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Understanding Excitable Cells and Membrane Potentials Study Guide

This guide explains the fundamental concepts of graded potentials in excitable cells. It covers the nature of chemically gated channels, the local and decremental characteristics of graded potentials, and the processes of depolarization and hyperpolarization. The role of the axon hillock in summing graded potentials to trigger action potentials is also detailed. This content is suitable for students and professionals in biology, neuroscience, and physiology.

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Physiology of Excitable Cells and Membrane Potential

Membrane Potential in Excitable Cells

Excitable cells in muscle and nervous tissue utilize membrane potential and electrochemical gradients to facilitate ion movement through protein channels.

  • membrane potential
  • resting membrane potential
  • extracellular fluid
  • intracellular fluid
  • potassium
  • sodium
  • calcium
  • chlorine
  • proteins
  • chemical gradient
  • electrical gradient
  • electrochemical gradient
  • facilitated diffusion
  • protein channels
  • leak channels
  • permeability

Physiology of Excitable Cells

Excitable cells maintain resting membrane potential through the sodium potassium pump and generate electrical changes via graded or action potentials.

  • resting membrane potential
  • sodium potassium pump
  • active transport
  • antiport
  • excitable cells
  • graded potential
  • action potential
  • electrical gradients
  • concentration gradients

Understanding Resting Membrane Potential

The resting membrane potential represents the difference between the inside and outside of a cell, such as a typical neuron.

  • resting membrane potential
  • neuron
  • skeletal muscle
  • smooth muscle
  • cardiac muscle
  • intracellular
  • extracellular fluid
  • voltmeter
  • sodium channels
  • potassium channels

Chemical Gated Channels and Graded Potentials

Mechanisms of Graded Potentials

Chemical gated ion channels produce graded potentials that are local and decremental, causing depolarization or hyperpolarization of the cell membrane.

  • voltage gated channels
  • chemical gated channels
  • graded potentials
  • membrane potential
  • depolarization
  • hyperpolarization
  • sodium gates
  • calcium gates
  • chlorine gates
  • potassium gates
  • local effect
  • decremental effect
  • ligands
  • receptors

Membrane Potential and Excitation

  • membrane potential
  • ion channels
  • voltage gated channels
  • chemical gated channels
  • graded potentials
  • threshold
  • action potential
  • initial segment
  • sodium
  • potassium
  • calcium
  • chlorine

Characteristics of Graded and Voltage Gated Potentials

This content discusses graded potentials, voltage gated ion channels, and the process of repolarization through potassium efflux.

  • graded potentials
  • decremental characteristics
  • voltage gated ion channels
  • voltage gated potassium channel
  • resting membrane potential
  • maximum membrane potential
  • potassium efflux
  • repolarization

Mechanisms of Excitable Cell Membrane Potentials

The movement of sodium and potassium through voltage gated channels facilitates repolarization, hyperpolarization, and the maintenance of resting membrane potential.

  • potassium voltage gate
  • sodium voltage gated channel
  • activation gate
  • inactivation gate
  • resting membrane potential
  • threshold
  • repolarization
  • hyperpolarization
  • depolarize
  • sodium and potassium leak channels
  • graded potentials

Gated Ion Channels in Excitable Cells

Gated Ion Channels in Excitable Cells

Excitable cells utilize protein channels with gates that open in response to electrical, chemical, or mechanical signals.

  • excitable cells
  • chemical gated ion channels
  • voltage gated ion channel
  • mechanical gated ion channel
  • membrane potential
  • stretch receptor
  • resting membrane potential
  • sodium leak channels
  • potassium leak channels
  • sodium potassium pump

Defining and Understanding Action Potentials

Defining Action Potentials in Excitable Cells

An action potential is a brief and temporary change in the membrane potential from resting membrane potential to a more positive value and back to resting, accomplished by voltage gated channels.

  • action potential
  • membrane potential
  • resting membrane potential
  • voltage gated channels
  • excitable cells

Chapter 9 and 10 Muscle Concepts

Muscle Agonist and Antagonist Actions

The instructor discusses muscle roles including agonist and antagonist during specific actions.

  • Agonist
  • Antagonist
  • Muscle action

Ion Movement and Membrane Potential Changes

Membrane Potential and Excitable Cells

Movement of ions across the electrochemical gradient causes changes in membrane potential including hyperpolarization, depolarization, and repolarization.

  • resting membrane potential
  • hyperpolarization
  • depolarization
  • repolarization
  • electrochemical gradient
  • concentration gradient
  • potassium ions
  • sodium ions
  • chlorine channels
  • calcium channels
  • neurons
  • skeletal muscle cells
  • dendrites

Communication and Ion Channels in Excitable Cells

Information flows from dendrites towards the axon terminal in communicating cells using chemical gated ion channels and voltage gated ion channels to create graded potentials.

  • chemical gated ion channels
  • dendrites
  • depolarize
  • graded potential
  • hyperpolarize
  • motor end plate
  • muscle fiber
  • neuromuscular junction
  • voltage gated ion channels

Phases of the Action Potential

Phases of the Action Potential

The movement of membrane potential through graded potentials, rapid depolarization, repolarization, and hyperpolarization phases in excitable cells.

  • resting membrane potential
  • graded potentials
  • threshold
  • sodium voltage gates
  • activation gate
  • inactivation gate
  • rapid depolarization phase
  • sodium influx
  • repolarization phase
  • potassium efflux
  • hyperpolarization phase
  • absolute refractory period

Mechanisms of Action Potential Propagation

The movement of an action potential along a membrane involves voltage gated sodium channels and voltage gated potassium channels to reach maximum membrane potential and return to resting membrane potential.

  • relative refractory period
  • action potential
  • resting membrane potential
  • threshold
  • hyperpolarization
  • graded potentials
  • voltage gated sodium channels
  • activation gate
  • inactivation gate
  • maximum membrane potential
  • voltage gated potassium channels
  • propagation
  • absolute refractory period

Action Potentials and Muscle Contraction

Action potentials pass through voltage sensitive proteins in the T-tubule to trigger calcium release from the sarcoplasmic reticulum for muscle contraction.

  • action potential
  • muscle cell
  • T-tubule
  • sarcolemma
  • membrane potential
  • terminal cisternae
  • sarcoplasmic reticulum
  • voltage sensitive protein
  • mechanical gated ion channel
  • calcium
  • actin
  • thin filament
  • neuromuscular junction
  • acetylcholine
  • motor end plate

Overview of the Muscular System

Overview of the Muscular System

An overview of the muscular system involving muscles, joints, tendons, and the structural differences between skeletal, cardiac, and smooth muscle.

  • agonist
  • antagonist
  • synergist
  • fixator
  • origin
  • insertion
  • skeletal muscle
  • cardiac muscle
  • smooth muscle
  • contractile
  • excitable
  • conductive
  • distensible
  • elastic
  • sarcolemma
  • sarcoplasm
  • sarcoplasmic reticulum
  • T-tubules
  • myofibrils
  • thick filaments

Muscle Contraction and Sliding Filament Mechanism

This content explains how skeletal muscle generates tension through the sliding filament mechanism involving actin, myosin, and regulatory proteins.

  • actin
  • regulatory proteins
  • tropomyosin
  • troponin
  • calcium ions
  • sarcomere
  • A band
  • I band
  • H zone
  • Z disk
  • M line
  • sliding filament mechanism
  • thick filament
  • thin filament

The Sliding Filament Mechanism and Neuromuscular Junction

Neuromuscular Junction and Excitation Contraction Coupling

Events at the neuromuscular junction, excitation of the muscle fiber, and excitation contraction coupling involve acetylcholine, action potentials, and calcium binding to troponin.

  • neuromuscular junction
  • acetylcholine
  • sodium gates
  • graded potentials
  • threshold
  • action potential
  • calcium influx
  • motor end plate
  • excitation of the muscle fiber
  • excitation contraction coupling
  • T-tubule
  • sarcoplasmic reticulum
  • sarcolemma
  • voltage sensitive protein
  • mechanical calcium gate
  • calcium binding to troponin

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