1. CHAPTER 6 STUDY GUIDEMUSCULAR SYSTEM Anatomy Test Prep

2. Three Major types of muscle tissue(understand the differences) • Skeletal muscle -”striated muscle” -”voluntary muscle” • Cardiac muscle -”striated muscle” -”involuntary muscle” • Smooth muscle -”voluntary muscle” -”visceral muscle” For each, know where it is located, the physical description, and what it does

3. Muscle Types • Skeletal muscle: • Is in our biceps, triceps, postural muscles, etc • Smooth muscle: • Is found along our digestive tract: used to move food along • Cardiac muscle: • Is found in the heart

4. Structure of Skeletal muscle • Origin • The stationary attachment to bone • Insertion • The more movable attachment site to bone • Tendons • Anchor muscles firmly to bones • Made of dense fibrous connective tissue in the shape of heavy cords • Bursae • Lie in between some tendons and bones beneath them • Synovial membrane • Secretes a slippery lubricating fluid that fills the bursa • Tendon sheaths • Enclose some tendons

5. Microscopic structure of skeletal muscle • Muscle fibers • Specialized contractile cells that are grouped together and arranged in a highly organized way • Thin and thick myofilaments • Thick filaments are composed of myosin • Thin filaments composed of actin • Actin • Thin filaments • Myosin • Thick filaments • Sarcomere • The basic functional or contractile unit of skeletal muscle

6. Muscle stimulus • Understand what a motor unit is and how it works Define: • Neuromuscular junction • Specialized point of contact between a nerve ending and the muscle fiber it innervates • Motor neuron • a specialized nerve that transmits an impulse to a muscle • Know how the process of muscle stimulus works • When does a muscle fiber fire? • Acetylcholine / Ca2+ • “All or none” muscle response • Muscles will not partially contract. It will contract or remain the same

7. Types of skeletal muscle contraction • Know the difference between: • A twitch contraction vs. a tetanic contraction • An isotonic contraction vs. an isometric contraction

8. Contractions • Twitch contraction • Is laboratory • Does not play a significant role in normal muscular activity • Tetanic • Are sustained and steady contractions caused by a series of stimuli bombarding the muscle

9. Exercise effects • What happens when you don’t exercise? Know and define: • Disuse atrophy • Atrophy is when the muscle fibers weak due to lack of stimulation • What happens when you do exercise? Know and define: • Hypertrophy • Hypertrophy is the increased size of a muscle due to increase of cells

10. Exercise • What are different types of exercise? Know and define: • Strength training • Exercise involving the contraction of muscle against heavy resistance • Endurance training • Increases a muscles ability to sustain moderate exercise over a long period of time • is also called “Aerobic training” • Allows for more efficient deliver of oxygen to muscles

11. Skeletal muscle groups Know the muscles of each group and what each muscle does • Muscles of the Head and Neck • Facial muscles • Orbicularis oculi • Orbicularis oris • Zygomaticus • Frontalis • Muscles of Mastication • Masseter • Temporal • Sternocleidomastoid • Trapezius • Buccinator

12. SKELETAL MUSCLE GROUPS • Muscles that move the Upper Extremities • Pectoralis major- flexes upper arm • Latissimus dorsi- extends upper arm • Deltoid- abducts upper arm • Biceps brachii-flexes forearm • Triceps brachii- extends forearm • Muscles of the Trunk • Rectus abdominis • External oblique • Internal oblique • Transversus abdominis • Muscles that move the Lower Extremities • Iliopsoas-flexes hip • Gluteus maximus- extends thigh • Adductors - adducts thighs • Hamstrings- flex lower leg • Quadriceps- extends lower leg • Gastrocnemius • Soleus • Tibialis anteror

13. Movements produced by skeletal muscle contractions • Flexion • Movement that decreases the angle between two bones at their joint: bending • Extension • Movement that increases the angle between two bones • Abduction • Movement of a part away from the midline of the body • Adduction • Movement of a part towards the midline of the body • Rotation • Movement around a longitudinal axis • Supination and pronation • Hand positions that result from rotation of the forearm; • Supination results in palms facing up • Pronation results in palms facing down • Dorsiflexion and plantar flexion • Foot movements; • Dorsiflexion results in elevation of dorsum or top of foot • During plantar flexion- the bottom of the foot is directed downward