Chapter 10: Muscle Terms 2 Flashcards
(34 cards)
acetylcholinesterase (enzyme)
breaks down acetylcholine into acetyl and choline which can no longer bind to receptor
what is included in the sliding filament theory of contraction?
(excitation/contraction coupling)
what are the 4 steps in the generation of a muscle action potential?
- release of acetylcholine
- activation of acetylcholine receptors
- production of muscle action potential
- termination of acetylcholine activity
what are the 5 steps in the sliding filament theory?
- action potential
- release of calcium ions
- exposure of myosin binding site
- contraction cycle
- relaxation
rigor mortis
-occurs in the first 3-4 hours and lasts about 24hr
-lack of ATP so myosin heads cant detach from actin. hence rigidity
-lysosomes rupture and eventually soften
curare
-binds to acetylcholine receptors, cant generate an action potential
-cant be destroyed by acetylcholinesterase
-blocks binding site
-leads to paralysis, and death if the diaphragm
acetylcholinesterase inhibitors
-seven dust + sarin (nerve gas)
-blocks the destruction of acetylcholine.
-remains in synaptic cleft bound to receptors prolonging depolarization
- repolarization cannot reoccur and new ATP unable to be regenerated
-death through asphyxiation diaphragm cant relax
botulism
-clostridium botulinum
-blocks release of acetylcholine from motor neuron
-action potential cannot be generated in skeletal muscle cell and cannot contract
What is the length-tension relationship?
-the greatest force of contraction generated by a slight stretch
-sarcomere too shortened = thick filaments crumple against z discs, fewer formed cross bridges
-sarcomere too stretched = less filament overlap and less myosin cross-bridge formation = lower force of contracton
muscle tone
-the firmness of skeletal muscle in a relaxed state
- this tone/firmness is a result of some muscle fibers being contracted, while most relaxed
-important for smooth muscles ex. walls of the gastrointestinal tract and blood vessel
flaccid paralysis or hypotonia
neurological disorders associated with muscle tone
hypertonicity
spasticity - stiff muscles due to increased tendon reflexes
rigidity - increased muscle tone without reflexes affected (Parkinson’s disease)
creatine phosphate
-stores ADP, forming ATP
-10-15 seconds of energy for muscle contraction
- good for short bursts of energy of maximal muscle contraction
anaerobic cellular respiration
- no oxygen
-2/ATP per glucose - 30-90 seconds of muscle activity
- bi-product of lactic acid, diffuses back into the blood in the liver and then back to glucose
Aerobic respiration
- no oxygen
-36ATP per glucose - 30-90 seconds of muscle activity
- bi-product of lactic acid, diffuses back into the blood in the liver and then back to glucose
- 1 glucose = 2 ATP from glycolysis and 34 from cellular respiration (36 total)
- ## bi-product = water + carbon dioxide
oxygen debt
-added oxygen that is taken into the body after exercise
-used to restore muscles to resting level
1. convert lactic acid to glucose then glycogen
2. synthesize creatine phosphate and ATP
3. replace oxygen removed by myoglobin
myogram
recording of a muscle contraction/ contraction of all muscle cells in a motor unit
refractory period
the time it takes for the fiber to recover before it can be stimulated again
wave summation
when a muscle fiber is stimulated after the refractory period- a larger contraction can be generated
isotonic contractions (concentric + eccentric)
occur when muscle maintains the same tension or force of contraction as it changes length
concentric contraction
-overcome resistance ex. bicep curl
eccentric contraction
lowering book slowly ex bicep extension
isometric contractions
the tension created does not move the object nor change muscle length
slow oxidative fibers
-red, lots of myoglobin to store O2
-generate ATP by aerobic cellular respiration using blood glucose
- don’t tire quickly but don’t contract quick either
-good for postural muscles and endurance activities
