Anatomy Bowl Prep By: Amanda Morden CHAPTER 7 STUDY GUIDE MUSCULAR SYSTEM

1.Skeletal muscle -”striated muscle” -”voluntary muscle” 2.Cardiac muscle -”striated muscle” -”involuntary muscle” 3.Smooth muscle -”voluntary muscle” -”visceral muscle” For each, know where it is located, the physical description, and what it does THREE MAJOR TYPES OF MUSCLE TISSUE (UNDERSTAND THE DIFFERENCES)

 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

 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 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 MICROSCOPIC STRUCTURE OF SKELETAL MUSCLE

 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?  When stimulated a muscle fiber will fire when it has reached its threshold  When does it not?  If the stimulus is not strong enough the muscle will not fire Understand and define:  Threshold stimulus  Minimal level of stimulation needed to make a muscle contract  “All or none” muscle response  Muscles will not partially contract. It will contract or remain the same MUSCLE STIMULUS

 Know the difference between: 1.A twitch contraction vs. a tetanic contraction 2.An isotonic contraction vs. an isometric contraction TYPES OF SKELETAL MUSCLE CONTRACTION

 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

 What happens when you don’t exercise? Know and define:  Disuse atrophy  Atrophy is when the muscle fibers become 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 EXERCISE EFFECTS

 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 delivery of oxygen to muscles

Know the muscles of each group and what each muscle does  Muscles of the Head and Neck  Facial muscles  Orbicularis oculi  Orbicularis oris  Zygomaticus  Muscles of Mastication  Masseter  Temporal  Sternocleidomastoid  trapezius 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  Adductor magnus- adducts thighs  Hamstrings- flex lower leg  Quadriceps- extends lower leg

 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 MOVEMENTS PRODUCED BY SKELETAL MUSCLE CONTRACTIONS