How Many Muscles Occur in the Human Body?

It’s considered that there are above 650 named skeletal muscles in the body. Smooth muscle occurs on a cellular level, to have billions of smooth muscle cells. Skeletal muscles can be controlled, while cardiac & smooth muscles work involuntarily.

Types of muscles

The body has three distinct kinds of muscles. They include:

1. Skeletal muscle

  • Attached to your bones via tendons
  • Comprised of thousands of muscle fibres
  • All are bundled together.
  • The organized arrangement of fibres leads to a striped pattern.
  • Referred to as striated muscle.
  • Predominantly involved in the movement.
  • Enables movement of a specific area of the body
  • These are voluntary.
  • You can control their movement. 

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2. Smooth muscle

  • Found in different organ systems of the body, including:
  • Digestive System
  • Respiratory System
  • Cardiovascular System
  • Renal System
  • Reproductive System
  • Smooth muscle cells are rounded at the centre and tapered off at the sides.
  • They aren’t striated & involuntary.
  • Forms a mesh-like network.

3. Cardiac muscle

  • Found only in the heart.
  • Allows heart to beat.
  • Referred to as the myocardium.
  • Three layers of tissue in the heart.
  • Located within the inner lining of the heart (endocardium)
  • The protective sac that surrounds the heart (pericardium)
  • Organized into fibres and has a striated appearance.

4. Skeletal muscle functions

  • Enabling movement of the body
  • Providing structural support
  • Maintaining posture
  • Generating heat, which helps maintain body temperature

Division of Skeletal muscles 

1. Muscles of the head and neck

Controls movement of the face, head, and neck.

  • Zygomaticus: Involved in facial expression and lifts the corners of mouth while smiling.
  • Masseter: Found in the jaw and is used to close the mouth and to chew food.
  • Eye (extraocular) muscles: Movements of eyes and opening-closing of eyelids.
  • Powers of the tongue: Help to elevate & lower the tongue and help it move in-out.
  • Sternocleidomastoid: Rotate or tilt head to the side & front.

2. Muscles of the trunk: Located in torso and abdomen

  • Erector spinae: Supports spine and enabling movements like bending, arching, and twisting of the spine.
  • Oblique muscles: Helps to bend to the side or twist the body at the waist.
  • Intercostal muscles: Located around ribs to help facilitate inhaling & exhaling.
  • Diaphragm: Separates torso from the abdomen & involved in breathing, contracting while inhaling, relaxing while exhaling.
  • Levator ani: Supports the organs and tissues around your pelvis. Important for urination and bowel movements.

3. Muscles of the upper extremities: Move shoulders, arms, wrists, hands.

  • Trapezius: Used for several movements, tilting head back, raising shoulders, and moving shoulder blades.
  • Pectoralis major: Located in the upper chest, Utilized in rotational, vertical, & lateral movements of the arm.
  • Deltoid: Lift or rotate the arm at the shoulder.
  • Biceps brachii: Flexes the forearm.
  • Triceps brachii: Extends the forearm, aligning the elbow.

4. Muscles of the lower extremities: Move legs and feet.

  • Gluteus maximus: movement of hips and thighs for maintaining posture, standing up.
  • Quadriceps: Positioned at the front of the thigh to straighten the leg at the knee.
  • Hamstrings: Located in the back part of the leg. Extend thigh and bend leg at the knee.
  • Tibialis anterior: Raises the sole from the ground
  • Soleus: Lowers the sole of foot to the ground, maintains posture while walking.

5. Smooth muscle

  • Digestive system: push food through the digestive tract.
  • Respiratory system: Cause airways to widen or narrow
  • Cardiovascular system: Aids in the flow of blood and regulate blood pressure.
  • Renal system: Regulate the flow of urine from the bladder.
  • Reproductive system: In the female reproductive system helps in contractions during pregnancy. In the male reproductive system, it propels sperm.
  • Smooth muscle is involved in sensory processes.

6. Cardiac muscle

  • Allows heart to beat with an electrical impulse.
  • Contracts on receiving an electrical signal
  • Closely connected
  • Contract in a coordinated wave-like

The Bottom Line

Muscle tissue is found everywhere in the body, and its composition and function can be very different. You have three distinct types of muscle: skeletal, smooth, and cardiac. Skeletal muscle solely accounts for over 650 muscles.

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