What You Should Know About Your Muscles

For years, muscles were considered simple organs that merely followed orders from the brain. Today, science reveals a far more complex picture: muscles are dynamic powerhouses, controlling key metabolic processes and acting as crucial sensory organs. Here’s everything you need to know about these superstars of the human body.

The Basics About Muscles

Your body contains between 639 and 650 muscles, depending on the source. Among these, around 400 skeletal muscles are responsible for movement. For instance, taking a single step engages more than 40 muscles. Muscles are the largest trainable organ in your body, becoming stronger and more efficient with regular use.

Key facts about your muscles:

• Composition: Muscles are 75 % water and 18,5 % protein, plus small amounts of fat, salt, and carbohydrates.
• Energy factories: Muscles house countless mitochondria, tiny cells that generate energy using adenosine triphosphate (ATP).
• Structure: Muscles are organized in a layered system:
  • Fiber bundles: Wrapped in fascia, which maintains their shape and position.
  • Muscle fibers: These bundles are rich in blood vessels that deliver oxygen and glucose.
  • Myofibrils: These tiny structures (just 1/1000th of a millimeter in diameter) are made up of sarcomeres, which control muscle contractions.
  • Filaments: The smallest units, made of actin and myosin, slide and lock together during contractions to produce tension.

How Muscles Work

Muscles convert chemical energy into movement through a complex „tug-of-war“ mechanism. This process uses a mix of:

• Creatine phosphate
• Glucose
• Glycogen
• Lactate
• Fatty acids
• Triglycerides

Some fuels are stored in the muscle, while others are delivered via the bloodstream. The energy is either converted without oxygen into ATP or burned completely into carbon dioxide and water for efficiency.

The Three Types of Muscle Tissue

1. Skeletal Muscles:
   • These muscles are voluntary and respond to your will.
   • Contains slow-twitch fibers (for endurance) and fast-twitch fibers (for power).
2. Smooth Muscle Tissue:
   • Found in organs like the stomach, intestines, and bladder.
   • These muscles work automatically, without conscious control.
3. Cardiac Muscle Tissue:
   • The heart muscle is both involuntary and incredibly adaptable.
   • With proper training, the heart can become stronger and more efficient.

Special Muscles You Should Know About

• Strongest muscle: The chewing muscle (masseter) generates the most force relative to its size.
• Hardest working muscles: The eye muscles move up to 10,000 times per hour when reading.
• The most reliable muscle: The heart, which pumps 70 milliliters of blood per beat—a staggering 300 liters per hour, enough to fill a bathtub.
• Largest muscle: The gluteal muscles dominate in size.
• Smallest muscle: The stapedius, located in the middle ear.

Muscles and Health

Muscles are your body’s largest metabolic organ, playing a key role in calorie burning and oxygen supply. Beyond movement, they impact many aspects of health:

• Thermoregulation: Muscles help regulate body temperature. They trigger sweating in heat and shivering in cold.
• Lymphatic System: Stretching and movement push toxins from lymph nodes into the lymphatic system for excretion.
• Brain Connection: Muscles act as an extension of the brain, improving mental performance when functioning well.
• Blood Circulation: Training opens up capillaries, enhancing oxygen and nutrient delivery to distant tissues.