Physiology Of Muscle Contraction Flashcards
In skeletal 4 Ca bind to?
Troponin C, but in heart 3 Ca, changes conformation, shuts off Tn1 tropomyosin- troponin leaves F-actin groove unmasks the myosin binding site on actin
Troponin I is a marker for?
Total muscle breakdown
Cardiac TnI is marker for?
Myocardial infarct
Macro molecular contraction?
Contraction depends on myosin head binding to think actin filaments at specific binding sites.
Otherwise blocked by tropomysoin
Cross bridge cycle?
- To allow myosin head to let go, release ADP, require ATP to allow myosin to let go of actin
- Myosin head cleaves ATP
- Myosin binds actin, when moved tropomysoin out of way (ca was present)
- Power stroke
What is rigor mortis?
ATP is needed to pump ca in sarcoplasmic reticulum.
ATP deleted
Myosin stuck to actin,
Rigor mortis ends when muscle tissue degrades after 3 days
How do you store ATP?
Creatinine is stored in muscle after phosphorylation
How to get energy from. Muscles?
Creatine phosphate (in mitochondria) gives a phosphate group to ADP.
Creatine phospho kinase does what?
Adds phosphate to creatine
Phosphokinase is a marker of?
Muscle destruction
Creatinine is?
Breakdown product of creatine, marker for kidney function
Depolarisation allows influx of calcium?
Active nicotine cells acetylcholine receptor, net inward current.
Causing depolarisation spread via T-Tubules
Local action potentials trigger Ca2+ efflux from terminal cisternae
Across membrane of sarcoplasmic reticulum
into the fibre cytoplasm
SERCA does what?
Puts ca back in the SR
Ryanodine receptor does what?
Releases ca from SR, triggered by voltage sensor on ca channel
Frequent APs cause complete tetany because?
Insufficient Ca resequestration so summation of contraction