1. The Muscular System, pt. 2

2. A muscle depends on other muscles to assist in movement. For this reason muscles are called prime movers, antagonists or synergysts.

3. Prime Mover: Muscle that actively produces a movement

4. Antagonist: Muscle that works in opposition to the prime movers

5. Synergist: Muscles that contract with the prime mover to help execute a movement or steady a part

6. Names for muscles are based on six points of identification: Action Origin/insertion point Location Shape or use Direction of their fibers The number of their sections

7. Adjectives That Describe Muscles

8. Azygous : not paired

10. Bi, Tri, Quadri : two, three, four

12. Externus : external or outer

13. Gracilis : slender

14. Latissimus : wide

15. Longissimus, longus : long

16. Medius : intermediate

17. Orbicularis : surrounding

18. Quadratus : square

19. Rectus : straight

20. Rhomboideus : diamond shaped

21. Scalenus : unequally three sided

22. Serratus : sawtoothed

23. Teres : round or cylindrical

24. Transversus : crosswise

25. Vastus : great

26. Facial muscles

27. Orbicularis oculi

28. Masseter

29. Muscles of the neck, back and thorax. These muscles assist in: Rotation of the head Flexion and extension of the head on the neck Breathing Attachment of the forelimbs to the body

30. Serratus muscle group

31. Pectoral muscle group

32. Latissimus dorsi broadest muscle in the back, supports forelimb and flexes shoulders

33. The important muscles of the dorsum include the epaxial group: iliocostalis longissimus transversosspinalis

34. These muscles extend the vertebral column and produce lateral movement of the trunk

35. Transversospinalis

36. Important muscles of the thorax: External intercostals Internal intercostals Diaphragm

37. During respiration: External intercostals lift the ribs Internal intercostals lower the ribs Diaphragm contracts and flattens out causing thorax to enlarge and the lungs to expand

41. Muscles of the Forelimbs With help from the back and upper thorax, the muscles of the upper forelimbs contribute to movement of the distal extremities. Muscles include the triceps brachii and biceps brachii

42. Triceps Brachii

43. Biceps brachii

44. Abdominal Muscles: These muscles keep the organs in place, support and compress the abdomen, contract during parturition, defecation, urination and coughing. They also assist in rotating the vertebral column.

45. Abdominal muscles include: External oblique Internal oblique Rectus abdominis Transversus abdominis

46. Linea Alba A fibrous band running the length of the abdomen, which is a central attachment of the abdominal muscles. A very important landmark for abdominal surgery

48. Linea alba

49. Muscles of the Hindlimb These muscles have several functions in movement. The most important muscle groups include *Gluteal group *Quadricep group *Semi group

50. Gluteal Major muscles over pelvis, extends and abducts limb

51. Quadriceps femoris flex and extend the leg

52. Semi group descends the posterior hind leg and form the “hamstrings”. These muscles flex the distal extremity.

53. Gastrocnemius: flexes the leg and foot, the tendon at the insertion is commonly called the Achilles tendon

56. Miscellaneous muscles Arrector pili: Smooth muscles attached to hair on the dorsum. When stimulated these muscles raise the hair on the back.

58. Cutaneous trunci: a muscle that attaches to the dermis and controls the insect twich in large animals

59. Cremaster Another large animal muscle that is part of the spermatic cord and attaches to the scrotum. This muscle contracts and relaxes, raising and lowering the testicles, helping to regulate testicular temperature