Difference between Voluntary and Involuntary muscles

Introduction to Voluntary and Involuntary muscles

Introduction:


What is muscle? In simple terms, these are a bundle of fibrous tissue in our body which can contract and expand, capable of producing movement in various parts of the body. Muscle is a soft tissue that is found in most animals. Muscle cells contain proteins. They are of two types called actin and myosin. These proteins slide past each other which produces a contraction movement. This contraction changes both the length and the shape of the cell. 
 
When you lift weights or run you need to exert force. This is provided by the muscle. Muscles provide force and help in motion. They are responsible for external motions, postures of sitting or standing, and for internal movements like the heartbeat. Also, the food that you take in through your mouth moves down the system. This movement is also done by the muscles and this movement is called peristalsis. 
 
Key attributes:


Predominantly there are three types of muscles called, skeletal muscles also called striated muscles, cardiac muscle, and smooth muscle. Another classification of muscles is Voluntary and Involuntary muscles. The muscles which move without our volition are called involuntary muscles. For example, the cardiac muscle in the heart and the smooth muscles are involuntary muscle. The skeletal muscles, on the other hand, are subject to our control, for example: bending of the hand.

The voluntary muscle or skeletal muscles are connected to the bones by tendons. These muscles help in movement or locomotion and help in maintaining body postures. An average male has approximately 42% of skeletal muscle and an average female about 36%. 
 
Smooth muscles are found in the internal organs like esophagus which is the food pipe, stomach, intestines, urethra etc: The smooth muscles are not under our conscious control, unlike the skeletal muscle. 
 
Cardiac muscle is found in the heart only and structurally resembles the skeletal muscle. Cardiac muscles and skeletal muscles are striated. They contain sarcomeres. Sarcomeres are the basic building blocks in muscle tissue. They are packed in regular arrangements and hence resemble striations. In skeletal muscles, the sarcomeres are in regular parallel bundles whereas in cardiac muscles they are in irregular angles. Striated muscles contract and relax in short bursts in intermittent fashion but the smooth muscles can sustain for a prolonged duration of time. 
 
Skeletal muscles are divided into two types: They are the slow twitch and fast twitch.

Slow twitch muscles are red and are dense with capillaries. They carry more myoglobin and thus have a dark red color. This muscle can carry more oxygen and can support any aerobic activity for a longer duration. 
 
Fast twitch tissues can contract very fast, but they will get fatigued very soon. They can sustain short bursts of anaerobic activity but soon the muscle contraction becomes painful. They contribute to muscle strength. 
 
The three types of muscles namely (cardiac, skeletal and smooth) have some key differences. Nonetheless, all three use the movement of actin against myosin for contraction. The contraction in skeletal muscles is stimulated by electrical impulses. In cardiac and smooth muscle cells this is done by the internal pacemaker cells which keep contracting regularly.

DIFFERENCES BETWEEN VOLUNTARY AND INVOLUNTARY MUSCLES


AttributesVoluntaryInvoluntary
ShapeStriped, skeletalPlain and unstriped
Type of cellMultinucleatedUninucleate
NucleusPeripherally locatedCentrally located
sarcolemmathickThin
Controlled byCentral Nervous systemAutonomic nervous system
ContractionsrapidSlow
EnergyRequires high energyRequires low energy
fatigueGets fatigued easilySlowly
functionUnder our willNot under our will