2. Cardiovascular Physiology

Question 1

How does the heart function effectively?

Answer 1

Heart contracts between 50 and 200 times per minute depending on the load
Contraction must be precisely timed so that atria contract first followed by a delay which allows ventricles to fill, with a subsequent contraction of ventricles form the base

Question 2

What happens during systole?

Answer 2

Ventricles contract

Question 3

Why is it significant that the S.A. node is automatic?

Answer 3

It will depolarise itself

Question 4

When do the atria contract?

Answer 4

When the S.A node is activated

Question 5

Where does the electrical signal travel?

Answer 5

Septum

down LHS then turn RHS and depolarises left centricles

Question 6

What does the T wave indicate?

Answer 6

The heart repolarising

Question 7

What is sinus arrhythmia?

Answer 7

Speeding up of the heart when you breathe in

Question 8

What does the vagus heart do to the nerve?

Answer 8

Slows the heart down

Question 9

What happens to the vagus nerve when you breathe in?

Answer 9

It is turned off and heart rat

Question 10

What is a heart block?

Answer 10

Ventricles and atria beat at own rate separately, atria beat with S.A. rate and ventricles beat with bundle of his

Question 11

What does a heart block result in?

Answer 11

Results in stokes adam syndrome

Question 12

What is a first degree heart block?

Answer 12

Extensive delay between atria and ventricles

Question 13

What is meant by circus movements? read up on this

Answer 13

Situation in the heart where the current is going round in a circle rather than apex to base

Question 14

What is Wolff Parkinson White syndrome?

Answer 14

Where there is a genetic abnormality conducting electricity between the ventricles and the atria

Question 15

What are ectopics?

Answer 15

Where parts of the heart that normally don’t initiate and impulse do causing extrasystoles

Question 16

What happens in late diastole?

Answer 16

AV valves open, blood flows in to the atria and ventricles passively

Question 17

What happens in atrial systole?

Answer 17

Atrial contraction primes the main pump. 70% of ventricular filling is passive
Contraction of muscles around great veins minimise backflow along with inertia of blood
A wave of atrial pressure and JVP trace

Question 18

How long into the cardiac cycle does atrial systole occur?

Answer 18

0-0.1

Question 19

What happens in ventricular systole?

Answer 19

Isovolumetric contraction; ventricles contract against closed valves until P vent > P art. This builds up pressure head
Aortic and pulmonary valves burst open, giving the ventricular ejection phase
C wave of atrial and JV pressures

Question 20

How long into the cardiac cycle does ventricular systole occur?

Answer 20

0.1-0.4

Question 21

What happens in early diastole?

Answer 21

Protodiastole, ventricles stop contracting, blood still flows out through the momentum imparted by ventricular contraction.
Aortic and pulmonary valves close and we get isovolumetric relaxation until pressure falls to below atrial pressure
V wave on JVP and atrial pressure trace from blood flowing into atria
Then AV valves open

Question 22

How far into the cardiac cycle does early diastole occur?

Answer 22

0.4-0.6 into cycle

Question 23

What are the difference in systolic and diastolic murmurs?

Answer 23

Systolic murmurs are on the beat and diastolic murmurs off the beat