Structure and function of the muscular system

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• Higher Education (non-degree)

ANATOMY AND PHYSIOLOGY FOR SPORTS MASSAGE 

THE STRUCTURE AND FUNCTION OF THE SKELETAL SYSTEM

ANATOMY AND PHYSIOLOGY FOR SPORTS MASSAGE

THE STRUCTURE AND FUNCTION OF THE MUSCULAR SYSTEM

What are you going to learn?

In this lesson you're going to learn to . . .

1

2

3

Describe characteristics of types of muscle tissue

Locate and describe action of the major anterior and posterior skeletal muscles

Identify and locate muscle attachment and insertion points. 

Describe the role of muscles during movement

4

6

5

Explain different types of muscle contraction

Explain the principle of muscle contraction

CHARACTERISTICS OF TYPES OF MUSCLE TISSUE  

In the muscular system, muscle tissue is categorised into three distinct types: 

1) Skeletal 2) Cardiac 3) Smooth. 

Each type of muscle tissue in the human body has a unique structure and a specific role. Skeletal muscle moves bones and other structures. Cardiac muscle contracts the heart to pump blood. The smooth muscle tissue that forms organs like the stomach and bladder changes shape to facilitate bodily functions. 

CHARACTERISTICS OF TYPES OF MUSCLE TISSUE  

<b>Skeletal muscles</b> attach to and move bones by contracting and relaxing in response to voluntary messages from the nervous system. Skeletal muscle tissue is composed of long cells called muscle fibers that have a striated appearance.&nbsp;

<b>Smooth muscle</b> is found in the walls of hollow organs throughout the body. Smooth muscle contractions are involuntary movements triggered by impulses that travel through the autonomic nervous system.&nbsp;

<b>Cardiac muscle</b> is found only in the myocardium of the heart, it contracts in response to signals from the cardiac conduction system to make the heart beat.&nbsp;

Muscle fibers are organized into bundles supplied by blood vessels and innervated by motor neurons.

<b>Smooth muscle </b>tissue allows for contraction and relaxation with great elasticity. In the urinary bladder they allow those organs to expand and relax. In the digestive tract they facilitate swallowed food and nutrients. In artery walls they relax and contract to move blood through the body.

Cardiac muscle is made from cells called cardiocytes. Like skeletal muscle cells cardiocytes have a striated appearance, but their overall structure is shorter and thicker.&nbsp;

Match up the descriptions to the muscle tissue types

Contract by shortening in length

Located in the walls of the myocardium

Striated in appearance 

Voluntary - under conscious control

Involuntary - under unconscious control

Contract with peristaltic (wave) action 

Located in skeletal muscles

 Located in the walls of  organs and digestive system

Involuntary - under unconscious control

Appear spindle-shaped 

MUSCLE ATTACHMENTS 

Learning the muscular system often involves memorising details about each muscle, like where a muscle attaches to bones and how a muscle helps move a joint. 

A skeletal muscle attaches to bone (or sometimes other muscles or tissues) at two or more places. 

Origin

If the place is a bone that remains immobile for an action, the attachment is called an origin. 

Insertion

If the place is on the bone that moves during the action, the attachment is called an insertion. 

MUSCLE ACTION 

The muscles surrounding synovial joints are responsible for moving the body in space. These muscle actions are often paired, like flexion and extension or abduction and adduction. Below the common terms are listed and defined. 

Flexion and Extension

<b>Flexion:&nbsp;</b>decreasing the angle between two bones (bending).<div><div><b><br></b></div><div><b>Extension: </b>increasing the angle between two bones (straightening a bend).
</div><div><br></div><div><b>Example: At the elbow joint</b></div><div>The triceps brachii muscle extend the elbow. The biceps brachii, brachialis, and brachioradialis flex the elbow.</div></div>

Abduction and Adduction

<div><div><b>Abduction: </b>moving away from the body’s midline.
</div><div><br></div><div><b>Adduction: </b>moving toward the body’s midline.
</div><div><b><br></b></div><div><b>Example: At the hip joint</b></div><div>The gluteus medius, gluteus minimus, tensor fasciae latae, and sartorius are muscles that abduct the hip. The pectineus, adductor longus, adductor brevis, adductor magnus, and gracilis adduct the hip.</div><div>
</div><div>
</div></div>

Dorsiflexion and Plantarflexion

<b>Dorsiflexion: </b>bringing your foot upward toward your shin.<div><br><div></div><div><b>Plantar flexion:</b> depressing your foot down.&nbsp;</div></div><div><br></div><div><b>Example: at the ankle joint</b></div><div>The tibialis anterior dorsiflexes the ankle joint. Whereas the gastrocnemius plantarflexes the ankle joint.&nbsp;</div><div><br></div>

Elevation and Depression

<div>
</div><div><b>Elevation</b>: moving a body part up.
</div><div><br></div><div><b>Depression</b>: moving a body part down.</div><div><br></div><div><b>Example: at the shoulder girdle</b></div><div>The upper traperzius, rhomboids and levator scapula are muscles that elevate the shoulder girdle. Whereas the lower traperzius and pectorial minor depress the shoulder girdle.</div><div>
</div>

Eversion and Inversion

<b>Inversion: </b>turning the sole of the foot inward.<div><br><div></div><div><b>Eversion:</b> turning the sole of the foot outward.</div></div><div><br></div><div><b>Example: at the ankle joint</b></div><div>The tibialis anterior and tibialis posterior are muscles that invert the ankle joint. Whereas the peroneus longus, peroneus brevis and peroneus tertius evert the ankle joint.</div>

Protraction and Retraction

<b>Pronation: </b>rotating the forearm so the palm is facing backward or down.
<div>
</div><div><b>Supination: </b>rotating the forearm so the palm is facing forward or up.</div><div><br></div><div><b>Example: at the shoulder girdle</b></div><div>The mid / lower traperzius and rhomboids are muscles that retract the shoulder girdle. Whereas the pectorialis minor and serratus anterior protract the shoulder girdle.</div>

Pronation and Supination

<div><b>Pronation: </b>rotating the forearm so the palm is facing backward or down.
</div><div><b><br></b></div><div><b>Supination: </b>rotating the forearm so the palm is facing forward or up.</div><div><b><br></b></div><div><b>Example: at the elbow joint</b></div><div>The pronator teres and pronator quadratus pronate the forearm. Whereas the biceps brachii and brachioradialis supinate the forearm.&nbsp;</div><div><b>
</b></div><div>
</div>

MUSCLES OF THE SHOULDER GIRDLE 

Rhomboids

<b>Origin-</b> C7-T5<div><b><br></b><div></div><div><b>Insertion</b>- Medial border of the scapula</div><div><br></div><div><b>Primary action/s-</b> Elevation and retraction of shoulder girdle.&nbsp;</div><div>
</div></div>

Trapezius

<b>Origin-</b> Base of cranium and cervical and thoracic vertebrae&nbsp;<div><b><br></b><div><b>
</b></div><div><b>Insertion</b>- Clavicle and scapula&nbsp;</div><div><br></div><div><b>Primary action/s</b>- Elevation, depression and retraction of shoulder girdle.&nbsp;</div><div>
</div></div>

Pectoralis Minor

<b>Origin-</b> 3rd, 4th, 5th ribs<div><b><br></b><div></div><div><b>Insertion</b>- Coracoid process (anterior scapula)</div><div><br></div><div><b>Primary action/s</b>- Depression and protraction of shoulder girdle.</div><div>
</div></div>

Serratus Anterior

<b>Origin-</b> Upper 8/9 ribs<div><br><div></div><div><b>Insertion-</b> Medial border of scapula</div><div><br></div><div><b>Primary action/s</b>- IProtraction of shoulder girdle.</div><div>
</div></div>

Levator Scapula

<b>Origin</b>- C1-C4<div><br><div></div><div><b>Insertion-</b> Superior angle of scapula</div><div><b><br></b></div><div><b>Primary action/s</b>- Elevation of shoulder girdle and lateral flexion of neck.&nbsp;</div><div>
</div></div>

MUSCLES OF THE SHOULDER JOINT

Latissimus Dorsi

<b>Origin</b>- T6-T12, L1-L5, iliac crest and lower 3 ribs.&nbsp;<div><b><br></b><div><b>
</b></div><div><b>Insertion</b>- Anterior surface of humerus
</div><div><br></div><div><b>Primary action/s</b>- Extension, adduction and medial rotation of shoulder.</div><div>
</div></div>

Pectoralis Major

<b>Origin- </b>Clavicle, sternum and 1st to 6th ribs<div><b><br></b><div></div><div><b>Insertion-</b> Anterior humerus</div><div><br></div><div><b>Primary action/s-</b> Adduction, horizontal flexion and medial rotation shoulder joint.</div><div>
</div></div>

Deltoids

<b>Origin-</b> Scapula and clavicle<div><b><br></b><div></div><div><b>Insertion-</b> Lateral humerus
</div><div><br></div><div><b>Primary action/s</b>- Flexion and extension, horizontal flexion and extension, lateral and medial rotation, abduction of shoulder joint.&nbsp;</div><div>
</div></div>

Teres Major

<b>Origin</b>-Inferior angle of scapula<div><b><br></b><div></div><div><b>Insertion</b>- Superior anterior humerus
</div><div><br></div><div><b>Primary action/s</b>- Extension, adduction and medial rotation of shoulder joint.</div><div>
</div></div>

MUSCLES OF THE ROTATOR CUFF   

Supraspinatus

<b>Origin</b>- Superior surface of scapula<div><br><div>
</div><div><b>Insertion</b>- Superior humerus</div><div><br></div><div><b>Primary action/s-</b> Initiates abduction of shoulder joint.</div><div>
</div></div>

Infraspinatus

<b>Origin-</b> Posterior surface of scapula<div><br><div></div><div><b>Insertion</b>- Superior posterior humerus
</div><div><br></div><div><b>Primary action/s</b>- Adduction and lateral rotation of shoulder joint.</div><div>
</div></div>

Subscapularis

<b>Origin</b>- Anterior surface of scapula<div><b><br></b><div></div><div><b>Insertion</b>- Superior&nbsp; anterior humerus
</div><div><br></div><div><b>Primary action/s</b>- Medial rotation of shoulder joint.</div><div>
</div></div>

Teres Minor

<b>Origin-</b> Lateral border of scapula<div><b><br></b><div></div><div><b>Insertion</b>- Superior posterior humerus
</div><div><br></div><div><b>Primary action/s-</b> Medial rotation of shoulder joint.</div><div>
</div></div>

UPPER LIMB SKELETAL MUSCLES   

Wrist Extensors

<b>Origin- </b>Lateral humerus<div><b><br></b><div></div><div><b>Insertion</b>- Back of hand
</div><div><br></div><div><b>Primary action/s</b>- Extension of wrist.</div><div>
</div></div>

Coracobrachialis

<b>Origin</b>- Superior scapula<div><b><br></b></div><div><b>Insertion</b>- Medial humerus&nbsp;</div><div><br><div><b>Primary action/s</b>- Flexion and adduction of humerus.&nbsp;</div><div>
</div></div>

Brachialis

<b>Origin</b>- Mid humerus&nbsp;<div><br><div>
</div><div><b>Insertion</b>- Superior ulna&nbsp;</div><div><br></div><div><b>Primary action/s</b>- Flexion of forearm.&nbsp;</div><div>
</div></div>

Brachioradialis

<b>Origin-</b> Distal humerus<div><br><div>
</div><div><b>Insertion</b>- Distal radius</div><div><br></div><div><b>Primary action/s-</b> Flexion and supination of forearm.&nbsp;</div><div>
</div></div>

Wrist Flexors

<b>Origin</b>- Medial humerus<div><b><br></b><div></div><div><b>Insertion</b>- Palm of hand</div><div><b><br></b></div><div><b>Primary action/s</b>- Flexion of wrist.</div><div>
</div></div>

Triceps Brachii

<b>Origin-</b> <i>Long head:</i> superior scapula, <i>Lateral head</i>: lateral posterior humerus, <i>Medial head</i>: Posterior humerus<div><b><br></b><div></div><div><b>Insertion-</b>&nbsp;Superior ulna (olecranion)</div><div><b><br></b></div><div><b>Primary action/s-</b>&nbsp;Extension of shoulder and elbow joint.&nbsp;</div><div>
</div></div>

Bicep Brachii

<b>Origin- </b><i>Long head</i>: superior scapula, <i>Short head</i>: anterior scapula<div><br><div>
</div><div><b>Insertion-</b>&nbsp;Radius&nbsp;</div><div><br></div><div><b>Primary action/s-</b> Flexion of shoulder and elbow joint, supination of forearm.&nbsp;</div><div>
</div></div>

MUSCLES OF THE PELVIC GIRDLE AND HIP

Gluteus Medius

<b>Origin</b>- Lateral and posterior ilium<div><b><br></b><div>
</div><div><b>Insertion</b>- Posterior and lateral surface of upper femur</div><div><br></div><div><b>Primary action/s</b>- Abduction and medial rotation of hip.&nbsp;</div><div>
</div></div>

Tensor Fascia Latae

<b>Origin</b>- Anterior iliac crest<div><b><br></b><div></div><div><b>Insertion</b>- Lateral tibia via iliotibal band (ITB)</div><div><br></div><div><b>Primary action/s</b>- Flexion and abduction of hip. Medial rotation as hip flexes.&nbsp;</div><div>
</div></div>

Iliopsoas

<b>Origin</b>- Lumbar spine and pelvis&nbsp;<div><b><br></b><div><b>
</b></div><div><b>Insertion</b>- Less trochnater of femur&nbsp;</div><div><br></div><div><b>Primary action/s</b>- Flexion of hip and spine.&nbsp;</div><div>
</div></div>

Gluteus Minimus

<b>Origin-</b> Lateral ilium<div><br><div></div><div><b>Insertion-</b> Anterior surface of upper femur
</div><div><br></div><div><b>Primary action/s</b>- Abduction and medial rotation of hip.&nbsp;</div><div>
</div></div>

Piriformis

<b>Origin-</b> Anterior sacrum<div><b><br></b><div></div><div><b>Insertion</b>- Upper surface of upper femur
</div><div><b><br></b></div><div><b>Primary action/s</b>- Abduction and medial rotation of hip.&nbsp;</div><div>
</div></div>

Gluteus Maximas

<b>Origin</b>- Iliac crest, sacrum and coccyx<div><b><br></b><div></div><div><b>Insertion</b>- Upper posterior femur and ITB</div><div><br></div><div><b>Primary action/s</b>- Extension and lateral rotation of the hip.</div><div>
</div></div>

TRUNK SKELETAL MUSCLES   

External Obliques

<b>Origin-</b> Lower 8 ribs<div><b><br></b><div></div><div><b>Insertion</b>- Iliac crest and linea alba
</div><div><b><br></b></div><div><b>Primary action/s</b>- Rotation and lateral flexion of spine.&nbsp;</div><div>
</div></div>

Internal Obliques

<b>Origin</b>- Iliac crest and lumbar fascia<div><br><div>
</div><div><b>Insertion</b>- 8-10th ribs and linea alba</div><div><b><br></b></div><div><b>Primary action/s</b>- Rotation and lateral flexion of spine.&nbsp;</div><div>
</div></div>

Rectus Abdominis

Origin- Pubic symphysis, pubic crest<div><br><div></div><div>Insertion- Xiphoid process and 5th-7th ribs</div><div><br></div><div>Primary action/s-&nbsp; Flexion of spine.&nbsp;</div><div>
</div></div>

Quadratus Lumborum

<b>Origin</b>- Iliac crest<div><b><br></b><div><b>
</b></div><div><b>Insertion</b>- 12th rib and L1-L4</div><div><b><br></b></div><div><b>Primary action/s</b>- Lateral flexion of spine, bilaterially extends the spine.&nbsp;</div><div>
</div></div>

Erector Spinae

<b>Origin-</b> Along the length of the vertebral cloumn, ribs and pelvis<div><b><br></b><div><b>
</b></div><div><b>Insertion</b>- Vertebral column and ribs</div><div><br></div><div><b>Primary action/s-</b> Extension of the spine.</div><div>
</div></div>

Transversus Abdominis

<b>Origin-</b> Iliac crest, lower 6 ribs and lumbar fascia<div><b><br></b><div><b>
</b></div><div><b>Insertion</b>- Linea alba and pubis</div><div><br></div><div><b>Primary action/s</b>- Drawing abdomen inwards.</div><div>
</div></div>

LOWER LIMB SKELETAL MUSCLES   

Adductor Longus

<b>Origin-</b> Anterior pubis<div><br><div></div><div><b>Insertion</b>- Medial femur
</div><div><br></div><div><b>Primary action/s</b>- Adduction of hip.</div><div>
</div></div>

Adductor Magnus

<b>Origin</b>- Anterior pubis<div><br><div></div><div><b>Insertion</b>- Medial femur
</div><div><br></div><div><b>Primary action/s</b>- Adduction of hip.</div><div>
</div></div>

Gracilis

<b>Origin</b>- Ischiopubic ramus&nbsp;<div><br><div>
</div><div><b>Insertion</b>- Medial tibia</div><div><b><br></b></div><div><b>Primary action/s</b>- Adduction of hip and flexion of knee.&nbsp;</div><div>
</div></div>

Sartorius

<b>Origin</b>- Anterior Superior iliac spine (ASIS)<div><b><br></b><div></div><div><b>Insertion-</b> Medial condyle of tibia</div><div><b><br></b></div><div><b>Primary action/s</b>- Flexion, abduction and lateral rotation of hip. Flexion and medial rotation of knee.&nbsp;</div><div>
</div></div>

Pectineus

<b>Origin- </b>Anterior pubis&nbsp;<div><b><br></b><div><b>
</b></div><div><b>Insertion</b>- Upper femur</div><div><b><br></b></div><div><b>Primary action/s</b>- Adduction and flexion of the hip.&nbsp;</div><div>
</div></div>

Adductor Brevis

<b>Origin-</b> Anterior pubis<div><b><br></b><div></div><div><b>Insertion</b>- Medial femur</div><div><b><br></b></div><div><b>Primary action/s-</b> Adduction of hip.</div><div>
</div></div>

MUSCLES OF THE UPPER LEG

Vastus Medialis

<b>Origin</b>- Medial femur<div><b><br></b><div></div><div><b>Insertion</b>- Tibial tuberosity via patella
</div><div><b><br></b></div><div><b>Primary action/s</b>- Extension of knee (especially last 20 degrees of movement)</div><div>
</div></div>

Vastus Intermedius

<b>Origin-</b> Anterior femur<div><b><br></b><div></div><div><b>Insertion</b>- Tibial tuberosity via patella
</div><div><br></div><div><b>Primary action/s</b>- Extension of knee.</div><div>
</div></div>

Vastus Lateralis

<b>Origin</b>- Lateral upper femur&nbsp;<div><br><div></div><div><b>Insertion-</b> Tibial tuberosity via patella
</div><div><br></div><div><b>Primary action/s-</b>&nbsp; Extension of knee.</div><div>
</div></div>

Rectus Femoris

<b>Origin</b>- Anterior inferior iliac spine (AIIS)<div><b><br></b><div></div><div><b>Insertion</b>- Tibial tuberosity via patella&nbsp;</div><div><b><br></b></div><div><b>Primary action/s</b>- Flexion of hip and extension of knee</div><div>
</div></div>

MUSCLES OF THE UPPER LEG

Biceps Femoris

<b>Origin-</b> Ischial tuberosity and posterior femur<div><br><div></div><div><b>Insertion</b>- Head of fibula and lateral condyle of tibia</div><div><br></div><div><b>Primary action/s</b>- Extension of hip and flexion of knee.</div><div>
</div></div>

Semimembranosus

<b>Origin</b>- Ischial tuberosity&nbsp;<div><b><br></b><div></div><div><b>Insertion</b>-&nbsp; Medial condyle of tibia
</div><div><br></div><div><b>Primary action/s</b>- Extension of hip and flexion of knee.</div><div>
</div></div>

Semitendinosus

<b>Origin</b>- Ischial tuberosity<div><b><br></b><div>
</div><div><b>Insertion</b>- Medial condyle of tibia
</div><div><br></div><div><b>Primary action/s</b>- Extension of hip and flexion of knee.</div><div>
</div></div>

MUSCLES OF THE LOWER LEG

Plantaris

<b>Origin-</b> Lateral upper femur<div><br><div></div><div><b>Insertion</b>- Calcaneus&nbsp;</div><div><br></div><div><b>Primary action/s</b>- Plantarflexion of ankle.&nbsp;</div><div>
</div></div>

Gastrocnemius

<b>Origin-</b> Posterior medial / Lateral upper femur<div><b><br></b><div></div><div><b>Insertion</b>- Calcaneus
</div><div><br></div><div><b>Primary action/s-</b> Flexion of knee and Plantarflexion of ankle.&nbsp;</div><div>
</div></div>

Tibialis Anterior

<b>Origin</b>- Lateral tibia<div><b><br></b><div></div><div><b>Insertion</b>- Plantar surface of foot</div><div><br></div><div><b>Primary action/s</b>- Dorsiflexion and Inversion of ankle.&nbsp;</div><div>
</div></div>

Tibialis Posterior

<b>Origin-</b> Posterior surfaces of tibia and fibula<div><b><br></b><div></div><div><b>Insertion</b>- Plantar surface of foot
</div><div><b><br></b></div><div><b>Primary action/s</b>- Plantarflexion and Inversion of ankle.&nbsp;</div><div>
</div></div>

Popliteus

<b>Origin</b>- Lateral upper femur&nbsp;<div><br><div></div><div><b>Insertion</b>- Posterior upper tibia</div><div><b><br></b></div><div><b>Primary action/s</b>- Flexion and medial rotation of the knee</div><div>
</div></div>

Soleus

<b>Origin- </b>Upper posterior tibia and fibula<div><br><div>
</div><div><b>Insertion-</b> Calcaneus</div><div><br></div><div><b>Primary action/s-</b> Plantarflexion of ankle.&nbsp;</div><div>
</div></div>

MUSCLES OF THE LOWER LEG  

Peroneus Brevis

<b>Origin</b>- Lower lateral surface of fibula<div><br><div></div><div><b>Insertion-</b> Plantar surface of foot
</div><div><br></div><div><b>Primary action/s</b>- Plantarflexion and Eversion of ankle.&nbsp;</div><div>
</div></div>

Peroneus Longus

<b>Origin- </b>Upper lateral surface of fibula<div><b>&nbsp;</b><div><b>
</b></div><div><b>Insertion</b>- Plantar surface of foot</div><div><br></div><div><b>Primary action/s</b>- Plantarflexion and Eversion of ankle.&nbsp;</div><div>
</div></div>

Peroneus Tertius

<b>Origin-</b> Lower anterior surface of fibula<div><b><br></b><div></div><div><b>Insertion</b>- Dorsal surface of foot
</div><div><b><br></b></div><div><b>Primary action/s</b>- Dorsiflexion and Eversion of ankle.&nbsp;</div><div>
</div></div>

MUSCLES OF THE LOWER LEG  

Extensor Digitorum Longus

<b>Origin</b>- Lateral upper tibia and anterior fibula<div><b><br></b><div><b>
</b></div><div><b>Insertion</b>- Dorsal surface of 4 outer toes</div><div><b><br></b></div><div><b>Primary action/s</b>- Dorsiflexion and Eversion of ankle. Extension of the 4 outer toes.&nbsp;</div><div>
</div></div>

Extensor Hallucis Longus

<b>Origin-</b> Anterior surface of the fibula&nbsp;<div><br></div><div><b>Insertion-</b> Dorsal surface of 1st (big) toe</div><div><br></div><div><b>Primary action/s</b>- Dorsiflexion and Inversion of ankle. Extension of the 1st (big) toe.&nbsp;</div>

Flexor Digitorum Longus

<b>Origin</b>- Posterior surface of the tibia<div><b><br></b><div></div><div><b>Insertion</b>- Plantar surface of 4 outer toes</div><div><br></div><div><b>Primary action/s</b>- Plantarflexion and Inversion of ankle. Flexion of the 4 outer toes.&nbsp;</div><div>
</div></div>

Flexor Hallucis Longus

<b>Origin</b>- Lower fibula<div><br><div></div><div><b>Insertion</b>- Plantar surface of 1st (big) toe</div><div><br></div><div><b>Primary action/s-</b> Plantarflexion and Inversion of ankle. Flexion of the 1st (big) toe.&nbsp;</div><div>
</div></div>

ROLE OF MUSCLES DURING MOVEMENT  

While many muscles may be involved in any given action, muscle function terminology allows you to quickly understand the various roles different muscles play in each movement.

Prime movers and antagonists are often paired up on opposite sides of a joint, with their prime mover/antagonist roles reversing as the movement changes direction.

Prime movers / agonist

<div>The prime mover, sometimes called the agonist, is the muscle that provides the primary force driving the action.&nbsp;</div>

Antagonist

<div>An antagonist muscle is in opposition to a prime mover in that it provides some resistance and/or reverses a given movement.&nbsp;</div>

Fixator / Stabilisers

<div>Stabilisers act to keep bones immobile when needed. Your back muscles, for example, are stabilizers when they are keeping your posture sturdy.
</div><div><br></div><div><br></div>

Synergists.

<div>One or more synergists are often involved in an action. Synergists are muscles that assist the prime mover in its role.
</div><div><br></div>

STRUCTURE OF SKELETAL MUSCLE 

1.

Muscles are bound together by different fascia made of dense irregular connective tissue. This is composed mainly of collagen fibres that run in many different directions.&nbsp;

2.

The fascia of the muscle eventually converge to become the tendon which will attach to the bone. The tendon is made of dense regular connective tissue. The collagen fibres in the tendon run in one direction to create a strong connection for the muscle in the direction of pull.&nbsp;

5.

A bundle of fibres is referred to as the fascicle

4.

Many fibres are bundled together and wrapped in the perimysium. Around the fascicles.&nbsp;

3.

The outer covering of the muscle is called the epimysium.

6.

A sheath of endomysium surrounds each muscle fibre cell. The endomysium is continuous with the muscle fibre's membrane, or sarcolemma

8.

Myofibrils are divided along their length into repeating units called sarcomeres.

7.

Muscle fibres (cells) are the approximate width of a human hair and often run the full length of a muscle. They are composed of smaller elements known as myofibrils.&nbsp;

9.

Sarcomeres are packed with two different types of protein filaments (myofilaments); thin actin and thick myosin. The myosin and actin filaments are strictly arranged inside the sarcomere to overlap each other.&nbsp;

What you have learnt

Following this lesson you should now be able to . . .

1

2

3

Describe characteristics of types of muscle tissue

Locate and describe action of the major anterior and posterior skeletal muscles

Identify and locate muscle attachment and insertion points. 

Describe the role of muscles during movement

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5

Explain different types of muscle contraction

Explain the principle of muscle contraction