A&P II lab

Question 1

Occurs during relaxation of the ventricles (diastole) and is made by the closure of the semilunar valves. The dupp of “lubb-dupp”

Answer 1

Second heart sound

Question 2

Made by the turbulence of the blood as it fills the ventricles during atrial and ventricular diastole (passive filling) following the opening of the atrioventricular valves.

Answer 2

Third heart sound

Question 3

Made by the turbulence of the blood as it moves from the atria into the ventricles during atria systole (active filling). This occurs right before the ventricles begin to contract and force the atrioventricular valves closed.

Answer 3

Fourth heart sound

Question 4

Zero line or baseline

Answer 4

Isoelectric line

Question 5

Depolarization of the atria; 0.07-0.18s

Answer 5

P wave

Question 6

Extends from the start of the P wave to the start of the QRS complex; depolarization wave travels from SA node to the ventricles; 0.12-0.20s

Answer 6

PR interval

Question 7

Extends from the end of the P wave to the start of the QRS complex; time between depolarization of the atria and depolarization of the ventricles; 0.02-0.10s

Answer 7

PR segment

Question 8

Depolarization of the ventricles and repolarization of the atria

Answer 8

QRS complex

Question 9

Onset of ventricular depolarization to the end of ventricular repolarization; refractory period of the ventricles

Answer 9

QT interval

Question 10

Extends from the end of the S wave and the start of the T wave; ventricles are uniformly depolarized

Answer 10

ST segment

Question 11

Repolarization of the ventricles

Answer 11

T wave

Question 12

Repolarization of the ventricles to atrial depolarization

Answer 12

TP segment

Question 13

Occurs during contraction of the ventricles (systole) and is made by closure of the atrioventricular valves and the opening of the semilunar valves. The lubb part of lubb-dupp

Answer 13

First heart sound

Question 14

In “standard” electrocardiography, cardiac electrical activity is recorded from three perspectives, leads I, II, and III, Why are all 3 perspectives necessary? In other words, what’s the advantage of recording and analyzing all, as opposed to just one?

Answer 14

The heart is a 3 dimensional structure and its electrical activity is also in 3 dimensions. Each lead looks at the heart from a different perspective determined by the placement of the leads electrodes. Thus each lead is sensitive to a particular region of the heart in expense of the others.

Question 15

The “typical” mean QRS axis for humans is about +59 degrees. How far from +59 degrees can the axis deviate and still be considered within normal limits? What are some causes fro pathologically significant left and right mean QRS axis deviations?

Answer 15

The normal range is between -30 and +90 degrees. Normal deviation can be due to body position, height, weight, and fitness level. Significant abnormal deviations to the left can occur if the left ventricle become hypertrophied. This is a common occurrence in peripheral vascular resistance. A significant right deviation that is pathological can be caused by the opposite. Not common

Question 16

What would happen to the ECG trace if the subject sneezed or laughed during the recording? Why?

Answer 16

Just before sneezing, most people take a deep breath. This increases pressure in the chest and briefly inhibits the flow of blood to the heart, which can lower blood pressure and increase the heart rate. But as you exhale, you blood pressure increases and heart rate, in turn, goes down. At the same time, sneezing stimulate the vagus nerve, which runs from the brain through the abdomen.

Question 17

If ventricular myocyte (cardiac muscle cell) is in mid to late plateau phase, what segment of the ECG are we in? What is happening in the ventricle at this time?

Answer 17

During the plateau phase of the action potential the EKG line will be flat (isoelectric line) because the ventricles are completely depolarized. This is also the point at which the ventricles experience isovolumetric contraction-the pressure has not built up enough to open the semilunar valves and thus no blood is being ejected yet. On the EKG this flat line would correspond to the ST segment

Question 18

1. Predict what would happen to your subject’s BP if they began to run in place.

Answer 18

During exercise the sympathetic NS will increase cardiac output (amount of blood pumped/minute) and increase vasoconstriction. The overall result will be an increase in BP. During light exercise this may not be noticeable, or may only be in the systolic BP measurement.

Question 19

2. What specifically is meant by the term auscultation and how is it used to deduce systolic and diastolic pressures?

Answer 19

Auscultation describes the technique by which internal bodily sounds are detected using a stethoscope. This can be used to deduce BP with the help of a blood pressure cuff. The cuff is wrapped around the arm and the pressure is increased until blood flow through the brachial artery is shut off. The cuff pressure is then slowly released. At the point when blood begins to spurt through the vessel below the cuff a sound is detected using the stethoscope. This indicates the pressure during contraction (systolic BP). As the pressure continues to decline, eventually the sound will go away; this indicates that blood flow is again laminar. This represents the diastolic BP, or pressure when the heart is at rest.

Question 20

3.What changes in the finger pulse would you have expected to find?

Answer 20

The finger pulse transducer would detect arterial pressure only when the brachial artery was not compressed. Thus, it would read a pulse prior to the cuff being tightened, and again after the cuff pressure was released enough to allow blood to flow.

Question 21

4. What is the difference btwn the sounds heard when taking BP and the sounds heard in the heart during the cardiac cycle? what causes these sounds?

Answer 21

Korotkoff sounds are heard as blood flows through the brachial artery, but only after flow has been shut off briefly by the cuff and is caused by turbulence. The first 2 heart sounds are heard when the AV valves close (S1) and semilunar valves close (S2) respectively.

Question 22

5. What can cause a “heart murmur?” Can a heart murmur be detected using a stethoscope? How about by examining an EKG?

Answer 22

Murmurs are caused by faulty valves, stenotic valves or septal defects. These are easy to detect using auscultation. ECG recordings will not directly indicate a murmer from a valve or septal defect. However, an ECG is typically not done without the physician having first listened to the heart.

Question 23

flow that is silent

Answer 23

laminar

Question 24

flow that is noisy

Answer 24

turbulent

Question 25

peak arterial pressure (normal 100-139 mmHg)

Answer 25

systolic pressure

Question 26

arterial pressure during ventricular diastole (normal 60-89mmHg)

Answer 26

diastolic pressure