W5 - CV System Flashcards
What are the purposes of the CV system?
Blood transport around body
Regulation of body temp
Supports immune function
In the heart sounds, what is the “Lub”?
Closing of AV valves
In the heart sounds, what is the “Dub”?
Closing of SL valves
What can the SA node be broken down into?
Anterior internodal tract
Middle internodal tract
Posterior internodal tract
Bachmanns bundle
P wave
Atrial depolarisation
QRS complex
Ventricular depolarisation
T wave
Ventricular repolarisation
What initiates atrial depolarisation?
SA node
What does the flat part on an ECG between the end of P wave + the start of QRS complex represent?
Impulse being delayed by AV node.
At which part of the QRS complex does ventricular depolarisation happen?
At apex
Where on an ECG graph does it show where ventricular depolarisation is complete?
Flat part between S of QRS complex + start of T wave
Where on an ECG graph does ventricular repolarisation begin?
At apex of T wave
Where on an ECG graph does it show that ventricular repolarisation is complete?
Flat part after T wave
Resting HR for untrained females + males
~70 bpm
Resting HR for trained females + males
~50 bpm
Resting HR for bradycardia
Less than 60 bpm
Resting HR for tachycardia
More than 100 bpm
How is SV calculated?
End diastolic vol - end systolic vol
Resting values for SV in untrained females
50ml
Resting values for SV in untrained males
70ml
Resting values for SV in trained females
80ml
Resting values for SV in trained males
110ml
Define the Ejection Fraction (EF)
Proportion of blood pumped out of left ventricle w/ each beat
(%)
Average ejection fraction at rest
60%
How is EF calculated?
(SV / End diastolic vol) x 100
Define blood pressure
Force exerted by blood vs arterial walls during cardiac cycle
What are the units for bp
mmHg
What is systolic bp
Force exerted during ventricular systole
Which is the highest pressure w/in the vascular system?
Systolic bp
What is the diastolic bp
Force exerted during ventricular diastole
Which is the lowest pressure w/in the vascular system?
Diastolic bp
On a graph showing arterial pulse waveforms, where can the dicrotic notch be found?
As a secondary upstroke in the descending part of a pulse.
What does the dicrotic notch represent?
End of systole + beginning of diastole in those arteries.
What comes under after the dicrotic notch on a graph showing arterial pulse waveforms?
Diastolic run-off
How is bp expressed?
As a ratio:
SBP over DBP
S- Systolic
D - Diastolic
What is the normal value for SBP
120 mmHg
What is the normal value for DBP
80 mmHg
Define mean arterial pressure (MAP)
Avg arterial pressure throughout 1 cardiac cycle.
What are the 2 formulas to calculate MAP
DBP + 1/3(SBP-DBP)
2/3(DBP) + 1/3(SBP)
Define Rate-pressure product (RPP)
Estimation of myocardial workload + resulting O2 consumption
How is RPP calculated?
SBP x HR
How is vessel resistance calculated?
(Vessel length x viscosity ) / Vessel radius ^4
How is vessel flow calculated?
Pressure grad / vessel resistance
How is blood flow calculated?
(Pressure grad x vessel rad^4) / (vessel length x viscosity)
What part of this equation to calculate blood flow stays constant?
(Pressure grad x vessel rad^4) / (vessel length x viscosity)
Vessel length
What part of this equation to calculate blood flow has a slight variation?
(Pressure grad x vessel rad^4) / (vessel length x viscosity)
Viscosity
List the key determinants for bp
Blood vol
Peripheral resistance
Blood viscosity
HR
SV
Intrinsic HR
What is the internal rhythm set at?
100bpm
What 2 parts can the CCC (Cardiac control centre) be split into?
CAC (Cardioaccelerator centre) at SNS
CIC (Cardioninhibitory centre) at PNS
