Muscles are soft tissues found in most of the animals. Muscle contains muscle cells. Muscle cells consist of protein filament known as actin and myosin. These filaments produce contraction that changes the length and shape of a muscle. The main function of a muscle is to produce force and motion. Muscles are responsible for changing postures, locomotion, and movement of internal organs. The tissues from which the muscles are made are derived from the mesodermal layer of embryonic germ cells. The process in which the muscle tissues are derived from the mesodermal layer is known as Myogenesis.



There are mainly three types of muscles which are
1. Skeletal muscle
2.  Cardiac muscle
3.   Smooth muscle

Muscles can also be classified according to their action into voluntary and involuntary muscles. Voluntary muscle is under the control of a person while the involuntary muscle is out of control of a person. Smooth and cardiac muscles are involuntary while the skeletal muscle is voluntary.

The muscle gets energy from ATP which powers the myosin head. Muscle is a Latin word that means little mouse and this name is given to it because on contraction muscles look like mice moving.

What are the types of muscles?

Muscle tissue is a fundamental type of tissue present in the body. There are main types of muscles.

1. Skeletal muscle

Skeletal muscle is a voluntary muscle. These muscles are anchored to the bone. These tissues are responsible for locomotion and maintaining postures.

2.  Smooth muscle

These are involuntary tissues and are found in the wall of internal organs such as the stomach, intestine, uterus, bronchi, urethra, blood vessels, and esophagus, etc. These tissues are not under conscious control.

Cardiac muscle

These are also involuntary tissues and are found only in the heart of the body. These tissues are also known as myocardium.



What are the functions of muscles?

The main function of the muscle tissues is given below. Some of these functions are directly performed by the muscles while other functions given below are not directly performed by muscles but muscle tissues play a major role in these functions.
1. mobility
2.  Stability
3.  Posture
4.  Circulation
5.  Respiration
6.  Digestion
7.   Urination
8.   Childbirth
9.   Vision
10.     Organ protection
11.   Temperature regulation




What is a muscular system?

It is a system that consists of all the muscles present in the body. Approximately six hundred fifty muscles are present in the body but this is not an exact number. The variation in the number occurs due to some muscles such as palmaris longus that are not always present.

The muscular system is a part of the musculoskeletal system. The musculoskeletal system is a system that consists of muscles, bones, joints, tendons, and other structures that produce movements.

Development of muscles

All muscle present in the body is derived from the paraxial mesoderm. The paraxial mesoderm is divided into somites and somite has three divisions that are sclerotome, dermatome, and myotome. The myotome is further divided into two parts that are epimere and hypomere. Myotome form the epaxial and hypaxial muscle.  Epaxial in the human is erect or spine and intervertebral muscles. All other muscle tissues that include limbs are hypaxial.

What are the properties of a muscle?

To perform the normal and stable functions muscles have some unique properties that are

1. Muscles receive and respond to stimulation from nerves.
2. Muscle has the ability to change its size.
3.  Muscle has the ability to stretched without any damage.
4.  Muscle changes its structures according to its use such as hypertrophy and atrophy.
5. Muscle has the ability to regain its normal state after contraction.

What is muscle physiology?

There is a lot of difference between the three types of muscle tissues but all tissues use the movement of protein filament actin against the myosin to produce a contraction. In skeletal muscle electrical impulse is responsible for the contraction while in cardiac and smooth muscle pacemaker cell cause the contraction.

The action that a muscle generates is determined by two factors that are origin and insertion of a muscle.

What is hypertrophy?

Hypertrophy is a condition in which muscles grow larger. Hypertrophy is caused by a number of factors that included strength training, diseases, hormone signaling, and developmental factors.

Muscle hypertrophy occurs in males at puberty at an accelerated rate because of the increase in stimulating hormones.

What is Atrophy?

The decrease in muscle mass or size is known as atrophy. Muscle Atrophy is caused by starvation and inactivity.  Other factors that cause muscle atrophy are aging, and diseases.

Prolonged immobilization such as bed rest results in muscle weakening and cause atrophy. Diseases that cause muscle atrophy are
Congestive heart disease
And diseases of the liver.

Why muscles are important?

Muscle tissues are important because these tissues create movement by pulling our bones. Cardiac muscle tissues help the heart to pump the blood through life. Muscle tissues also help the systems of the body to perform its function such as the circulatory system, and digestive system.

What are some of the major muscles?

Some of the major muscles present in the body are
Pectoralis major
Rectus abdominalis
Rectus femoris etc.



List of Some of the skeletal muscle

1. Occipitofrontalis
2.  Occipitalis
3.  Frontalis
4.  Orbicularis oculi
5.  Corrugator supercilli
6.  Depressor supercilli
7.  Levator superioris
8.  Superior tarsal
9.  Rectus superior
10.  Rectus inferior
11.  Rectus medial
12.  Rectus lateral
13.  Oblique superior
14.  Oblique inferior
15.   Auriculares
16.   Temporoperatilis
17.   Stapedius
18.   Tensor tympanic
19.   Procerus
20.   Nasalis
21.   Dilator naris
22.   Septi nasi
23.   Levator labii
24.   Anguli Oris
25.    Depressor anguli oris
26.   Levator labii superior
27.   Depressor labii inferiors
28.   Mentalis
29.   Buccinator
30.   Orbicularis oris
31.    Zygomatic major
32.    Zygomatic minor
33. .   Masseter
34.   temporalis
35.   Pterygoid muscles
36.   Genioglossus
37.   Hypoglassus
38.    Chondroglossus
39.    Styloglossus
40.     Palatoglossus
41.     Superior longitudinal
42. superior longitudinal
44.     Verticalis
45. .    Levator villi
46.     Tensor villi
47.      Musculus uvulae
48.      Palatoglossus
49.       Palatopharyngeus
50.      Stylopharyngeus
51.     Salpingopharyngeus
52.       Pharyngeal Muscles
53.      Cricothyroid
54.      Arytenoid
55.       Thyroarytenoid
56.       Cricoarytenoid muscles
57.       Platysma
58.       Sternocleidomastoid
59.        Digastric
60.       Stylohyoid61.        Mylohyoid
62.        Geniohyoid
63.        Sternohyoid
64.        Sternothyroid