How Many Muscles Are In The Body?

There are more than 650 muscles in the human body. They perform a wide range of functions such as helping in movement, locomotion, respiration, and other important functions. The human body is made up of three types of muscles: Skeletal muscle, smooth muscle, and cardiac muscle. There are some voluntary muscles and some involuntary muscles. Voluntary muscles are under our control whereas involuntary muscles are not under our control. To know more about muscles, their types, locations, and function continue reading this article.

What are muscles?

Muscles are soft tissues present in both animals and humans. These muscles perform the function of contraction and relaxation. Muscles are made up of two types of protein: actin and myosin.

Types of muscles

There are mainly three types of muscles in the human body:

• Skeletal muscle

• Smooth muscle

• Cardiac muscle

Skeletal muscle

Skeletal muscles are attached to the skeleton system of the body through tendons. The following are some of the important characteristics of skeletal muscle:

• These muscles are long and cylindrical.

• These muscles contain more than one nucleus and are known as multinucleated

• They have a striated appearance due to the presence of alternate actin and myosin filament.

• These muscles are also excitable means these muscles expand on stretching

• Elasticity is also one of the important properties of these muscles.

• Contractility is the ability of a skeletal muscle to contract when receiving a stimulus.

• These are voluntary muscles.

Smooth muscle

The important characteristics of smooth muscles are explained below:

• These are involuntary muscles

• They are fusiform shaped

• These muscles have a single nucleus and are known as uninucleate

• These muscles have a nonstriated appearance

• They are unbranched

Cardiac muscle

The important characteristics of cardiac muscles are explained below:

• Cardiac muscles are striated in appearance

• They are branched

• These are involuntary muscles

• These muscles only present in the heart

• These muscles contain intercalated discs which are gap junctions connecting adjacent cardiac muscles.

Functions of skeletal muscle

The important functions of skeletal muscles are given below:

• Skeletal muscles help in maintaining posture.

• These muscles also allow body movements.

• Some skeletal muscles generate heat which helps in maintaining body temperature.

• They also serve as an energy source during starvation and fasting, as they store some amino acids.

• These muscles also provide structural support.

Functions of smooth muscle

The following are some of the important functions of smooth muscle:

• Smooth muscles are present everywhere in the body.

• These muscles aid in digestive functions and absorption

• These muscles are also found in the urinary system and help in excretory functions.

• Smooth muscles are strong muscles that help in childbirth.

Functions of cardiac muscle

The following are some of the important functions of smooth muscle:

• As it is already said that cardiac muscles are only found in the heart, so they perform special functions in the heart.

• These muscles help in pumping action.

• These muscles also help in the contraction of the heart

• These muscles contract continuously but never get fatigued.

Distribution of skeletal muscles in the body

Some of the Skeletal muscles of the head and neck:

• Zygomaticus: It is involved in facial expression and used while smiling.

• Masseter: This muscle is found in the jaw and used during food chewing

• Extraocular muscle: These muscles are found in the eye and control the movement of the eyes when opening and closing.

• Muscle of tongue: Tongue muscle help it movement

• Sternocleidomastoid: This muscle is involved in rotating or tilting the head.

Some of the Skeletal muscles of the trunk

• Intercostal muscle: These muscles are present around the ribs and thoracic cavity and help in respiration.

• Diaphragm: This muscle separates the abdominal cavity from the thoracic cavity. It is one of the primary muscles that help in respiration.

• Oblique muscle: There are two types of oblique muscle. Internal and external oblique muscles help us to bend and twist.

• Levator ani: These Muscles mainly help in urination and support our pelvic structure.

Some of the upper and lower limb muscle

• Trapezius: This muscle is used in raising our shoulder, tilting our head back, and several other movements of hand and shoulder

• Pectoralis major: This muscle is used for vertical, rotational, and lateral movement of our arm and is present in the upper chest region.

• Tricep brachii: This muscle is used for straightening the elbow

• Deltoid: This muscle helps us to lift and rotate our arm at the shoulder

• Quadriceps: These muscles are used to straighten out legs at the knee and are present in the thigh region.

• Hamstring: These muscles help in the movement of the leg and are present in the back part of the leg.

• Soleus: This Muscle helps in maintaining our posture while walking.