Action Potential revisited When a stimulus reaches threshold level, Sodium channels open up and Sodium rushes into the axon along the concentration gradient.

Slides:

Advertisements

Similar presentations

Objectives Electrophysiology

Advertisements

Nerve Impulses and Reflex Arcs

Section 9.2 Assignment Electrochemical Impulse

Nerves, hormones and homeostasis

6.5 (part 1)The nervous system

The Electrical Nature of Nerves

9.2 Electrochemical Impulse

Chapter 11-Part II Biology 2121

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

Questions 17-1 Q: What happens to a nerve impulse once it reaches the end of an axon? Q: How does one neuron communicate with another?

See also the NOTE GUIDES posted online on the wiki, the online self-quizzes posted on the wiki, and USG pages 6 to 10. Main Content: 1. Sodium Potassium.

David Sadava H. Craig Heller Gordon H. Orians William K. Purves David M. Hillis Biologia.blu C – Il corpo umano Neurons and Nervous Tissue.

Transmission of Nerve Impulses WALT Neurones transmit impulses as a series of electrical signals A neurone has a resting potential of – 70 mV Depolarisation.

Chapter 9.2: Electrochemical Impulse Pages

Chapter 48.  Short distance communication ◦ Synapses between cells  Neurotransmitters.

NERVOUS TISSUE Chapter 44. What Cells Are Unique to the Nervous System? Nervous systems have two categories of cells: Neurons generate and propagate electrical.

Neurons, Synapses and Signaling

MARION COPELAND AND LYNNETTE LACEK FIRST YEAR MEDICAL STUDENTS PENN STATE HERSHEY COLLEGE OF MEDICINE The Action Potential and Neurotransmission.

The Nervous System Neuron –Cell body; Dendrites; Axon Three general groups of neurons –Sensory neurons (afferent or receptor) Receive the initial stimulus.

9.2 Electrochemical Impulses. Nerves impulses are similar to electrical impulses but are slightly slower. They stay the same strength throughout the entire.

9.2 Electrochemical Impulse. Late 18 th Century: Luigi Galvani  leg muscle of dead frog could be made to twitch under electrical stimulation.

Unit 1B: Nerve Impulses and Synapses. Nerve Impulse A neuron’s job is to transmit a message to a muscle, gland, or another neuron The message travels.

11-2. LIGAND OR CHEMICAL GATE Voltage-Gated Channel Example: Na + channel Figure 11.6b.

Action Potential: Resting State Leakage accounts for small movements of Na + and K + Each Na + channel has two voltage-regulated gates.

The Nervous System Nerve Cell Function History Galvani (1759) proposed that nerves work exactly the same way that the wiring in your house. That they.

How neurons communicate ACTION POTENTIALS Researchers have used the axons of squids to study action potentials The axons are large (~1mm) and extend the.

8.2 Structures and Processes of the Nervous System

Presentation title slide

Structures and Processes of the Nervous System – Part 2

November 10, 2015 Journal: What is the difference between dendrites and the axon terminal? After completing today’s journal, hand in all of your journals.

Chapter 17 The nervous system.

Notes XdCrZm_JAp0.

Nerve Impulses.

2 Functional Properties of Neurons 1. Irritability Ability to respond to stimuli 2. Conductivity Ability to transmit an impulse.

The Electrochemical Impulse Action Potential Threshold Level All-or-None Response.

Section 9.2 Page 418 The Electrochemical Impulse.

The Action Potential. Four Signals Within the Neuron  Input signal – occurs at sensor or at points where dendrites are touched by other neurons.  Integration.

NERVE IMPULSE TRANSMISSION  nerve cells are like no other cell in the body because they possess an electrical charge  the axon of a neuron has a cell.

Electrochemical Impulses

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

Do Now 1/9/15 1.Name 3 glial cells and describe their function and location. 2.Which neural pathway transmits a signal when the internal body temperature.

Electrical Properties of the Nervous System Lundy-Ekman, Chapter 2 D. Allen, Ph.D.

Neurons and Synapses 6.5. The Nervous System Composed of cells called neurons. These are typically elongated cells that can carry electrical impulses.

Nervous System Notes Part 4

13.1 Overview of the nervous system

What is the part of the neuron that receives signals? Sends them?

Nerve Signals 11.2 (Image from:

Action Potential Propagation

Nerve cell membrane Electrochemical message is created by the movement of ions across the nerve cell membrane The resting nerve membrane has a electrical.

Electrochemical Impulse

Neuron Function.

Nerve Impulses.

The action potential Section 9.2.

Neurons and Synapses Topic 6.5.

Nervous System Impulse Transmission Saltatory Impulse Transmission

6.5 Nerves, Hormones, and Homeostasis

2 Functional Properties of Neurons

Cell Communication: Neuron.

Effects of Excitatory and Inhibitory Potentials on Action Potentials

Electrochemical Gradient Causing an Action Potential

ELECTROCHEMICAL IMPULSE

Notes Ch. 10c Nervous System 1

Gates + Potentials.

Today you will: Define threshold and use it to explain the all-or-none response Describe a synapse Explain how chemical transmitters aid in transmission.

Action Potential Terms

Action Potential.

Transmission of Nerve Signals

Presentation transcript:

Action Potential revisited When a stimulus reaches threshold level, Sodium channels open up and Sodium rushes into the axon along the concentration gradient. depolarization Once a membrane potential of 40mV is reached, the sodium channels close, and Potassium channels open. This causes a rush of Potassium ions to the outside of the cell, and the cell is repolarized.

The potassium gates close relatively slowly, therefore, hyperpolarization occurs, and the cell is said to be in a refractory period (toilet flushing) The Sodium-Potassium pump moves ions back across the membrane against the concentration gradient, and resting potential is restored. The refractory period helps to ensure that stimulus only flows in one direction.

Neurotransmitters Neurotransmitters are chemicals that alter the membrane potentials of postsynaptic neurons. Acetylcholine is a neurotransmitter found in the end plates of many nerve cells. It acts as an excitatory neurotransmitter on many postsynaptic neurons by opening Sodium ion channels.

What would happen if the sodium channels remained open? The presynaptic neuron releases the enzyme cholinesterase which breaks down acetylcholine, allowing the sodium channels to close, and repolarization to take place. Why is this important to neuron function?

Some neurotransmitters act on the postsynaptic membrane by making the membrane more permeable to Potassium. This causes the cell to go through a state of hyperpolarization. What effect do you think this has on the neuron? These are called inhibitory neurotransmitters. The inhibitory neurotransmitter GABA is the most abundant neurotransmitter in the brain.

Summation refers to multiple presynaptic neurons acting at one time on a postsynaptic neuron. When do you think summation would be necessary? Now, lets look at how different drugs act on the synapse.