MUSCULAR SYSTEM

 Muscular system

• One of the basic tissue of the body.
• They are around 650 muscles in our body.
• Contractile tissues.
• Muscle cell's (myocytes) are called as muscle fibres.
• They give shapes to the body and provide heart.
• Derived from latin word musculus= little mouse.
• Study of muscle is called myology.

Functions

• Skeletal movement.
• Posture and body shape
• Support of soft tissues 
• Joint stabilisation.
• Maintenance of the body temperature.
• Protection
• Facial expression.

 classification

STRUCTURAL (morphological)

3 types 

• Skeletal muscles
• smooth-muscle
• Cardiac muscle

BASED ON FUNCTION

• Voluntary muscle
• Involuntary muscle

Skeletal muscle

• Voluntary muscle 
• Forms 42% of the body weight 
• Some actions are automatic -stretch reflexes
• Produce movement by shortening 
• Contraction is rapid hence they fatigue easily.
• Long tapering end of a muscle is called as tendon, which is made by collagenous fibres.
• If end is flat seat like, it is known as aponeurosis
• Flashy part -belly

TENDON

• Fibrous cord- like end of a muscle
• Non-contractile 
• Composed of collagen fibre
• Less vascular, whenever injured, heals slowly.
• In areas, where it is subjected to friction, covered by synovial sheath or a  bursa-filled with fluid.

Functions of tendon:

• Concentrate the pull of muscle on a narrow area.
• Can bear the weight.
• Can alter the direction of muscle pull by using bony projections as pulleys.

CLINICAL IMPORTANCE:

• Information of Tendon.
• Healing is prolonged if injured due to poor blood supply.

APONEUROSIS

• Insertion portion is thin ,broad sheet.
• Composed of parallel bundles of collagen fibres.
• Acts as shock absorbs  to bear extra pressure and tension.
• Very poor blood supply and nerve supply.

ANTERIOR ABDOMINAL WALL- external oblique ,internal oblique aponeurosis.

LIMBS-palmar and plantar aponeurosis,bicipital aponeurosis.

SCALP- epicranial aponeurosis.

SOFT PALATE- palatine aponeurosis.

RAPHE

• Interdigitation of tendinous ends of a flat muscle is called raphe.

Example:

Mylohyoid raphe .

Pterygopalatine raphe.

FASCICULAR ARCHITECTURE 

Arrangement of muscle fibre varies according  to direction force

PARALLEL FASCICLE

• Muscle fibres are parallel to the line of pull.
• Fibres are more but numbers are relatively less.  

TYPES

• Quadrilateral  :fibres arranged parallely ex: thyrohyoid.
• Strap-like  : ex sartorius
• Strap like with tendinous intersection.

        ex: Rectus abdominis.

• Fusiform 

Ex: biceps brachii.

OBLIQUE ARRANGE FASCICLE

• Flesh fibres are oblique to the line of pull.
• Fibres are short number of muscles are more.

TYPES

1. Triangular, ex :temporalis
2. Unipennate, ex: extensor digitorum longus.
3. Bipennate,ex: rectus femoris.
4. Multipennate ,ex: deltoid.
5. Circumpennate, ex: tibialis anterior.

SPINAL MUSCLES.

• Muscle is twisted in the arrangement close to its insertion.

Ex: supinator.

• Cruciate muscles

• Muscle fibres are arranged in superficial and deep planes .

Ex: sternocleidomastoid.

Origin of muscle and insertion of muscle.

ORIGIN: end of muscle which is relatively fixed during its contraction .

INSENTION: the end of a muscle which moves during contraction.

Nomenclature of muscles 

According to the shape:

• Deltoid - triangular 
• Quadratus - square 
• Rhomboid - diamond shape 
• Lumbrical - worm like.

According to the size :

1. Major ,minor, longus- pectoralis major and minor .
2. Brevis- short.

Number of head 

Biceps - Biceps brachi

Tricep - Triceps brachi

Quadricep- Quadricep femrosis

Digastrive- 2 bellis ( anterior and posterior)

According to the position :

• Superficial : flexer digitorium superficialis.
• Profundus (deep) flexer digitorum

External : external oblique muscle 

Internal  : internal oblique muscle

According to the action :

• Extenson / flexon
• Adductor / abductor
• Elevator / depressor
• Supinator / pronator
• Constrictor / dilator

According to attachment :

1. Sternocleidomastoid
2. Coracobrachialis

According to structure:

• Half of muscles , half tendon - semitendinosis
• Serrated edge- serrates Anterior

PROPERTY OF MUSCLE TISSUES

• Excitability
• Conductivity 
• Contractility
• Extenbility
• Elastibility