Muscles Flashcards
(36 cards)
Myofiber
Skeletal muscles
Proteins found in muscles
Superficial to deep
Fascicles -> myofiber -> fibrils -> myofilament
What makes muscle cells so special?
- Contractability!
- converting of chemical energy to mechanical energy.
What are the 3 classes of myofilaments?
1) Actin
2) Myosin
3) Elastic
Actin
Contraction
Thin filaments
Myosin
Thick filament
Contraction
Elastic
Recoil!
What is dystrophin?
The protein that attaches actin and myosin to the plasma membrane
What are the parts of a sarcomere?
A-band
I-band
H-band
A-Band
Both thick and thin filaments
H-band
Thick filaments only
I-band
Thin filaments only
What is a sarcomere?
Each segment of a myofibril from one z-disc to another z-disc
What is Action Potential?
The voltage shift in an excited cell from (-) to (+) to (-) again
What maintains Resting Membrane Potential?
The Na/K pump
Neuromuscular junction
The place where a nerve cell meets a muscle cell and delivers a synapse.
Nerve ends at synoptic knob
Why is ATP needed for contraction?
A myosin head must have ATP to hydrolize into ADP + P. the energy released by the reaction activates the myosin head.
Why is ATP needed for relaxation?
ATP is needed to actively pump Ca back into the SR.
What causes rigor mortis?
Deterioration of the SR -> release Ca into the cytosol
No ATP to pump Ca away from cytosol and break the myosin-actin crossbridge
Isometric contraction
Tension changes
No change in length
Isotonic contraction
No tension change
Changes in length
Eccentric contraction
Shortening
Eccentric contraction
Lengthening
ATP production during immediate energy demands
Myoglobin
Phosphagen system
