Announcements Homework #8 assigned today 4/19/10): FRET, Nerves Due next Monday, 4/26/10 (Last one). Wednesday, 4/21/10: Quiz on reading from ECB, Nerves.

Slides:

Advertisements

Similar presentations

Today: Ion Channels II Ion Channels, particularly voltage driven are what causes nerves to fire, by generate an action potential. [Know the various steps.

Advertisements

Dr. Hammoudi??? Are You Smarter Than Dr. Hammoudi?

Monday April 9, Nervous system and biological electricity II 1. Pre-lecture quiz 2. A review of resting potential and Nernst equation 3. Goldman.

Nerve Impulses and Reflex Arcs

Nerves, hormones and homeostasis

Neurones Dendrites Axon Facilitated diffusion Schwann cells Active transport Myelin Na + /K + pump Synapse.

There are blue molecules on the left red molecules on the right. They are separated by a barrier that is permeable to both blue and red. 1) What happens.

Announcements. Today Review membrane potential What establishes the ion distributions? What confers selective permeability? Ionic basis of membrane potential.

Neurophysiology Opposite electrical charges attract each other

Chapter 3 The Neuronal Membrane at Rest.

Neurophysiology Opposite electrical charges attract each other In case negative and positive charges are separated from each other, their coming together.

General Organization - CNS and PNS - PNS subgroups The basic units- the cells - Neurons - Glial cells Neurophysiology - Resting, graded and action potentials.

7 December 2014 CHANNELS OF THE NEURON: ACTING ON IMPULSE.

Announcements Paper – due on final at 7pm Monday May 6th 8-10 pages double-spaced, NOT including pictures. You must have an introduction which clearly.

Cell Membranes Animal cells have a cell membrane that separates them from the environment Cell membranes are phospholipid bilayers with associated proteins.

Ion Channels are membrane-bound proteins Involved in communication 3 types, voltage, ligand and mechanically-sensitive Nerves: They rely on “batteries”—constant.

The Nervous System.

Learning Objectives Organization of the Nervous System Electrical Signaling Chemical Signaling Networks of Neurons that Convey Sensation Networks for Emotions.

Membrane Potentials All cell membranes are electrically polarized –Unequal distribution of charges –Membrane potential (mV) = difference in charge across.

MEMBRANE POTENTIAL DR. ZAHOOR ALI SHAIKH Lecture

Physiology as the science. Defining of “physiology” notion Physiology is the science about the regularities of organisms‘ vital activity in connection.

Muscle Action Muscle cells are polarized, have charge Excess of Na+ ions in ECF Excess of K+ ions in ICF mixed with PO 4 -3 cause muscle fiber to have.

Active Transport, Transmembrane Proteins, and Neurons AP Biology 2006.

Nervous System Every time you move a muscle & every time you think a thought, your nerve cells are hard at work. They are processing information: receiving.

Physiology as the science. Bioelectrical phenomena in nerve cells

Membrane Transport1 Not responsible for: Nernst Equation, other than to know what it’s used for. Chapter 12 Membrane Transport Questions in this chapter.

Equilibrium Potential E x (where x is an ion) Membrane potential with an electrical driving force equal but opposite to the driving force of the concentration.

How Ion Channels Move to Create Action Potentials.

Nerve Impulse Every time you move a muscle & every time you think a thought, your nerve cells are hard at work. They are processing information: receiving.

28 Sept Announcements Pick up answer sheet for Quiz 2 from front Friday absentees: pick up Quiz 1 & Andro Paper from Piano Read & bring Androstenedione.

1 Membrane Potentials (Polarity) Information found in 2 places: –Chapter 3 - pp –Chapter 9 - pp /22/12 MDufilho.

Biomedical Instrumentation

Bioelectrical phenomena in nervous cells. Measurement of the membrane potential of the nerve fiber using a microelectrode membrane potential membrane.

Membrane Protein Channels

The Action Potential And the synaptic junction Joy Killough Round Rock ISD.

Announcements Homework #8 assigned today 4/19/10, due next Wednesday. Wednesday, 4/21/10: Quiz on reading from ECB, Nerves. This Friday, 4/23/10: .

II. Movement across the Cell Membrane A. Simple Diffusion 1. Movement for high concentration [ ] to low concentration [ ] a. “passive transport” b. no.

PHYSIOLOGY OF THE NERVOUS SYSTEM Neurons are IRRITABLE Ability to respond to a stimulus! (What’s a stimulus?)

Membrane Protein Channels Potassium ions queuing up in the potassium channel Pumps: 1000 s -1 Channels: s -1.

Principles of Bioelectricity. Key Concepts The cell membrane is composed of a phospholipid bilayer The cell membrane may have transport channels (made.

AP Biology Nervous System. AP Biology Essential Knowledge: Animals have nervous systems that detect external and internal signals, transmit.

Afferent Nerves Efferent Nerves cell body: cell body: central part of cell; contains the nucleus axon: axon: long slender extension from cell body; used.

NEUROPHYSIOLOGY. OBJECTIVES: Describe resting membrane potential. Explain how action potentials are generated and propagated along nerves. Explain how.

Central nervous system (CNS)

Definition of terms Potential : The voltage difference between two points. Membrane Potential :The voltage difference between inside and outside of the.

The Resting Membrane Potential

Lecture 1 –Membrane Potentials: Ion Movement - Forces and Measurement

Electrochemical Impulses

Nervous System Notes Part 4

Animal Cell Chromatin.

17 September 2018 Title: Resting potentials

Action Potential Every time you move a muscle & every time you think a thought, your nerve cells are hard at work. They are processing information: receiving.

Do what you can, with what you have, where you are.

Action Potential Propagation

Nerve Impulses.

Events of action potential

Animal Cell Chromatin.

Channels & Transporters

Announcements Homework due Wednesday, 4/16/08.

Neuron Physiology.

Nerve Cell Structure and Function

Neural Condition: Synaptic Transmission

Biology 12 Neuron Function.

Structure and Physiology of Neurons

Animal Cell Cell Membrane.

Do Now: 1. What is 1 of the characteristics of nerve signals that you defined from the “dominos” lab? 2. What is the role of the axon? 3. What creates.

Do Now: 1. What is 1 of the characteristics of nerve signals that you defined from the “dominos” lab? 2. What is the role of the axon? 3. What creates.

Presentation transcript:

Announcements Homework #8 assigned today 4/19/10): FRET, Nerves Due next Monday, 4/26/10 (Last one). Wednesday, 4/21/10: Quiz on reading from ECB, Nerves. This Friday, 4/23/10: your final topic verbal and oral presentation. Include both a write-up and PDF of the research paper. It must be on a totally different topic (technique and biology) than mid-term presentation. I will get back to you by Monday 4/26/10. Final Paper: due evening May 5 th. Final presentation—need two days (3 meetings): Monday May 3 rd, Wednesday May 5 th, night of Wednesday May 5 th., 5pm (okay?) (Pizza included.) Mid-term paper comments back today (Finally). Final Lectures: W, April 21 st ; M April 26 th ; W April 28 th

how many different ion channels? Ans:25-30,000 genes: ,000 genes. One or more polypeptide/ion channel– could get less, or more, ion channels.

Ion Channels 0 mV (Outside) -60 to -100 mV (Inside) closed (polarized) 0 mV (Inside) open (depolarized)

Valium binds to serotonin (ligand) receptor called GABA receptor– relaxes nerves.

Action Potential– Nerves Firing

To close ion channels, to stop wave: 4. Na + spontaneously close 5. K + open  brings membrane potential back down negative.

Gradient set-up by Na/K Transporters [will go over]

V>0 or <0? What causes charge to stop flowing? Membrane permeant to Na + Membrane permeant to K + Membrane permeant to only one ion What is voltage (electrical potential) in each case Given that V ~ -60mV and Na/K are two major ions, which is your membranes permeant to? K+K+ Just a tiny amount of charge causes potential, much less than 15 mM or 150 mM. A sufficiently large force (electrical potential) preventing more ions from going.

What is Boltzmann’s Factor?: exp(E out -E in /kT) Let  = voltage Energy outside? = q  out Zexp(-E i /kT) Probability of being inside/outside? = 0 Energy inside? = q  in e e -

q = ? For Na + ? -59 mV If permeant to only K +, resting potential = +59 mV if permeable only to Na +

Is the Ion Channel Digital or Analog?

Charged amino acids (largely in the voltage sensor) move.

K+ S5 S6 S4 S3 S2 S1

Suggests model where 2 states that differ in energy by qV Where q is about 13e, or 13e/4 per S1-S4 sub-unit; V= -80mV. q is part of channel—gating current, not ionic current!

How does gate spontaneously shut-off? How fast?

Nerve Impulse propagate, not spread, because Na + spontaneously shut-off.

Point mutation in Potassium Gene that affects Potassium Channel

Class evaluation 1.What was the most interesting thing you learned in class today? 2. What are you confused about? 3. Related to today’s subject, what would you like to know more about? 4. Any helpful comments. Answer, and turn in at the end of class.