients to attract the ion in and out of the neuron]]> 2023-10-18 17:50:33 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753170485 1. selectivity filter gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753175161 - voltage sensor: narrowest region of an ion channel pore interacts with permeating ions to ensure it passes through the channel
- highly conserved

factors that contribute to movement through the pore:
- size of the ion
- charge of the amino acids in the filter, opposites attract

- only voltage gated channels

]]> 2023-10-18 17:53:36 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753175161 2. functional states of voltage-gated Na+ and K+ channels gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753177756 - ion channels open due to changes in membrane potential --> they are voltage gated]]> 2023-10-18 17:54:44 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753177756 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753178392 2023-10-18 17:55:09 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753178392 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753410229 - during hyperpolarization ( - charged membrane stage), channels are closed
- during depolarization ( + charged membrane stage), channels have an increasing probability of being open]]> 2023-10-18 21:00:46 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753410229 electrophysiology: neuron at rest gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753412906 2023-10-18 21:04:18 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753412906 electricity and electrical stimulation gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753415147 - electricity: flow of electrons from body w higher charge (more electrons) to a body w lower charge (less electrons)
- negative pole: source of electrons
- positive pole: where electrons flow to, lower charge]]> 2023-10-18 21:07:25 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753415147 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753417110 - electrical potential: an electric charge measured in volts, the ability to do work through the use of stored potential electrical energy
- volt: measure of differences in electrical potential
- mV is millivolts which is refering to the charge of the membrane]]> 2023-10-18 21:09:56 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753417110 measuring a neurons electrical activity gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753424372 - giant axons of squids
- Hodgkin and Huxley in 1930s and 1940s]]> 2023-10-18 21:19:23 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753424372 microelectrodes gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753425261 2023-10-18 21:20:32 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753425261 ion & ion flux gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753425975 cations: Na+, K+, Ca2+
anions: Cl-, protein molecules A-]]> 2023-10-18 21:21:37 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753425975 1. diffusion gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753426497 movement of ions from high conc areas to low conc


]]> 2023-10-18 21:22:19 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753426497 2. concentration gradient gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753427613 differences in concentration of substance among regions of a container allowing substance to diffuse from high > low conc]]> 2023-10-18 21:23:46 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753427613 3. voltage gradient gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753428212 difference in charge between two regions
ions move down voltage gradient from high > low charge]]> 2023-10-18 21:24:34 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753428212 membrane potential gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753429441 difference in electrical potential btwn interior and exterior of biological cell]]> 2023-10-18 21:26:04 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753429441 resting potential gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753430498 - higher conc outside the cell: Na+, Cl-
- higher conc inside the cell: K+, A-
- electrical charge across the cell membraine in the absence of stimulation
- store negative energy in the intracellular side relative to extracellular side
>> inside of membrane rests at -70 millivolts relative to extracellular side (-50 to -80 mV)]]> 2023-10-18 21:27:27 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2753430498 maintaining the resting potential gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754650863 - l]]> 2023-10-19 14:00:45 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754650863 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754664409 Na, Ca, Cl are all influx of the ions INTO the cell
K are eflex of the ion OUT of the cell]]> 2023-10-19 14:08:43 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754664409 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754670461 each of the 4 domains have 6 segments
segment 4 of each domain is the voltage sensor, positively charged]]> 2023-10-19 14:11:58 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754670461 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754679956 to predict membrane electrical potential]]> 2023-10-19 14:17:32 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754679956 goldman equation gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754680988 2023-10-19 14:18:10 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754680988 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754728193 need to activate selectively pore AND ball and chain mechanism]]> 2023-10-19 14:45:33 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754728193 use of microelectrodes gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754761126 measure voltage across the membrane
- tip of first microelectrode on outside of an axon
- second microelectrode, used as the reference inserted into the axon

patch clamp:
- microelectrode placed on neuron's membrane, and aply suction until the tipe becomes sealed to a patch of the membrane
- record activity in a small patch of the membrane]]> 2023-10-19 15:04:49 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754761126 concentration gradient gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754771750 2023-10-19 15:11:32 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754771750 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754772950 2023-10-19 15:12:19 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754772950 electrophysiology defn gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754776958 record flow of ions through biological tissue
measure current: strength of current
measure speed of movement]]> 2023-10-19 15:14:55 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754776958 intracellular recording gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754781038 1. voltage clamp
- hold in place the charge of the membrane (voltage), then measure strength of flow (current)
>hold voltage, measure current

2. current clamp: inject current into the cell, then measure change voltage
> hold current, measure voltage]]> 2023-10-19 15:17:48 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2754781038 electrical potential or voltage: gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755154057 how much things could move if they were to be released]]> 2023-10-19 19:58:01 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755154057 current gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755154455 amount of electricity flowing past a point, volume per time]]> 2023-10-19 19:58:27 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755154455 resistance or impedance gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755154986 how narrow channels are for things to flow through]]> 2023-10-19 19:59:04 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755154986 glycerophospholipids gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755156507 main consistent of biological membranes]]> 2023-10-19 20:00:37 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755156507 either open or closed conformation of channel gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755193234 depends on selectivity of pores]]> 2023-10-19 20:42:14 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755193234 gap juntions gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755195331 posts that extend between cells, across one cell to the cytosol of a closely adjacent cell
molecules can go both ways through the junction, molecules have to be a certain size]]> 2023-10-19 20:45:04 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755195331 gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755201425 neurons w the same resting potential, supported by different electrochemical mechanism, have diff levels of excitability]]> 2023-10-19 20:53:36 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755201425 resting potential forces gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755203780 2023-10-19 20:56:19 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755203780 influx v efflux gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755205685 2023-10-19 20:58:59 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755205685 types of ligands = ionotropic receptors gregoretti668 https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755207382 competitive and noncompetitive antagonists]]> 2023-10-19 21:01:01 UTC https://padlet.com/gregoretti668/wqj7g13y6sv7as3a/wish/2755207382