MUSCULAR TISSUEPrepared by:

Sharmin SusiwalaFY BPT

Definition of muscle:

Muscles are red, fleshy mass of the body located under deep fascia.

The muscles are also found in heart and in various organs like stomach, intestine, urinogenital organs and also in blood vessels.

Facts on muscles:

Muscle is a contractile tissue which brings about movements.

Muscles can be regarded as motors of body.

Study of muscle is called General myology.

TYPES OF MUSCULAR TISSUES

• Smooth Muscle tissue• Cardiac Muscle tissue• Skeletal Muscle tissue

Skeletal Muscle Tissue: Skeletal (voluntary & striated) muscle fibers are

multinucleated cylindrical structures having a clear display of longitudinal and cross striations.

Skeletal muscle or "voluntary muscle" is anchored by tendons (or by aponeurosis at a few places) to bone and is used to effect skeletal movement such as locomotion and in maintaining posture. Though this postural control is generally maintained as a subconscious reflex, the muscles responsible react to conscious control like non-postural muscles. An average adult male is made up of 42% of skeletal muscle and an average adult female is made up of 36% (as a percentage of body mass)

Skeletal muscle fibers is striated, or striped and is under control of the individual’s will.

For this reason, it is often called “voluntary” muscle tissue.

Skeletal muscle tissues are usually attached to bones. That is known as osseous tissues which is innervated with somatic nerves through which volitional control is performed.

When muscle fibers are stimulated by an action of a never fiber, the fibers contract and relax.

This interaction between muscle and nerve fibers produces movement.

It can perform works of rapid, powerful contraction as well as that of prolonged slow sustained tonic contraction.

Musculoskeletal system: comprises those muscles that have an attachment to skeletal system.

There are over 600 muscles in the musculoskeletal system.

Axial skeleton muscles: control facial expression; mastication; eye; tongue and neck movements; respiration; the abdominal wall; pelvic region; movement of the vertebral column.

Appendicular skeletal muscles: include the pectoral girdle, pelvic girdle, and upper and lower extremities.

Sarcomere:

Terms used in muscle:1. Muscle Belly: The fleshy bulging, central part of a muscle.2. Muscle fiber: A cylindrical, multinucleate cell composed of numerous myofibrils that

contracts when stimulated.3. Myofibrils: A myofibril is a basic unit of a muscle. Muscles are composed of tubular cells

called myocytes or myofibers. Myofibers are composed of tubular myofibrils. Myofibrils are composed of long proteins such as actin, myosin, and titin, and other proteins that hold them together.

Myofilaments: Myofilaments, the filaments of myofibrils constructed from proteins. The principal types of muscle are striated muscle, obliquely striated muscle and smooth muscle. Various arrangements of myofilaments create different muscles. S has transverse bands of filaments. In obliquely striated muscle, the filaments are staggered, and smooth muscle has irregular arrangements of filaments.

There are three different types of myofilaments: thick, thin, and elastic filaments. Thick filaments consist primarily of the protein myosin. Each thick filament are approximately

15 nm in diameter, and each is made of several hundred molecules of myosin. Thin filaments, 7 nm in diameter, consist primarily of the protein actin. All thin filaments are

attached the Z disc. Elastic filaments, 1 nm in diameter, are made of titin, a large springy protein. They flank each

thick filament and anchor it to the Z disc, the end point of a sarcomere.

1. Origin2. Insertion3. Tendon4. Aponeurosis

9. Epimysium10.Perimysium11.Endomysium12.Sarcomere13.Sarcolemma14.Sarcoplasm15.Sarcoplasmic reticulum16.Motor nerve17.Motor end-plate18.Neurovascular hilum19.Motor point20.Myotome

21.Dermatome22.Prime movers23.Antagonists24.Fixators25.Synergists

Forms of muscle:

Arrangement of fibers

Shape

• The arrangement of muscle fibers varies according to the direction, force and range of habitual movement at a particular joint. • The force of movement is directly proportional to the number and size of muscle fibers and range of movement is directly proportional to length of muscle fibers.

The muscles can be classified according to arrangement of their fasciculi into the following groups:

1. Parallel: muscles whose fibers run parallel to one another.

Quadrilateral (thyrohyoid) Strap (sternohyoid and Sartorius) Strap-like with tendinous intersections

(rectus abdominis) Fusiform (biceps brachii and digastric)

2. Oblique: feather-shaped muscles with oblique fibers and a central tendon.

Unipennate (flexor pollicis longus, extensor digitorum longus, peroneus tertius and palmar interossei)

Bipennate (rectus femoris, dorsal interossei, peroneus longus and flexor hallucis longus)

Multipennate (deltoid and subscapularis) Triangular (adductor longus and

temporalis) Circumpennate (tibialis anterior)

3. Circular: muscles whose fibers encompass an opening.

Sphincter radial

4. Convergent: fan-shaped muscle fibers at the origin that converge at the insertion point.

tricipital