1. Muscular System

2. Muscles are contractile organs responsible for the voluntary and involuntary movements of animals.

3. Types of Muscle Skeletal Muscle – Allow for all voluntary movement – Appears to be striated under a microscope Cardiac Muscle – Controls the involuntary beating of the heart – Appears striated under a microscope Smooth Muscle – Responsible for all other involuntary movement, such as breathing, digesting, peristalsis, blinking, etc.

4. Movement Ambulation – Moving from one place to another Abduction – Moving away from the median plane Adduction – Moving towards the median plane Flexion – Moving the distal part of the limb towards the body Extension – Moving the distal part of the limb away from the body

5. Muscle Function All muscles can do is CONTRACT of RELAX – Generally work in pairs Agonist-Prime mover of a joint Antagonist-Opposes movement of the agonist Example – Elbow flexion Agonist  Bicep Antagonist  Tricep

6. Major Muscles Masseter-Superficial muscle of the cheek Trapezius-Superficial triangular muscle of the shoulder Latissimus dorsi-Long, superficial, dorsal muscle that attaches the humerus to the lumbar region of the back. Abdominal obliques-Large flat muscles that support digestive and reproductive organs

7. Major Muscles Gluteals-Large muscle of the upper hindquarters. Biceps femoris-lateral superficial muscle, one of the three which forms the “hamstrings” Biceps brachii-primary flexor of the elbow joint Triceps brachii-primary extensor of the elbow joint Pectorals-Primary adductors of the forelimbs Serratus ventralis-attaches forelimb to the trunk

8. Masseter Brachiocephalicus Biceps femoris Gastrocnemius Semitendinous Intercostal Triceps brachii Deltoid Gluteals Trapezius Latissimus dorsi External abdominal oblique Pectorals