Which of the following two time day changes for SI sessions would work BEST for you Please choose two A B C D Monday 9 9 50am Wednesday 11 11 50am Thursday 11 11 50am Wednesday 8 8 50am 30 30 23 16 Clicker channel 70 Session ID psio201 A B C D Lecture 16 Introduction to the Muscular System Claudia Stanescu Ph D Office hours Tuesday and Thursday 1 2pm in Gittings 108 or by appointment Objectives pp 329 333 sec 11 1 11 2 1 List and describe the specific functions of skeletal muscle 2 Define the terms origin and insertion and describe the action and the reverse action of a muscle using these terms 3 List and describe the three classes of levers giving examples of each 4 Describe the classification of muscles based on action and be able to determine the role played by a muscle in a particular movement i e agonist antagonist synergist fixator Muscle Structure and Function Three types of muscle 1 Skeletal Muscle 2 Cardiac Muscle 3 Smooth Muscle Basic function of all three types is the same Generate Tension Functions of skeletal muscle Locomotion Facial expression Posture and body position Regulation of body temperature Skeletal muscle contraction is voluntary Requires nervous system input Some skeletal muscles can be automatic but we have the ability to change their activity Diaphragm usually automatic but you can take a deep breath or hold your breath whenever you choose Basics of human movement Muscles pull on bones they do not push can predict the action of a muscle based on location Origin the place where the muscle starts on a bone stays stationary Insertion the place where the muscle ends on a bone moves toward the origin Muscle action The insertion moves towards the origin flexion of the forearm decreasing the angle at elbow Flexion ORIGINS from scapula BELLY of biceps brachii muscle INSERTION on radius Example biceps curl Types of Body Movements General guidelines In standard anatomical position everything is extended except the feet When naming a movement include the action and the name of the segment that moves Flexion of the forearm Adduction of the thigh 1 Flexion Extension Movement to reduce flexion or increase extension the angle between articulating bones at a joint These motions typically occur along a sagittal plane anterior posterior Flexion Extension 1 Flexion Extension Flexion of the forearm Extension of the forearm Flexion of the leg Extension of the leg 1 Flexion Extension cont Flexion of the thigh Extension of the thigh Flexion of the arm Extension of the arm 2 Abduction Adduction Movement away or toward the longitudinal axis or midline These motions typically occur along a frontal plane in reference to the midline of the body Abduction Adduction of the arm Abduction Adduction of the thigh Reverse muscle action RMA ORIGINS from scapula BELLY of biceps brachii muscle INSERTION on radius When the insertion is anchored the origin moves towards the insertion Example pull ups Muscle action Action Leg extension increasing the angle at knee Muscle group quadriceps Origin femur Insertion tibial tuberosity Which one is the reverse action for the quadriceps muscle group 1 2 92 8 1 Getting up from a chair 2 Kicking leg forward Classifying a muscle based on action Agonist muscle primarily responsible for the movement aka prime mover Antagonist muscle which opposes the action of the agonist Synergist assists the agonist in making the action more efficient Fixator special synergists which help to prevent movement at muscle origin Note in this course we will not specify the prime mover for an action Classifying a muscle based on action Supraspinatus Abduction of the arm Agonist deltoid Antagonist latissimus dorsi Synergist supraspinatus Fixator trapezius Deltoid Trapezius Latissimus dorsi Pectoralis minor Classifying a muscle based on action Flexion of forearm Agonist brachialis Antagonist triceps brachii Synergist biceps brachii Fixator pectoralis minor Brachialis Triceps brachii Biceps brachii Why is brachialis the prime mover Leverage Psoas minor Iliacus RECTUS FEMORIS Psoas major Anterior deep view For hip flexion the agonist prime mover is psoas major not rectus femoris Leverage Rectus femoris acting at the hip what we need acting at the hip psoas major Leverage Lever rigid bar bone Fulcrum fixed point around which the rigid bar bone moves joint Muscles act to facilitate movement at a fulcrum joint by exerting force on the lever bone Example of lever system Types of levers 1 First class levers 2 Second class levers 3 Third class levers First class levers LFE Not many examples in the human body Second class levers FLE Not many examples in the human body Third class levers FEL Most common type of lever system in the body F L E Suggested Learning Activities Demonstrate the difference between muscle action and reverse muscle action using examples bicep curls vs pull ups or seated leg extension vs standing up from a chair and referring to the joint angle Draw a diagram and list the components of the three classes of levers in order