Cardiovascular 1

Question 1

T/F

Cardiac muscle has more mitochondria than skeletal muscle

Answer 1

True
(Highly dependant aerobic respiration which is why heart attacks are so detrimental)

Question 2

What is the average cardiac output?

Answer 2

5L/min

Question 3

Why is it that athletes can have a lower resting heart rate without have a different resting cardiac output?

Answer 3

Their heart can pump out more blood in a single contraction

Question 4

Does cardiac output go up or down when exercising?

Answer 4

Up

Question 5

What is the pericardium and what is its purpose?

Answer 5

It is a fibrous sac that surrounds the heart which provides a smooth surface for the heart to contract against

Question 6

What promotes blood flow into the heart?

Answer 6

Pleural pressure becomes negative creating a pressure gradient between the venous pool and the RV which inreases preload to the RV and LV

Question 7

What seperates the atria and the ventricle?

Answer 7

Atrioventricular septum

Question 8

What seperates the right and left side of the heart?

Answer 8

interatrial and interventricular septums

Question 9

What chamber does deoxygenated blood from the superior/inferior venae cavae and the coronary sinus go into?

Answer 9

Right atrium

Question 10

What valve is in-between the right atrium and ventricle?

Answer 10

tricuspid atrioventricular valve

Question 11

T/F

The left side of the heart is weaker

Answer 11

False
It is stronger because it has to overcome higher pressures to pump blood

Question 12

What blood does the left atrium retreive?

Answer 12

oxygenated blood from the pulmonary veins

Question 13

What valve is located in between the left atrium and ventricle?

Answer 13

Bicuspid (mitral) atriventricular valve

Question 14

What is the ‘normal state’ of the papillary muscles?

Answer 14

Relaxed
When heart contracts the valves shut

Question 15

When does majority of blood flow to the coronary arteries occur?

Answer 15

During diastole

Question 16

Why is a heart attack where the blockage is close to the aorta less survivavble?

Answer 16

A larger part of the heart is not receiving oxygenated blood and so the tissue will die. If the blockage is closer to the apex of the heart, less tissue will be deprived of oxygen and be damaged making it more survivable

Question 17

T/F

Coronary Arteries and veins transport blood to/from the myocardium

Answer 17

True

Question 18

What are the unique properties of cardiac muscle?

Answer 18

• branch freely
• intercalated discs bound by desosomes
• gap junctions

Question 19

What is unique about the heart in terms of its contractile ability? What is this known as?

Answer 19

cardiac myocytes have the initiate their own electrical potential at a fixed rate which spreads through the gap junctions

This is known as autorythmicity

Question 20

What are the 2 types of cardiac muscles cells? Which are more common?

Answer 20

• Myocardial contractile cells (~99%)
• Myocardial Conducting cells (~1%)

Question 21

Definition:

Conduct impulses and are responsible for contractions that pump blood through the body

Answer 21

Myocardial contractile cells

Question 22

Definition:

Myocardial conducting cells

Answer 22

initiate and propogate action potentials which travel throughout the heart

Question 23

Name the components of the cardiac cinduction system:

Answer 23

• sinoatrial node
• atrioventricular node
• atrioventricular bundle
• atrioventricular bundle branches
  -purkinje cells

Question 24

What establishes our normal cardiac rythm? How?

Answer 24

SA node
initates sinus rythm of heart contractions

Question 25

Pacemaker of the heart?

Answer 25

SA node

Question 26

What is the purpose of the AV node?

Answer 26

To spread the impulse from the atria to the ventricles as they are electrically independant

Question 27

How long does it take an impulse to pass through the AV node?

Answer 27

100ms

Question 28

What does the time delay at the AV node allow for?

Answer 28

Allows atria to complete its contractioe

Question 29

What happens to diastolic filling time with increased heart rate?

Answer 29

It gets shorter

Question 30

Explain cardiac conduction once it goes through the AV node.

Answer 30

Travels through the atrioventircular bundle (bundle of His), travelling along the interventircualr septum before deividng into two atrioventricular bundle branches At the apex of the heart, teh bundle branches connect with the purkinje fibres which spread the impulse to the myocardial contractiule cells in the ventricles

Question 31

Why can athletes have such low HR?

Answer 31

Their stroke volume is extremely high due to stringer venticles (cen eject more blood per beat so HR can be slower)

Question 32

If both the SA and AV node malfunction, can you live?

Answer 32

Likeley not, HR would be too low and not enough blood would be getting pumped

Question 33

# T/F: Cardiac conductive cells and contractive cells have the same action potentials.

Answer 33

False!

Question 34

Explain the action potential of cardiac conductive cells.

Answer 34

Conductive cells contain a series of Na+ channels that allow a spontaneous depolarization due to slow influx of Na+ - at 40mV, Ca2+ channel open causing rapid depolarization to +15 - Ca channels cloase and K+ channels open leading to depolarization to - 60 where prepotential phas ebegins again

Question 35

What is the pre-potential phase of the conductive cell AP called?

Answer 35

Funny channel - the slow leaky phase

Question 36

Explain the AP of cardiac contractile cells.

Answer 36

- once activated, rapid depolarization (Na+ influx) - plateau phase (depolarization maintained through slow Ca channels) - repolarization (outflux of K+)

Question 37

Is the atria or venticle more depolarized?

Answer 37

ventricle (-90 vs -80 for atria)

Question 38

What is the purpose of the plateau in contractile cells?

Answer 38

Gives a period of time where another contraction cannot occur, enabling filling time and rest to occur in the ventricles

Question 39

How long is the absolute refractory period? Relative?

Answer 39

Absolute - 200ms Relative - 50ms

Question 40

How do cardiac APs differ from skeletal muscle?

Answer 40

slower, last longer, greater refractory period

Question 41

What do the adaptatiopns in cardiac tissue aid in?

Answer 41

- preventing tetanus - reducing fatigue - enable adequate filling time for the heart chambers

Question 42

How does the sympathetic system affect the leaky channel? Parasympathetic?

Answer 42

Sympathetic - more leakage, increased HR Parasympathetic - less leakage, lower HR