ANATOMY(MUSCULAR SYSTEM)
SCHOOL: OXFORD UNIVERSITY
Muscular System
MUSCULAR SYSTEM
,
,MUSCULAR SYSTEM
, Musкular system
- Muscle cells are found in every organ in the body and participate in every
activity that requires movement.
Together, they constitute nearly half of our body mass. The most obvious are
the skeletal muscles that attach to the skeleton and give us strength and
mobility.
There are 3 types of muscles in our body:
1. Skeletal muscles: sculpt the body and contribute to our sense of
attractiveness and well-being. Some of the smallest skeletal muscles
control the focus of our eyes; some of the largest are responsible for
the shivering that helps keep us warm when it is cold.
2. Cardiac muscles: Rhythmic contractions of the cardiac muscle of
the heart pump blood throughout the body.
3. Smooth muscles: Powerful intermittent contractions of smooth muscle in
the walls of the uterus propel the child through the birth canal. Slower
waves of smooth muscle contractions push food through the digestive
tract and transport urine from the kidney to the bladder. Steady,
sustained contractions of smooth muscle in the walls of blood vessels
regulate blood flow to every living cell in the body.
Following are the major functions of the muscular system:
1. Movement of the body. Contraction of skeletal muscles is responsible for
the overall movements of the body, such as walking, running, and manipulating
objects with the hands.
2. Maintenance of posture. Skeletal muscles constantly maintain tone, which
keeps us sitting or standing erect. We tend to think of muscles as producing
movement, but another very important function of many muscles is to resist
movement. The maintenance of posture while standing is a good example. If
you faint, you collapse because you lose control over the muscles that support
your upright posture.
3. Respiration. Muscles of the thorax carry out the movements necessary for
respiration.
4. Production of body heat. When skeletal muscles contract, heat is given off
as a by-product. Under normal circumstances, contraction of our skeletal
muscles accounts for over three-quarters of all the heat generated by the body.