Muscular System Chapter 7

640 muscles in our bodies! Muscles All muscles contract A contraction or shortening of a muscle causes movement We have…. 640 muscles in our bodies!

Types of Muscles Smooth Muscle Cardiac Muscle Located in the walls of hollow internal organs. These muscles are involuntary or uncontrolled Cardiac Muscle Forms the heart wall Involuntary Have intercalated disks – contractions spread quickly

Types of Muscles

Types of Muscles

Types of Muscles Skeletal Muscle Located all over the body and they attach directly to the skeleton These muscles are voluntary and controlled by the nervous system

Types of Muscles

Functions of Skeletal Muscles Support the body Allows movement Help maintain body temperature Assists blood circulation Protect internal organs

Skeletal Muscle Physiology A muscle fiber is the same as a muscle cell Muscle fibers are composed of two main protein filaments: Myosin – thick filaments Actin – thin filaments

Skeletal Muscle Physiology The actin and myosin fibers overlap to make a sarcomere. The sarcomere is the functional unit of the muscle

Skeletal Muscle Physiology When a nerve stimulates a muscle fiber calcium is released The actin and myosin fibers slide over each other The sarcomere then shortens That is a contraction!

Skeletal Muscle Physiology Contracted muscles can only “relax” when an opposing muscle contracts. Ex. biceps vs. triceps Rigor mortis – all of the muscles contract when a body dies

Muscle Contraction Animation https://www.youtube.com/watch?v=BMT4PtXRCVA

Skeletal Muscle Physiology Slow twitch fibers Darker in color (more blood vessels and mitochondria) Aerobic, steady power, endurance Fast twitch fibers Lighter in color Anaerobic, explosive power, fatigue easily Marathon runner vs. Body builder

Muscle Basics Each muscle has a name, origin, insertion, and movement. The origin is the stationary point where the muscle attaches. Usually a bone. The insertion is the attachment on the bone that moves When a muscle contracts it brings the insertion closer to the origin Naming is usually based on size, shape, and location of the muscle

Muscles of the Body

Muscles of the Face Frontalis Corrugator supercilii O – Parietal I – skin of eyebrows A – Wrinkle forehead Corrugator supercilii O – Nasal I – skin of forehead

Muscles of the Face Orbicularis oculi Nasalis O – Frontal bone, Lacrimal bone I – Outer eye A – Closes eye Nasalis O – Maxilla I – Nose A – Nostril movement

Muscles of the Face Zygomaticus major Platysma O – Zygomatic bone I – corner of mouth A – Draws up corner of the mouth Platysma O – under clavicle I – Skin of cheek, mandible A – Neck flexion, lateral mouth stretch

Muscles of the Face Temporalis Masseter O – Parietal bone I – Mandible A – Closes jaw Masseter O – Zygomatic and maxilla

Muscles of the Face Orbicularis oris Buccinator I – Skin around lips O – Maxilla, mandible I – Skin around lips A – Puckers lips (kissing) Buccinator I – Orbicularis oris A – Compresses cheeks (blowing & chewing)

Muscles of the Face Sternocleidomastoid O – Sternum, clavicle I – Temporal bone A – Rotate and flexes head and neck

Muscles of the Core External intercostals Internal intercostals O – Upper rib I – Lower rib A – Elevate ribs for inhaling Internal intercostals A – Depresses ribs for exhaling

Muscles of the Core External intercostals Internal intercostals O – Upper rib I – Lower rib A – Elevate ribs for inhaling Internal intercostals A – Depresses ribs for exhaling

Muscles of the Core Transverse abdominis Internal oblique O – Ilium, lower rib cartilage I – Pelvis and linea alba A – Compresses ribs, core stabilization Internal oblique O – Ilium I – Linea alba, sternum, and inferior ribs A – Spinal rotation and abdomen compression

Muscles of the Core External oblique Rectus Abdominis O – Lower ribs I – Pelvis A – Flexion and rotation of the spine Rectus Abdominis O – pelvis I – sternum and ribs

Muscles of the Core Trapezius Latissimus Dorsi O – Cervical-Thoracic vertebrae, cranium I – Clavicle & Scapula A – Elevate, rotate, and adduct scapula Latissimus Dorsi O – T vertebrate, pelvis, lower ribs I – Humerus A – Extends, adducts, and internally rotates shoulder

Muscles of the Core Gluteus Maximus Gluteus Minimus O – Pelvis and Sacrum I – Femur A – Extension and lateral rotation of hip Gluteus Minimus O – Pelvis A – Abducts and laterally rotates hip

Muscles of the Core Gluteus Medius O – Pelvis I – Femur A – Abducts hip and rotates femur

Muscles of the Core Levator Scapula Rhomoideus O – Cervical vertebrae I –Scapula A – Elevates scapula and rotates and extends neck Rhomoideus O – Thoracic vertebrate I – Scapula A – Retracts scapula

Muscles of the Core Teres Major Erector spinae O – Inferior scapula I – Humerus A – Adducts, medial rotation, and arm extension Erector spinae O – Sacrum, Ilium, Lower vertebrae I – Ribs & upper vertebrae A – Spinal extension and side-bending

Muscles of the Core Teres Major Erector spinae O – Inferior scapula I – Humerus A – Adducts, medial rotation, and arm extension Erector spinae O – Sacrum, Ilium, Lower vertebrae I – Ribs & upper vertebrae A – Spinal extension and side-bending

Muscles of the Core Pectoralis Minor Pectoralis Major O – Middle ribs I – Scapula A – moves scapula forward and downward Pectoralis Major O – Clavicle, sternum, costal cartilage I – Humerus A – Shoulder adduction, protraction, arm rotation

Muscles of the Arm Deltoid Biceps Brachii O – Clavicle and scapula I – Humerus A – abducts arm Biceps Brachii O – Scapula I – Radius A – Flexes elbow and supinates forearm

Muscles of the Arm Brachialis Triceps Brachii O – Humerus I – Ulna A – elbow flexion Triceps Brachii O – Scapula and humerus A – elbow extension

Muscles of the Arm Brachialis Triceps Brachii O – Humerus I – Ulna A – elbow flexion Triceps Brachii O – Scapula and humerus A – elbow extension

Muscles of the Arm Supinator Pronator Teres O – Ulna and Humerus I – Radius A – Supinates forearm Pronator Teres A – Pronates forearm

Muscles of the Arm Pronator Quadratus O – Distal ulna I – Distal radius A – Pronates forearm

Muscles of the Arm Extensor carpi radialis Extensor carpi ulnaris O – Humerus I – Metacarpal A – extends wrist Extensor carpi ulnaris O – Posterior ulna and humerus

Muscles of the Arm Flexor carpi radialis Flexor carpi ulnaris O – Humerus I – Metacarpals A – flexes wrist Flexor carpi ulnaris O – Ulna and humerus I – pisiform, hamate, and metacarpals

Muscles of the Arm Extensor digitorum Flexor digitorum profundus O – Humerus I – Phalanges A – Extends fingers and wrist Flexor digitorum profundus O – Ulna I – phalanges A – flexes wrist and fingers

Muscles of the Leg Tensor Fasciae latae Iliopsoas I – Femur O – lumbar vertebrae I – Femur A – Flex and rotate leg Tensor Fasciae latae O – Ilium I – Iliotibial tract (IT band) A – Hip flexion, abduction and medial rotation

Muscles of the Leg Adductor longus Adductor magnus I – Femur O – Pelvis I – Femur A – Hip adduction and flexion Adductor magnus A – Hip adduction and extension

Muscles of the Leg Adductor longus Adductor magnus I – Femur O – Pelvis I – Femur A – Hip adduction and flexion Adductor magnus A – Hip adduction and extension

Muscles of the Leg Sartorius Rectus Femoris I – Tibia O – Pelvis I – Tibia A – Thigh flexion, abduction, and lateral rotation Rectus Femoris O –Ilium I – Patella and tibia A – Extends knee and flexes hip

Muscles of the Leg Vastus medialis Vastus Lateralis O – Femur I – Patella and tibia A – Knee extension Vastus medialis A – Knee extension

Muscles of the Leg Biceps femoris Vastus intermedius O – Femur I – Patella and tibia A – Knee extension Biceps femoris O – Pelvis and Femur I – Fibula A – Knee flexion and hip extension

Muscles of the Leg Semimembranosus Semitendinosus I – Tibia O – Pelvis I – Tibia A – Knee flexion and hip extension Semimembranosus

Muscles of the Leg Gastrocnemius Tibialis Anterior O – Tibia I – Cuneiform and metatarsal A – Dorsiflexion and inversion Gastrocnemius O – Femur I – Calcaneus A – Plantar flexion and knee flexion

Muscles of the Leg Soleus O – Fibula and Tibia I – Achilles Tendon A –Plantar flexion and inversion

Muscles of the Leg Flexor halliucis longus Extensor Halliucis longus O – Fibula I – Big Toe (phalange) A – Extends big toe Flexor halliucis longus I – Big toe (phalange) A – Flexes big toe