There are three types of muscle cells. Skeletal, smooth
and cardiac, which tend to regulate blood pressure and move food though the digestive tissue. Skeletal muscle cells are used
for voluntary movements, which can include: dancing to the winking of an eye. These movements are controlled by the nervous
system. Smooth muscles
move food through the digestive tract to the walls of the stomach to the small intestine. They also control the blood flow
in the circulatory system. They decrease the size of pupils. They are connected by gap junctions, which allow an impulse to
travel to the muscle cells. They are also controlled by the nervous system. Cardiac muscles are found in the heart. They are
under the control of the nervous system however; they are not completely controlled by it.
Myosin and actin filaments cause
the muscles to contract and relax. When the thin filaments overlap the thick filaments it decreases the distance between the
z lines, which cause a contraction in your muscle. This is a reoccurring cycle by ATP. The ATP is produced by cell respiration
and fermentation. Neuromuscular junction is the contact between the motor neuron and the skeletal muscle cell. Vesicles are
pockets, which release a transmitter called acetylcholine. They diffuse and an impulse in a cell membrane muscle fiber release
calcium ions, which are found inside the fibers. These calcium ions allow the interaction with Myosin and actin. Muscle relaxes
when acetylcholine stops, and the remaining calcium ions are pumped to storage cross bridges and stop the contraction too. Our
body doesn’t waste cells. When lifting something light, only a few cells contract, whereas if you life something heavy
you need more cells working. Tendons are connective tissues at your joints that help your joints pull like levers. This is
a controlled movement. When muscles contracts the other relaxes. This is a form of balance. Muscle tone is a partial contraction
that keeps the body aligned when you are sitting or standing. The more exercise in muscles the more actin and myosin filaments
are built which causes your muscles to get bigger. Aerobic exercise strengthens the efficiency of your heart and lungs and
strengthens bones.
|