Lecture 4

Question 1

Answer 1

Question 2

Question 3

Question 4

Heart sounds

Answer 4

Two sounds:
First = Low-pitched, soft & relatively long, sounds like “lub”
– AV valves closing

Second = Higher pitch, shorter & sharper, sound like “dup”
– Semilunar valves closing

Question 5

Question 6

Question 7

Layers of the heart

Answer 7

Endo-, Myo- and pericardium

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Twisting motion of left ventricle

Answer 13

Question 14

Cardiac muscle fibres
Muscle cells are

Answer 14

= cardiomyocytes
Joined by intercalated discs

Question 15

Question 16

causes cardiac contraction

Answer 16

Electrical activity in the heart

Question 17

Electrical impulses known as action potentials are initiated and conducted by specialised cells known as:

Answer 17

Autorhythmic cells

‘Auto’ = self

‘rhythmic’

Question 18

Action potentials are transmitted to

Answer 18

cardiomyocytes to enable contraction

Question 19

Arrhythmias

Answer 19

An arrhythmia is an abnormality of the heart’s rhythm. It may beat too slowly, too quickly, or irregularly. These abnormalities range from a minor inconvenience or discomfort to a potentially fatal problem.

Question 20

Question 21

Question 22

How does atrial muscle contractioncompare left to right?

Question 23

Question 24

Question 25