1. Chapter -The Origin of Bio potentials Anotomy
Unit I
Chapter -The Origin of Bio potentials Anotomy

2. Cell membrane and resting potential
electro-chemical activity and equilibrium, permeability, active a passive transport, channels, osmosis
Excitable cell
neuron: properties, action potential, signal integration, muscle cell
Nervous a muscle excitable tissue
ElectroEncefaloGraphy, ElectroCardioGraphy, ElectroMyoGraphy,
ElectroRetinoGraphy, ElectroOculoGraphy, ElectroHysteroGraphy,
ElectroGasteroGraphy, MagnetoEncefaloGraphy
Another types biosignals
synaptic potentials, unit activity, population response, evoked potentials

3. Cell membrane

4. Na-K pump Vm

5. Membrane Current im
membran current im t
time / ms
distance / mm

6. Cytoplasmic membrane (or plasmalema)
Function:
selective transport between cell and vicinity
contact and mediation of information between cell and vicinity
Structure:
thin semi-permeable cover surrounding the cell
consists from one lipid double-layer and proteins anchored in there
lipid double-layer … gives basic physical features to plasmalema
… on / in: floating or anchored proteins (ion channels)
proteins … anchored in lipid double-layer in different ways
… give biological activity and specificity to plasmalema
glykokalyx … protective cover of some cells formed of oligosacharides, … there are receptors, glykoproteins and other proteoglikans
… protects against chemical and mechanical damage

7. Material transport across the cytoplasmic membrane
Passive transport
Difusion
- free transport of small non-polar molecules across membrane
Membrane channel
- transmembrane protein
transport is possible without additional energy
cell can regulate whether it is open or not (deactivated)
channel is specific for particular molecule
Osmosis
solvent molecules go through semipermeable membrane from low concentration site to the higher concentration site  development of chemical potential
Aktivní transport
cell has to do a work (in form of chemical energy, mostly ATP) for transportation
it’s done by pumps, plasmatic membrane protein anchored in both lipid layers (e.g. Na+-K+-ATPase)
result of ion transport  different ion concentration in/out cell  electric potential
‘Macro’ transport
endocytosis & exocytosis

8. Action Potential = ALL x NOTHING

9. Action Potential

10. Action Potential = opening of sodium and potassium channels

11. Action Potential excitable cell Vm resting potential time
Na+ -channels
K+ -channels
time
resting potential

12. proceeding AP in MUSCLE

13. equivalent Current Dipole

14. Active and Passive Transport 
 chemical (concentration) + electric gradient 
 electro-chemical potential on membrane
!!! Cell INSIDE is NEGATIVE compare to OUTSIDE (in rest usually –75mV)

15. Excitable cell: NEURON
structure:
dendrites with synapses
body
axon with myelin and synapses
function:
thresholding of input signals
integration (temporal and spacial) of input signals
generation of action potentials

16. Synapse

17. Synapse

18. HOW to measure potentials ?
by electrodes - intracellular,
- extracellular,
- superficial
indirectly – by recording of charge spread ... probes (e.g. fluorescence)
FROM WHERE to measure potentials ?
- from whole body, organ, tissue slices, tissue culture, isolated cell

19. Types of biosignals Synaptic potentials –
excitatory pre- / post-synaptic potentials,
inhibitory pre- / post-postsynaptic potentials mostly they don’t cause AP because of weak time and spacial summations
(correlation) … they don’t reach threshold for AP
Unit activity – activity of one neuron, ACTION POTENTIALS
Population response – summary response of neuronal population
APs of thousands of neurons
Evoked potentials – response of sensory pathway to the stimulus 

20. Synaptic potentials
EPSP a IPSP

21. Synaptic potentials

22. Unit activity vs. Population response

23. Evoked potentials
… averaged signal of many cells
… recorded from:
Cerebral cortex
Brainstem
Spinal cord
Peripheral nerves …

24. Excitable cell: NEURON and MUSCLE CELL

25. skeletal muscle – controlled by CNS via moto-neurons
Striated muscles
skeletal muscle – controlled by CNS via moto-neurons
heart muscle - not controlled by CNS
- refractory phase is longer than contraction (systolic) a relaxation (diastolic) time
Smooth muscles – not controlled by CNS, but by autonomic system

26. Heart

27. Heart
Atrial systole
Ventricular systole

28. cardiac dipol added up the local dipols:
Heart
cardiac dipol added up the local dipols:

29. Heart
cardiac cycle

30. cardiac vector field in transverse plane
Heart
cardiac vector field in transverse plane M

31. Heart
cardiac vector field
j =const

32. Heart ElectroCardioGram Change of electric potential
 heart muscle activation
 atrium depolarization
3 diff. recording schemes:
Einthoven, Goldberger, Wilson
Frequency = 1-2 Hz !

33. 2-dimensional recording
Heart
2-dimensional recording

34. Heart
Eindhoven’s triangle

35. Brain ElectroEncefaloGram Waves:
Delta: < 4 Hz ... sleeping, in awakeness pathological
Theta: Hz ... drowsiness in children, pathological in aduls
(hyperventilation, hypnosis, ...)
Alfa: Hz ... relaxation physical / mental
Beta: Hz ... wakefulness, active concentration
Gama: 30–80 Hz …higher mental activity including perception and consciousness

36. Biosignals Recording:
ElectroMyoGraphy – electric activity of skeletal muscles
ElectroRetinoGraphy – electric activity of retina
ElectroOculoGraphy – electric activity of eye movements
ElectroHysteroGraphy – electric activity of hystera (uterus)
ElectroGasteroGraphy – electric activity of stomach
MagnetoEncephaloGraphy – electric activity of brain
...

37. Electroneurogram (ENG)
Recording the field potential of an excited nerve.
Neural field potential is generated by
- Sensory component
- Motor component
Parameters for diagnosing peripheral nerve disorder
Conduction velocity
Latency
Characteristic of field potentials evoked in muscle supplied by the stimulated nerve (temporal dispersion)
Amplitude of field potentials of nerve fibers < extracellular potentials from muscle fibers.

38. Field Potential of Sensory Nerves
Extracellular field response from the sensory nerves of the median or ulnar nerves
To excite the large, rapidly conducting sensory nerve fibers but not small pain fibers or surrounding muscle, apply brief, intense stimulus ( square pulse with amplitude 100-V and duration sec). To prevent artifact signal from muscle movement position the limb in a comfortable posture.
Figure 4.8 Sensory nerve action potentials evoked from median nerve of a healthy subject at elbow and wrist after stimulation of index finger with ring electrodes. The potential at the wrist is triphasic and of much larger magnitude than the delayed potential recorded at the elbow. Considering the median nerve to be of the same size and shape at the elbow as at the wrist, we find that the difference in magnitude and waveshape of the potentials is due to the size of the volume conductor at each location and the radial distance of the measurement point from the neural source.

41. Reflexly Evoked Field Potentials
Some times when a peripheral nerve is stimulated, a two evoked potentials are recorded in the muscle the nerve supplies. The time difference between the two potentials determined by the distance between the stimulus and the muscle.
Stimulated nerve: posterior tibial nerve
Muscle: gastrocnemius