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Flashcards in Revision Session Deck (12)
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1
Q

What is the cardiac cycle duration?

A

850ms

2
Q

How much does atrial contraction contribute to ventricular filling?

A

approx 5ml

more important at higher heart rates

3
Q

Draw graph of overview of left cardiac cycle and explain it

  • aortic pressure
  • ventricular pressure
  • atrial pressure
  • left ventricle volume
  • ECG
  • heart sounds
A

see lectures

4
Q

What are the pressures ranges for the following?

  1. aortic
  2. pulmonary
  3. left ventricular
  4. right ventricular
  5. left atrial
  6. right atrial
A
  1. 80-120
  2. 10-25
  3. 0-120
  4. 0-25
  5. 0-10
  6. 0-4
5
Q

What is a normal EDV and ESV?

and therefore stroke volume?

A
EDV = 120
ESV = 50
SV = 70
6
Q

What colours are the ECG leads?

A

right leg = black
left leg = green
right arm = red
left arm = yellow

7
Q

Draw graph that shows ECG trace, SAN action potential, atrial cell action potential, ventricular cells action potential.

A

See ECG lecture

8
Q

Which proteins are responsible for the reuptake of Ca2+ into the SR?

A

Phospholamban

SERCA

9
Q

Apart from the 5 factors that affect venous return, what other 2 factors affect EDV?

A

Atrial contraction - In exercise, filling time is shorted. Atria contract to ensure efficient filling, SNS of atrial muscle increases force of contraction and EDV
Heart rate above 180bpm - atrial contraction can no longer compensate, EDV decreases

10
Q

What are the intrinsic and extrinsic factors that affect cardiac output?

A
Intrinsic = EDV and length dependent increase in calcium sensitivity 
Extrinisic = ESV and length independent increase in calcium sensitivity
11
Q

What parts of the apparatus become more sensitive to calcium when sympathetic activity is increased?

A

Tn-C

12
Q

Define the following:

  • chronotropy
  • inotropy
  • lusitropy
  • automaticity
A
chronotropy = firing of SAN
inotropy = contraction of myocardium
lusitropy = relaxation of myocardium
automaticity = ability to spontaneusly generate electrical impulse