CHAPTER 7 STUDY GUIDE MUSCULAR SYSTEM Anatomy Bowl

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

THREE MAJOR TYPES OF MUSCLE TISSUE (UNDERSTAND THE DIFFERENCES) 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

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

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

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

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? § 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 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

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

EXERCISE EFFECTS 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 is the increased size of a muscle due to increase of cells

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

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 § Muscles of Mastication § § Masseter Temporal Sternocleidomastoid trapezius

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

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