BPK 105 FINAL EXAM PREPARATION TEST
BANK WITH CORRECT ANSWERS
●● What is the purpose of shaving hair, abrading, and applying ethanol
at the skin where an electrode is to be placed?
Answer: The purpose of preparing the skin is to increase electrical
conductivity.
Rubbing the skin with liquid solvents such as ethanol or ether remove
skin oil
Shaving hair exposes skin. Prevents skin hair from preventing direct
contact between the electrode and the skin surface
●● Explain the Difference between "wire" or "patient cable" and "lead"
with respect to electrocardiography.
Answer: The electrodes which measure the electrical activity are
attached to a "patient cable" which are made up of a bundle of wires
These wires transmit the electric signal from the electrode to the
electrocardiograph.
The patient cable is connected to the electrocardiograph, the machine
used to detect, amplify, and display electrical potentials from
depolarization and repolarization in the heart which can be detected at
the surface of the skin
A "lead" is a specific configuration, or combination, of electrodes. Leads
can be placed at various locations and measure the electrical signal being
transmitted to the skin at that particular location.
,Each lead has a positive and negative pole attached to the surface of the
skin, which can then be used to measure the spread of electrical activity
within the heart. Upward deflection on the ECG- is produced when
electrical impulses travel towards a positive electrode.
Difference between the three: wire is a component of the patient cable.
The patient cable is attached to electrodes on the skin measuring
electrical signals. A lead is the configuration of electrodes which can
measure movement of current to determine electrical activity and
direction in the heart
●● How can one record a 12 lead ECG with only 10 electrodes?
Answer: A lead is a view of the electrical activity of the heart from a
particular angle across the body. Think of a lead as a picture of the heart
and the 10 electrodes give you 12 pictures. In other words, a lead is a
picture that is captured by a group of electrodes
12-lead ECG, there are 10 electrodes providing 12 perspectives of the
heart's activity using different angles through two electrical planes —
vertical and horizontal planes.
●● When the positive electrode and the negative electrode are at the
same electrical potential (ex. voltage), does the ECG stylus deflect up,
down, or remain unchanged? Explain.
Answer: When current flows towards the positive electrode, the needle
on the ECG will deflect upwards. When current flows away from the
positive electrode, the needle deflects downwards.
If the positive and negative electrodes are at the same electrical
potential, no current will be created and therefore there will be no
,current movement relative to the positive electrode. The ECG stylus will
remain unchanged?
●● When current flows toward the positive electrode, does the EKG
stylus deflect up, down, or remain unchanged?
Answer: When current flows towards the positive electrode, the needle
on the ECG will deflect upwards. When current flows away from the
positive electrode, the needle deflects downwards.
●● On which of the following - Lead I, Lead II or Lead III - would you
expect the QRS complex to have the highest positive amplitude?
Explain.
Answer: The mean electrical axis of the heart is generally on an angle
from the right shoulder down towards the left hip?
Lead II had a negative electrode at the right wrist and a positive
electrode on the left ankle, creating a similar path as the mean electrical
axis (which can also change)
As the wave of depolarization moves down the interventricular septum
and spreads through the myocardium on the ventricles during ventricular
systole, the QRS complex of the ECG should be largest for Lead II as it
is more in line with the wave of depolarization
●● What is the purpose of the reference electrode in electrocardiography
(and other electrical recordings from the body)?
Answer: A reference electrode improves the quality of the tracing
, Allows the ECG to identify and eliminate "noise" found over a large
region of the body
Once the noise is eliminated, the small electrical potential between two
sites can be detected much more clearly
Also important for reducing electrical signals from the muscles
Often called the ground electrode
Helps prevent electrical shock to the subject or operator
Provides low resistance pathway to earth for current which might reach
the outer case of the ECG machine due to a fault
Procedures where nerves or muscles are electrically stimulated from the
surface, the current from the stimulus travels not only into the tissues but
also across the skin (stimulus artifact)
Stimulus artifact can distort or obliterate the much smaller signal being
recorded from the nerve or muscle unless it is diverted into the lower-
resistance pathway to earth
●● Give three reasons for exercise stress testing.
Answer: 1) to diagnose an abnormal response to exercise denoting
cardiovascular disease
2) to assess the physical tolerance of patients with known cardiovascular
disease
3) to assess the physical fitness of individuals without known
cardiovascular disease
●● What is a PAR-Q, and what is it used for?
BANK WITH CORRECT ANSWERS
●● What is the purpose of shaving hair, abrading, and applying ethanol
at the skin where an electrode is to be placed?
Answer: The purpose of preparing the skin is to increase electrical
conductivity.
Rubbing the skin with liquid solvents such as ethanol or ether remove
skin oil
Shaving hair exposes skin. Prevents skin hair from preventing direct
contact between the electrode and the skin surface
●● Explain the Difference between "wire" or "patient cable" and "lead"
with respect to electrocardiography.
Answer: The electrodes which measure the electrical activity are
attached to a "patient cable" which are made up of a bundle of wires
These wires transmit the electric signal from the electrode to the
electrocardiograph.
The patient cable is connected to the electrocardiograph, the machine
used to detect, amplify, and display electrical potentials from
depolarization and repolarization in the heart which can be detected at
the surface of the skin
A "lead" is a specific configuration, or combination, of electrodes. Leads
can be placed at various locations and measure the electrical signal being
transmitted to the skin at that particular location.
,Each lead has a positive and negative pole attached to the surface of the
skin, which can then be used to measure the spread of electrical activity
within the heart. Upward deflection on the ECG- is produced when
electrical impulses travel towards a positive electrode.
Difference between the three: wire is a component of the patient cable.
The patient cable is attached to electrodes on the skin measuring
electrical signals. A lead is the configuration of electrodes which can
measure movement of current to determine electrical activity and
direction in the heart
●● How can one record a 12 lead ECG with only 10 electrodes?
Answer: A lead is a view of the electrical activity of the heart from a
particular angle across the body. Think of a lead as a picture of the heart
and the 10 electrodes give you 12 pictures. In other words, a lead is a
picture that is captured by a group of electrodes
12-lead ECG, there are 10 electrodes providing 12 perspectives of the
heart's activity using different angles through two electrical planes —
vertical and horizontal planes.
●● When the positive electrode and the negative electrode are at the
same electrical potential (ex. voltage), does the ECG stylus deflect up,
down, or remain unchanged? Explain.
Answer: When current flows towards the positive electrode, the needle
on the ECG will deflect upwards. When current flows away from the
positive electrode, the needle deflects downwards.
If the positive and negative electrodes are at the same electrical
potential, no current will be created and therefore there will be no
,current movement relative to the positive electrode. The ECG stylus will
remain unchanged?
●● When current flows toward the positive electrode, does the EKG
stylus deflect up, down, or remain unchanged?
Answer: When current flows towards the positive electrode, the needle
on the ECG will deflect upwards. When current flows away from the
positive electrode, the needle deflects downwards.
●● On which of the following - Lead I, Lead II or Lead III - would you
expect the QRS complex to have the highest positive amplitude?
Explain.
Answer: The mean electrical axis of the heart is generally on an angle
from the right shoulder down towards the left hip?
Lead II had a negative electrode at the right wrist and a positive
electrode on the left ankle, creating a similar path as the mean electrical
axis (which can also change)
As the wave of depolarization moves down the interventricular septum
and spreads through the myocardium on the ventricles during ventricular
systole, the QRS complex of the ECG should be largest for Lead II as it
is more in line with the wave of depolarization
●● What is the purpose of the reference electrode in electrocardiography
(and other electrical recordings from the body)?
Answer: A reference electrode improves the quality of the tracing
, Allows the ECG to identify and eliminate "noise" found over a large
region of the body
Once the noise is eliminated, the small electrical potential between two
sites can be detected much more clearly
Also important for reducing electrical signals from the muscles
Often called the ground electrode
Helps prevent electrical shock to the subject or operator
Provides low resistance pathway to earth for current which might reach
the outer case of the ECG machine due to a fault
Procedures where nerves or muscles are electrically stimulated from the
surface, the current from the stimulus travels not only into the tissues but
also across the skin (stimulus artifact)
Stimulus artifact can distort or obliterate the much smaller signal being
recorded from the nerve or muscle unless it is diverted into the lower-
resistance pathway to earth
●● Give three reasons for exercise stress testing.
Answer: 1) to diagnose an abnormal response to exercise denoting
cardiovascular disease
2) to assess the physical tolerance of patients with known cardiovascular
disease
3) to assess the physical fitness of individuals without known
cardiovascular disease
●● What is a PAR-Q, and what is it used for?
