Lab 2

Question 1

What causes electrical currents to be generated?

Answer 1

impulses travelling through heart

Question 2

Where do electrical current go?

Answer 2

into tissues around heart and some reach surface of the body.

Question 3

How can u detect and record electrical currents?

What is a recording called?

Answer 3

a machine called an Electrocardiograph.

-recording called an electrocardiogram (ECG)

Question 4

How do you determine the length of 1 heartbeat?

Answer 4

measuring time from one peak of QRS complex to another.

Question 5

What does the cardiac cycle include?

Answer 5

1 complete cycle of contraction and relaxation of all chambers of the heart.

Question 6

When both atria contract and then relax, what follows?

Answer 6

the contraction and then relaxation of both ventricles.

Question 7

What does the cardiac cycles start with?

Answer 7

Ventricular filling phase- semilunar valves are closed and AV valves are open, allowing blood to flow from the atria to the ventricles.

Question 8

What happens when the ventricles start to contract?

Answer 8

AV valves close and the 1 heart sound (S1) is heard.

Question 9

What is the phase where pressure builds in the ventricles until the pressure in the ventricles meets the pressure in the vessels leaving the heart?

Answer 9

isovolumetric contraction phase

Question 10

Which valves are open during the isovolumetric contraction phase?

Answer 10

none, all valves are closed and no blood leaves ventricles.

Question 11

As pressure builds, _________ valves open and blood leaves the heart in the ________ and ____. this is called the ventricular ejection phase.

Answer 11

Semilunar;
pulmonary trunk;
aorta

Question 12

What phase occurs when the ventricles relax causing blood to start moving backwards, down pressure gradient, forcing semilunar valves shut?

Answer 12

Isovolumetric relaxation

Question 13

Which valves are closed during the isovolumetric relaxation phase?

Answer 13

all and no blood enters or leaves the ventricles.

Question 14

S1 and S2 occur at the closure of what valves?

Answer 14

S1= both AV valves
S2= both semilunar valves

Question 15

When can a ‘splitting’ of either S1 or S2 be heard as the 2 valves closing separately?

Answer 15

in some healthy hearts and some disease conditions

Question 16

Deep inspiration _____ pressure in thoracic cavity and _______ venous return into heart (atrial suction).

Answer 16

decreases, increases.

Question 17

Where is the aortic valve located?

Answer 17

-2nd intercostal space, right of the sternum at the level of the sturnal angle

Question 18

Where is the Pulmonary valve located?

Answer 18

2nd intercostal sapce or left of the sternum at the level of the sturnal angle

Question 19

Where is the tricuspid valve located?

Answer 19

4th or 5th intercostal space

Question 20

Where is the Mitral valve located?

Answer 20

4th or 5th intercostal space or just under left nipple

Question 21

What is a heart murmur?

Answer 21

valve prolapse and regurgitation

Question 22

The amount of blood that may be pumped by the heart in one min is called?

Answer 22

cardiac output (CO)

Question 23

what is the average CO?

Answer 23

5 L/min but can increase to up to 25 L/min with strenuous exercise.

Question 24

CO is directly related to?

Answer 24

Stroke volume (SV) and Hear rate (HR)

Question 25

When a person exercises, signals from proprioceptors travel to the cardiac acceleratory center which signals the heart what?

Answer 25

signals the heart that the muscles are active and will need more oxygen

Question 26

The cardiac acceleratory center exerts a positive chronotropic effect on the heart to increase ________.

Answer 26

HR

Question 27

Effectors that connect the cardiac acceleratory center with the heart include?

Answer 27

sympathetic nerves, and SA and AV nodes.

Question 28

With exercise, stroke volume ____.

Answer 28

increases

Question 29

What is stroke volume?

Answer 29

the amount of blood that leaves the ventricle with each beat.

Question 30

When is more blood returned to the heart then usual?

Answer 30

during exercise. (increasing SV)

Question 31

The sympathetic nervous system signals the myocardium to contract ___ ________.

Answer 31

more strongly (increasing SV)

Question 32

What is the major difference between action potential in a cardiac muscle cell (cardiosyte) compared to a skeletal muscle cell?

Answer 32

- Ca channals hold excitation at peak for prolonged time. | - allows for heart contraction to last longer

Question 33

When the P wave occurs, the SA node fires causing the atria to _____.

Answer 33

depolarize

Question 34

During the QRS complex on the ECG, signals travel down the AV bundle, bundle branches, to the ____________. ventricles __________. now ventricles contract.

Answer 34

purkinje fibers (apex), depolarize.

Question 35

During the t wave, the ventricles _______.

Answer 35

repolarize.

Question 36

The cardiac cycle ends with the ventricles in _________.

Answer 36

relaxation.

Question 37

What structure electrical conduction system sets the heart rate? what would the resting heart rate be if this was the only regulator of heart rate?

Answer 37

the structure is SA nodes | if this was the only regulator, resting HR would rest at 100 bpm.

Question 38

What division of the autonomic system plays a role in setting the Resting HR?

Answer 38

the parasympathetic nervous system.

Question 39

Which division of the autonomic nervous system acts to increase the heart rate during exercise?

Answer 39

sympathetic nervous system

Question 40

Which division of the autonomic nervous system acts on the cardiac muscle to increase the strength of contraction during exercise?

Answer 40

sympathetic nervous system

Question 41

What receptor is used when the stimuli is the increase of CO2 in the blood? Where is it located? does HR go up or down?

Answer 41

chemoreceptors location: carotid arteries and aortic bodies HR- increases

Question 42

What receptor is used when the stimuli is the increase of blood pressure? Where is it located? does HR go up or down?

Answer 42

Baroreceptors location: carotid arteries and aortic arch HR-Decreases

Question 43

What receptor is used when the stimuli is exercise (muscle contractions)? Where is it located? does HR go up or down?

Answer 43

Proprioceptors location: muscles and joints HR-increases

Question 44

What 2 control centers regulate HR?

Answer 44

cardioacceleratory center and cardioinhibitory center. both located in medulla

Question 45

What are the effectors that actually change the heart?

Answer 45

sympathetic and parasympathetic

Question 46

How can a stressful thought can lead to an increase in HR even when your sitting quietly?

Answer 46

activates cardiac center

Question 47

What are the average resting values of the equation to determine resting cardiac output?

Answer 47

SV(70mL/beat) x HR(75beats/min)=resting CO(5250mL/min)

Question 48

What are the 3 factors that affect Stoke Volume?

Answer 48

1. Preload= amount of tension in ventricles before contraction 2. Contractility= the force of contraction for a given preload. 3. afterload= the blood pressure in arteries just outside the semilunar valves.

Question 49

What is the difference in HR for a ranking of 'poor' vs. 'excellent'?

Answer 49

excellent result would be due to lower overall HR meaning your body can meet your bodies need without working to hard.