CHAPTER 8 MUSCULAR Part 2 The Muscular System

CHAPTER 8 MUSCULAR Part 2

The Muscular System • Consists only of skeletal muscles

Origins and Insertions • Muscles have 1 fixed point of attachment (origin) and 1 moving point of attachment (insertion) • Most muscles

Actions • Movements produced by muscle contraction • Body movements –e. g. , flexion, extension, adduction, etc. • Described in terms of bone, joint, or region

WORDS YOU NEED TO KNOW

Muscle Terminology on Function • Based Agonist (prime mover): –produces a particular movement • Antagonist: –opposes movement of a particular + agonist pic. Explanation next slide • Synergist: –a smaller muscle that assists a larger agonist

Muscle Terminology Function • Based Synergist: on a smaller muscle that assists a larger agonist – helps start motion or stabilize origin of agonist (fixator)

Muscle Opposition • Agonists and antagonists work in pairs: –when 1 contracts, the other stretches –i. e. , flexors–

Names for Skeletal Muscles 1. Location in the body 2. Origin and insertion 3. Fascicle organization 4. Relative position 5. Structural characteristics 6. Action

Divisions of the Muscular System 1. Axial muscles: – position head and spinal column – move rib cage – 60% of skeletal muscles 2. Appendicular muscles: – support pectoral and pelvic Pics next 2 slides girdles

AXIAL MUSCLES

AXIAL MUSCLES position head and spinal column move rib cage 60% of skeletal muscles

Muscles of Facial Expression

Muscles of Facial • Expression – • • Frontalis: Wrinkle forehead, raise eyebrows Orbicularis oris: – constricts the mouth opening, protrudes lips, kissing muscle Buccinator: – moves food around the cheeks Orbicularis oculi: – closes the eye Pics next slide Zygomaticus

Muscles of Facial Expression

3 Muscles of • Masseter: Mastication (chew –the strongest jaw muscle ing) –elevates and closes the jaw • Temporalis: –helps lift the mandible • Pterygoid muscles: –position mandible for Pics next 2 slides

3 Muscles of Mastication

Removing Zygomatic Bone and Masseter Muscle

Muscles of the • Scalenes: (see in picture in 3 slides Neck w/ neck flexors) – Flex the neck • Sternocleidomastoid: Enlarged pic next slide – Flexes the neck (when both working) – Rotates the neck (when one working) • Trapezius: – Extend the neck • Platysma: – covers anterior surface of neck

s of the • Spinal Spine extensors or erector spinae muscles (superficial 1 of 2

Muscles of the • Spine Spinal flexors 2 of 2

ABDOMINAL MUSCLES • External & Internal obliques: • Flexes and rotates vertebral column(trunk) • Rectus abdominus: • Flexes vertebral column(trunk) Picture next slide

MUSCLES OF THE Diaphragm: CHEST Muscular partition that separates abdominopelvic and thoracic cavities Major respiratory muscle External intercostals: Elevate ribs Internal intercostals: Depress ribs

INHALING AND EXHALING

APPENDICULAR MUSCLES support pectoral and pelvic girdles support limbs 40% of skeletal muscles

MUSCLES THAT MOVE THE Coracobrachialis: SHOULDER Ex next slide Adduction and flex the shoulder Latissiumus dorsi: Extension, adduction of the shoulder Pectoralis major: Flexion, adduction of the shoulder Deltoid: Pic next 2 slides

SHOULDER MUSCLES

MUSCLES THAT MOVE THE SHOULDER Muscles often injured during the throwing motion. Rotator cuff muscles: Made of four muscles (S I T S) Supraspinatus: abduction of the shoulder Infraspinatus: lateral(external) rotation of the shoulder Teres minor: lateral(external)

MUSCLES THAT MOVE THE SHOULDER

MUSCLES OF THE E LBOW & FOREARM Brachioradialis : Flexion of the elbow Brachialis: Flexes the elbow Biceps brachii: Flexion of the elbow and supination

MUSCLES OF THE ELBOW & FOREARM Triceps brachii: Extends the elbow Anconeus: Extends the elbow

WORDS YOU NEED TO KNOW

MUSCLES OF Supinator: THE FOREARM Supination Pronator teres: Pronation Pronator quadratus: Explained in next slide

MUSCLES OF Supinator: THE FOREARM Supination Pronator teres: Pronation Pronator quadratus: next 3 slides Pronation

MUSCLES OF THE FOREARM, HAND, & Anterior muscles act as flexors FINGERS Posterior muscles act as extensors *(same as in the legs)

MUSCLES OF THE THIGH Gluteus Adductor longus maximus Adduction of the hip Extension of the hip Adductor Gluteus medius magnus Abduction of Adduction of the hip

PSO AS MUS CLE

MUSCLES THAT MOVE THE LEG Hamstring group Biceps Femoris Semimembran osus Semitendinosu s Extension of the hip, flexion of

MUSCLES THAT Sartorius MOVE THE LEG Crosses the leg Quadriceps group Rectus femorisflexes the hip, extends the knee Vasti muscles – extend the knee

MUSCLES THAT MOVE THE FOOT Gastrocnemi Tibialis us Posterior Plantar flexion & Plantar flexes inversion the foot Soleus Fibularis longus Plantar flexes & brevis the foot Tibialis Plantar flexion & Pictures on next 2 slides

MUSCLES THAT MOVE THE FOOT

MUSCLES THAT MOVE THE FOOT

MUSCLES THAT MOVE THE FOOT

MUSCLES THAT MOVE THEFlexors TOES Extensors Located on the anterior part Extension of the toes Located on posterior Flexion of the toes

SUPERFICIAL MUSCLES: ANTERIOR Figure 6. 21

SUPERFICIAL MUSCLES: POSTERIOR Figure 6. 22

HUMAN BODY VIDEO FROM MUSCULAR SYSTEM Look in the Skeletal System Folder!