BIOSIGNALS Flashcards
WHAT IS A SIGNAL?
physical quantity that carries information
WHAT IS A NOISE?
unwanted modifications of a signal, carry no information
GIVE SOME EXAMPLES OF BIOSIGNALS.
electrical, magnetic, acoustical, chemical, optical, mechanical, thermal, radiologic
WHAT ARE ACTIVE SIGNALS?
signals generated by the body -> activity of an organism which is the source of energy
-> can be sensed passively
-> many related to electric potentials
ELECTRICAL - ECG, EEG
NON-ELECTRICAL - blood pressure, body temperature, pH, breathing, movements
(measured by electronic transducer)
WHAT ARE PASSIVE SIGNALS?
-interaction between organism and physical / chemical factors
-excitatory loss of molecules after interaction with the body
X-RAY, MRI
HOW ARE BIOSIGNALS MEASURED?
as a function of voltage or current (resistance / capacitance)
-usually as a difference of potentials on the body surface
-> voltmeter, amplifiers, reference electrodes
ECG
ElectroCardioGraphy
-differences in electrical potential on the surface of the skin which arise due to depolarization and repolarization of the cardiac muscle
-electrodes and amplifiers #
-vertical ECG indicates the direction of the propagation of the electrode potential, given by the size and location of individual parts of the heart
-electrical heart axis refers to the general direction of the hearts depolarization wavefront in the frontal plane and is influenced by the anatomical location of the heart
-non invasive tool to diagnose heart abnormalities
-shows heart irritation but not contraction
EEG
ElectroEncephaloGraphy
- electrical activity in the brain
-brains spontaneous electrical activity
-20 to 40 mins
-electrodes on the scalp
- epilepsy, coma, brain death, sleep disorder
-interpretation by wave analysis
-electrode locations and names are specified by the International “10/20” system (relationship between location of electrode and cerebral cortex)
-19 recording electrodes used
-frequencies of 1-30 Hz
EMG
ElectroMyoGraphy
– electric activity of skeletal muscles
EHG
ElectroHysteroGraphy
– electric activity of hystera (uterus)
EOG
ElectroOculoGraphy
– electric activity of eye movements
-resulting signal is called the electrooculogram .
The main applications are in ophthalmological diagnosis and in recording eye movements .
Eye movement measurements: Usually, pairs of electrodes are placed either above and below the eye or to the left and right of the eye.
(If the eye is moved from the central position towards one electrode, this electrode “sees” the positive side of the retina and the opposite electrode “sees” the negative side of the retina.
Consequently, a potential difference occurs between the electrodes. Assuming that the resting potential is constant, the recorded potential is a measure for the eye position
EGG
ElectroGlottoGraphy
-non-invasive measurement of the time variation of the degree of contact between the vibrating vocal folds during voice production
MEG
MagnetoEncephaloGraphy
– electric activity of brain
WHAT TYPE OF ELECRODE IS USED TO ESTABLISH A CONNECTION BETWEEN THE SKIN AND MEASURING DEVICE?
Ag / Cl electrode
WHAT ARE ALPHA WAVES?
frequency range from 8 Hz to 12 Hz
-emerge with closing of the eyes and with relaxation
-attenuates with eye opening or mental exertion
WHAT ARE BETA WAVES?
frequency range from 12 Hz to about 30 Hz
-closely linked to motor behavior and is generally attenuated during active movements
-low amplitude beta with multiple and varying frequencies is often associated with active, busy or anxious thinking and active concentration
-rhythmic beta with a dominant set of frequencies is associated with various pathologies and drug effects especially benzodiazepines
WHAT ARE GAMMA WAVES?
frequency range approximately 30–100 Hz
-represent binding of different populations of neurons together into a network for the purpose of carrying out a certain cognitive or motor function
WHAT ARE DELTA WAVES?
frequency range up to 4 Hz
-slowest waves
-highest in amplitude
-usually seen in adults sleep phase
WHAT ARE THETA WAVES?
frequency range from 4 Hz to 7 Hz
-usually seen in young children
-associated with reports of relaxed, meditative, and creative states
WHAT REPRESENTS BIPOLAR LIMB LEADS?
I, II, III
-record cardiac potentials projection in the FRONTAL PLANE
->when these 3 points are connected we get Einthovens triangle
WHAT DOES BIPOLAR LIMB LEAD I CONNECT?
-right hand and left hand
WHAT DOES BIPOLAR LIMB LEAD II CONNECT?
-right arm and left leg
WHAT DOES BIPOLAR LIMB LEAD III CONNECT?
-left arm and left leg
WHAT ARE THE BIPOLAR LIMB LEADS ALSO CALLED?
Einthoven limb head
WHAT ARE THE UNIPOLAR LIMB LEADS?
aVR, aVL, aVF
-a = augmented
-Goldberger
WHAT ARE THE THORACIC UNIPOLAR LEADS?
V1 = fourth intercostal space to the right of the sternum
V2 = fourth intercostal space to the left of the sternum
V3 = between V2 and V4
(potentials of right side)
V4 = fifth intercostal space in midclavicular line
V5 = fifth intercostal space in the front axillary line
V6 = fifth intercostal space in mid axillary line
(potentials of the left side)
HORIZONTAL PLANE
(WINSONS CENTRAL TERMINAL)
WHAT POTENTIAL DOES aVR GIVE?
difference of voltage between left hand, left leg and right hand
WHAT POTENTIAL DOES aVL GIVE?
difference of voltage between right hand, left leg and left hand
WHAT POTENTIAL DOES aVF GIVE?
difference of voltage between right hand, left hand and left leg
WHAT IS A NORMAL ECG CURVE COMPOSED OF?
P segment, QRS complex and T segment
WHAT DOES THE T WAVE OF AN ECG REPRESENT?
Repolarisation of the heart ventricles
-interval from QRS to apex of T wave reflects the absolute refractory period
-last half of T wave refers to the relative refractory period
WHAT IS THE RANGE OF THE DURATION OF A P WAVE?
0.08s to 0.10s
WHAT DOES THE P WAVE OF AN ECG REPRESENT?
depolarisation of atria
-> SA node to AV node
-> right atrium to left atrium
WHAT IS A GOOD ESTIMATE OF AV NODE FUNCTION?
the PR interval reflects the time the electrical impulse takes to travel from the sinus node
through the AV node and entering the ventricles
WHERE IS THE ACTIVE ELECTRODE OF THE aVR LOCATED?
right hand
WHERE IS THE ACTIVE ELECTRODE OF THE UNIPOLAR PRECORDIAL LEAD V4 LOCATED?
above the 5th intercostal space in the midclavicular line just to the right of the sternum
WHAT IS SYSTOLE?
the process during which blood is ejected from the right ventricle into the pulmonary circulation and blood from the left ventricle is ejected into the systemic circulation
WHAT IS DIASTOLE?
the phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood
WHAT IS MEAN ARTERIAL PRESSURE DEFINED AS?
Average perfusion pressure over a cardiac cycle
WHAT DO THE INTERNODAL PATHWAYS OF THE ELECTRICAL CONDUCTION SYSTEM DO?
Connect the sinoatrial node (SA) with the atrioventricular (AV) inside the myocardium of the right atrium.
WHAT IS THE RESTING MEMBRANE OF CARIOMYOCYTES?
-80 up to -90 mV
WHAT TOOL IS NEEDED FOR THE AUSCULTATORY METHOD OF BLOOD PRESSURE MEASUREMENT?
stethoscope
WHERE IS THE SA NODE LOCATED?
Inside the myocardium of the right atrium
WHAT IS THE RESTING HEART RATE OF A HEALTHY PERSON?
60-80 beats per minute
WHAT ARE THE DEFLECTIONS ABOVE AND BELOW THE ISOELECTRIC POINT REFERRED TO?
above = positive +
below = negative -
WHAT IS THE STANDARD BLOOD PRESSURE OF A HEALTHY PERSON?
approximately 120/80 mmHg
WHAT IS THE MOST OFTEN USED SETTING ON ECG GRAPH?
25mm/s and 10mm/mV
WHAT IS THE HEMODYNAMICAL MANIFESTATION OF THE T WAVE ON AN ECG GRAPH?
heart ventricular diastole
WHAT IS THE HEMODYNAMICAL MANIFESTATION OF THE P WAVE ON AN ECG GRAPH?
heart ventricles systole
WHAT IS THE HEMODYNAMICAL MANIFESTATION OF THE QRS COMPLEX ON AN ECG GRAPH?
Heart atria systole
WHAT DOES THE X AXIS OF AN ECG GRAPH REPRESENT?
Time in sec
WHAT DOES THE Y AXIS OF AN ECG GRAPH REPRESENT?
Potential in mV
WHAT DOES AN ECG REGISTER?
electrical activity of the cardiomyocytes
WHEN CAN SYSTOLIC BLOOD PRESSURE BE READ?
when we hear the first korotkoff sound
WHAT DO WE MONITOR WHILE USING THE PALPIATION METHOD OF BLOOD PRESSURE MEASUREMENT?
aorta abdominalis pulse
WHAT IS THE DURATION OF THE QRS COMPLEX DURING AN ECG?
80-120ms
COLOURS OF ELECTRODE CORRESPONDING TO THE ECG BODY PLACEMENTS
WHICH BODY PART IS USED AS A SUPPORT ELECTRODE IN ECG?
right leg (furthest from heart)
WHAT ARE KOROTKOFF SOUNDS CAUSED BY?
turbulent blood flow in the artery
WHAT DO WE MONITOR WHILE USING THE PALPATATION METHOD OF BLOOD PRESSURE MEASUREMENT?
aorta abdominalis pulse
DURING THE BLOOD PRESSURE MEASUREMENT, THE INFLATABLE CUFF NEEDS TO BE POSITIONED AT THE HEIGTH OF THE HEART IN ORDER TO WHAT?
eliminate hydrostatic pressure
DETERMINISTIC BIOSIGNAL
bio-signals which illustrate the initial conditions
-transitional or stationary
STOCHASTIC BIOSIGNALS
contain a random component
WHAT ARE UNIPOALR CHEST LEADS?
monitor the hearts electrical activity in the horizontal plane
-provide a spatial picture of the cardiac electrical field
-potentials from different electrode to indifferent electrode
WHAT IS THE PR INTERVAL?
-measured from the beginning of the P wave to the beginning of the QRS complex
-> measures time from SA node to AV node to the ventricles
-good for AV node function
-AV -> bundle His -> bundle branches -> Purkinje fibres
-shows as flat line on ECG
WHAT IS THE QRS COMPLEX?
rapid depolarization of the left and right ventricles
-> large muscle mass so larger amplitude than P wave
WHAT IS THE Q-T INTERVAL?
measured from the beginning of the QRS complex to the end of the T wave
-prolonged QT interval is a risk factor for ventricular tachyarrhythmia
-varies with heart rate
-0.35 -0.43 sec
WHAT IS THE U WAVE?
-repolarization of the interventricular septum
-low amplitude or absent
-follows T wave
-too prominent indicates hypokalemia, hypercalcemia or hyperthyroidism
WHAT IS THE U WAVE?
-repolarization of the interventricular septum
-low amplitude or absent
-follows T wave
-too prominent indicates hypokalemia, hypercalcemia or hyperthyroidism
TYPICAL RESTING HEART RATE FREQUENCY?
1 - 1.5 Hz
ECG GRAPH X AXIS
time in seconds
ECG GRAPH Y AXIS
amplitude / potential in mV
WHEN CAN SYSTOLIC BLOOD PRESSURE BE READ?
when we hear the first korotkoff sound
WHAT DO INTERMODAL PATHWAYS OF HEART SYSTEM DO?
connect SA and AV node inside myocardium of right atrium
WHAT IS THE KOROTKOFF SOUND PRODUCED BY?
turbulent blood flow in artery
WHAT DOES A DEFLECTION ABOVE THE ISOELECTRIC LINE MEAN?
positive
ISOELECTRIC LINE
-electrically neutral baseline of an ECG
EEG WAVES
ALPHA = relaxed state
BETA = alert state
DELTA = pathological state
THETA = deep sleep
HOW MANY LEADS DOES A COMPLETE ELECTROCARDIOGRAM HAVE?
12
IS ELECTROPHORESIS A TYPE OF ELECTROTHERAPY?
no
-> galvinisation and ionophoresis are
FROM THE LEFT VENTRICLE
aorta
FROM THE RIGHT VENTRICLE
pulmonary artery
WHEN DOES BLOOD PRESSURE RISE?
quickly during systole
WHAT DOES SYSTOLE INITIATE?
atria contraction
WHAT PRODUCES LUB DUB SOUNDS?
cuspid valves
semilunar valves
WHICH SIDE OF THE HEART HAS OXYGENATED BLOOD?
left side
WHICH SIDE OF THE HEART HAS DEOXYGENATED BLOOD?
right side
WHAT IS THE PRESSURE IN THE AORTA?
16kPa
WHAT IS THE SA NODE ALSO CALLED?
Keith-flacks
60-80/min
WHAT IS THE NODAL RHYTHM OF AV NODE?
30-40/min
WHAT IS THE RESTING POTENTIAL OF HEART?
-80 to -90 mV
WHAT IS THE VOLTAGE OF THE HEART UNDER RESTING CONDITIONS?
-50mV to -100mV
WHAT MUSCLE GENERATES THE LONGEST TYPE OF ACTION POTENTIAL?
cardiac
