Action Potential (AP) NEUROEXCITABILITY II-III. Na + and K + Voltage-Gated Channels. Voltage-Gated Channels. Voltage-Gated Channels

Size: px
Start display at page:

Download "Action Potential (AP) NEUROEXCITABILITY II-III. Na + and K + Voltage-Gated Channels. Voltage-Gated Channels. Voltage-Gated Channels"

Transcription

1 NEUROEXCITABILITY IIIII Action Potential (AP) enables longdistance signaling woohoo! shows threshold activation allornone in amplitude conducted without decrement caused by increase in conductance PNS Ch. 8, 9 and K + Once upon a time, two famous scientists figured out that changes in and K + permeability occur during action potentials Since they were so smart, they realized that voltagegated ion must be responsible for the observed currents, dubbed I Na and I K However, these overlap in time and alter V m and K + So, they simply invented the voltage clamp: forces membrane potential to stay put at any command V m via I clamp = I ion (measurable) still react normally to an imposed V m ions still go in and out, but they don t affect V m conductance (g ion ) can be calculated via g = I / V and K + Circuit form: V m = E I Na / g Na membrane potential is determined by battery force and the voltage drop across resistors Ohm s law form: I Na = g Na (V m E Na ) current is determined by conductance (= # open x single channel conductance) and the driving force for flow (no driving force = no flow) Voltage clamp form: g Na = I Na / (V m E Na ) calculated conductance is proportional to measured current (constant driving force set by voltage clamp) and K + Then, they used specific toxins to paralyze one type of channel and analyze the other: tetraethylammonium (TEA) blocks voltagegated K + tetrodotoxin (TTX) blocks voltagegated 1

2 and K + Here is what they discovered: depolarization increases the probability that any single voltagegated channel will open the greater the depolarization, the more voltagegated open the greater the depolarization, the faster they open and K + Furthermore: voltagegated K + are slow and lazy, so they open slowly in response to depolarization, and they stay open as long as the depolarization continues Whereas: voltagegated are quick, so they open as soon as there is depolarization, but they also close right after they open seems fishy VoltageGated Channels It turns out that have an extra gate, causing them to cycle through 3 different states: VoltageGated Channels Resting state (closed) depolarization 2. Activated (open) prolonged depolarization 1. Resting (closed) time 3. Inactivated (closed) activation gate (normal) inactivation gate (extra) VoltageGated Channels Activated state (open) VoltageGated Channels Inactivated state (closed) activation gate (normal) inactivation gate (extra) activation gate (normal) inactivation gate (extra) 2

3 AP Generation Nernst equilibrium potential for : E Na = +55 mv Nernst equilibrium potential for K + : E K = 75 mv Resting membrane potential: V m = 60 mv AP Generation At rest, the only open are membrane leakage, which are permeable to K + : g K >> g Na K + likes to flow out (down its gradient) V m is closer to E K than E Na because the membrane is more permeable to K +, therefore K + dominates at rest AP Generation Suddenly, a depolarization comes along! are the quickest to respond likes to flow in (down its gradient) This inward positive flow starts to counter the outward leaking AP Generation Threshold = potential at which enough are open to dominate the net current: g Na > g K Net inward pos current = further depolarization, causing even more voltagegated to open: g Na >> g K So V m is driven closer to E Na than E K because the membrane is more permeable to, for now Fast Positive Feedback Depolarization Slow Negative Feedback Depolarization time Inward I Na increases Cycle Generates Action Potential open open Inward I Na increases time inactivate Inward I Na ceases + + K + open late Outward I K increases Action Potential Repolarization 3

4 Action Potential Membrane potential (mv) E Na peak 0 thres hold V m E K I Na (in) depolarization Time (ms) I K (out) repolarization recovery hyperpolarization area of depolarization Na Na + Na + + currently how you doin? Local circuit flow of current direction of propagation Na Na + Na + + Na + died out because currently area of depolarization Local circuit flow of current direction of propagation Passive spread of local depolarization is a ratelimiting factor in AP propagation Active regeneration of AP is required to maintain fidelity of signal, i.e. in order to prevent depolarization from dying out Contribute to allornothing AP propagated without decrement (= constant amplitude) To inc conduction time, inc current (I) by dec resistance (R) or dec capacitance (C): I = V/ t and I = V/R and V = Q/C So membrane conduction time ( V/ t) determined by axial resistance (r a ) and membrane capacitance per unit length (c a ) Membrane length constant (lambda, λ) measures efficiency of passive spread: defined as distance at which an injected signal has decayed to 37% of its original amplitude λ = (r m / r a ) Membrane resistance determined by leakage, which is generally constant Inc diameter = dec axial resistance (more influx) Causes inc length constant = inc efficiency 4

5 Membrane time constant (tau, τ) measures rate of passive spread: τ = (r a * c m ) Inc diameter = dec axial resistance Causes dec time constant = inc velocity Inc conduction velocity via inc axon diameter: r a 1 / diameter 2 c m diameter inc diameter = dec axial resistance and inc capacitance, but resistance dominates Net effect is dec τ = (r a * c m ), faster velocity Also inc λ = (r m / r a ), greater efficiency Inc conduction velocity via myelination: inc effective membrane thickness by 100x c m 1 / thickness of plates inc thickness = dec capacitance (by a lot) insulation = inc effective membrane resistance (less opposing leakage out) Net effect is dec τ = (r a * c m ), faster velocity Also inc λ = (r m / r a ), greater efficiency smaller diameter, but myelinated > bigger diameter, but nonmyelinated Myelination causes a proportionally greater increase in conduction velocity than does an equivalent increase in diameter alone In a myelinated neuron, an action potential is initiated upon threshold summation of all synaptic inputs (excitatory and inhibitory) converging on the trigger zone of the axon hillock, which is not myelinated and has a very high density of extra sensitive voltagegated. The resultant inward flow is sufficient to start passive spread down the axon, but not strong enough to depolarize the entire length of the axon (fully discharge the capacitor plates). The signal spreading under the myelin sheath is like being trapped under ice; it needs to come up for air periodically by gaining reinforcement or it will decay exponentially. Hence, the nodes of Ranvier. 5

6 The membrane at the nodes (vs. under sheath) is very rich in voltagegated, causing an intense inward depolarizing current in response to passive depolarization. These jolts provide regular regeneration of the allornone AP, preventing signal decay. Because conduction velocity is so fast beneath the myelin sheath (due to its low c m ), but slows significantly at the nodes of Ranvier (high c m ), the propagated signal appears to be jumping from node to node. This is called saltatory conduction. Channelopathies Concepts not details to review: Diversity of ion (styles of gating, firing) General structures of gene superfamilies Roles of intracellular Ca 2+ Neuron variability in terms of inputs (dendrites) and signaling (ion channel types/distribution) Mutation types that can cause channelopathies Diseases reflecting phenotypic or genotypic variability (myotonia vs. paralysis) Diseases caused by regional specificity of ion (myotonia vs. epilepsy) Heterozygotes in Cl channel dimer mutations GOOD LUCK!!! Ben Kennedy (bck2104@columbia.edu) Jessica Sims (jas2033@columbia.edu) 6

Channels can be activated by ligand-binding (chemical), voltage change, or mechanical changes such as stretch.

Channels can be activated by ligand-binding (chemical), voltage change, or mechanical changes such as stretch. 1. Describe the basic structure of an ion channel. Name 3 ways a channel can be "activated," and describe what occurs upon activation. What are some ways a channel can decide what is allowed to pass through?

More information

Equivalent Circuit Model of the Neuron

Equivalent Circuit Model of the Neuron Generator Potentials, Synaptic Potentials and Action Potentials All Can Be Described by the Equivalent Circuit Model of the Membrane Equivalent Circuit Model of the Neuron PNS, Fig 211 The Nerve (or Muscle)

More information

Nervous Systems: Neuron Structure and Function

Nervous Systems: Neuron Structure and Function Nervous Systems: Neuron Structure and Function Integration An animal needs to function like a coherent organism, not like a loose collection of cells. Integration = refers to processes such as summation

More information

Neural Conduction. biologyaspoetry.com

Neural Conduction. biologyaspoetry.com Neural Conduction biologyaspoetry.com Resting Membrane Potential -70mV A cell s membrane potential is the difference in the electrical potential ( charge) between the inside and outside of the cell. The

More information

Overview Organization: Central Nervous System (CNS) Peripheral Nervous System (PNS) innervate Divisions: a. Afferent

Overview Organization: Central Nervous System (CNS) Peripheral Nervous System (PNS) innervate Divisions: a. Afferent Overview Organization: Central Nervous System (CNS) Brain and spinal cord receives and processes information. Peripheral Nervous System (PNS) Nerve cells that link CNS with organs throughout the body.

More information

BIOL Week 5. Nervous System II. The Membrane Potential. Question : Is the Equilibrium Potential a set number or can it change?

BIOL Week 5. Nervous System II. The Membrane Potential. Question : Is the Equilibrium Potential a set number or can it change? Collin County Community College BIOL 2401 Week 5 Nervous System II 1 The Membrane Potential Question : Is the Equilibrium Potential a set number or can it change? Let s look at the Nernst Equation again.

More information

Physiology Unit 2. MEMBRANE POTENTIALS and SYNAPSES

Physiology Unit 2. MEMBRANE POTENTIALS and SYNAPSES Physiology Unit 2 MEMBRANE POTENTIALS and SYNAPSES Neuron Communication Neurons are stimulated by receptors on dendrites and cell bodies (soma) Ligand gated ion channels GPCR s Neurons stimulate cells

More information

Neurons and Nervous Systems

Neurons and Nervous Systems 34 Neurons and Nervous Systems Concept 34.1 Nervous Systems Consist of Neurons and Glia Nervous systems have two categories of cells: Neurons, or nerve cells, are excitable they generate and transmit electrical

More information

Structure and Measurement of the brain lecture notes

Structure and Measurement of the brain lecture notes Structure and Measurement of the brain lecture notes Marty Sereno 2009/2010!"#$%&'(&#)*%$#&+,'-&.)"/*"&.*)*-'(0&1223 Neurons and Models Lecture 1 Topics Membrane (Nernst) Potential Action potential/voltage-gated

More information

V m = the Value of the Na Battery Plus the Voltage Drop Across g Na. I Na is Isolated By Blocking I K. and g K

V m = the Value of the Na Battery Plus the Voltage Drop Across g Na. I Na is Isolated By Blocking I K. and g K VoltageGated Ion Channels and the Action Potential VoltageGated Ion Channels and the Action Potential jdk3 Principles of Neural Science, chaps 8&9 The Action Potential Generation Conduction VoltageGated

More information

Equivalent Circuit of the Membrane Connected to the Voltage Clamp. I mon. For Large Depolarizations, Both I Na and I K Are Activated

Equivalent Circuit of the Membrane Connected to the Voltage Clamp. I mon. For Large Depolarizations, Both I Na and I K Are Activated VoltageGated Ion Channels and the Action Potential jdk3 Principles of Neural Science, chaps 8&9 VoltageGated Ion Channels and the Action Potential The Action Potential Generation Conduction VoltageGated

More information

Nervous System: Part II How A Neuron Works

Nervous System: Part II How A Neuron Works Nervous System: Part II How A Neuron Works Essential Knowledge Statement 3.E.2 Continued Animals have nervous systems that detect external and internal signals, transmit and integrate information, and

More information

! Depolarization continued. AP Biology. " The final phase of a local action

! Depolarization continued. AP Biology.  The final phase of a local action ! Resting State Resting potential is maintained mainly by non-gated K channels which allow K to diffuse out! Voltage-gated ion K and channels along axon are closed! Depolarization A stimulus causes channels

More information

Control and Integration. Nervous System Organization: Bilateral Symmetric Animals. Nervous System Organization: Radial Symmetric Animals

Control and Integration. Nervous System Organization: Bilateral Symmetric Animals. Nervous System Organization: Radial Symmetric Animals Control and Integration Neurophysiology Chapters 10-12 Nervous system composed of nervous tissue cells designed to conduct electrical impulses rapid communication to specific cells or groups of cells Endocrine

More information

Propagation& Integration: Passive electrical properties

Propagation& Integration: Passive electrical properties Fundamentals of Neuroscience (NSCS 730, Spring 2010) Instructor: Art Riegel; email: Riegel@musc.edu; Room EL 113; time: 9 11 am Office: 416C BSB (792.5444) Propagation& Integration: Passive electrical

More information

Physiology Unit 2. MEMBRANE POTENTIALS and SYNAPSES

Physiology Unit 2. MEMBRANE POTENTIALS and SYNAPSES Physiology Unit 2 MEMBRANE POTENTIALS and SYNAPSES In Physiology Today Ohm s Law I = V/R Ohm s law: the current through a conductor between two points is directly proportional to the voltage across the

More information

Resting Distribution of Ions in Mammalian Neurons. Outside Inside (mm) E ion Permab. K Na Cl

Resting Distribution of Ions in Mammalian Neurons. Outside Inside (mm) E ion Permab. K Na Cl Resting Distribution of Ions in Mammalian Neurons Outside Inside (mm) E ion Permab. K + 5 100-81 1.0 150 15 +62 0.04 Cl - 100 10-62 0.045 V m = -60 mv V m approaches the Equilibrium Potential of the most

More information

Chapter 48 Neurons, Synapses, and Signaling

Chapter 48 Neurons, Synapses, and Signaling Chapter 48 Neurons, Synapses, and Signaling Concept 48.1 Neuron organization and structure reflect function in information transfer Neurons are nerve cells that transfer information within the body Neurons

More information

MEMBRANE POTENTIALS AND ACTION POTENTIALS:

MEMBRANE POTENTIALS AND ACTION POTENTIALS: University of Jordan Faculty of Medicine Department of Physiology & Biochemistry Medical students, 2017/2018 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Review: Membrane physiology

More information

COGNITIVE SCIENCE 107A

COGNITIVE SCIENCE 107A COGNITIVE SCIENCE 107A Electrophysiology: Electrotonic Properties 2 Jaime A. Pineda, Ph.D. The Model Neuron Lab Your PC/CSB115 http://cogsci.ucsd.edu/~pineda/cogs107a/index.html Labs - Electrophysiology

More information

NEURONS, SENSE ORGANS, AND NERVOUS SYSTEMS CHAPTER 34

NEURONS, SENSE ORGANS, AND NERVOUS SYSTEMS CHAPTER 34 NEURONS, SENSE ORGANS, AND NERVOUS SYSTEMS CHAPTER 34 KEY CONCEPTS 34.1 Nervous Systems Are Composed of Neurons and Glial Cells 34.2 Neurons Generate Electric Signals by Controlling Ion Distributions 34.3

More information

2401 : Anatomy/Physiology

2401 : Anatomy/Physiology Dr. Chris Doumen Week 6 2401 : Anatomy/Physiology Action Potentials NeuroPhysiology TextBook Readings Pages 400 through 408 Make use of the figures in your textbook ; a picture is worth a thousand words!

More information

Fundamentals of the Nervous System and Nervous Tissue

Fundamentals of the Nervous System and Nervous Tissue Chapter 11 Part B Fundamentals of the Nervous System and Nervous Tissue Annie Leibovitz/Contact Press Images PowerPoint Lecture Slides prepared by Karen Dunbar Kareiva Ivy Tech Community College 11.4 Membrane

More information

LESSON 2.2 WORKBOOK How do our axons transmit electrical signals?

LESSON 2.2 WORKBOOK How do our axons transmit electrical signals? LESSON 2.2 WORKBOOK How do our axons transmit electrical signals? This lesson introduces you to the action potential, which is the process by which axons signal electrically. In this lesson you will learn

More information

Electrical Signaling. Lecture Outline. Using Ions as Messengers. Potentials in Electrical Signaling

Electrical Signaling. Lecture Outline. Using Ions as Messengers. Potentials in Electrical Signaling Lecture Outline Electrical Signaling Using ions as messengers Potentials in electrical signaling Action Graded Other electrical signaling Gap junctions The neuron Using Ions as Messengers Important things

More information

Neurophysiology. + = Na + - = Cl - Proteins HOW? HOW?

Neurophysiology. + = Na + - = Cl - Proteins HOW? HOW? All animal cells have electric potential differences (voltages) across plasma s only electrically excitable cells can respond with APs Luigi Galvani (1791) Animal electricity Electrical fluid passed through

More information

Nerve Signal Conduction. Resting Potential Action Potential Conduction of Action Potentials

Nerve Signal Conduction. Resting Potential Action Potential Conduction of Action Potentials Nerve Signal Conduction Resting Potential Action Potential Conduction of Action Potentials Resting Potential Resting neurons are always prepared to send a nerve signal. Neuron possesses potential energy

More information

Action Potentials & Nervous System. Bio 219 Napa Valley College Dr. Adam Ross

Action Potentials & Nervous System. Bio 219 Napa Valley College Dr. Adam Ross Action Potentials & Nervous System Bio 219 Napa Valley College Dr. Adam Ross Review: Membrane potentials exist due to unequal distribution of charge across the membrane Concentration gradients drive ion

More information

9 Generation of Action Potential Hodgkin-Huxley Model

9 Generation of Action Potential Hodgkin-Huxley Model 9 Generation of Action Potential Hodgkin-Huxley Model (based on chapter 12, W.W. Lytton, Hodgkin-Huxley Model) 9.1 Passive and active membrane models In the previous lecture we have considered a passive

More information

Lecture 2. Excitability and ionic transport

Lecture 2. Excitability and ionic transport Lecture 2 Excitability and ionic transport Selective membrane permeability: The lipid barrier of the cell membrane and cell membrane transport proteins Chemical compositions of extracellular and intracellular

More information

Rahaf Nasser mohammad khatatbeh

Rahaf Nasser mohammad khatatbeh 7 7... Hiba Abu Hayyeh... Rahaf Nasser mohammad khatatbeh Mohammad khatatbeh Brief introduction about membrane potential The term membrane potential refers to a separation of opposite charges across the

More information

Nervous Tissue. Neurons Electrochemical Gradient Propagation & Transduction Neurotransmitters Temporal & Spatial Summation

Nervous Tissue. Neurons Electrochemical Gradient Propagation & Transduction Neurotransmitters Temporal & Spatial Summation Nervous Tissue Neurons Electrochemical Gradient Propagation & Transduction Neurotransmitters Temporal & Spatial Summation What is the function of nervous tissue? Maintain homeostasis & respond to stimuli

More information

Nervous Tissue. Neurons Neural communication Nervous Systems

Nervous Tissue. Neurons Neural communication Nervous Systems Nervous Tissue Neurons Neural communication Nervous Systems What is the function of nervous tissue? Maintain homeostasis & respond to stimuli Sense & transmit information rapidly, to specific cells and

More information

Νευροφυσιολογία και Αισθήσεις

Νευροφυσιολογία και Αισθήσεις Biomedical Imaging & Applied Optics University of Cyprus Νευροφυσιολογία και Αισθήσεις Διάλεξη 5 Μοντέλο Hodgkin-Huxley (Hodgkin-Huxley Model) Response to Current Injection 2 Hodgin & Huxley Sir Alan Lloyd

More information

Resting Membrane Potential

Resting Membrane Potential Resting Membrane Potential Fig. 12.09a,b Recording of Resting and It is recorded by cathode ray oscilloscope action potentials -70 0 mv + it is negative in polarized (resting, the membrane can be excited)

More information

Supratim Ray

Supratim Ray Supratim Ray sray@cns.iisc.ernet.in Biophysics of Action Potentials Passive Properties neuron as an electrical circuit Passive Signaling cable theory Active properties generation of action potential Techniques

More information

PNS Chapter 7. Membrane Potential / Neural Signal Processing Spring 2017 Prof. Byron Yu

PNS Chapter 7. Membrane Potential / Neural Signal Processing Spring 2017 Prof. Byron Yu PNS Chapter 7 Membrane Potential 18-698 / 42-632 Neural Signal Processing Spring 2017 Prof. Byron Yu Roadmap Introduction to neuroscience Chapter 1 The brain and behavior Chapter 2 Nerve cells and behavior

More information

Introduction to Neural Networks U. Minn. Psy 5038 Spring, 1999 Daniel Kersten. Lecture 2a. The Neuron - overview of structure. From Anderson (1995)

Introduction to Neural Networks U. Minn. Psy 5038 Spring, 1999 Daniel Kersten. Lecture 2a. The Neuron - overview of structure. From Anderson (1995) Introduction to Neural Networks U. Minn. Psy 5038 Spring, 1999 Daniel Kersten Lecture 2a The Neuron - overview of structure From Anderson (1995) 2 Lect_2a_Mathematica.nb Basic Structure Information flow:

More information

Nervous System Organization

Nervous System Organization The Nervous System Chapter 44 Nervous System Organization All animals must be able to respond to environmental stimuli -Sensory receptors = Detect stimulus -Motor effectors = Respond to it -The nervous

More information

Ionic basis of the resting membrane potential. Foundations in Neuroscience I, Oct

Ionic basis of the resting membrane potential. Foundations in Neuroscience I, Oct Ionic basis of the resting membrane potential Foundations in Neuroscience I, Oct 3 2017 The next 4 lectures... - The resting membrane potential (today) - The action potential - The neural mechanisms behind

More information

Peripheral Nerve II. Amelyn Ramos Rafael, MD. Anatomical considerations

Peripheral Nerve II. Amelyn Ramos Rafael, MD. Anatomical considerations Peripheral Nerve II Amelyn Ramos Rafael, MD Anatomical considerations 1 Physiologic properties of the nerve Irritability of the nerve A stimulus applied on the nerve causes the production of a nerve impulse,

More information

لجنة الطب البشري رؤية تنير دروب تميزكم

لجنة الطب البشري رؤية تنير دروب تميزكم 1) Hyperpolarization phase of the action potential: a. is due to the opening of voltage-gated Cl channels. b. is due to prolonged opening of voltage-gated K + channels. c. is due to closure of the Na +

More information

Ch 7. The Nervous System 7.1 & 7.2

Ch 7. The Nervous System 7.1 & 7.2 Ch 7 The Nervous System 7.1 & 7.2 SLOs Describe the different types of neurons and supporting cells, and identify their functions. Identify the myelin sheath and describe how it is formed in the CNS and

More information

ACTION POTENTIAL. Dr. Ayisha Qureshi Professor MBBS, MPhil

ACTION POTENTIAL. Dr. Ayisha Qureshi Professor MBBS, MPhil ACTION POTENTIAL Dr. Ayisha Qureshi Professor MBBS, MPhil DEFINITIONS: Stimulus: A stimulus is an external force or event which when applied to an excitable tissue produces a characteristic response. Subthreshold

More information

Lecture 10 : Neuronal Dynamics. Eileen Nugent

Lecture 10 : Neuronal Dynamics. Eileen Nugent Lecture 10 : Neuronal Dynamics Eileen Nugent Origin of the Cells Resting Membrane Potential: Nernst Equation, Donnan Equilbrium Action Potentials in the Nervous System Equivalent Electrical Circuits and

More information

The Neuron - F. Fig. 45.3

The Neuron - F. Fig. 45.3 excite.org(anism): Electrical Signaling The Neuron - F. Fig. 45.3 Today s lecture we ll use clickers Review today 11:30-1:00 in 2242 HJ Patterson Electrical signals Dendrites: graded post-synaptic potentials

More information

Neurons. The Molecular Basis of their Electrical Excitability

Neurons. The Molecular Basis of their Electrical Excitability Neurons The Molecular Basis of their Electrical Excitability Viva La Complexity! Consider, The human brain contains >10 11 neurons! Each neuron makes 10 3 (average) synaptic contacts on up to 10 3 other

More information

Information processing. Divisions of nervous system. Neuron structure and function Synapse. Neurons, synapses, and signaling 11/3/2017

Information processing. Divisions of nervous system. Neuron structure and function Synapse. Neurons, synapses, and signaling 11/3/2017 Neurons, synapses, and signaling Chapter 48 Information processing Divisions of nervous system Central nervous system (CNS) Brain and a nerve cord Integration center Peripheral nervous system (PNS) Nerves

More information

Neuron Func?on. Principles of Electricity. Defini?ons 2/6/15

Neuron Func?on. Principles of Electricity. Defini?ons 2/6/15 Neuron Func?on 11 Fundamentals of the Nervous System and Nervous Tissue: Part B Neurons are highly Respond to adequate s?mulus by genera?ng an ac?on poten?al (nerve impulse) Impulse is always the regardless

More information

Basic elements of neuroelectronics -- membranes -- ion channels -- wiring

Basic elements of neuroelectronics -- membranes -- ion channels -- wiring Computing in carbon Basic elements of neuroelectronics -- membranes -- ion channels -- wiring Elementary neuron models -- conductance based -- modelers alternatives Wires -- signal propagation -- processing

More information

Neurons: Cellular and Network Properties HUMAN PHYSIOLOGY POWERPOINT

Neurons: Cellular and Network Properties HUMAN PHYSIOLOGY POWERPOINT POWERPOINT LECTURE SLIDE PRESENTATION by LYNN CIALDELLA, MA, MBA, The University of Texas at Austin Additional text by J Padilla exclusively for physiology at ECC UNIT 2 8 Neurons: PART A Cellular and

More information

9.01 Introduction to Neuroscience Fall 2007

9.01 Introduction to Neuroscience Fall 2007 MIT OpenCourseWare http://ocw.mit.edu 9.01 Introduction to Neuroscience Fall 2007 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. 9.01 Recitation (R02)

More information

Neurons, Synapses, and Signaling

Neurons, Synapses, and Signaling Chapter 48 Neurons, Synapses, and Signaling PowerPoint Lectures for Biology, Eighth Edition Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp and Janette Lewis Copyright

More information

BIOLOGY 11/10/2016. Neurons, Synapses, and Signaling. Concept 48.1: Neuron organization and structure reflect function in information transfer

BIOLOGY 11/10/2016. Neurons, Synapses, and Signaling. Concept 48.1: Neuron organization and structure reflect function in information transfer 48 Neurons, Synapses, and Signaling CAMPBELL BIOLOGY TENTH EDITION Reece Urry Cain Wasserman Minorsky Jackson Lecture Presentation by Nicole Tunbridge and Kathleen Fitzpatrick Concept 48.1: Neuron organization

More information

Chapter 9. Nerve Signals and Homeostasis

Chapter 9. Nerve Signals and Homeostasis Chapter 9 Nerve Signals and Homeostasis A neuron is a specialized nerve cell that is the functional unit of the nervous system. Neural signaling communication by neurons is the process by which an animal

More information

Chapter 37 Active Reading Guide Neurons, Synapses, and Signaling

Chapter 37 Active Reading Guide Neurons, Synapses, and Signaling Name: AP Biology Mr. Croft Section 1 1. What is a neuron? Chapter 37 Active Reading Guide Neurons, Synapses, and Signaling 2. Neurons can be placed into three groups, based on their location and function.

More information

Neurons, Synapses, and Signaling

Neurons, Synapses, and Signaling Chapter 48 Neurons, Synapses, and Signaling PowerPoint Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions

More information

What are neurons for?

What are neurons for? 5 th & 6 th Lectures Mon 26 & Wed 28 Jan 2009 Vertebrate Physiology ECOL 437 (MCB/VetSci 437) Univ. of Arizona, spring 2009 Kevin Bonine & Kevin Oh 1. Finish Solutes Water 2. Neurons Neurons Chapter 11

More information

BIOLOGY. 1. Overview of Neurons 11/3/2014. Neurons, Synapses, and Signaling. Communication in Neurons

BIOLOGY. 1. Overview of Neurons 11/3/2014. Neurons, Synapses, and Signaling. Communication in Neurons CAMPBELL BIOLOGY TENTH EDITION 48 Reece Urry Cain Wasserman Minorsky Jackson Neurons, Synapses, and Signaling Lecture Presentation by Nicole Tunbridge and Kathleen Fitzpatrick 1. Overview of Neurons Communication

More information

STUDIES OF CHANGING MEMBRANE POTENTIAL * : 1. BASIC ELECTRICAL THEORY, 2. GRADED AND ACTION POTENTIALS 3. THE VOLTAGE CLAMP AND MEMBRANE POTENTIALS

STUDIES OF CHANGING MEMBRANE POTENTIAL * : 1. BASIC ELECTRICAL THEORY, 2. GRADED AND ACTION POTENTIALS 3. THE VOLTAGE CLAMP AND MEMBRANE POTENTIALS STUDIES OF CHANGING MEMBRANE POTENTIAL * : 1. BASIC ELECTRICAL THEORY, 2. GRADED AND ACTION POTENTIALS 3. THE VOLTAGE CLAMP AND MEMBRANE POTENTIALS I. INTRODUCTION A. So far we have only considered the

More information

Action potentials. Conductances channels

Action potentials. Conductances channels Action potentials Conductances channels Cole and Curtis AC Wheatstone bridge resistance decreased during action potential R1 & R2 divide one path, Rv (variable) and Ru divide the other Galvanometer between

More information

Housekeeping, 26 January 2009

Housekeeping, 26 January 2009 5 th & 6 th Lectures Mon 26 & Wed 28 Jan 2009 Vertebrate Physiology ECOL 437 (MCB/VetSci 437) Univ. of Arizona, spring 2009 Neurons Chapter 11 Kevin Bonine & Kevin Oh 1. Finish Solutes + Water 2. Neurons

More information

Neurons. 5 th & 6 th Lectures Mon 26 & Wed 28 Jan Finish Solutes + Water. 2. Neurons. Chapter 11

Neurons. 5 th & 6 th Lectures Mon 26 & Wed 28 Jan Finish Solutes + Water. 2. Neurons. Chapter 11 5 th & 6 th Lectures Mon 26 & Wed 28 Jan 2009 Vertebrate Physiology ECOL 437 (MCB/VetSci 437) Univ. of Arizona, spring 2009 Neurons Chapter 11 Kevin Bonine & Kevin Oh 1. Finish Solutes + Water 2. Neurons

More information

QUESTION? Communication between neurons depends on the cell membrane. Why is this so?? Consider the structure of the membrane.

QUESTION? Communication between neurons depends on the cell membrane. Why is this so?? Consider the structure of the membrane. QUESTION? Communication between neurons depends on the cell membrane Why is this so?? Consider the structure of the membrane. ECF ICF Possible ANSWERS?? Membrane Ion Channels and Receptors: neuron membranes

More information

Voltage-clamp and Hodgkin-Huxley models

Voltage-clamp and Hodgkin-Huxley models Voltage-clamp and Hodgkin-Huxley models Read: Hille, Chapters 2-5 (best) Koch, Chapters 6, 8, 9 See also Clay, J. Neurophysiol. 80:903-913 (1998) (for a recent version of the HH squid axon model) Rothman

More information

BIOELECTRIC PHENOMENA

BIOELECTRIC PHENOMENA Chapter 11 BIOELECTRIC PHENOMENA 11.3 NEURONS 11.3.1 Membrane Potentials Resting Potential by separation of charge due to the selective permeability of the membrane to ions From C v= Q, where v=60mv and

More information

Phys 102 Lecture 9 RC circuits

Phys 102 Lecture 9 RC circuits Phys 102 Lecture 9 RC circuits 1 Recall from last time... We solved various circuits with resistors and batteries (also capacitors and batteries) ε R 1 R 2 R 3 R 1 ε 1 ε 2 R 3 What about circuits that

More information

CELL BIOLOGY - CLUTCH CH. 9 - TRANSPORT ACROSS MEMBRANES.

CELL BIOLOGY - CLUTCH CH. 9 - TRANSPORT ACROSS MEMBRANES. !! www.clutchprep.com K + K + K + K + CELL BIOLOGY - CLUTCH CONCEPT: PRINCIPLES OF TRANSMEMBRANE TRANSPORT Membranes and Gradients Cells must be able to communicate across their membrane barriers to materials

More information

UNIT I INTRODUCTION TO ARTIFICIAL NEURAL NETWORK IT 0469 NEURAL NETWORKS

UNIT I INTRODUCTION TO ARTIFICIAL NEURAL NETWORK IT 0469 NEURAL NETWORKS UNIT I INTRODUCTION TO ARTIFICIAL NEURAL NETWORK IT 0469 NEURAL NETWORKS Elementary Neuro Physiology Neuron: A neuron nerve cell is an electricallyexcitable cell that processes and transmits information

More information

Nerves and their impulses. Biology 12 C-11

Nerves and their impulses. Biology 12 C-11 Nerves and their impulses Biology 12 C-11 Nerves and their impulses Nerves are designed to transmit electrical impulses from the dendrites, over the cell body and through the axon. The impulse will then

More information

Nervous System Organization

Nervous System Organization The Nervous System Nervous System Organization Receptors respond to stimuli Sensory receptors detect the stimulus Motor effectors respond to stimulus Nervous system divisions Central nervous system Command

More information

Neurons, Synapses, and Signaling

Neurons, Synapses, and Signaling Chapter 48 Neurons, Synapses, and Signaling PowerPoint Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions

More information

Nervous Lecture Test Questions Set 2

Nervous Lecture Test Questions Set 2 Nervous Lecture Test Questions Set 2 1. The role of chloride in a resting membrane potential: a. creates resting potential b. indirectly causes repolarization c. stabilization of sodium d. it has none,

More information

Passive Membrane Properties

Passive Membrane Properties Passive Membrane Properties Communicating through a leaky garden hose... Topics I Introduction & Electrochemical Gradients Passive Membrane Properties Action Potentials Voltage-Gated Ion Channels Topics

More information

Introduction and the Hodgkin-Huxley Model

Introduction and the Hodgkin-Huxley Model 1 Introduction and the Hodgkin-Huxley Model Richard Bertram Department of Mathematics and Programs in Neuroscience and Molecular Biophysics Florida State University Tallahassee, Florida 32306 Reference:

More information

37 Neurons, Synapses, and Signaling

37 Neurons, Synapses, and Signaling CAMPBELL BIOLOGY IN FOCUS Urry Cain Wasserman Minorsky Jackson Reece 37 Neurons, Synapses, and Signaling Lecture Presentations by Kathleen Fitzpatrick and Nicole Tunbridge Overview: Lines of Communication

More information

9 Generation of Action Potential Hodgkin-Huxley Model

9 Generation of Action Potential Hodgkin-Huxley Model 9 Generation of Action Potential Hodgkin-Huxley Model (based on chapter 2, W.W. Lytton, Hodgkin-Huxley Model) 9. Passive and active membrane models In the previous lecture we have considered a passive

More information

Chapter 3. Voltage- Dependent Membrane Permeability. Overview. Ionic Currents Across Nerve Cell Membranes

Chapter 3. Voltage- Dependent Membrane Permeability. Overview. Ionic Currents Across Nerve Cell Membranes Chapter 3 Overview The action potential, the primary electrical signal generated by nerve cells, reflects changes in membrane permeability to specific ions. Present understanding of these changes in ionic

More information

The Nervous System. Nervous System Organization. Nerve Tissue. Two parts to the nervous system 11/27/2016

The Nervous System. Nervous System Organization. Nerve Tissue. Two parts to the nervous system 11/27/2016 The Nervous System Nervous System Organization Animals must be able to respond to environmental stimuli. Three functions of the nervous system: Sensory input conduction of signals from sensory receptors.

More information

PROPERTY OF ELSEVIER SAMPLE CONTENT - NOT FINAL

PROPERTY OF ELSEVIER SAMPLE CONTENT - NOT FINAL CHAPTER 5 Membrane Potentials and Action Potentials UNIT II Electrical potentials exist across the membranes of virtually all cells of the body. In addition, some cells, such as nerve and muscle cells,

More information

Neurochemistry 1. Nervous system is made of neurons & glia, as well as other cells. Santiago Ramon y Cajal Nobel Prize 1906

Neurochemistry 1. Nervous system is made of neurons & glia, as well as other cells. Santiago Ramon y Cajal Nobel Prize 1906 Neurochemistry 1 Nervous system is made of neurons & glia, as well as other cells. Santiago Ramon y Cajal Nobel Prize 1906 How Many Neurons Do We Have? The human brain contains ~86 billion neurons and

More information

Chapter 2: Neurons and Glia

Chapter 2: Neurons and Glia Chapter 2: Neurons and Glia The Prototypical Neuron The Soma Cytosol: watery fluid inside the cell Organelles: membrane-enclosed structures within the soma Cytoplasm: contents within a cell membrane, e.g.,

More information

2002NSC Human Physiology Semester Summary

2002NSC Human Physiology Semester Summary 2002NSC Human Physiology Semester Summary Griffith University, Nathan Campus Semester 1, 2014 Topics include: - Diffusion, Membranes & Action Potentials - Fundamentals of the Nervous System - Neuroanatomy

More information

Universality of sensory-response systems

Universality of sensory-response systems excite.org(anism): Electrical Signaling Universality of sensory-response systems Three step process: sensation-integration-response Bacterial chemotaxis Madigan et al. Fig. 8.24 Rick Stewart (CBMG) Human

More information

Nervous System AP Biology

Nervous System AP Biology Nervous System 2007-2008 Why do animals need a nervous system? What characteristics do animals need in a nervous system? fast accurate reset quickly Remember Poor think bunny! about the bunny signal direction

More information

Voltage-clamp and Hodgkin-Huxley models

Voltage-clamp and Hodgkin-Huxley models Voltage-clamp and Hodgkin-Huxley models Read: Hille, Chapters 2-5 (best Koch, Chapters 6, 8, 9 See also Hodgkin and Huxley, J. Physiol. 117:500-544 (1952. (the source Clay, J. Neurophysiol. 80:903-913

More information

Membrane Potentials and Action Potentials

Membrane Potentials and Action Potentials C H A P T E R 5 Membrane Potentials and Action Potentials Electrical potentials exist across the membranes of virtually all cells of the body. In addition, some cells, such as nerve and muscle cells, are

More information

Neurons, Synapses, and Signaling

Neurons, Synapses, and Signaling CAMPBELL BIOLOGY IN FOCUS URRY CAIN WASSERMAN MINORSKY REECE 37 Neurons, Synapses, and Signaling Lecture Presentations by Kathleen Fitzpatrick and Nicole Tunbridge, Simon Fraser University SECOND EDITION

More information

Action Potential Propagation

Action Potential Propagation Action Potential Propagation 2 Action Potential is a transient alteration of transmembrane voltage (or membrane potential) across an excitable membrane generated by the activity of voltage-gated ion channels.

More information

NOTES: CH 48 Neurons, Synapses, and Signaling

NOTES: CH 48 Neurons, Synapses, and Signaling NOTES: CH 48 Neurons, Synapses, and Signaling A nervous system has three overlapping functions: 1) SENSORY INPUT: signals from sensory receptors to integration centers 2) INTEGRATION: information from

More information

6.3.4 Action potential

6.3.4 Action potential I ion C m C m dφ dt Figure 6.8: Electrical circuit model of the cell membrane. Normally, cells are net negative inside the cell which results in a non-zero resting membrane potential. The membrane potential

More information

1. Neurons & Action Potentials

1. Neurons & Action Potentials Lecture 6, 30 Jan 2008 Vertebrate Physiology ECOL 437 (MCB/VetSci 437) Univ. of Arizona, spring 2008 Kevin Bonine & Kevin Oh 1. Intro Nervous System Fxn (slides 32-60 from Mon 28 Jan; Ch10) 2. Neurons

More information

Dendrites - receives information from other neuron cells - input receivers.

Dendrites - receives information from other neuron cells - input receivers. The Nerve Tissue Neuron - the nerve cell Dendrites - receives information from other neuron cells - input receivers. Cell body - includes usual parts of the organelles of a cell (nucleus, mitochondria)

More information

CELLULAR NEUROPHYSIOLOGY CONSTANCE HAMMOND

CELLULAR NEUROPHYSIOLOGY CONSTANCE HAMMOND CELLULAR NEUROPHYSIOLOGY CONSTANCE HAMMOND Chapter 1 Zoom in on Patch configurations In the jargon of electrophysiologists, a patch is a piece of neuronal membrane. Researchers invented a technique known

More information

Neurophysiology. Danil Hammoudi.MD

Neurophysiology. Danil Hammoudi.MD Neurophysiology Danil Hammoudi.MD ACTION POTENTIAL An action potential is a wave of electrical discharge that travels along the membrane of a cell. Action potentials are an essential feature of animal

More information

The Nervous System and the Sodium-Potassium Pump

The Nervous System and the Sodium-Potassium Pump The Nervous System and the Sodium-Potassium Pump 1. Define the following terms: Ion: A Student Activity on Membrane Potentials Cation: Anion: Concentration gradient: Simple diffusion: Sodium-Potassium

More information

Resting membrane potential,

Resting membrane potential, Resting membrane potential Inside of each cell is negative as compared with outer surface: negative resting membrane potential (between -30 and -90 mv) Examination with microelectrode (Filled with KCl

More information

Electrophysiology of the neuron

Electrophysiology of the neuron School of Mathematical Sciences G4TNS Theoretical Neuroscience Electrophysiology of the neuron Electrophysiology is the study of ionic currents and electrical activity in cells and tissues. The work of

More information

Transmission of Nerve Impulses (see Fig , p. 403)

Transmission of Nerve Impulses (see Fig , p. 403) How a nerve impulse works Transmission of Nerve Impulses (see Fig. 12.13, p. 403) 1. At Rest (Polarization) outside of neuron is positively charged compared to inside (sodium ions outside, chloride and

More information

Membrane Potentials, Action Potentials, and Synaptic Transmission. Membrane Potential

Membrane Potentials, Action Potentials, and Synaptic Transmission. Membrane Potential Cl Cl - - + K + K+ K + K Cl - 2/2/15 Membrane Potentials, Action Potentials, and Synaptic Transmission Core Curriculum II Spring 2015 Membrane Potential Example 1: K +, Cl - equally permeant no charge

More information