Biology Questions and Answers
The excitation is conduced to the
sarcoplasmicrealeases calcium reticulum that th ions into theen
sarcomeres.
In the sarcomeres thto troponin molecules associated toe calcium ions bind
actin activatingactin. The myosin, th myosin bien able to bind tonding sites of
actin, pulls this protein and the
sarcomersimultanee shortens. Tous contraction ohe summation of sarcomeresf (^)
and myofibrils constitutes the muscle
contraction.the calcium ions return back to th During muscle relaxatione
sarcoplasmic reticulum.
For myosin to bind to actin, and thus for
the contraction to one ATP molecule is neoccur, hycessary.drolysis During of (^)
relaxation the return of calcium ions to
the sarcoplasmicprocess that spends A reticulum is an TP too. So bactiveoth
muscle contraction and relaxation are
energy-spending processes.
- What is myoglobin? What
is the function of this
molecule in the muscle tissue?
Myoglobin is a pigment similar to
hemoglobin and present in mfibers. Myoglobin has a great afusclefinity for (^)
oxygen. It keeps oxyreleases the gas under strenuousgen bound and
muscle work. So myoglobin acts as an
oxygen reserve for the muscle cell.
- How does phosphocreatine
act in the muscle contraction
and relaxation?
Phosphocreatine is the main means of
energy storage of the muscle cells.
During relaxed periods ATP molecules
made by the aerobic cellular transfer highly energized phosphaterespiration
groups to creatine formingphosphocreatinphosphocreatine. In exercise periodse and ADP resynthesize (^)
ATP to dispose energy for the muscle
contraction.
- What happens when the
oxygen supply is insufficient
to maintain aerobic cellular
respiration during muscle
exercise?
If oxygen from hemoglobin or
myoglobin is not supply of the muscle cell the cell theenough for the energyn
begins to do lactic fermentation in an
attempt to compensate the deficiency.
The lactic fermentation releases lactic
acid and this substance causes mfatigue and predisposes the muscles touscle (^)
cramps.
- What is the
neurotransmitter of the
neuromuscular junction? How
does the nervous system
trigger muscle contraction?
The nervous cells that trigmuscle contraction are the motorger the (^)
neurons. The neurotransmitter of the
motor motor neurons is acetylcholine. Wneuron is excited the depolarizihen ang (^)
current flows along the membrane of its
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