Muscles || Scientific FS
Muscles
What are muscles?
Muscles are soft tissues, which can be described as the 'engine' that our body uses to propel itself. Like any other engine, muscles turn energy into motion. They are long-lasting, self-healing, and able to grow stronger with practice. A normal human body has more than 600 muscles. They account for about half of a person's weight.
What do muscles do?
Muscles do everything from allowing us to walk to keep our blood flowing. It would be impossible for us to do anything without our muscles. Muscles have the ability to contract and expand, and so they can maintain the position of the body parts, as well as facilitate the movement of internal organs.
What are the muscles made up of?
Muscles are made up of fibers, a type of elastic tissue. Each fibre is made up of long thin cells which are packed in bundles. Each bundle is wrapped in a thin skin called the perimysium. The bigger the muscle, the more bundles of fibres it has. Inside the muscles, there are nerves that carry messages to and from the brain. Muscle fibres contain filaments of two kinds of proteins, actin and myosin, that slide past one another, producing a contraction that changes both the length and the shape of the cell.
How many types of muscles does a human body have?
A human body has three different types of muscles: skeletal muscles, attached to the skeleton and come in pairs, smooth muscles, found in our digestive system, blood vessels, bladder, airways and in a female, the uterus and cardiac muscle, found only in the heart. the skeletal muscle is under voluntary control, and the smooth muscle is under involuntary control. The diaphragm (which controls breathing) is an exception to the smooth muscles being under involuntary control, to which a person can exert a limited amount of voluntary control also; for example: purposely holding one's breath or breathing quickly or deeply.
What are skeletal muscles?
Skeletal muscles are the ones we can see and feel. They are anchored by tendons to the skeleton and come in pairs - one muscle to move the bone in one direction and another to move it back the other way. They are used in skeletal movement or in maintaining posture. They are also called striated muscles because their light and dark parts make them look striped. They can do a short, single contraction (twitch) or a long, sustained contraction (tetanus).
What are smooth muscles?
Smooth muscles are usually in sheets or layers. We can't move them voluntarily. Smooth muscles have the ability to stretch and maintain tension for long periods of time and are used in involuntary actions, like breathing, digestion, etc. For example, our stomach and intestines do their muscular action all day long and that too, involuntarily.
What is the cardiac muscle?
The cardiac muscle is found only in the heart and is also known as the myocardium. it can stretch in a limited way, like the smooth muscle, and contract with the force of a skeletal muscle. The thick muscles of the heart contract to pump blood out and then relax to let blood back in after it has circulated through the body. Just like smooth muscles, cardiac muscles work under involuntary control.
Does a muscle perform a specific function?
Yes! Each muscle in our body has a specific function. For example, the biceps and triceps in the arms are used for writing, picking up things, or while playing tennis; the quadriceps and calf muscles in the legs are used for walking, running or jumping; the deltoids in the shoulders and trapezius in the back are used for moving the arms and shoulders; the pectorals in the chest and abdominals near the stomach are used for bending down, etc. We also have many muscles in our face; the masseter helps us to chew food.
Muscles can only pull or contract, not push. Thus, many muscles come in sets of antagonists that do opposite jobs. For example, the muscle on the top of our arm bends the arm at the elbow, while the muscle under our arm straightens the arm.
The tongue is the strongest muscle. The biggest muscle in the human body is the gluteus maximums, in the buttock; the smallest is the stapedius, in the ear.
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