Muscle is made up of elastic tissue. Thousands of muscle fibres constitute elastic tissues. These muscles work together with the nerve fibres to do all voluntary and involuntary functions of the body. Depending on the presence of muscle fibres the muscle strength varies. There are three types of muscles skeletal muscle, striated muscles, and smooth muscle.
Approximately about 30%- 40% of our body weight is comprised of skeletal muscles. These muscles are connected with the bones and perform a variety of functions. All the voluntary functions of the body are controlled by the skeletal muscles. At the time of contract and release, this muscle produces heat and this maintains the body temperature. The skeletal muscles are further subdivided into red muscles and white muscles. Mitochondria and myoglobin are rich in red muscles while in white muscles they present in less amount. In this, we will learn about red and white muscles in depth.
Red muscles are the type of skeletal muscles. This is muscles are also known as slow-twitch muscles. Myoglobin and mitochondria are present in abundance in this type of muscle. The oxygenated blood is transported to the muscles with the help of capillaries which are small blood vessels. Myoglobin which is rich in these muscles absorbs oxygen. Then myoglobin transfers the oxygen to the mitochondria which are known as the powerhouse of the cell. Mitochondria use oxygen and other substances to produce a lot of energy.
The red muscles are red in colour due to the presence of an abundance of myoglobin, which imparts red colour in addition to this mitochondrion and rich capillary gives the dense red colour to these muscles.
Red muscles are composed and designed in such a way that they give a lot of energy. The red muscles are able to contract slowly but for an extended period of time because of the presence of slow twitch fibres. These types of muscles are always active.
More than one type of muscle fibre is present in muscles in our body. As the muscles have the same functions again and again for long periods of time some of the muscles have slow twitch fibres. Back muscles and lower leg muscles are made up of slow twitch fibres. As these muscles help to stand and make a correct posture for a longer period of time. Slow twitch fibres work enormously for doing work, exercise, or even in still posture. These activities are included
Morphological studies reveal that red fibres are small in size in diameter. Mitochondria are present in between the myofibrils and beneath the sarcolemma. Lipid drops are present in the sarcolemma. Red muscles are very efficient in maintaining posture.
White muscles are the type of skeletal muscles. This is muscles are also known as fast-twitch muscles. They have lower myoglobin and mitochondria. Their oxygen contents in the muscles are low as the myoglobin concentration is not abundant. They are not reddish in colour instead they are whitish as the name is suggested. As low concentrations of oxygen are present in white muscles they gain energy anaerobically mainly from the glycogen. In a shorter time glycogen can provide energy in a quick manner. That is the reason white muscles are stronger and contract faster. It is also become exhausted very quickly as it contracts faster. These muscles also become fatigued in a short period of time.
While muscle fibres are thicker and have a high chance to grow. This type of muscle is responsible for most of the body’s muscle strength and its increase in mass after periods of weight training
The white muscle fibres are activated when the body is doing high-energy impact activities like
Above mentioned activities can do only for a short period of time. Morphological studies of white muscles show that these are larger in diameter in comparison to red muscles. Mitochondria and lipids are smaller in diameter and are not present as abundant as red muscles. These muscles are suitable for intense muscle activities.
| White muscles | Red muscles |
|---|---|
| Rich in myoglobin, capillaries and mitochondria | Less amount of myoglobin and mitochondria. |
| Smaller and thinner in size | Larger and thicker in size. |
| Red in colour | White in colour |
| Presence of numerous mitochondria | Less amount of mitochondria is present |
| Sarcoplasmic reticulum are moderately developed | Sarcoplasmic reticulum is well-developed |
| Blood capillaries are more in number | Blood capillaries are less in number |
| Do not accumulates lactic acid | Accumulate lactic acid |
| Contraction is slow | Contraction is fast |
| Can work longer period of time | Can work slow period of time |
All the voluntary functions of the body is controlled by skeletal muscles. Skeletal is further subdivided into red muscles and white muscles. Red muscles have an abundance of capillaries, mitochondria, and myoglobin and are red in colour. White muscles have less amount of mitochondria and myoglobin and are white in colour. Physiologically red muscles contract slowly and are resistant to fatigue in comparison to white muscles.
Q1. What is myoglobin?
Ans. Myoglobin is a protein found in skeletal muscles as well as cardiac muscles. It works as a storage unit of oxygen and supplies oxygen to the muscles.
Q2. Why mitochondria are known as the powerhouse of the cell?
Ans. Mitochondria are known as the powerhouse of cells as they release energy from food. They are responsible for making adenosine triphosphate (ATP), the cell’s main energy-carrying molecule. ATP represents the short-term stored energy of the cell. Cellular respiration is the process of making ATP using the chemical energy found in glucose and other nutrients. In mitochondria, this process uses oxygen and produces carbon dioxide as a waste product.
Q3. What is sarcoplasmic reticulum?
Ans. It is composed of different types of cisternae and tubules present in the skeletal muscles. It is responsible for the storage of intercellular calcium. It also controls the concentration of calcium and plays an important role in the determination of contractions of muscles.
Q4. What is glycogen?
Ans. Most mammalian cells, nonmammalian cells, microorganisms, and even some plants contain polysaccharides. It is the source of stored glucose. It is stored mainly in the liver as well as in fats and muscle cells.
Q5. What are voluntary functions?
Ans. The action which is completely controlled by us is known as voluntary functions. It is complete dependence on the consciousness of individuals. Voluntary actions include walking, running, taking, picking up things, switching on or off the television, etc.
Q6. What are capillaries?
Ans. Capillaries are the thinnest blood vessels that are present throughout the body. It transports blood, nutrients, and oxygen all over the body.
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