MYOLOGY

STUDY OF MUSCLE IS CALLED “MYOLOGY”

•MUSCLE : It is an ordinary arrangement of Connective tissue and contractile cells.

•FUNCTIONS :

1. Movement -> alternative contraction and

relaxation 2. Protection of vessels and nerves 3. Pumping of blood. 5. Shapes to the organs & body

6. Transportation (food, blood, waste products)

MYOLOGY

• TYPES OF MUSCLES :

- Based on their shape and innervation

muscles are divided in to 3 Types

1. SKELETAL MUSCLE (Striated Voluntary)

2. CARDIAC MUSCLE (Striated Involuntary)

3. SMOOTH MUSCLE (Plain Involuntary)

MYOLOGY1. SKELETAL MUSCLE :-- Attached to bone and produce movement.- Also called striated voluntary. (Presence of striations and under will control)

PARTS (MACROSTRUCTURE) :-

1. PROXIMAL ATTACHEMENT (ORIGIN OR HEAD)

2. BELLY (BODY)

3. DISTAL ATTACHEMENT (INSERTION OR TENDON)

MYOLOGY

1. PROXIMAL ATTACHEMENT :- Attachment that least moves

2. DISTAL ATTACHEMENT :- Attachment that moves most

- Ends of muscles form in to cards of fiber tissue

called “TENDONS”

3. Belly :-

- Middle flabby part of muscle is called “BELLY”

APONEUROSIS:- Thin & strong fibrous sheet of flat muscles

RAPHAE:- Inter digitations of tendenious ends of muscle fibers

MYOLOGY

• STRUCTURE OF SKELETAL MUSCLE (MICRO):-

• PARTS :-

1. FASCICLE

2. MUSCLE CELL (Muscle fiber)

3. MYOFIBRIEL 4. MYOFILEMENTS

MYO FILAMENTS

MYOLOGY

1.FASCICLE :- - Group of muscle cell bind together

and form “Fascicle”

2. Muscle cell :- - Elongated cells

3. MYOFIBRIEL:- - Cylindrical, threadlike bundles of

myofilaments

4. MYOFILAMENT:- - Contractile protein elements of muscle

MYOLOGY• MUSCLE CELL OR FIBER :- (INTRACELLULAR ORGANIZATION)

1. NUCLEUS : Cellular structure contains D.N.A. (genetic) material 2. SARCOLEMMA : Specific name of the plasma membrane.

3. SARCOPLASMIC RETICULUM (S.R.) : Name of Endoplasmic reticulum. It interconnects tubules surrounding each myofibril like a slaves of a swatter

4.TERMINAL CISTERNAE : Sac like regions of Sarcoplasmic Reticulm (S.R.). It carries Ca+ ions.

MUSCLE CELL OR FIBER

MYOLOGY5. T – TUBULES: Invaginations of sarcolemma projecting deep in to muscle fibers called “T-tubules” opens out on to the surface of the Sarcolemma.

6. TRIAD : - -> Terminal cisternae It is a group of 3 units -- - -> T-tubule - -> Terminal cisternae

7. CYTOSOL : Intra cellular fluid. Organelles of cell are suspended init.

8. MITOCHONDRIA : A.T.P. Synthesizers, powerhouses of cell, suspended in cytosol.

MYOLOGY

• MYOFIBRIL : - Thread like Cylindrical bundles of contractile filaments

• MYOFILAMENTS : - Contractile proteins of muscle cell.

2 TYPES : 1. THIN FILAMENT (Protein – ACTIN) 2. THICK FILAMENT (Protein – MYOSIN )

MYOFIBRIL

MYOLOGY

COVERS OF MUSCLE TISSUE Muscle tissue is covered by 3 layers of connective tissue

sheathes. They are,

1. Epimysium : Outermost sheath covers each muscle bulk.

2. Perimysium : Middle sheath that covers each fascicle.

3. Endomysium : Innermost sheath that covers each muscle fiber.

1. SKELETAL MUSCLE

• HISTOLOGY :

- Elongated cells

- Visible striations

- Multiple, peripheral nuclei.

- Voluntary Eg: Biceps brachi

CARDIAC MUSCLE :

- Branched cells

- single central nuclei

- visible strations

- Involuntary

PROPERTY –> SPONTANIOUS & RHYTHMICAL CONTRACTION

Eg: Myocardium of heart.

SMOOTH MUSCLE

• - Spindle shaped cells

- Single central nucleus

- No visible striations

- Involuntary

Eg: Stomach, Urinary bladder, Uterus.

MYOLOGY• TWO JOINT MUSCLE : Muscle which crosses two or more joints and performs

two opposite actions at the two different joints are called “TWO JOINT MUSCLE”

Eg.: Gastrocnemius

contraction -> Flexion of knee & Ext. of foot (D.F.)

APPLIED ANATOMY :

Spasticity (Hypertonecity): Increased tone of the muscle

Flacidity (Hypotonecity) : Decreased tone of the muscle

Atrophy or wasting : Decreased size of muscle

Hypertrophy : Increased size of muscle bulk

Fatigue : Short lasting weakness of muscle

- x -