Course detail

Biophysics

FEKT-MBFYAcad. year: 2017/2018

Interpretation of bioelectric phenomena. Electrical activity of living tissue on molecular, cellular and organ level. Methods of measurement of membrane voltage and membrane currents in isolated cells, recording of random pulse signals from membrane channels on molecular level. Origin and propagation of impulses of action voltage. Cellular basis of diagnostically significant electromagnetic field generated by organs. Coupling between electrical excitation and muscle contraction. Introduction to biomechanics. Mechanics of cardiovascular system. Introduction to biothermodynamics. Gibbs energy and electrochemical potentials in biophysics. Biophysics of ecosystem.

Learning outcomes of the course unit

Having finished the subject, the student is able:
- applying the known physical laws to explain genesis of membrane voltage in the living cells and to define quantities that appear in the Nernst formula for equilibrium voltages,
- to describe electrical equivalent scheme of the cell,
- to explain origin of action voltages in excitable cells and mechanism of its propagation along cell fibers,
- to describe principles of the methods of measurement of membrane voltage and membrane current,
- to characterize electrical signals recorded on cellular and molecular level and to explain their mutual relations,
- to describe differences between the function of membrane channels and carriers,
- to describe the relation between the propagated excitation at the level of cell and genesis of electromagnetic field in the surrounding tissue,
- to describe origin of ECG signal as a result of action voltage propagation in the net of cardiac cells (syncytium),
- to prepare physiological solutions including measurement and adjustment of their pH, to measure tissue impedance and properties of the electrodes,
- to explain principles of excitation-contraction coupling in muscle cells,
- to apply physical principles to situation in cardiovascular system,
- to define the terms ‘chemical potential’ and ‘electrochemical potential’, and to illustrate their importance in interpretation of bioelectric phenomena,
- to discuss the function of the ecosystem (circulation of substance and flow of energy) from the viewpoint of thermodynamics.

Prerequisites

The subject knowledge on the Bachelor´s degree level is requested.

Co-requisites

Not applicable.

Recommended optional programme components

Not applicable.

Recommended or required reading

J.Šimurda: Bioelektrické jevy I, CERM Brno, 1995 (CS)
Ghista D.N., Van Vollenhoven E., Yang W.J., Reul H., Bleifeld W.: Advances in Cardiovascular Physics, Karger, Basel-Munchen-Paris-London-New York-Tokyo-Sydney,1983 (EN)
Peusner L.: Základy bioenergetiky, Alfa Bratislava, 1984 (CS)
F. Bezanilla: Electrophysiology and the Molecular Basis of Excitability. (University of California at Los Angeles) http://nerve.bsd.uchicago.edu/ (EN)
Weiss,Thomas Fischer: Cellular Biophysics, Massachusetts Institute of Technology,1996 (EN)
R.Plonsey, R.C. Barr: Bioelectricity: A Quantitative Approach. Plenum Press, New York, 1988 (EN)
Biophysics - Wikipedie - the free encyklopedia http://en.wikipedia.org/wiki/Biophysics (EN)
J. Šimurda: Bioelektrické jevy, Elektronická skripta, 2007 (CS)

Planned learning activities and teaching methods

Teaching methods depend on the type of course unit as specified in the article 7 of BUT Rules for Studies and Examinations.

Assesment methods and criteria linked to learning outcomes

Requirements for completion of a course are specified by a regulation issued by the lecturer responsible for the course and updated for every academic year.

Language of instruction

Czech

Work placements

Not applicable.

Course curriculum

A. Bioelectric phenomena
Cellular level
1 Origin and function of electrical signals in living cells (membrane voltage, action voltage in excitable cells, propagation of action voltage, physiological significance of electrical activity)
2 Methods of measurements of membrane voltage and membrane current (electrical contacts with cell interior, technical problems and variants of their solving)
3 Physical bases of bioelectric phenomena:
Resting membrane voltage (model of the cell, electrical equivalent scheme of the cell membrane)
Action voltage (underlying mechanisms, principal components of ionic membrane current, quantitative relation between total ionic current and action voltage configuration, classification of channels from the viewpoint of time and voltage dependence, propagation of action voltage along cellular fibres)
4 Quantitative description of electrical activity of excitable cell (Hodgkin and Huxley equations for squid nerve fibres, solution under current-clamp and voltage-clamp conditions, generalization for other excitable cells, quantitative description of propagation of excitation)
5. Thermodynamic description of bioelectric phenomena (chemical and electrochemical potential, derivation of Nernst equation, Donnan equilibrium, Nernst-Planck equation, constant electrical field model)
Molecular level
6 Membrane ionic channels (biological membrane, structure and function of ionic channels,
gating process, drug-channel interactions, measurements of single channel currents, principle of patch clamp method, characteristics of the current recorded on molecular level)
7 Membrane ion transporting carriers (function, Na/K and Na/Ca exchangers)
Excitation-contraction coupling (ECC) in muscle cell
8 Structure and function of muscle, differences between types of muscle cells
9 Main structural and functional elements of ECC in cardiac cells and signalling role of Ca ions (quantitative description of transmembrane transport of calcium ions, explanation of frequency dependence of contractions )
10 Molecular processes underlying muscle contraction
Tissue and organ level
11 Electromagnetic field as a consequence of action voltage propagation (related clinical diagnostic methods, passive electrical properties of living tissue)
12 Biophysical background of electrocardiography (mechanism and propagation of the wave of excitation in the heart, lead systems, ECG signal, arrhythmias and natural protective mechanisms, equivalent generators of cardiac electrical field)
13 Quantitative description of the electromagnetic field generated by biological sources (application of Maxwell equations, simplifications for cardiac electrical field)

B. Biomechanics
1 Excitation-contraction coupling in muscle cell (principle structural and functional elements in cardiomyocytes, the role of calcium ions as a signal to trigger and control contraction)
2 Molecular processes underlying muscle contraction
3 Structure and function of muscle
4 Mechanics of cardiovascular system (structure and function of cardiovascular system, blood flow in vessel, conditions in aorta, left ventricular work, tension in the wall of vessel, regulation of the circulation)

C. Biothermodynamics
1. Introduction into thermodynamics of the living systems
2. Gibbs’ energy, chemical and electrochemical potential (change of the Gibbs energy in the course of chemical reaction , change of the standard Gibbs energy)
3. Thermodynamic description of bioelectric phenomena (direction of transmembrane ion transport, derivation of the Nernst equation, Donnan equilibrium, Nernst-Planck equation, constant field model of the membrane)
4. Conduction of electrical current in the living tissue (tissue impedance, properties of the electrodes)
5. Fundamental principles of bioenergetics (energy and biological processes, preservation (storage) and retrieval (regaining) of chemical energy, flow of energy in ecosystems)

Aims

The aim is to teach students to apply physical theories and experimental methods to living organisms.

Specification of controlled education, way of implementation and compensation for absences

The content and forms of instruction in the evaluated course are specified by a regulation issued by the lecturer responsible for the course and updated for every academic year.

Classification of course in study plans

  • Programme EEKR-M1 Master's

    branch M1-BEI , 1. year of study, winter semester, 5 credits, theoretical subject

  • Programme EEKR-CZV lifelong learning

    branch ET-CZV , 1. year of study, winter semester, 5 credits, theoretical subject

Type of course unit

 

Laboratory exercise

13 hours, compulsory

Teacher / Lecturer