Portage Learning BIOD 151 a&p module 5

Portage Learning BIOD 151 a&p module 5 Anatomy of the Muscular System: Introduction & Muscles of the Head, Neck, and Trunk Notice: To optimize your learning in this course, we advise that you complete the labs and modules as indicated in the BIOD 151 Lab Schedule. The muscular system and the skeletal system work together to provide movement for the human body. Muscle tissue is found in three distinct types in the body; skeletal, smooth, and cardiac. Skeletal muscles must have a blood and nervous supply to provide movement. Skeletal muscles are under conscious control, meaning that a person can consciously decide to use these muscles to complete an action. Communication within the body to coordinate movement starts in the brain with a message that is sent through the spinal cord and eventually attaches to a muscle. Peripheral nerves carry the signal from the central nervous system (brain and spinal cord) to a specific muscle destination to provide movement. Messages from the central nervous system to a muscle are called a motor actions. Nerves also carry information from the external environment to the central nervous system, called sensation or sensory input. (see Figure 5.1 and Figure 5.2) Spinal nerves combine to form complex networks of peripheral nerves throughout the body. Figure 5.1 Posterior view of the nervous system. The brain and spinal cord (central nervous system) connect to the peripheral nervous system. Examples of peripheral nerves are spinal nerves (cervical, thoracic, and lumbar), the upper trunk of the brachial plexus, and the radial nerve. Figure 5.2 Peripheral nerves carry the communication from the central nervous system (brain and spinal cord) to the muscle. Peripheral nerves also carry information from the environment to the central nervous system. Tendons are connective tissues that connect skeletal muscle to bone at each end (see Figure 5.3). Tendons are flexible, can bend at the joints, and help cushion against sudden movement. Ligaments are connective tissue that connects bone to bone, helping to stabilize joints where bones meet. Figure 5.3 Skeletal muscles attach to bones via tendons at points called the origin and insertion. The origin is the fixed point while the insertion is the place that is moved during a muscle contraction. All skeletal muscles have an origin, insertion, and action. The origin is the bony site of attachment which is stationary during the movement. The insertion of a muscle is the bony site of attachment that is moved by the muscle contraction. (see Figure 5.3) The origin and insertion can be reversed in different types of movement. For this module, the standard origin and insertion points are referenced from anatomical position. The action of the muscle is what effect is produced by the muscle’s contraction. For example, the triceps is the primary extensor of the forearm. The innervation is the peripheral nerve that supplies a muscle with the message from the brain. For example, the innervation of the biceps brachii is the musculocutaneous nerve. (see Figure 5.4) Figure 5.4 Anterior view of the musculocutaneous nerve (blue) innervates the biceps brachii muscle. Muscles are generally studied in groups. The following muscle list is an overview of some of the major muscles in the body. Study the location of the muscle in the body. In addition, if listed, study the origin, insertion, innervation and action of these muscles. Muscles of Facial Expression: (See Figure 5.5) The muscles in this grouping help to facilitate all the actions within the face. All the varied facial expressions are enabled by these muscles. CN is an abbreviation for cranial nerve. There are twelve pairs of cranial nerves that originate on the ventral surface of the brain, controlling muscles and functions of several organs and glands. Orbicularis oculi Action: eye closure Innervation: Facial nerve (CN VII) Orbicularis oris Action: mouth closure: closes lips, protrudes lips forward, presses lips against teeth Innervation: Facial nerve (CN VII) Zygomaticus major/minor Action: pull corners of lips upward Innervation: Facial nerve (CN VII) Risorius Action: pulls the corners of the mouth posteriorly (grin or grimace) Innervation: Facial nerve (CN VII) Frontalis (occipitofrontailis) Action: raise eyebrows Innervation: Facial nerve (CN VII) Buccinator Action: compress cheeks Innervation: Facial nerve (CN VII) Masseter Action: jaw closure Innervation: Trigeminal nerve (CN V, mandibular branch) Temporalis Action: Elevates mandible, closes jaw Innervation: Trigeminal nerve (CN V, mandibular branch) Figure 5.5 Muscles of facial expression. Note that the buccinator is deep to zygomaticus major/minor and risorius. Muscles of the Head and Neck: (See Figure 5.6) The muscles in this grouping help to facilitate actions which move the head (occiput) and control the neck. Side bending of the neck is also called side flexion or lateral flexion, which refers to moving one of the ears to the same side shoulder. Neck flexion refers to the action of moving the chin towards the sternum. Note there are several muscles that have differing actions if acting together on both sides (bilaterally) or acting on one side only (unilaterally). Semispinalis Capitis Origin: Articular processes of inferior cervical & transverse process of superior thoracic vertebrae Insertion: Occipital bone Action: Bilateral extend head Unilateral laterally flexes neck to same side Innervation: Spinal nerves Sternocleidomastoid Origin: Sternal end of clavicle and manubrium Insertion: Mastoid region of skull Action: Bilateral: Neck flexion Unilateral: Turns face to opposite side Innervation: Accessory nerve (CN XI) Splenius Capitis Origin: Spinous process/ligaments of inferior cervical vertebrae Insertion: Mastoid process, occipital bones of skull Action: Bilateral extend head Unilateral laterally flexes neck to same side Innervation: Cervical spinal nerves Longissimus cervicis Origin: transverse processes of superior thoracic vertebrae Insertion: transverse process of middle and superior cervical vertebrae Action: Bilateral extend head Unilateral laterally flexes neck to same side Innervation: Cervical and thoracic spinal nerves Longissimus thoracis Origin: Transverse process of inferior thoracic, superior lumbar vertebrae Insertion: Transverse process of middle and superior cervical vertebrae Action: Bilateral extend head Unilateral laterally flexes neck to same side Innervation: Thoracic and lumbar spinal nerves Thyrohyoid Origin: Thyroid cartilage of larynx Insertion: Hyoid bone Action: Elevates thyroid, depresses hyoid bone Innervation: Hypoglossal nerve Scalenes (anterior, middle, posterior) Origin: Transverse processes of C2- C7 Insertion: 1st and 2nd Ribs Action: Elevates ribs 1 & 2 Innervation: Cervical spinal nerves Figure 5.6 Lateral view: Muscles of the head and neck Vertebral Column: Erector Spinae (See Figure 5.7) The erector spinae group are superficial muscles in the back. These muscles act as the prime extensors of the vertebral column. Flexion of the spine refers to forward bending the trunk (such as a “cat” stretch). Extension of the spine refers backward bending. The vertebral column is also able to perform side bending (or lateral flexion) as well as movement around an axis (rotation). Spinalis: Medial column of erector spinae Made up of three divisions (spinalis thoracis, spinalis cervicis, and spinalis capitis) Longissimus: Intermediate column of erector spinae Made up of three divisions (longissimus dorsi, longissimus cervicis, longissimus capitits) Iliocostalis: Lateral column of erector spinae Made up of three divisions (iliocostalis lumborum, iliocostalis thoracis, iliocostalis cervicis) Figure 5.7 Posterior view: Erector Spinae Group Oblique and rectus muscles: Anterior (See Figure 5.8) The abdominal muscles perform many functions. These muscles help to support and protect the abdominal viscera (which are not protected by bony structures). These muscles, along with the muscles in the back (see above) help to provide support for upright posture and balance. Rectus abdominis Origin: Pubic Crest, pubic symphysis Insertion: Pubis, cartilages of ribs 5-7, xiphoid process Action: Flexion of spine, compression of abdominal viscera Innervation: Spinal nerves (T 7-T 12) External oblique Origin: Sternum, ribs (5-12) Insertion: Linea alba, iliac crest Action: Bilaterally: Flexion of the spine, compress the abdomen; Unilaterally: Flexes trunk to same side, rotates to opposite side Innervation: Lower intercostal, ilioinguinal nerves Internal oblique Origin: Iliac crest, lumbodorsal fascia Insertion: Inferior ribs, linea alba Action: Compresses abdomen, depresses ribs, flexes spine Innervation: Lower intercostal, ilioinguinal nerves Transverse abdominis – deep to internal oblique Origin: Lateral inguinal ligament, inner iliac crest Insertion: Linea alba, pubis Action: Compression of abdomen Innervation: First lumbar nerve (T 7- L1), iliohypogastric (T12-L1), ilioinguinal (T12-L1) Figure 5.8 Muscles and landmarks of the anterior trunk Muscles of Breathing (See Figure 5.9) The diaphragm is the primary muscle necessary for intaking air. The internal intercostals and the external intercostals work in opposite functions. Notice the difference in their muscle fiber orientation (see Figure 5.9). Diaphragm Origin: Cartilage of ribs 7-12, xiphoid process, lumbar vertebrae Insertion: Anterior longitudinal ligament (vertebral column) Action: Expands thoracic cavity, compresses abdominal cavity Innervation: Phrenic nerve (C3-5) Internal Intercostals Origin: Superior border of ribs 2-12 Insertion: Inferior of ribs above (1-11) Action: Depresses ribs (forced expiration) Innervation: Intercostal nerves External Intercostals Origin: Lower border of ribs 1-11 Insertion: Upper border of ribs below (1-12) Action: Elevates ribs (normal inspiration) Innervation: Intercostal nerves Figure 5.9 Anterior view of the muscles of breathing. The diaphragm is the primary muscle of inspiration. Anatomy of the Muscular System Part II: Muscles of the Upper and Lower Extremities Muscles of the Shoulder and Upper Extremity (See Figures 5.10, 5.11, 5.12) The muscles on the posterior thorax assist in movement of the shoulder girdle. The trapezius is a large muscle that acts on the shoulder as well as the neck and upper spine. The trapezius is superficial to the remaining muscles shown (see Figure 5.10). Trapezius (upper, middle, lower) Origin: Occipital bone, spinous process of T1-12, Insertion: Lateral clavicle, acromion, and scapular spine of scapula Action: Rotation, retraction, elevation, depression of scapula; extends neck; stabilizes shoulder Innervation: Accessory nerve (Cranial Nerve 11) Levator scapulae Origin: Transverse process of C1-4 Insertion: Medial border of scapula Action: Elevates scapula Innervation: Dorsal scapular nerve Rhomboids (major, minor) Origin: Spinous process (minor: C7-T1) (major: T2-5) Insertion: Medial border of scapula Action: Retraction of scapula Innervation: Dorsal scapular nerve Figure 5.10 Posterior view of the shoulder girdle muscles. The trapezius is a superficial muscle (shown on left). On the right, the trapezius is cut away to show the muscles underneath. *Note: Additional muscles are labeled in this figure for clarification. Pectoralis minor Origin: Ribs 3-5 Insertion: Coracoid process of scapula Action: Elevates ribs, draws scapula down and medially Innervation: Medial pectoral nerve Serratus Anterior Origin: Upper 8-9 ribs Insertion: Medial border of scapula Action: Protraction of scapula Innervation: Long thoracic nerve Figure 5.11 Anterior view of the muscles of the thorax and shoulder girdle. Serratus anterior (left and right) is highlighted in blue. Muscles of the shoulder girdle continued: (See Figures 5.12, 5.13, 5.14) The shoulder is a ball and socket joint, which permits many types of movement. The glenoid cavity of the scapula is very small compared to the head of the humerus. The large bony structure of the shoulder requires many ligaments and layers of muscle for stability. A muscle grouping known as the rotator cuff is necessary to stabilize the humeral head inside the shoulder joint. The rotator cuff is made up of the “SITS” muscles: Supraspinatus, Infraspinatus, Teres minor, and Subscapularis. (See Figure 5.14) Deltoid (anterior, posterior, middle) Origin: Clavicle and scapula Insertion: Deltoid tuberosity of humerus Action: Abduction at shoulder (whole muscle) Innervation: Axillary nerve Pectoralis major Origin: Ribs 2-6, body of sternum Insertion: Greater tubercle of humerus Action: Flexion, adduction and medial rotation at shoulder Innervation: Pectoral Nerves Supraspinatus- (above spine of scapula) Origin: Supraspinatus fossa of scapula Insertion: Greater tubercle of humerus Action: Abduction at the shoulder Innervation: Suprascapular nerve Infraspinatus (below spine of scapula) Origin: Infraspinatus fossa of scapula Insertion: Greater tubercle of humerus Action: Lateral rotation at shoulder Innervation: Suprascapular nerve Teres Minor Origin: Lateral border of scapula Insertion: Greater tubercle of humerus Action: Lateral rotation at shoulder Innervation: Axillary nerve Teres Major – not part of the rotator cuff Origin: Inferior angle of scapula Insertion: Intertubercular groove of humerus Action: Extension, adduction, and medial rotation at shoulder Innervation: Lower subscapular nerve Subscapularis- along inner surface of the scapula Origin: Subscapular fossa of scapula Insertion: Lesser tubercle of humerus Action: Medial rotation at the shoulder Innervation: Subscapular nerves Latissimus Dorsi Origin: Spinous process of inferior thoracic and lumbar vertebrae, ribs 8-12 Insertion: Intertubercular groove of humerus Action: Extension, adduction, and medial rotation at shoulder Innervation: Thoracodorsal nerve Coracobrachialis Origin: Coracoid process of scapula Insertion: Medial shaft of humerus Action: Adduction and flexion at shoulder Innervation: Musculocutaneous nerve Figure 5.12 Anterior view of shoulder girdle muscles. These are the prime movers of the upper limbs. Figure 5.13 Posterior view of shoulder girdle muscles. The superficial muscles (deltoid, teres major) are cut away to show the deep muscles of the shoulder (right). The latissimus dorsi is highlighted on the right in blue to show the origin and insertion points of this large muscle. Figure 5.14 Anterior view of the right rotator cuff. Subscapularis is highlighted in blue on the anterior surface of the scapula. Muscles of the Forearm and Elbow (See Figures 5.15, 5.16, 5.17) Biceps brachii Origin: Short head- coracoid process; Long head- supraglenoid tubercle of scapula Insertion: Tuberosity of radius Action: Flexion at elbow and shoulder; supination Innervation: Musculocutaneous nerve Brachialis Origin: Anterior/distal surface of humerus Insertion: Tuberosity of ulna Action: Flexion at elbow Innervation: Musculocutaneous nerve and radial nerve Brachioradialis Origin: Lateral epicondyle of humerus Insertion: Lateral aspect of styloid process of radius Action: Flexion at elbow Innervation: Radial nerve Triceps (long head, lateral head, medial head) Origin: Lateral head- superior, lateral margin on humerus Long head – Infraglenoid tubercle of scapula Medial head- Posterior surface of humerus Insertion: Olecranon of ulna Action: Extension at elbow Innervation: Radial nerve Pronator Teres Origin: Medial epicondyle of humerus Insertion: Mid-lateral surface of radius Action: Pronation Innervation: Median nerve Supinator Origin: Lateral epicondyle of humerus Insertion: Anterolateral surface of radius Action: Supination Innervation: Deep radial nerve Figure 5.15 Anterior view of the right elbow flexors. Figure 5.16 Posterior view of the right elbow extensors. Figure 5.17 Anterior view of the right supinator and pronators of the forearm. Muscles of the Hand and Wrist For the muscles listed for the hand and wrist, only the location of the muscle, action, and innervation are listed. Note the long tendons on many of these muscles, crossing the wrist to insert on the digits. Superficial flexors: (See Figure 5.17) Flexor carpi radialis Action: Wrist flexion, radial deviation of the hand Innervation: Median nerve Palmaris longus Action: Wrist flexion Innervation: Median nerve Flexor carpi ulnaris Action: Wrist flexion, ulnar deviation of the hand Innervation: Ulnar nerve Flexor digitorum superficialis (FDS) Action: Flexion of the wrist and digits 2-5 (middle and proximal phalanx) Innervation: Median nerve Figure 5.18 Anterior view of the right superficial wrist flexors. Lines indicate the muscle bellies. Notice how the tendons cross the wrist and insert onto the metacarpals of the digits. *FDS is deep to palmaris longus and flexor carpi radialis longus. Deep flexors: (See Figure 5.18) Flexor pollicis longus Action: Flexion of thumb Innervation: Median nerve Flexor digitorum profundus (FDP) Action: Wrist flexion, flexion of digits 2-5 (distal phalanx) Innervation: Palmar interosseous nerve Figure 5.19 Anterior view of the right deep hand flexors. FDP is highlighted in blue. Note the long tendons of the muscles that insert on the metacarpals of the digits. Superficial Extensors of the Wrist: (See Figure 5.19) Extensor carpi radialis longus Action: Extension, abduction of the wrist Innervation: Radial nerve Extensor carpi radialis brevis Action: Extension, abduction of the wrist Innervation: Radial nerve Extensor digitorum Action: Wrist extension, extension of digits 2-5 Innervation: Deep radial nerve Extensor digiti minimi (digit 5) Action: Wrist extension, extension of digit 5 Innervation: Deep Radial nerve Extensor carpi ulnaris Action: Extension, adduction of the wrist Innervation: Deep Radial nerve Figure 5.20 Posterior view of the superficial extensors of the right wrist. Deep extensors of the wrist (See Figure 5.20) Abductor pollicis longus (APL) Action: Abduction of wrist and thumb Innervation: Deep Radial nerve Extensor pollicis longus (EPL) Action: Thumb extension, wrist abduction Innervation: Deep Radial nerve Extensor pollicis brevis (EPB) Action: Thumb extension, wrist abduction Innervation: Deep Radial nerve Extensor indicis (EI) Action: Extension of wrist and digit 2 Innervation: Deep Radial nerve Figure 5.21 Posterior view of the deep extensors of the right wrist. Muscles of the Lower Extremity Several movements are important to clarify when discussing muscles of the lower extremity. Hip extension involves moving the thigh posteriorly (or backward movement of the thigh). Hip flexion is moving the thigh anteriorly (or forward movement of the thigh). Knee extension means to straighten the knee, or to increase the angle of the joint. Knee flexion is bending the knee (decreasing the angle of the joint). Lateral rotation (external rotation) refers to rotation away from the center of the body. Internal rotation (medial rotation) refers to rotation towards the central axis of the body. Iliopsoas Group: Psoas major and iliacus together are called iliopsoas Psoas Major Origin: Transverse bodies of all lumbar vertebra Insertion: Lesser trochanter of the femur (with iliacus) Action: Hip flexion (or trunk flexion if femur is stationary) Innervation: Lumbar plexus Iliacus Origin: Iliac fossa of ilium Insertion: Lesser trochanter of femur Action: Hip flexion Innervation: Femoral nerve Figure 5.22 Anterior view of the iliopsoas group. Psoas major is highlighted in blue; note the muscle joining with the iliacus on the medial side of the femur. Gluteal Muscles of the thigh: The gluteal muscles extend and rotate the hip joint. Gluteus maximus is a large, superficial muscle covering the posterior thigh. (See figure 5.23) The hip is a ball and socket joint, permitting many ranges of movements such as: adduction, abduction, extension, flexion and rotation. The “hip” refers to the ball and socket joint. Thigh movements refer to movement of the femur. A muscle can have multiple actions depending on the location and orientation of the muscle fibers. For example, gluteus maximus can abduct and extend at the hip joint. In addition, a muscle may act on multiple joints. For example, the biceps femoris crosses the hip joint and the knee joint. At the hip, biceps femoris enables hip extension, while at the knee it enables knee flexion. Gluteus maximus Origin: Posterior gluteal line of the ilium, lower sacrum, side of the coccyx Insertion: Gluteal tuberosity Action: Abducts, extends, laterally rotates hip joint Innervation: Inferior gluteal nerve Gluteus medius Origin: Gluteal surface of the ilium Insertion: Greater trochanter of the femur Action: Abducts thigh, stabilizes the hip joint Innervation: Superior gluteal nerve Gluteus minimus Origin: Gluteal surface of the ilium Insertion: Greater trochanter of the femur Action: Abducts thigh, stabilizes hip joint Innervation: Superior gluteal nerve TFL – tensor fascia latae Origin: ASIS (Anterior superior iliac spine) Insertion: Iliotibial tract Action: Abducts and internally rotates thigh, stabilizes hip and knee joints Innervation: Superior gluteal nerve Figure 5.23 Posterior view of the gluteal muscles of the thigh. The gluteus maximus is superficial (shown on the left). Both gluteus maximus and medius are cut away to show gluteus minimus, deep within the thigh (Gluteus minimus is shown in blue on the left). Lateral Rotators of the Thigh (Deep) These muscles are a series of small muscles that are close to the hip joint, helping to stabilize and laterally rotate the hip. Only the action and innervation are listed for the lateral rotator group. (See Figures 5.24, 5.25) Obturator externus Action: Lateral rotation of thigh Innervation: Obturator nerve Obturator internus Action: Lateral rotation of thigh Innervation: Spinal nerves S1-3 Superior gemellus Action: Lateral rotation, adduction, extension of hip joint Innervation: Spinal nerves L5, S1 Inferior gemellus Action: Lateral rotation, adduction, extension of hip joint Innervation: Spinal nerves L5, S1 Quadratus Femoris Action: Lateral rotation, adduction of hip joint Innervation: Spinal nerves L5, S1 Piriformis Action: Lateral rotation, adduction, extension of hip joint Innervation: Spinal nerves L5-S2 Figure 5.24 Posterior view of the small lateral rotators of the hip. These muscles are deep to gluteus maximus, and inferior to gluteus medius. Figure 5.25 Anterior view of the small lateral rotators of the hip. These muscles are deep to gluteus maximus, and inferior to gluteus medius. Obturator externus is highlighted in blue on both the left and right sides. Posterior, Hamstring Group: (See Figure 5.26) Biceps Femoris Origin: Head of the femur, lateral surface Insertion: Head of the fibula, lateral surface Action: Knee flexion, hip extension Innervation: Common fibular nerve (peroneal) Semitendinosus Origin: Ischial tuberosity Insertion: Medial surface of tibia Action: Knee flexion Innervation: Tibial nerve Semimembranosus Origin: Ischial tuberosity Insertion: Medial condyle of tibia Action: Knee flexion Innervation: Tibial nerve Figure 5.26 Posterior view of the hamstring group. Semimembranosus is highlighted in blue. Anterior, Quadriceps (See Figure 5.27) Rectus Femoris Origin: AIIS (Anterior inferior iliac spine) Insertion: Common tendon of the quadriceps to tibial tuberosity Action: Knee extension, Hip flexion Innervation: Femoral nerve Vastus Medialis Origin: Intertrochanteric line of femur Insertion: Patella via quadriceps tendon; tibial tuberosity Action: Knee extension Innervation: Femoral nerve Vastus Lateralis Origin: Greater trochanter of femur Insertion: Patella via quadriceps tendon; tibial tuberosity Action: Knee extension Innervation: Femoral nerve Vastus Intermedius Origin: Anterior/lateral surfaces of femur Insertion: Common tendon of the quadriceps to tibial tuberosity Action: Knee extension Innervation: Femoral nerve Figure 5.27 Anterior view of the quadriceps group. Note that the rectus femoris (shown on right) is cut away on the left to show the deeper muscle, vastus intermedius. Medial Compartment: (See Figure 5.28) Adductor Group: Adductor Longus Origin: Front of the pubis Insertion: linea aspera Action: Adducts, medially rotates thigh Innervation: Obturator nerve Adductor Brevis Origin: Superior and inferior rami of the pubis Insertion: Medial shaft femur, into the upper linea aspera Action: Adducts, medially rotates thigh Innervation: Obturator nerve Adductor Magnus Origin: Inferior ramus of pubis Insertion: Adductor tubercle, medial condyle of the femur, linea aspera Action: Adducts, medially rotates thigh Innervation: Obturator nerve Gracilis Origin: Lower half of pubic symphysis Insertion: Superior shaft of tibia Action: Adductor of the thigh, flexes knee Innervation: Obturator nerve Pectineus Origin: Pectineal line Insertion: Posterior surface of the femur Action: Adducts thigh Innervation: Femoral nerve Sartorius Origin: ASIS (Anterior superior iliac spine) Insertion: Superior shaft of tibia Action: Hip: Flexion, abduction, external rotation; Knee: flexion, internal rotation Innervation: Femoral nerve Figure 5.28 Anterior view of the medial compartment of the thigh. The superficial muscles are cut away to show the deep muscles on the right side of the body, above. Sartorius is a superficial muscle (in blue). Muscles of the Lower Leg: (See Figures 5.29 – 5.33) (Anterior) Tibialis Anterior Origin: Lateral condyle of tibia Insertion: Base of metatarsal 1, medial cuneiform Action: Dorsiflexion, inversion of foot Innervation: Deep peroneal nerve Extensor Digitorum longus Origin: Lateral condyle of tibia Insertion: Distal phalanges of digits 2-5 Action: Extends digits 2-5, dorsiflexion of foot Innervation: Deep peroneal nerve Extensor hallucis longus Origin: Anterior surface of fibula Insertion: Dorsal surface of digit 1 (great toe) Action: Extension of digit 1, dorsiflexion of foot Innervation: Deep peroneal nerve Peroneus Brevis Origin: Lateral, distal fibula Insertion: Lateral side of 5th metatarsal Action: Plantarflex and evert foot (pronate) Innervation: Superficial peroneal nerve Peroneus Longus Origin: Posterior surface of tibia, superior fibula Insertion: Base of metatarsal 1 Action: Plantarflex and evert foot (pronate) Innervation: Superficial peroneal nerve (Posterior) Gastrocnemius Origin: Medial and lateral heads: posterior surfaces of medial and lateral femoral condyles Insertion: Posterior surface of calcaneus via Achilles tendon Action: Plantarflexion of foot, knee flexion Innervation: Tibial nerve Soleus Origin: Posterior surface of fibula, medial region of posterior tibia Insertion: Posterior surface of calcaneus via Achilles tendon Action: Plantarflexion of foot Innervation: Tibial nerve Tibialis Posterior Origin: Posterior surface of tibia, interosseous membrane, medial surface of fibula Insertion: Navicular bone, cuneiforms (3), cuboid, and metatarsals 2-4 Action: Plantarflexion, inversion and adduction of foot Innervation: Tibial nerve Flexor digitorum longus Origin: Posterior surface of tibia Insertion: Inferior surface of distal phalanges 2-5 Action: Flexion of digits 2-5; inversion and plantarflexion of foot Innervation: Deep peroneal nerve Flexor hallucis longus Origin: Posterior fibula Insertion: Inferior surface of distal phalanx of digit 1 (great toe) Action: Flexion of digit 1, inversion and plantarflexion of foot Innervation: Tibial nerve (deep peroneal branch) Figure 5.29 Anterior view of the lower leg. Extensor digitorum longus is highlighted in blue on the left leg to indicate long tendons which insert on digits 2-5. Figure 5.30 Anterior view of the lower leg. Extensor hallucis longus is highlighted in blue to indicate long tendon which inserts on the great toe. Figure 5.31 Lateral view of the lower leg. Extensor digitorum longus is highlighted in blue on the left leg to indicate long tendons which insert on digits 2-5. The lateral view shows the insertion points of many of the lower leg muscles. Figure 5.32 Posterior view of the lower leg. Tibialis posterior is highlighted in blue bilaterally. The gastrocnemius is cut away on the right leg to view the deeper muscles. Figure 5.33 Posterior/lateral view of the lower leg. Peroneus longus is highlighted in blue bilaterally. The gastrocnemius is cut away on the right leg to view the deeper muscles. Physiology of the Muscular System Muscle tissue is found in three distinct types in the body; skeletal, smooth, and cardiac. Skeletal muscle is under voluntary control. Voluntary control means a conscious decision is made to move this type of muscle. Skeletal muscle tissue allows for conscious movement of the body and limbs. Smooth muscle and cardiac muscle are under involuntary control, meaning contraction of this muscle happens without a conscious decision. Smooth muscle is found within the internal organs of the body, such as the digestive tract and blood vessels. Cardiac muscle is only found within the heart. Under the microscope, skeletal and cardiac muscle appear to be striated or striped in appearance, while smooth muscle is free of striations. Figure 5.34 Histological view of the three different types of muscle tissue: Cardiac (top), skeletal (middle) and smooth (bottom). Figure 5.35 Histology of skeletal muscle tissue. Note the visible striations (striped appearance). Figure 5.36 Histology of smooth muscle tissue. Note there are not visible striations. Skeletal muscles, which make up over 40% of the body's weight, are attached to the skeleton by tendons, made of fibrous connective tissue. Tendons connect muscle to bone, while ligaments connect bone tissue to bone. When muscles contract, they become shorter. Muscles can only pull; they cannot push. Skeletal muscles must work in antagonistic pairs because muscles are only able to pull in the direction of their fiber orientation. If one muscle of an antagonistic pair bends the joint and brings the limb toward the body (the flexor), the other one straightens the joint and extends the limb (the extensor) as shown in the figure below. The following is a review of action terminology (see Module 1) with examples of antagonistic pairs found within the muscular system: Action Terms- body movement Flexion- closing of a joint, “bending” Extension- opening of a joint, “straightening” Antagonistic pair example: Flexor- Biceps brachii Extensor- Triceps brachii Figure 5.37 Flexion (top) and extension (bottom) of the elbow Abduction - movement away from midline Adduction- movement towards midline Antagonistic pair example: • Abductor: TFL (of the hip) • Adductor: Adductor longus, adductor magnus Dorsiflexion- flexion superiorly occurring at the subtalar (ankle) joint (movement of the toes “up”) Plantarflexion- flexion inferiorly occurring at the subtalar (ankle) joint (movement of the toes “down”) Antagonistic pair example: • Dorsiflexor: Tibialis anterior • Plantarflexor: Gastrocnemius Radial Deviation- lateral movement of the wrist towards the radius Ulnar Deviation- medial movement of the wrist towards the ulna Antagonistic pair example: • Radial Deviator: Flexor carpi radialis • Ulnar Deviator: Extensor carpi ulnaris Pronation- rotation of the forearm so that the palm faces posteriorly • (or) rotation of the ankle so the sole of the foot faces laterally Supination- rotation of the forearm so that the palm faces anteriorly • (or) rotation of the ankle so the sole of the foot faces medially Antagonistic pair example: • Pronator: (of forearm) Pronator teres • Supinator: (of forearm) Biceps brachii Elevation– upward movement of a structure Depression– downward movement of a structure Antagonistic pair example: • Elevator: Levator scapulae • Depressor: Trapezius (lower fibers) Retraction- movement of a structure to be drawn in the posterior direction (drawn backward) Protraction- movement of a structure to be drawn in the anterior direction (drawn forward) Antagonistic pair example: • Retractor: Rhomboids, trapezius • Protractor: Serratus anterior Physiology of Muscle Contraction A whole skeletal muscle is composed of many muscle fibers in bundles. Each muscle fiber is a cell containing thousands of myofibrils, which are the contractile portions of the fibers (see Figure 5.38). Myofibrils are cylindrical in shape and run the length of the muscle fiber. The light microscope shows that a myofibril has light and dark bands called striations. It is these bands that cause skeletal muscle to appear striated. Striations of myofibrils are formed by protein myofilaments within contractile units called sarcomeres (see Figure 5.38). A sarcomere contains two types of protein myofilaments (also referred to as filaments). The thick filaments are made up of a protein called myosin, and the thin filaments are made up of a protein called actin. As a muscle fiber contracts, the sarcomeres within the myofibrils shorten. When a sarcomere shortens, the actin (thin) filaments slide past the myosin (thick) filaments and approach one another. The movement of actin filaments in relation to myosin filaments causes the muscle to shorten. Figure 5.38 View of a muscle fiber, to the microscopic view of a thick and thin filament. Note the heads on the myosin filaments which enable the work of the muscle contraction. Various terms help to describe the components of a sarcomere, as viewed from a microscope (see Figure 5.39). One sarcomere is from one Z line to one Z line. Z lines connect parallel bands of thin filaments. The thick filaments are held together by the M line. The I band (light band) appears light when stained because it only contains thin filaments. The A band (dark band) stains darker because it contains the thick filaments. When a muscle contraction occurs, the Z lines move closer together towards the center of the sarcomere (M line). Figure 5.39 Histological view of a sarcomere (top) with diagram (below) with labeled components. For a muscle to contract, the nervous system must work together with the muscular system (see Figure 5.40 and 5.41). First, a nerve impulse must be sent to the muscle. Once the nerve impulse reaches the muscle fiber (called a neuromuscular junction), acetylcholine (a special chemical called a neurotransmitter) is released from the motor nerve ending (Figure 5.40). Acetylcholine binds to receptors on the muscle cell, opening sodium channels, and allowing sodium to flow inside the sarcoplasm (cytoplasm of a muscle cell). The presence of sodium ions causes an action potential to occur in the sarcolemma (cell membrane of a muscle fiber). The action potential causes calcium ions to be released from the sarcoplasmic reticulum (Figure 5.41). The sarcoplasmic reticulum is a specialized type of smoother ER found within striated muscle tissue. In the presence of calcium ions, portions of the myosin filaments called cross-bridges bend backward and attach to actin filaments. After attaching to the actin filament, the cross-bridges bend forward and the actin filament is pulled along. The cross-bridges attach and detach some fifty to 100 times as the thin filaments are pulled to the center of a sarcomere. ATP is needed on a cellular level for the myosin cross-bridges to pull the actin filaments. The movement of the many actin filaments together is what produces a muscle contraction. Muscle contraction ceases when the nerve impulses no longer stimulates the muscle fiber. With the cessation of a muscle action potential, calcium ions are pumped back into the sarcoplasmic reticulum by active transport. Once the calcium ions return to the sarcoplasmic reticulum, relaxation of the muscle occurs. Figure 5.40 The neuromuscular junction, step 1: The motor neuron (yellow) releases acetylcholine into the neuromuscular junction. Acetylcholine (red) binds with receptors on the muscle cell membrane (sarcolemma), opening sodium channels. Sodium (white) rushes in, creating an action potential which reaches the sarcolemma and then the sarcoplasmic reticulum (blue). Figure 5.41 The neuromuscular junction, step 2: Once the action potential reaches the sarcoplasmic reticulum (dark blue), calcium ions (light blue) are released. The influx of calcium triggers the cross-bridge formations to and muscle contraction. Actin moves towards the center of the sarcomere. Module 5: Review Questions Anatomy of the Muscular system: Introduction & Muscles of the Head, Neck and Trunk 1. Name the three types of muscle tissue found in the body: skeletal, smooth, cardiac 2. What does it mean that skeletal muscles are under conscious control? it means that someone voluntarily, consciously, and physically decide to use the muscles to do soemthing. 3. What is included in the central nervous system? brain and spinal cord 4. Describe a motor action vs. sensory input in terms of the nervous system. a motor action is messages from the central nervous system to a muscle. sensory input is nerves carrying information from the external environment to the central nervous system 5. True or false: The brachial plexus supplies nerves to the lower extremities. false 6. Describe the difference between tendons and ligaments. tendons are connective tissues that connect skeletal muscle to bone. ligaments are connective tissue that connects bone to bone 7. Describe the origin and insertion of attachment to bones. the origin is the bony site of attachment which does not move during muscle contraction. the insertion is the bony site of attachment that is moved by the muscle contraction . 8. Describe muscle action and innervation. muscle action is what effect is produced by the muscle's contraction. the innervation is the peripheral nerve that supplies a muscle with the message from the brain 9. Make a chart for the origin, insertion, action and innervation for the following muscles: *Note: All muscles listed in the module will need to be memorized for the exam. This is not an exhaustive list. Making a chart to organize the information is a helpful way to study the muscles. You may want to make a full chart on your own to study and review for the exam. Other Muscle Origin Insertion Action Innervation notes: (Option al) Orbicularis oculi medial orbital margin & the skin of the lateral cheek, eye closure cranial nerve 7 - Click here to enter answer - medial palpebral ligament lateral palpebral raphe pterygomandib angel of Buccinator ular raphe, mandible, & maxilla lateral the mouth & lateral compress CN 7 - Click here to enter to the molar teeth portion of cheeks the upper & lower lip answer - coronoid process of mandible elevates trigeminal nerve, CN - Click here to Temporalis & temporal fossa mandible, 5, enter & fascia anterior closes jaw mandibular answer Sternocleidomas surface of the ramus of amndible mastoid bilateral neck flexion, branch accessory - - Click here to toid sternal end of clavicle and manubrium region of unilateral turn nerve, CN the skull face to 11 opposite side enter answer - transvers Bilateral Longissimus transverse processes of e process extend head Thoracic - Click here to thoracis superior of middle Unilateral and lumbar enter thoracic vertebrae and superior cervical vertebrae laterally flexes neck to same side spinal nerves answer - spinous spinous processe s at extends & dorsal primary - Click here to Spinalis processes at superior laterally bends rami of enter inferior vertebral trunk & neck spinal answer Rectus levels & vertebral levels base of skull nerves (C2- - L3) - Click abdominis Pubis, Flexion of Spinal here to Pubic Crest, cartilagesspine, nerves enter pubic of ribs 5- compression of(thoracic 7- answer symphysis 7, xiphoidabdominal 12) - process viscera First lumbar nerve (Thoracic 7- Lumber 1), - Click iliohypogasthere to Transverse abdominis Linea Lateral inguinal alba, ligament, inner Compression of abdomen ric (Thoracic enter answer iliac crest pubis 12-Lumbar - 1), ilioinguinal (Thoracic 12-Lumbar 1) Cartilage of ribs 7-12, Anterior Expands - Click xiphoid longitudinthoracic cavity, Phrenic here to Diaphragm process, lumbar al ligament compresses abdominal nerve (C3- 5) enter answer vertebrae (vertebralcavity - column) 10. Label the following muscles of facial expression: A: frontalis C: orbicularis oculi F: zygomaticus minor H: risorius 11. Your patient has damage to bilateral facial nerves (CN VII). Name at least three muscles that would be impaired. buccinator, orbicularis oculi, risorius Anatomy of the Muscular system: Part II 12. Label the following muscles (posterior view): A: trapezius C: Posterior Serratus D: Minor Rhomboids 13. Your patient is having difficulty with scapular retraction. Name two muscles that are most likely involved in this limitation. Trapezius & rhomboids 14. Your patient injured her ankle while playing soccer. She sustained injuries to the tendons of peroneus longus and peroneus brevis. What actions would be impaired due to his injury? Plantarflexion and eversion of foot would be impaired due to the injury. 15. Make a chart for the origin, insertion, action and innervation for the following muscles: *Note: All muscles listed in the module will need to be memorized for the exam. This is not an exhaustive list. Making a chart to organize the information is a helpful way to study the muscles. You may want to make a full chart on your own to study and review for the exam. Muscle Origin Insertion Action Innervation Other notes: (Optional) Lateral clavicle, acromion, and Occipital bone, spinous scapular spine of Rotation, retraction, elevation, Accessory nerve, - Click here Trapezius process of T1-12 scapula depression of scapula; extends neck; stabilizes shoulder CN 11 to enter answer - Pectoralis Coracoid process Elevates ribs, Medial pectoral - Click here minor Ribs 3-5 of scapula draws scapula down and medially Flexion, adduction nerve to enter answer - - Click here Pectoralis major Ribs 2-6, body of sternum Greater tubercle of humerus and medial rotation at shoulder Pectoral Nerves to enter answer - Supraspinatus fossa of Greater tubercle Abduction at the - Click here Supraspinatus scapula of humerus shoulder Suprascapular nerve to enter answer - Teres Major Inferior angle of scapula Intertubercular groove of humerus Extension, adduction, and medial rotation at shoulder Lower subscapular nerve - Click here to enter answer - Subscapular fossa of Lesser tubercle of Medial rotation at - Click here Subscapularis scapula Anterior/distal surface humerus the shoulder Subscapular nerves Musculocutaneous to enter answer - - Click here Brachialis of humerus Tuberosity of ulna Flexion at elbow nerve and radial nerve to enter answer - Supinator Flexor carpi Lateral epicondyle of humerus common flexor tendon from the medial Anterolateral Supination Deep radial nerve surface of radius base of the 2nd & Wrist flexion, radial deviation of Median nerve - Click here to enter answer - - Click here to enter radialis Flexor pollicis longus epicondyle of the humerus anterior surface of radisu & interosseous membrane common extensor 3rd metacarpals base of the distal phalanx of the thumb extensor the hand Flexion of thumb Wrist extension, Median nerve answer - - Click here to enter answer - - Click here Extensor digitorum tendon (lateral epicondyle of the humerus) expansion of digits 2-5 extension of digits Deep radial nerve 2-5 to enter answer - Abductor middle 1/3 of the radial side of the Abduction of wrist Deep Radial nerve - Click here pollicis longus posterior surfce of the radius, interosseous base of the 1st membrane, mid-portion metacarpal of posterolateral ulna and thumb to enter answer - Iliacus Iliac fossa of ilium Lesser trochanter Hip flexion Femoral nerve of femur - Click here to enter answer - Gluteus medius Gluteal surface of the ilium Greater trochanter of the femur upper border of Abducts thigh, stabilizes the hip joint Lateral rotation, Superior gluteal nerve - Click here to enter answer - - Click here Piriformis anterior surface of greater trochanter adduction, Spinal nerves L5-S2 to enter Biceps Femoris sacrum Head of the femur, lateral surface of femur Head of the fibula, lateral surface Patella via extension of hip joint Knee flexion, hip extension Common fibular nerve (peroneal) answer - - Click here to enter answer - - Click here Vastus Intertrochanteric line of quadriceps Knee extension Femoral nerve to enter Medialis femur tendon; tibial tuberosity Hip: Flexion, answer - ASIS (Anterior superior Superior shaft of abduction, - Click here Sartorius Extensor hallucis longus iliac spine) Anterior surface of fibula tibia Dorsal surface of digit 1 (great toe) external rotation; Knee: flexion, internal rotation Extension of digit 1, dorsiflexion of foot Femoral nerve Deep peroneal nerve to enter answer - - Click here to enter answer - Tibialis Anterior Lateral condyle of tibia Base of metatarsal 1, medial cuneiform Dorsiflexion, inversion of foot Deep peroneal nerve - Click here to enter answer - 16. Review all figures and diagrams in Parts I and II. The locations of all the muscles must be memorized for the exam. Physiology of the Muscular system: 17. What types of muscle tissue are under involuntary control? smooth & cardiac muscle 18. Under the microscope, what types of muscle appear to be striated or striped in appearance? skeletal & cardiac muscle 19. What is the difference between tendons and ligaments? tendons connect muscle & bone ligaments connect bone tissue to bone 20. True or false: Muscle can only push, not pull. false 21. What muscle would be in an antagonistic pair with the tibialis anterior? Gastrocnemius 22. True or false: Myosin is known as the thin filament. False 23. True or false: One sarcomere is from one Z line to one Z line. True 24. When a muscle contraction occurs, what lines move closer together towards the center of the sarcomere (M line)? Z lines 25. What is the name of the junction where a motor neuron meets with a muscle? Neuromuscular junction 26. Acetylcholine released from the motor neuron triggers the influx of which ion? Sodium 27. In response to the action potential in the sarcolemma, the sarcoplasmic reticulum releases which ion? Calcium 28. What needs to happen for muscle relaxation to occur? for relaxation to occur, the calcium ions return to the sacroplasmic reticulum. 29. Review all figures in module 5. All muscles listed in bold must be memorized for the exam (location, action, innervation, origin and insertion- if listed) Module 5: Review Answers Anatomy of the Muscular system: Introduction & Muscles of the Head, Neck and Trunk 1. Cardiac, skeletal and smooth 2. Skeletal muscles are under conscious control, meaning that a person can consciously decide to use these muscles to complete an action. 3. Brain and spinal cord 4. Messages from the central nervous system to a muscle are called a motor actions. Nerves also carry information from the external environment to the central nervous system, called sensation or sensory input. 5. False 6. Tendons are connective tissues that connect skeletal muscle to bone at each end. Ligaments are connective tissue that connects bone to bone, helping to stabilize joints where bones meet. 7. The origin is the bony site of attachment which is stationary during the movement. The insertion of a muscle is the bony site of attachment that is moved by the muscle contraction. 8. The action of the muscle is what effect is produced by the muscle’s contraction. The innervation is the peripheral nerve that supplies a muscle with the message from the brain. 9. *Note: All muscles listed in the module will need to be memorized for the exam. This is not an exhaustive list. Making a chart to organize the information is a helpful way to study the muscles. You may want to make a full chart on your own to study and review for the exam. Muscle Origin Insertion Action Innervation Orbicularis oculi Not listed (does not need to be memorized for this class) Not listed (does not need to be memorized for this class) eye closure Facial nerve (CN VII) Buccinator Not listed Not listed compress cheeks Facial nerve (CN VII) Temporalis Not listed Not listed Elevates mandible, closes jaw Trigeminal nerve (CN V, mandibular branch) Sternocleidomastoid Sternal end of clavicle and manubrium Mastoid region of skull Bilateral: Neck flexion Unilateral: Turns face to opposite side Accessory nerve (CN XI) Longissimus thoracis Transverse process of inferior thoracic, superior lumbar vertebrae Transverse process of middle and superior cervical vertebrae Bilateral extend head Unilateral laterally flexes neck to same side Thoracic and lumbar spinal nerves Spinalis Not listed, know locations and divisions of erector spinae group Not listed extensor of the vertebral column Not listed Rectus abdominis Pubic Crest, pubic symphysis Pubis, cartilages of ribs 5-7, xiphoid process Flexion of spine, compression of abdominal viscera Spinal nerves (T 7-T 12) Transverse abdominis Lateral inguinal ligament, inner iliac crest Linea alba, pubis Compression of abdomen First lumbar nerve (T 7- L1), iliohypogastric (T12-L1), ilioinguinal (T12-L1) Diaphragm: Cartilage of ribs 7-12, xiphoid process, lumbar vertebrae Anterior longitudinal ligament (vertebral column) Expands thoracic cavity, compresses abdominal cavity Phrenic nerve (C3-5) A: Frontalis C: Orbicularis Oculi F: Zygomaticus Minor H: Risorius Could include any three: Orbicularis oculi, Orbicularis oris, Zygomaticus major/minor, Risorius, Frontalis, Buccinator Anatomy of the Muscular system: Part II A: Trapezius C: Serratus posterior D: Rhomboids, minor Trapezius, rhomboids (minor/major) Plantarflexion and eversion of foot *Note: All muscles listed in the module will need to be memorized for the exam. This is not an exhaustive list. Making a chart to organize the information is a helpful way to study the muscles. You may want to make a full chart on your own to study and review for the exam. Muscle Origin Insertion Action Innervation Other notes: (Optional) Trapezius Occipital bone, spinous process of T1-12, Lateral clavicle, acromion, and scapular spine of scapula Rotation, retraction, elevation, depression of scapula; extends neck; stabilizes shoulder Innervation: Accessory nerve (Cranial Nerve 11) Pectoralis minor Ribs 3-5 Coracoid process of scapula Elevates ribs, draws scapula down and medially Medial pectoral nerve Pectoralis major Ribs 2-6, body of sternum Greater tubercle of humerus - Flexion, adduction and medial rotation at shoulder Pectoral Nerves Supraspinatus Supraspinatus fossa of scapula Greater tubercle of humerus Abduction at the shoulder - Suprascapular nerve Part of rotator cuff Teres Major Inferior angle of scapula Intertubercular groove of humerus Extension, adduction, and medial rotation at shoulder - Lower subscapular nerve - not part of the rotator cuff Subscapularis Subscapular fossa of scapula Lesser tubercle of humerus Medial rotation at the shoulder - Subscapular nerves Brachialis Anterior/distal surface of humerus Tuberosity of ulna - Flexion at elbow Musculocutaneous nerve and radial nerve - Supinator Lateral epicondyle of humerus Anterolateral surface of radius Supination Deep radial nerve Flexor carpi radialis Not listed Not listed Wrist flexion, radial deviation of the hand Median nerve Flexor pollicis longus Not listed Not listed Flexion of thumb Median nerve Extensor digitorum (wrist) Not listed Not listed Wrist extension, extension of digits 2-5 Deep radial nerve Abductor pollicis longus Not listed Not listed Abduction of wrist and thumb Deep Radial nerve (APL) Iliacus Iliac fossa of ilium Lesser trochanter of femur Hip flexion Femoral nerve Psoas major + iliacus iliopsoas Gluteus medius Gluteal surface of the ilium Greater trochanter of the femur Abducts thigh, stabilizes the hip joint Superior gluteal nerve Piriformis Not listed Not listed Lateral rotation, adduction, extension of hip joint Spinal nerves L5-S2 Biceps Femoris Head of the femur, lateral surface Head of the fibula, lateral surface Knee flexion, hip extension Common fibular nerve (peroneal) Hamstrings Vastus Medialis Intertrochanteric line Patella via quadriceps tendon; tibial tuberosity Knee extension Femoral nerve Quadriceps Sartorius ASIS Superior shaft of tibia Hip: Flexion, abduction, external rotation; Knee: flexion, internal rotation Femoral nerve Extensor hallucis longus: Anterior surface of fibula Dorsal surface of digit 1 (great toe) Extension of digit 1, dorsiflexion of foot Deep peroneal nerve Tibialis Anterior Lateral condyle of tibia Base of metatarsal 1, medial cuneiform Dorsiflexion, inversion of foot Deep peroneal nerve See figures in module. Study the locations of all the muscles (listed in bold) in Part I and Part II. Physiology of the Muscular system: Smooth muscle and cardiac muscle are under involuntary control. Under the microscope, skeletal and cardiac muscle appear to be striated or striped in appearance. Tendons connect muscle to bone, while ligaments connect bone tissue to bone. False- muscles can only pull, not push. Gastrocnemius False True Z lines Neuromuscular junction Sodium Calcium Once the calcium ions return to the sarcoplasmic reticulum, relaxation of the muscle occurs. See figures in module. All muscles listed in bold must be memorized for the exam (location, action, innervation, origin and insertion if listed) Exam Page 1 Note: Essay answers must clearly be in your own words. All multiple-choice questions have one answer unless otherwise specified. Choose the best response with the information provided. Answer the following five true or false questions: 1. There are three types of muscle tissue found in the body. true 2. Smooth and cardiac muscle tissue are both under voluntary control. false 3. The lumbar plexus is part of the central nervous system. false 4. A sensory signal is a signal that is sent from a muscle to the central nervous system. true 5. The lumbar plexus contains nerves that innervate the thigh. false -2.0 points Answer Key Exam Page 2 Note: Essay answers must clearly be in your own words. All multiple-choice questions have one answer unless otherwise specified. Choose the best response with the information provided. Answer the following five short-answer questions: 1. Ligaments connect which types of tissue? ligaments connect bone tissue to bone tissue. 2. Acetylcholine is what type of substance? it is a neurotransmitter 3. During a muscle contraction which protein myofilament is pulled along? the sarcomeres 4. What is the name of the thin myofilament? actin 5. The return of calcium ions into the sarcoplasmic reticulum causes what to occur? relaxation of the muscle occurs -2.0 points Answer Key Muscle relaxation (Muscle contraction stops) Exam Page 3 Note: Essay answers must clearly be in your own words. All multiple-choice questions have one answer unless otherwise specified. Choose the best response with the information provided. Label the following five muscles: A: frontalis D: orbicularis oris F: zygomaticus minor H: risorius I: masseter Answer Key Exam Page 4 Fill in the following muscle chart (10 blank spaces): Origin Insertion Action Innervation 1. transverse bodies of all lumbar vertebra 2. lesser trochanter of the femur 3. lateral rotation of thigh 4. obturator nerve 5. ischial tuberosity 6. medial condyle of tibia 7. knee flexion 8. posterior fibula 9. flexion of digit 1 & inversion & plantarflexion of foor 10. tibial nerve Answer Key Origin Insertion Action Innervation Exam Page 5 Answer the following five questions: 1. Your patient sustained an injury to their facial nerve (CN VII). Which actions would be impaired? A. Extend head/neck B. Compress cheeks C. Grin/grimace D. Elevate mandible E. A&D F. B&C f 2. Your patient is in a seated position with his feet flat on the floor. He is having difficulty lifting his toes off the floor. What muscle(s) is impaired from contracting? A. Tibialis anterior B. Gastrocnemius C. Extensor digitorum longus D. Tibialis posterior E. A&C F. B&D e 3. Your patient is having difficulty when asked to bend his spine backward. What muscle is involved? A. Spinalis thoracis B. Scalenes C. External oblique D. Internal oblique E. Rectus abdominis c 4. True or False: When a muscle contracts, the M lines within a sarcomere come closer together towards the Z line. true 5. True or False: The A band contains thin filaments. false -4.0 points Answer Key Answer the following five questions: 1. Your patient sustained an injury to their facial nerve (CN VII). Which actions would be impaired? A. Extend head/neck B. Compress cheeks C. Grin/grimace D. Elevate mandible E. A&D F. B&C F.B &C (Buccinator & risorius) 2. Your patient is in a seated position with his feet flat on the floor. He is having difficulty lifting his toes off the floor. What muscle(s) is impaired from contracting? A. Tibialis anterior B. Gastrocnemius C. Extensor digitorum longus D. Tibialis posterior E. A&C F. B&D E. A&C Tibialis anterior & extensor digitorum longus (dorsiflexion) 3. Your patient is having difficulty when asked to bend his spine backward. What muscle is involved? A. Spinalis thoracis B. Scalenes C. External oblique D. Internal oblique E. Rectus abdominis A. Spinalis thoracis (Extensor of the vertebral column) Exam Page 6 Answer the following five questions: 1. Which muscle contracts to enable the main effort required to stand on your toes? A. Biceps femoris B. Quadriceps C. Gastrocnemius D. Tibialis anterior c 2. When gluteus maximus contracts, which bone is pulled posteriorly by this muscle? A. Tibia B. Ilium C. Ulna D. Femur b 3. When flexor digitorum profundus contracts, what action(s) occurs? A. Wrist flexion B. Elbow flexion C. Flexion of digits 2-5 D. Flexion of digit 1 E. A&C F. B&C e 4. Contraction of results in ? A. obturator externus, spine flexion B. obturator externus, spine extension C. iliacus, hip flexion D. iliacus, hip extension c 5. When piriformis contracts, what action(s) will not occur at the hip? A. Internal rotation B. Lateral rotation C. Adduction D. Flexion E. Extension F. A&D G. B&E f -2.0 points Answer Key A. Tibia B. Ilium C. Ulna D. Femur D. Femur 3. When flexor digitorum profundus contracts, what action(s) occurs? A. Wrist flexion B. Elbow flexion C. Flexion of digits 2-5 D. Flexion of digit 1 E. A&D F. B&C E. A&C (Wrist flexion, flexion of digits 2-5) 4. Contraction of results in ? A. obturator externus, spine flexion B. obturator externus, spine extension C. iliacus, hip flexion D. iliacus, hip extension C. iliacus, hip flexion 5. When piriformis contracts, what action(s) will not occur at the hip? A. Internal rotation B. Lateral rotation C. Adduction D. Flexion E. Extension F. A&D G. B&E F. A&D (Internal rotation, flexion do not occur) Exam Page 7 Use the figure answer the following five questions: 1. Which muscle is the prime mover of adduction, flexion and inward rotation of the humerus? teres major 2. Which muscle is innervated by the musculocutaneous nerve? biceps branchii 3. What is the name of muscle C? supraspinatus 4. What is the innervation of muscle C? suprascapular nerve 5. What is the origin of muscle E? lateral border of scapula -6.0 points Answer Key Exam Page 8 Use the figure to label the following six muscles: (Viewed posteriorly) A: extensor carpi radialis longus C: extensor digitorum D: extensor carpi ulnaris F: abductor pollicis longus H: extensor indicis I: extensor pollicis brevis Answer Key Exam Page 9 Use the figure to label the following six muscles: D: peroneus longus E: soleus F: tibialis posterior G: flexor digitorum longus H: flexor hallucis longus I: peroneus brevis Answer Key Use the figure to label the following six muscles: D: Peroneus (fibularis) longus Exam Page 10 Answer the following essay question: Describe how acetylcholine, sodium ions and calcium ions work together to enable a muscle contraction. a nerve impulse is first sent to the muscle. when it reaches reaches the muscle fiber, acetylcholine is released from the motor nerve ending. acetylcholine binds to receptors on the muscle cell, opening sodium channels, which allows sodium to go into the sacroplasm. the sodium ions cause an action potential to occur. the action potential causes calcium ions to be released from the sacroplasmic reticulum. the presence of the calcium ions, allows the myosin filaments to bend backwards and attach to actin filaments. the cross-bridge bend forward and the actin filament is pulled with it, this causes the thin filament to pull to the center of a sacromemer. the movement of the actin filaments produce muscle contraction. Answer Key A&P 1 - Lab 7 Key terms Myology – study of muscle Muscle make up nearly 50% of body weight Skeletal muscle – cover bone for movement // attached to diff bones on each end ex. long muscle w/ 2 tendons at each end, 1 tendon attach to a bone and other tendon to another bone // when muscle contracts, it moves one bone relative to the other Origin – stationary attachment // attachment of muscle to none moving bone Incursion – muscle attached to bone that is moving Smooth muscle – muscle typically found internally ex. lining the digestive tract or uterus or blood vessels // to help make substances propel through the systems or tract Cardiac muscle – only found in heart All 3 muscle types form to perform 1 specific job which is to take chemical energy of ATP & convert to mechanical energy of motion Major function of muscle: 1 Movement is biggest function of muscle. It will move individual body part ex. move arm over head // move body content (moving fetus through uterus or food residue through digestive tract) // communication (muscle move to allow us to speak, swallow, and nonverbal communication) 2 muscle provide stability & maintain upright posture & maintain stability In our joints & prevent our body from collaps