Types of muscle fibres - class-XI

• Muscle is a  bundle of fibrous tissue in a body that has the ability to contract, producing movement in or maintaining the position of parts of the body.
• The total number of muscles in the human body comes in the range of 640-850.
• Muscles appear in red color due to a pigment called myoglobin. It receives oxygen from the red blood cells and transports it to the mitochondria of muscle cells, where the oxygen is used in cellular respiration to produce energy. Hence myoglobin occurs in red muscle fibers. So, the correct answer is 'Red muscle fibers'.

• Collagen is a type of protein fibre found abundantly throughout our body.
•  It provides strength and protects many different areas of the body, including the skin.
•  These White fibres, made up of collagen are white and shining which are strong, non-elastic and tough. 
• More specifically, collagen is found in our various types of connective tissues such as cartilage, tendons, bones, and ligaments. Hence, collagen fibres are white.

• Muscle is a  bundle of fibrous tissue in a body that has the ability to contract, producing movement in or maintaining the position of parts of the body.
  
• Muscles appear in red color due to a pigment called myoglobin. Myoglobin receives oxygen from the red blood cells and transports it to the mitochondria of muscle cells, where the oxygen is used in cellular respiration to produce energy.
• Cytochrome is a protein associated with the inner membrane of mitochondria. As the number of mitochondria is abundant in red fibers thus represents the abundance of cytochrome in red muscles. 
• Hence red muscles are rich in myoglobin and cytochrome.
• So, the correct answer is 'Myoglobin and cytochrome'.

• Cardiac muscles are the muscles of the heart. They have striated appearance and are involuntary in nature.
• Each heart cell has about 5000 mitochondria i.e far more mitochondria than any other organ in the body!
• Mitochondria are more in cardiac muscles because the constantly-beating heart works harder than any other organ in your body and thus requires more amount of energy.
  
• So, the correct answer is 'Cardiac muscles.

• Sarcolemma is the cell membrane of a striated muscle fiber cell.
•  It is the outer layer of a striated muscle fibre
  
•  It consists of a lipid bilayer and a thin outer coat of polysaccharide material (glycocalyx) that contacts the basement membrane. Hence, Sarcolemma is the outer membrane of muscle fibre.

• White fibers appear white in color because They have lower myoglobin and therefore lower oxygen content, which is why they do not appear reddish.
• White fibers are made up of collagen whereas yellow fibers are made up of elastin.
• The function of white fibrous tissue is to connect structures of the body together while providing support and shock absorption to the structures. For Example, ligaments, and tendons.
  
• Hence The white fibers are chemically composed of Collagen.
• So, the correct answer is 'Collagen'.

Myosin filaments are thicker and confined to the A- bands only. They are composed of myosin protein.

• Muscle is a  bundle of fibrous tissue in a body that has the ability to contract, producing movement in or maintaining the position of parts of the body.
• Muscles appear in red colour due to a pigment called myoglobin. It receives oxygen from the red blood cells and transports it to the mitochondria of muscle cells, where the oxygen is used in cellular respiration to produce energy. Hence they are also called aerobic muscles.
• Hence the flight muscles in an eagle have more of aerobic muscles. These muscles are also called red muscles because they are rich in myoglobin.
  
• So,the correct answer is 'Myoglobin'.

The myofibril appears striated as they are composed of actin and myosin filaments, repeated in units called sarcomere, which is the basic functional unit of the muscle fiber. The sarcomere is responsible for the striated appearance of muscle.The actin is thin filament and myosin is thick filaments.

• Muscle is a  bundle of fibrous tissue in a body that has the ability to contract, producing movement in or maintaining the position of parts of the body.
• The total number of muscles in the human body comes in the range of 640-850.
• Red muscle fibers are rich in mitochondria. The muscle cells are red due to the presence of a protein called myoglobin. The myoglobin provides the oxygen to the mitochondria which in turn generate ATP. Hence red muscle fibers are rich in mitochondria.
• So, the correct answer is 'Mitochondria'.

The outer connection tissue covering of a muscle is the epimysium. Within muscle, there are subdivisions called fascicles. The perimysium surrounds these muscle fascicles. The endomysium is the covering around an individual muscle fibre.

The muscle that is dense with capillaries and is rich in mitochondria and myoglobin has a characteristic red color. Hence the name red muscle.  mitochondria which can utilize a large amount of oxygen stored in them for ATP production. Thus the correct answer is option D.

• Muscle is a  bundle of fibrous tissue in a body that has the ability to contract, producing movement in or maintaining the position of parts of the body.
• The total number of muscles in the human body comes in the range of 640-850.
• Muscles appear in red colour due to a pigment called myoglobin. It receives oxygen from the red blood cells and transports it to the mitochondria of muscle cells, where the oxygen is used in cellular respiration to produce energy. 
• Muscle fibres are named as white muscle fibres because It contains a low amount of myoglobin and mitochondria.compared to red muscle fibres.
• So, the correct answer is 'It contains a low amount of myoglobin and mitochondria'.

The slow twitch muscle fibres which are rich in myoglobins and have abundant mitochondria are 'white skeletal muscles'.

Red muscles (A) are rich in myoglobin, have many mitochondria, and rely on aerobic respiration. White muscles (B) have less myoglobin, fewer mitochondria, and rely more on anaerobic respiration with abundant sarcoplasmic reticulum.

Fast oxidative type of muscle fibres is generally found in the sprinters that need to run for a short amount of time. They do not need to have a very large number of mitochondria for continuous ATP production but they do need to have speed. So in such muscle fibres, there is a high glycogen content which is converting into lactic acid rapidly and fatigue is caused more early.

Red muscles contain a large amount of mitochondria as it requires large amount of energy. White muscles contain fewer mitochondria. Pectoralis major is the flight muscles of the birds. It helps birds to flight. It is a red muscle. The autonomic nervous system is involuntary. It controls cardiac and smooth muscles, glands and blood vessels. Cardiac muscle has abundant blood supply. It extracts approximately 75% of the oxygen from blood in the left ventricle.