1. The Muscular System
Muscles are attached to bones by tendons which are thick cords of collagen.
One end of a muscle will be relatively fixed and is called the Origin, eg the Pectorals attach at one end to the sternum which does not move.
The other end attaches to a bone that moves and this connection is called the Insertion, eg the pectorals attach at one end to the humerus which is pulled towards the sternum when the pectorals contract.

2. The Muscular System
Agonist (or Prime Mover) – is the muscle mainly responsible for causing an action, eg Biceps is the main muscle causing elbow flexion.
Antagonist – is the muscle that is mainly responsible for opposing an action.
Synergists – are muscles that assist agonists in causing a movement, eg Brachioradialis helps the Biceps cause elbow flexion.
Stabilisers – are muscles that keep the body parts in the correct position (stabilised) so an action can occur, eg in a bench press stabilisers keep the arms steady and in the correct position for pushing the weight up.

3. The Muscular System Reciprocal Inhibition
In each action the Agonist contracts and the Antagonist relaxes.
The Antagonist controls how quickly the Agonist contracts by how slowly it relaxes.

4. The Muscular System Biceps Brachii
Origin – 2 different spots on the scapula
Insertion – Radius
Main Action - Elbow flexion

5. The Muscular System Triceps Brachii
Origin – scapula & 2 different spots on the humerus
Insertion – Ulna
Main Action – Elbow extension
Synergist Action – shoulder extension

6. The Muscular System Erector Spinae
Origin – Ilium(pelvis bone) & various vertebrae
Insertion – Ribs, vertebrae and cranium
Main Action – Spine extension including neck

7. The Muscular System Rhomboids
Origin – Spinous process of Cervical no. 7 & first 5 thoracic vertebrae
Insertion – medial border of scapula
Main Action – adducts scapula, slight elevation of scapula and rotation of scapula

8. The Muscular System Trapezius
Origin – base of cranium, ligaments of neck & cervical 7 and all thoracic vertebrae
Insertion – outer third of clavicle, scapula
Main Action – adducts scapula, slight elevation of scapula and rotation of scapula

9. The Muscular System Levator Scapulae
Origin – transverse process of first 4 cervical vertebrae
Insertion – upper medial border of scapula
Main Action – elevates the scapula, rotates the scapula

10. The Muscular System Latissimus Dorsi
Origin – crest of Ilium, sacrum, lumbar and lower 5 thoracic vertebrae
Insertion – humerus
Main Action – adduction of shoulder, extension of shoulder, inward rotation of shoulder

11. The Muscular System Pectoralis Major Origin – clavicle & sternum
Insertion – humerus
Main Action – adduction of shoulder, inward rotation of shoulder

12. The Muscular System Deltoid Origin – clavicle & scapula
Insertion – humerus
Main Action – abduction, flexion, extension of shoulder

13. The Muscular System Rectus Abdominis Origin – crest of Pubis
Insertion – cartilage of 5th, 6th & 7th Ribs
Main Action – flexion of spine

14. The Muscular System External Oblique Abdominals
Origin – border of lower 8 ribs
Insertion – crest of Ilium & Pubis, inguinal ligament
Main Action – flexion of spine, right side twists spine left, left side twists spine right

15. The Muscular System Internal Oblique Abdominals
Origin – inguinal ligament, crest of Ilium
Insertion – cartilage of 8th, 9th & 10th ribs
Main Action – flexion of spine, right side twists spine right, left side twists spine left

16. The Muscular System Transverse Abdominals
Origin – inguinal ligament, crest of Ilium, lower 6 ribs
Insertion – crest of pubis
Main Action – pulls abdominal wall in

17. The Muscular System Hamstrings – Biceps Femoris Origin – Ishium, femur
Insertion – Tibia & Fibula
Main Action – hip extension, knee flexion, outward rotation of thigh

18. The Muscular System Hamstrings – Semitendinosus Origin – Ishium
Insertion – Tibia
Main Action – hip extension, knee flexion, inward rotation of thigh

19. The Muscular System Hamstrings – Semimembranosus Origin – Ishium
Insertion – Tibia
Main Action – hip extension, knee flexion, inward rotation of thigh

20. The Muscular System Quadriceps – Rectus Femoris Origin – Ilium
Insertion – Patella and patella ligament to Tibia
Main Action – hip flexion, knee extension

21. The Muscular System Quadriceps – Vastus Lateralis Origin – Femur
Insertion – Patella and patella ligament to Tibia
Main Action – knee extension

22. The Muscular System Quadriceps – Vastus Medialis Origin – Femur
Insertion – Patella and patella ligament to Tibia
Main Action – knee extension

23. The Muscular System Quadriceps – Vastus Intermedius Origin – Femur
Insertion – Patella and patella ligament to Tibia
Main Action – knee extension

24. The Muscular System Iliopsoas
Origin – Inner Ilium, sacrum, last thoracic and all lumber vertebrae
Insertion – Femur
Main Action – Hip flexion, outward rotation of thigh.

25. The Muscular System Adductor Longus Origin – Pubis Insertion – Femur
Main Action – Hip adduction
Synergist Action – flexion of hip

26. The Muscular System Gluteus Maximus Origin – crest of Ilium, sacrum
Insertion – Femur
Main Action – Hip extension, outwards rotation of thigh
Synergist Action – lower fibre assist in adduction of hip

27. The Muscular System Gluteus Medius Origin – just below crest
Ilium
Insertion – Femur
Main Action – Hip abduction, outwards rotation of thigh

28. The Muscular System Gastrocnemius Origin – bottom of femur
Insertion – Calcaneous(heel bone)
Main Action – Plantar Flexion of ankle, flexion of knee.

29. The Muscular System Soleus Origin – top two 3rds of Tibia & Fibula
Insertion – Calcaneous(heel bone), joins the tendon of the Gastrocnemius.
Main Action – Plantar Flexion of ankle

30. The Muscular System Tibialis Anterior
Origin – top two 3rds of front of Tibia
Insertion – tarsal and 1st metatarsal.
Main Action – Dorsi flexion, adduction, inversion.

31. The Muscular System Serratus Anterior
Origin – top 9 ribs at side of chest.
Insertion – underneath the medial border of the scapula.
Main Action – Abduction of scapula(shoulder girdle), slight rotation

32. Muscle types Skeletal Cardiac Striated,
Most of the muscle mass in the body
Voluntary
Cardiac
Heart
Involuntary

33. Muscle types continued
Smooth
Nonstriated,
viscera and all blood vessels
Involuntary

34. Comparison

35. Skeletal Muscle

36. Skeletal Muscle

37. Sarcomeres Functional contractile unit of striated muscle Striations
Represent the transverse alignment of myofibrils in sarcomeres
Made up of regular overlapping pattern
of actin (thin filaments)
myosin (thick filaments)
Delineated by Z lines
Center line is I band
2-3 mm in length

39. Sliding filament mechanism
Sarcomeres shortened
Thin filaments(actin) slide over thick filament(myosin)
Requires ATP
other proteins and calcium

40. Motor nerve supply Neuromuscular junction Motor end plate
motor neuron and its axonal branches sitting on the skeletal muscle fibers it innervates
Motor end plate
The end plate of the neuron

41. Motor nerve supply Motor Unit
The motor neuron and the muscle fibers it innervates
When a motor unit fires ALL the muscle fibres connected to the motor unit contract.