The muscular system is responsible for the locomotion or movement of the body. It maintains body posture and blood circulation.
This organ system contains more than 700 muscles and covers 40% of total body weight. The muscles get attached to blood vessels and bones. Muscle is made up of cylindrical and many long fibers which are arranged in parallel arrays. These fibers are made up of fine fabrics called myofibrils. Based on the movement there are three types of muscles.
1. Skeletal Muscles - It is a straight muscle and gets attracted to the bone by tendons.
2. Smooth Muscles - These muscles are present inside the blood vessels, stomach, and intestines.
3. Cardiac Muscles - These muscles are present inside the heart and mainly responsible for blood pumping.
[Image 2 – Muscular anatomy] Voluntary muscles are those muscles that are controlled by our will. For example skeletal muscle. Skeletal muscles are straight muscles that are attached to the bone. This straightness is caused by the presence of transverse marking muscle fiber in them. The muscle of a skeletal muscle is longer than other types of muscle tissue. It has a stripes-like appearance due to the presence of sarcomeres. Skeletal muscle also acts as an endocrine organ by secreting myokines. These voluntary muscles act under the control of the Somatic nervous system. Cardiac muscle and also straight muscle but it is a type of involuntary muscle and acts under the autonomic nervous system. The skeletal muscle contains fascicles and each muscle is formed from the fusion of myoblasts by the process of myogenesis.
The muscle fibers are composed of myofibrils. These myofibrils are made up of actin and myosin filaments called myofilaments. There are nearly 650 skeletal muscles present in the human body. Skeletal muscles are only muscle cells that are multinucleated and refer to as myonuclei.
The function of the Skeletal system
1. It provides support, movement, and protection to the body.
2. It is responsible for minerals, fat storage, and blood cell formation.
Involuntary muscles are those which don't depend on our will. For example smooth muscles. It is an involuntary non-striated muscle because it has no sarcomeres and no striations. Smooth muscles are found in hollow organs like the stomach, intestines, bladder, and uterus. Cardiac muscles are involuntary muscles that are striated. These muscles are found in the heart wall and enclosed in college fibers. The cell junction fuses the plasma membrane of cardiac muscle and helps to stick together. Cardiac muscle does not tire and contracts repeatedly. Smooth muscles are also a part of involuntary muscles. These are non-striations and taper at fusiform. It is present in the wall of internal organs like blood vessels, stomach, intestine. The function of smooth muscles is not directly controlled.
1. Involuntary muscles present in the skin are responsible for goosebumps during cold temperatures and fear.
2. It is responsible for the contraction of the iris.
3. Responsible for maintaining blood pressure and continuous blood flow.
1. Voluntary muscles are cylindrical long and unbranched in shape whereas involuntary muscles are small and spindle-shaped.
2. Voluntary muscles are multinucleated whereas involuntary muscles are uninucleate.
3. Voluntary muscles are found attached to the bones whereas involuntary muscles are found in a wall of internal organs.
4. Voluntary muscles have high energy requirements whereas involuntary muscles have low energy requirements.
5. Voluntary muscles have thick sarcolemma whereas involuntary muscle has thin Sarcolemma.
6. Action of voluntary muscles and regulated by somatic nervous system whereas the action of involuntary muscle and regulated by the autonomic nervous system.
7. Voluntary muscles have powerful and rapid contraction whereas involuntary muscles have a slow and rhythmic contraction.
8. Voluntary muscle requires high energy whereas involuntary muscle requires low energy.
9. Voluntary muscles are under the control of the Power bill as involuntary muscles are not governed by our will.
10. Voluntary muscle is involved in the movement of body parts and locomotion of a body whereas involuntary muscle involves internal movement of body parts organs and passage of leaves and food in the digestive system.
11. Voluntary muscles are present in the diaphragm, pharynx, abdominal wall of the tongue, muscles of the middle ear whereas involuntary muscles are present in blood vessels, Alimentary tracts, ducts of glands, urogenital tracts, respiratory tract, etc.
NCERT Class 10 Science Chapter 7 Control And Coordination introduces students to the concept of stimuli, which is the reaction and response of organisms respective to the changes in the environment. It also educates students about fundamental topics like voluntary and involuntary responses and what makes them different from each other.