Heart

Question 1

What muscle is the heart made of?

Answer 1

Cardiac muscle

Question 2

What is a difference between cardiac muscle and skeletal muscle?

Answer 2

Cardiac muscle doesn’t get fatigued as the coronary arteries supply it with the oxygenated blood it needs to contract and relax constantly

Question 3

Where does deoxygenated blood enter the heart?

Answer 3

The right atrium, and then is pumped out of the right ventricle to the lungs

Question 4

Through what blood vessel does deoxygenated blood enter the right atrium?

Answer 4

Blood enters through the right atrium through the inferior and superior vena cava

Question 5

Where does the deoxygenated blood in the inferior vena cava come from?

Answer 5

The lower body

Question 6

Where does the deoxygenated blood in the superior vena cava come from?

Answer 6

The upper body and head

Question 7

What are the two types of valves in the heart?

Answer 7

The atrio-ventricular and semi-lunar valve

Question 8

Where does oxygenated blood enter the heart?

Answer 8

The left artium, and then is pumped out to the rest of the body

Question 9

What are the two atrio-ventricular valves?

Answer 9

The tricuspid and bicuspid valves

Question 10

Where is the tricuspid valve found?

Answer 10

In between the right artium and right ventricle

Question 11

Where is the bicuspid valve found?

Answer 11

In between the left atrium and left ventricle

Question 12

Through what blood vessel does oxygenated blood enter the left atrium?

Answer 12

Pulmonary vein

Question 13

Through what blood vessel does oxygenated blood leave the left ventricle?

Answer 13

The aorta

Question 14

Through what blood vessel does deoxygenated blood leave the right ventricle?

Answer 14

Pulmonary artery

Question 15

What is systole?

Answer 15

Contraction. There is atrial and ventricular systole and they happen separately

Question 16

What is diastole?

Answer 16

Relaxation

Question 17

What are the 3 main stages of the cardiac cycle?

Answer 17

Atrial systole
Ventricular systole
Diastole

Question 18

What happens during atrial systole?

Answer 18

The atria contract to completely fill the ventricles with blood

Question 19

What happens during ventricular systole?

Answer 19

The ventricles contract to push blood out of the heart

Question 20

What happens during diastole?

Answer 20

The artia and ventricles relax to allow the heart to refill with blood

Question 21

What happens once the ventricular pressure is higher than the atrial pressure?

Answer 21

The atrio-ventricular valves close to prevent back flow of blood into the atria

Question 22

What happens once the ventricular pressure is higher than aortic/pulmonary artery pressure?

Answer 22

The semi-lunar valves open to allow blood to leave the ventricles through the aorta or pulmonary artery

Question 23

What happens once the ventricular pressure is lower than aortic/pulmonary artery pressure?

Answer 23

The semi-lunar valves close to prevent back flow of blood into the ventricles

Question 24

What happens once the ventricular pressure is lower than the atrial pressure?

Answer 24

The atrio-ventricular valves open to allow blood to enter the ventricles from the atria

Question 25

What is the purpose of tendinous cords in the heart?

Answer 25

Ensures the atrio-ventricular valves are not turned inside out by the pressure exerted when the ventricle contracts

Question 26

What side of the heart is more muscular?

Answer 26

The muscular wall of the left side of the heart is much thicker than the right

Question 27

Why is the left side of the heart more muscular than the right?

Answer 27

The right side of the heart has to pump a relatively short distance (to the lungs), and only has to overcome the resistance of pulmonary circulation. The left side of the heart has to pump blood to all extremities of the body, and has to overcome the resistance of aorta and arterial systems of the whole body

Question 28

What is the purpose of the septum?

Answer 28

The septum is the inner dividing wall of the heart, which prevents the mixing of deoxygenated and oxygenated blood

Question 29

What are the lub-dub sounds of the heart caused by?

Answer 29

The closing of the heart valves caused by the pressure of backflowing blood

Question 30

What is the word to describe how the heart controls its own contractions?

Answer 30

Myogenic

Question 31

How does the heart control its own contractions?

Answer 31

Through initiating its own electrical impulses

Question 32

What is the sino-atrial node known as and why?

Answer 32

The natural pacemaker, as it initiates the electrical impulse, causing atrial contraction

Question 33

What stops the excitation initiated by the SAN from passing directly to the ventricles?

Answer 33

A layer of non-conducting tissue

Question 34

What does the atrioventricular node do?

Answer 34

Once the excitation reaches the AVN, it imposes a delay before stimulating the bundle of His

Question 35

Why is it important that the atrioventricular node imposes a delay?

Answer 35

Allows time for the atria to fully contract, and for all the blood in the atria to enter the ventricles before they contract

Question 36

What is the bundle of His?

Answer 36

A bundle of conducting tissue made up of fibres known as Purkyne fibres, that penetrates through the septum of the ventricles, and splits into two branches surrounding the ventricles

Question 37

What surrounds the bundle of His and why?

Answer 37

Around the bundle of His is a layer on non-conductive tissue, which prevents the ventricles from being stimulated until the impulse reaches the apex.

Question 38

Where does the impulse start at the ventricles and where does its spread?

Answer 38

The impulses start from the bottom of the heart (the apex), and then spread impulses along the ventricles to complete ventricular contraction

Question 39

Why does contraction start at the apex?

Answer 39

Allows for more efficient emptying of the ventricles, ensuring all blood leaves the ventricles

Question 40

What can be used to measure the electrical activity of the heart?

Answer 40

Electrocardiograms (ECGs)

Question 41

What is tachycardia?

Answer 41

When heartbeat is very rapid (over 100bpm)

Question 42

What is bradycardia?

Answer 42

When heartbeat slows down to less than 60 bpm

Question 43

What is an ectopic heart beat?

Answer 43

An extra beat followed by a pause

Question 44

What is atrial fibrillation?

Answer 44

Where rapid electrical impulses are generated in the atria, leading to rapid incomplete contraction, but only some of these impulses are passed on to the ventricles which contract much less often

Question 45

How do you work out cardiac output?

Answer 45

Cardiac output = Stroke volume x Heart rate