Lecture Unit 1 Ch20

Question 1

Describe the location of the heart

Answer 1

The heart is located in the mediastinum and sits slightly to the left, enclosed and held in place by the pericardium

Question 2

Why is the pericardium beneficial to the heart?

Answer 2

It minimized friction since there is a lot of volume change.

Question 3

What does the pericardium consist of?

Answer 3

Outer fibrous pericardium and Inner serous pericardium

• Serous pericardium has 2 layers: visceral and parietal (separated by the serous cavity; a fluid filled space)

Question 4

Where does the right atrium receive blood from?

Answer 4

Superior and inferior vena cava

Question 5

Where does the right ventricle receive blood from?

Answer 5

Right atrium

Question 6

Which chamber sends blood to the lungs

Answer 6

Right ventricle

Question 7

Where does the left atrium receive blood from?

Answer 7

Pulmonary veins; blood comes from lung up to chamber

Question 8

Where does the left ventricle receive blood from?

Answer 8

Left atrium; sends blood all over body

Question 9

Why is the left ventricle thicker than the right ventricle?

Answer 9

While there is an equal amount of blood in both ventricles, the blood in left ventricle goes at a much higher pressure.

Question 10

How many chambers? How many entry points?

Answer 10

4;6

Question 11

What do the right and left atrioventricular valves do?

Answer 11

Prevent back flow from the ventricles into the atria

Question 12

What do the right and left semilunar valves do?

Answer 12

Prevent back flow from the arteries into the ventricles

Question 13

What activates heart valves?

Answer 13

Pressure

Question 14

Can the superior and inferior vena cava be blocked? Why or why not

Answer 14

No, it is too large

Question 15

Name the steps in the path of blood flow through systemic and pulmonary circulation

Answer 15

Closed system
(deoxygenated blood)
1. Right atrium (tricuspid valve)
2. Right ventricle (pulmonary valve)
3. Pulmonary trunk and pulmonary arteries
4. In pulmonary capillaries, blood loses CO2 and gains O2
(oxygenated blood)
5. Pulmonary veins
6. Left atrium (bicuspid valve)
7. Left ventricle (aortic valve)
8. Aorta and systemic arteries - lugs + heart supplied by this
9. In systemic capillaries, blood loses O2 and gains CO2
10. Superior, Inferior vena cava, and coronary sinus

Question 16

Why does your leg fall asleep?

Answer 16

Not getting enough oxygen

Question 17

Describe blood flow from the coronary arteries

Answer 17

Delivers oxygenated blood and nutrients to the myocardium; branches arise from the ascending aorta

Question 18

Describe blood flow from the coronary veins

Answer 18

Remove carbon dioxide and wastes from the myocardium; branches converge at the coronary sinus

Question 19

Describe the correlation between blood flow and a contraction

Answer 19

During a contraction, there is almost no blood flow due to the pressure

Question 20

Describe cardiac muscle cells

Answer 20

Self-excitable and autorhythmic; about 1% of cardiac muscle don’t contract because their job is self-excitability

Question 21

What is the conduction system?

Answer 21

The route for propagating action potentials through the heart muscle

Question 22

How do muscle cells cause heart contractions

Answer 22

By repeatedly generating spontaneous action potentials

Question 23

What part of the conduction system initiates action potentials most frequently

Answer 23

The autorhythmic fibers in the SA node; These are the natural pacemakers of the heart because they initiate action potentials most frequently

Question 24

How do signals from the nervous system and hormones play a role on the conduction system?

Answer 24

They can modify the heart rate and force a contraction; do not set the fundamental rhythm.

Question 25

Characteristics of an action potential in a ventricular contractile fiber

Answer 25

Rapid depolarization, plateau, and repolarization

Question 26

Ionic linkage role in ventricular fiber

Answer 26

ionic linkage into non contracting cells which make space and cause contraction

Question 27

ATP production in cardiac muscle

Answer 27

Cardiac muscle generates ATP via anaerobic cellular respiration and creatine phosphate

Question 28

What is an EKG

Answer 28

A recording of electrical changes that accompany each heart beat; looking at entire heart; measurement of change in cells

Question 29

What does the P-Q interval in an EKG measure

Answer 29

The atrial contraction; shorter

Question 30

What does the Q-T interval in an EKG measure

Answer 30

The ventricular contraction; longer

Question 31

Action potential propagation through the heart

Answer 31

1. Depolarization of atrial contractile fibers produce P waves 2. Atrial systole (contraction) 3. Depolarization of ventricular contractile fibers produces QRS complex 4. Ventricular systole (contraction) 5. Repolarization of ventricular contractile fibers produces T wave 6. Ventricular diastole (relaxation)

Question 32

Systole

Answer 32

Contraction

Question 33

Diasotle

Answer 33

Relaxation

Question 34

ECG: How long is the atrial systole

Answer 34

0.1 seconds

Question 35

ECG: How long is the ventricular systole

Answer 35

0.3 seconds

Question 36

ECG: How long is the relaxation period

Answer 36

0.4 seconds (shrinks when you start exercising)

Question 37

What happens to the Aortic pressure if you have a heart attack

Answer 37

Keeps going down

Question 38

How many sounds per 1 beat?

Answer 38

2

Question 39

Where to listen for aortic valve?

Answer 39

Between ribs 2 and 3 on right side

Question 40

Where to listen for tricuspid valve?

Answer 40

By rib 6 on left side

Question 41

Where to listen for pulmonary valve?

Answer 41

Between ribs 2 and 3 on left side

Question 42

Where to listen for bicuspid valve?

Answer 42

Between ribs 5 and 6 on left side

Question 43

Where does the diastolic volume end?

Answer 43

End of atrial systole

Question 44

Where does systolic volume end?

Answer 44

End of ventricular systole

Question 45

Name mechanical events in atrial systole

Answer 45

Atrial contraction

Question 46

Name mechanical events in ventricular systole

Answer 46

Isovolumetric contraction and ventricular ejection

Question 47

Name mechanical events in relaxation period

Answer 47

Isovolumetric relaxation and ventricular filling

Question 48

What is cardiac output

Answer 48

The volume of blood ejected from the left or right ventricle into the aorta or pulmonary trunk each minute

Question 49

What is stroke volume

Answer 49

The amount of blood pumped out of the ventricle in one beat

Question 50

Cardiac output equation

Answer 50

CO (mL/min) = SV (mL/beat) x HR (beats/min) - all increase together - CO changes when heart beat changes

Question 51

Explain Starling's Law of the heart

Answer 51

The more the heart muscle is stretched (filled) before the contraction (preload), the more forcefully the heart will contract - If increased SV and preload- the sympathetic tone will increase during exercise

Question 52

Factors regulating stroke volume

Answer 52

preload, contractility, and afterload

Question 53

What several factors regulate heart rate

Answer 53

autonomic nervous system, hormones, ions, age, gender , physical fitness, and temperature

Question 54

What can regular aerobic exercise do to the heart

Answer 54

increase cardiac output, increase HDL, decrease triglycerides (fat %), improve lung function, decrease blood pressure, assist in weight control

Question 55

Disorders: Homeostatic Imbalances Coronary artery disease

Answer 55

Plaque buildup in wall of arteries

Question 56

Disorders: Homeostatic Imbalances Atherosclerotic plaques

Answer 56

Buildup of fats, cholesterol, and other substances in artery walls

Question 57

Disorders: Homeostatic Imbalances Congenital heart defects

Answer 57

Birth defect

Question 58

Disorders: Homeostatic Imbalances Arrhythmia

Answer 58

Irregular heartbeat