More heart stuff yayy :(

Question 1

What EXACTLY is the cardiac cycle

Answer 1

It is the coordinated and consistent contraction (systole) and relaxation (diastole) of the atrial and ventricular functional synctia

Question 2

What is the total duration of the cardiac cycle

Answer 2

0.8 seconds

Question 3

What are the different phases of cardiac cycle

Answer 3

1. Phase of ventricular filling.
2. Phase of atrial systole.
3. Phase of isovolumetric contraction (ventricles contract)
4. Phase of ventricular ejection.
5. Phase of isovolumetric relaxation.

Question 4

What happens in ventricular filling

Answer 4

1. All 4 chambers diastole
2. AV valves open
3. Semilunar valves closed

• Blood enters via large veins into atria, into ventricles
• First 1/3 of phase= RAPID FILLING PHASE then filling speed decreases, DIASTASIS
  Pressure in the ventricles is 0 mmHg

Question 5

What happens in the phase of atrial systole

Answer 5

1. SAN fires AP and causes atria to contract then to AVN
   2, More blood enters ventricles

• pressure right= 4-6mmHg Left=7-8mmHg

Question 6

The phase of atrial systole is reflected as what wave on the ECG

Answer 6

P wave
And PQ interval

Question 7

What is the volume of blood that is contained in the ventricles at the end of diastole

Answer 7

End Diastolic Volume (EDV)

it is abt 130 ml

Question 8

If theres no valves at the start of the atria, how does the blood not flow back into the venous vessels

Answer 8

Bc of circular muscle fibers that contract at the beginning of the Atrial systole

Directs blood to the AV valves

Question 9

What is the pre ejection period divided into
Use left ventricle as example

Answer 9

Asynchronous= when tension starts to develop, not all the left ventricular cardiomyocytes are excited and the whole ventricle hasnt contracted yet Lasts until closure of mitral valve

Isovolumetric contraction= when mitral and aortic valve closed. The intraventricular volume DOES NOT change now

Question 10

What happens in Phase of isovolumetric contraction

Answer 10

1. ventricular pressure> atrial pressure so valves close
2. Hear the first heart sound (S1) (closure of AV valves)

Question 11

Phase of isovolumetric contraction (start of ventricular depolarization) is refelcted as what wav eon the ECG

Answer 11

Q wave

Question 12

What triggers the ejection phase

Answer 12

When ventricular pressure reaches diastolic pressure of the large arterial vessels, causes the semilunar valves to open

Question 13

What happens in the phase of ventricular ejection

Answer 13

1. Stroken volum is ejected out of Aorta/ Pulmonary artery
2. Pressure in arteries rech max systolic value
   Aorta =125mmHg Pulmonary=25mmHg
3. Myocardial relaxation begins at the end of ventrcular repolarization
4. Hear the 2nd heart sound (S2) when semilunar valves close due to drop in intraventricular pressure

Question 14

Isovolumetric ejection (ventricular repolarization) is reflected as what wave on ECG

Answer 14

T wave

Question 15

After ejection of stroke volume, what is left in ventricles

Answer 15

End systolic volume (ESV)

60 ml

Question 16

What happens in the phase of isovolumetric relaxation

Answer 16

1. Closure of semilunar valves (S2)
2. Bc of semilunar valve closure, some blood returns to the heart then back to periphery
   Ths causes small peak (on aortic oressure curve) called DICHROITIC WAVE
   Detected by caraotid SPG

Question 17

When does cardiac cycle begin again

Answer 17

When AV valves open due to interventricuao pressure being less than atrial pressure

Question 18

ECG AND PCG

Answer 18

Records the ELECTRICAL activity of heart during cardiac cycle

Records the SOUNDS of the heart during cardiac cycle

Question 19

How is pulse wave generated

Answer 19

By deformation of aortic wall during ventricykar systole

It is transmitted along arterial system

Question 20

What does a carotid sphygmogram register

Answer 20

MECHANICAL OSCILLATIONS of arterial wall

Question 21

WHat kind of sensor and where is the carotid sphygmogram placed

Answer 21

A piezelectric crystal is used placed on the RIGHT carotid artery

Question 22

Elements of sphygmogram

Answer 22

Ao: reflects the opening of aortic valve.

(i) incisure: reflects aortic valve closure.

The P-wave on the anachoretic limb reflects
the maximum pressure in the aorta (systolic
presser).

T-wave (tidal wave), reflects the “summation”
of the pulse wave with reflected pulse waves
from the peripheral part of the vascular
system.

D-wave (dichroitic wave): reflects the blood
that returns to the heart and goes back again
to the periphery, after closer of semilunar
valves during diastole.

Question 23

Where is the peripheral pulse curve (PPC) registered

Answer 23

These peripheral pulse oscillations from peripheral blood vessels are registered on one of the fingers or toes

Question 24

What detects the oscillations in the peripheral blood vessels

Answer 24

pressure transducer indirectly senses volume change in the area

Question 25

Why do we place the sensors for both sphygmogram and peripheral pulse curve on right side of body

Answer 25

Bc of BRACHIOCEPHALIC TRUNK

as thats where the rigt common carotid artery and right subclavian comes from

Question 26

What is the main difference btw carotid SPG and PPC

Answer 26

In PPC, opening of aortic valve delayed bc it takes time for pulse wave to propagate to site of registration

Due to this phenomenon, the simultaneous
registration of SPG and PPC allows to determine
the velocity of pulse wave (PWV).

Question 27

What determines the velocity of the Pulse wave

Answer 27

It increases w decreasing radius and increasig vessel wall thickness

PWV^2=Eh/2rρ

Question 28

Where is pulse wave velocity lowest and highest

Answer 28

low= AORTA

high= ARTERIOLES

Question 29

How to register linear blood velocity using Doppler flowmetry

Answer 29

Send ultrasonic waves
Relflected back by cells of blood
Leads to changing of frequency to hearing spectrum

Question 30

3 main things that determine pre ejection period

Answer 30

preload (end diastolic volume)

yocardial contractility

Afterload (arterial pressure)

Question 31

Duing isovolumetric period, how does the ventricle change

Answer 31

since some cardiomyocytes do change length (isotonic), ventricle:

Becomes more sphercal, circumference increases, base to apex distance decreases

Question 32

When do the aortic valves open in isovolumetric contraction

Answer 32

when it reaches diastolic value of arterial presssure

Question 33

Why do we have to work out central time for phase analysis of left ventricle

Answer 33

Delay of SPHYGMOGRAM compared to electrocardiogram and phonocardiogram

DELAY DUE TO time required for pulse ave to reach site of sphygmography recording