G1BH 2012 2013 HC-13-14 - Contractie mechanismen 1 en 2 - steendijk - PDF
1. G1BH 2012-2013 - HC-13 en HC-14
Cardiac mechanics
Paul Steendijk, PhD
Associate Professor Cardiovascular Physiology
Department of Cardiology, LUMC
p.steendijk@lumc.nl
2013.02.13
2. Determinants of cardiac function
Neurohormonal
systems
Electrical
activation
Excitation-contraction
Cardiovascular interactions
& loading conditions
Pump function
Contraction
mechanisms
Anatomy & geometry
4. Literature
•
•
•
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Medical Physiology - Boron & Boulpaep
Cardiovascular Physiology Concepts – Klabunde
Heart Disease – Braunwald
Cardiovascular Medicine - Camm
5. From the sarcomere to the heart
From shortening to ejection
myocardium:
beating heart
myofilaments:
contractile
sarcomeres:
proteins
contractile
units
myofibers
myocytes
~10 nm
myofibrils
~2 µm
10-8 m
~1-10cm
~20x100 µm
10-6 m
10-4 m
10-2 m
32. Possible mechanisms Frank-Starling Relationship
Starling: “Law of the Heart”
(Linacre Lecture, 1915)
Increased sarcomere length >>>
Increased force of contraction
Possible mechanisms:
- Optimal actin-myosin overlap
- Reduced lattice spacing
- Altered myosin head
orientation
- Increased Ca sensitivity