General principles of skeletal muscle

Speaker,Dr. Md. Mohiuddin MasumMS Anatomy, Phase-A, Year-1, Block-1

Guided by,

Prof. Laila Anjuman BanuProfessor, Genetics & molecular biologyDept. of Anatomy, BSMMU

Objectives At the end of the session the audience will be able to-

Classify muscles and their location in the body. Connective tissue covering and different parts of

skeletal muscle. Classify different types of skeletal muscles. Explain different functional terms related to muscle

action. Understand and discuss some principles related to

skeletal muscles.

Muscular tissue

Is a basic tissue.

The word muscle is derive from a Latin word “musculus” which means little mouse.

All muscle of the body are derived from mesoderm. (Except, arrectores pilorum and muscle of the iris)

Classification of Muscle

Classification of Muscle (Morphologically)

Classification of Muscle (Functionally)

Connective tissue covering of Skeletal Muscle

Parts of Skeletal Muscle

Fleshy part.

Fibrous part. Tendinous. Aponeurotic.

Attachments of Skeletal Muscle

Less movement/ fixed end → Origin.

Greater movement/ movable end → Insertion.

Attachments of Skeletal Muscle(Contd.)

Muscles inserted near proximal end of a bone, close to a joint → Increase range of movement but less power of action. Example: Biceps brachii.

Attachments of Skeletal Muscle(Contd.)

Muscles inserted near proximal end of a bone, close to a joint → Increase range of movement but less power of action. Example: Biceps brachii.

Attachments of Skeletal Muscle(Contd.)

Muscles inserted near distal end of a bone, away from a joint → More power of action but less range of movement.Example: Brachioradialis.

Attachments of Skeletal Muscle(Contd.)

Muscles inserted near distal end of a bone, away from a joint → More power of action but less range of movement.Example: Brachioradialis.

Classification of skeletal muscle(According to colour)

Classification of skeletal muscle(Cont.)(According to direction of muscle fibre)

Classification of skeletal muscle (cont.)(According to direction of muscle fibre)

Classification of skeletal muscle (cont.)(According to direction of muscle fibre)

Direction of muscle fibres & function

Range of movement in muscle is directly proportional to the length of muscle fibres.

Parallel muscle

Long muscle fibres

↑ Range of movement

Oblique muscle

Short muscle fibres

↓ Range of movement

Direction of muscle fibres & function

Force of contraction of muscle is directly proportional to the number of muscle fibres.

Oblique muscle

More muscle fibres

↑ Force of contraction

Parallel muscle

Less muscle fibres

↓ Force of contraction

Muscle action• Prime mover

Muscle action(Cont.)

• Antagonist

Muscle action(Cont.)

Muscle action(Cont.)

• Fixator

Muscle action(Cont.)

• Synergist

Terms associated with skeletal muscle

• Hypertrophy

Hypertrophied MuscleNormal

MuscleHypertrophied Muscle

Terms associated with skeletal muscle (Cont.)

• Atrophy

Thank You