Week 12 part 2

Question 1

Did you study the heart diagram

Answer 1

Yes

Question 2

What are the 2 ways a heart can grow?

Answer 2

1) chronic exercise = hypertrophy of heart / cardiac cells = increase in size of cells
2) pathologically (through disease), i.e. hypertrophic cardiomyopathy = left ventricle of heart becomes stiff and thick, and this leads to the heart not being able to pump properly

Question 3

Where in the blood system does gas exchange occur? What is being exchanged?

Answer 3

In the capillaries. Oxygen goes into the blood, carbon dioxide comes out.

Question 4

What are the 2 layers of the heart’s membrane (pericardium)?

Answer 4

1) outer fibrous pericardium
2) inner serous pericardium

Question 5

Where is the pericardial sac located and what is it’s job?

Answer 5

It surrounds the heart on three sides. It has two thin layers of fluid which keeps the heart cool and it reduces friction as the two layers rub against each other when the heart beats.

Question 6

What are the three layers of the heart (= cardiac muscle), in order of most to least superficial?

Answer 6

1) epicardium
2) myocardium
3) endocardium

Question 7

What are the two circuits of the heart? What do each do?

Answer 7

• pulmonary circuit = transport blood to lungs
• systemic circuit = transports oxygenated blood to rest of body and brings deoxygenated blood back to heart

Question 8

What is the job of the myocardium tissue?

Answer 8

To contract the heart, which allows for pumping of blood.
It is in a figure 8 pattern

Question 9

What kind of tissue is the endocardium? What is its function?

Answer 9

It is a thin layer of connective tissue that lines chambers and covers heart valves.
It prevents blood clotting.

Question 10

What is the septum of the heart?

Answer 10

It is a wall that divides the heart into chambers.

Question 11

What is the interatrial septum?

Answer 11

It is a thin wall of tissue that separates the right and left atria (two upper chambers of the heart)

Question 12

What is the interventricular septum?

Answer 12

Wall of tissue that separates the right and left ventricle

Question 13

What is a valve? What is its function?

Answer 13

It is like a door that keeps blood from going backwards

Question 14

What is an AV valve? What is its job?

Answer 14

The valves that separates the atria from the ventricles on each side of the heart. It prevents backflow from the ventricles into the atria

Question 15

What are chordae tendinae?

Answer 15

They connect flaps of valves to papillary muscles

Question 16

Which valves are open when the atria contract? Where is the blood going at this time?

Answer 16

AV valves are open, semilunar valves are closed, and blood is going to heart

Question 17

Which valves are open when the ventricles contract? Where is the blood going at this time?

Answer 17

AV valves are closed and the semilunar valves are open, and the blood is going to lungs and the body.

Question 18

What are the 3 differences of skeletal muscle vs cardiac muscle?

Answer 18

1) skeletal muscle needs action potential. Cardiac muscle uses autorhythmicity, which makes its own action potential and therefore can contract on its own
2) cardiac muscle uses only oxygen to work
3) cardiac muscle has intercalated disks

Question 19

What are the two parts that make up intercalated discs (of cardiac muscle)? Describe each one’s purpose.

Answer 19

• gap junctions = directs electrical connection
• desmosomes = allows cardiac cells to act as one big cell, firing together

Question 20

What is the job of the SA nodes?

Answer 20

It sets the rhythm / pace of your heart by initiating the action potential, which then goes to the atria

Question 21

What is sinus rhythm? What is an average synus rhythm?

Answer 21

Your normal heartbeat. The average sinus rhythm is 68-72 bpm

Question 22

What is bradycardia? What is the rhythm of the heart in this condition?

Answer 22

When heart rate is too low. Rhythm is below 60 bpm

Question 23

What is tachycardia? What is the rhythm of the heart in this condition?

Answer 23

When heart rate is too high. Rhythm is over 100 bpm

Question 24

When does the first heart sound “lubb” happen?

Answer 24

It happens at the start of a ventricular contraction, and is produced as AV valves close

Question 25

When does the second heart sound “dupp” happen?

Answer 25

It occurs when semilunar valves close

Question 26

What is the job of the AV node?

Answer 26

It allows for the signal to pause to let the atria completely empty the blood into the ventricle

Question 27

What is a systole phase?

Answer 27

Contraction

Question 28

What is a diastole phase?

Answer 28

Rest phase

Question 29

Describe the cardiac cycle, starting from what happens in the right atrium to left ventricle.

Answer 29

Atrial systole -> ventricular systole -> atrial diastole
-> ventricular diastole

Question 30

Explain the standard cardiac cycle in this ECG?

Answer 30

• P wave= contraction / depolarization of atria
• QRS complex = ventricle depolarization / contraction
• T wave = ventricles repolarization / resting

Question 31

What is the formula to calculate CO (cardiac output)?

Answer 31

CO (cardiac output) = HR (heart rate) x SV (stroke volume)

Question 32

What is the job of the medulla oblongata?

Answer 32

It regulates heart rate and respiratory system

Question 33

What makes the sound of the heart (“lub”, “dub”)

Answer 33

Valves closing