Studied by 1 personSmooth muscle fibers
short, single central nucleus, elongated with tapered ends, myofilaments randomly organized
lack striations
lak transverse tubules
SR not well developed
Multi-unit smooth muscle
less organized cells
function as separate units
fibers function independently
iris of eye, walls of blood vessels
stimulated by neurons, hormones
Visceral Smooth Muscle
single-unit smooth muscle; cells respond as a unit
sheets of spindle-shaped muscle fibers
fibers held together by gap junctions
rhythmicity
conduct peristalsis
walls of most hollow organs
more common
Smooth muscle resembles skeletal muscle contraction in these ways
interaction between actin and myosin
both use calcium and ATP
both are triggered by membrane impulses
Smooth muscle differs from skeletal muscle contraction in these ways
smooth muscle lacks troponin; uses calmodulin instead
two neurotransmitters that affect SmMuscle; Ach & NE
hormones can inhibit or stim. smooth muscle
stretching can trigger SmMuscle contraction
SmMuscle slower to contract and relax
SmMuscle more resistant to fatigue
SmMuscle can change length without changing tautness
Cardiac Muscle
striated muscle cells
muscle fibers joined together by intercalated discs
fibers branch, contain a single nucleus
network of fibers contracts as a unit (syncytium)
self-exciting and rhythmic
longer refractory period than skeletal muscle
no sustained or tetanic contractions
Component of levers
rigid bar or rod (bones)
fulcrum or pivot on which bar moves (joint)
object moved against resistance (weight)
force that supplies energy for movement (muscles)
Origin
less moveable end
Insertion
more moveable end
Muscle of Facial Expression
epicranius, orbicularis oculi, orbicularis oris, buccinator, zygomaticus major, zygomaticus minor, platysma
Epicranius
Origin: Occipital bone
Insertion: skin around eye
Action: elevated eyebrows as when surprised
Nerve supply: facial nerve
Orbicularis oculi
Origin: maxilla and frontal bone
Insertion: skin around eye
Action: closes eye as in blinking
Nerve supply: facial nerve
Orbicularis oculi
Origin: muscle near the mouth
Insertion: Skin of central lip
Action: closes lips, protrudes lips as for kissing
Nerve supply: facial nerve
Buccinator
Origin: alveolar processes of maxilla and mandible
Insertion: orbicularis oris
Action: compresses cheeks
Nerve supply: facial nerve
Zygomaticus major & major
Origin: Zygomatic bone
Insertion: Skin and muscle at corner of mouth
Action: Elevates corner or mouth as when smiling
Nerve supply: facial nerve
Platysma
Origin: fascia in the upper chest
Insertion: skin and muscle below mouth; mandible
Action: depresses lower lip and angle of mouth as when pouting
Nerve supply: facial nerve
Muscles of mastication
massester, temporalis, medial pterygoid, lateral pterygoid
Masseter
Origin: zygomatic arch
Insertion: lateral surface of ramus of mandible
Action: elevates and protracts mandible
Nerve supply: trigeminal nerve
Temporalis
Origin: Temporal bone
Insertion: coronoid process and anterior ramus or mandible
Action: elevates anf retracts mandible
Nerve supply: trigeminal nerve
Medial pterygoid
Origin: sphenoid, palatine, and maxillary bones
Insertion: medial surface of ramus of mandible
Action: elevates mandible and moves it from side to side
Nerve supply: trigeminal nerve
Lateral pterygoid
Origin: Sphenoid bone
Insertion: anterior surface of mandibular condyle
Action: depresses and protracts mandible and moves it from side to side
Nerve supply: trigeminal nerve
Muscle that move the head and vertebral column
Sternocleidomastoid, splenius capitis, semispinalis capitis, scalenes. quadratus lumborum, erector spinae (divides into three groups), iliocostalis (later) group, illiocostallis luborum, iliocostalis thoracis, iliocostalis cervicis
Sternocleidomastoid
Origin: Anterior surface of sternum and upper surface of clavicle
Insertion: mastoid process of temporal bone
Action: Each laterally flexes neck to the same side, rotates head to the opposite side. Together they pull the head forward and down; also aid in forceful inhalation by elevating sternum and first ribs.
Nerve supply: Accessory, C2 and C3 cervical nerves
Splenius capitis
Origin: Ligamentum nuchae and spinous processes of seventh cervical and upper thoracic vertebrae
Insertion: occipital bone
Action: Individually: rotates head to the same side; together bring head into upright position
Nerve supply: Cervical nerves
Semispinalis capitis
Origin: processes of lower cervical and upper thoracic vertabrae
Insertion: Occipital bone
Action: individually: rotates head to the opposite side; together: extend head and neck
Nerve supply: cervical and thoracic spinal nerves
Scalenes
Origin: Transverse process of cervical vertebrae
Insertion: Superior and lateral surfaces of first two ribs
Action: Individually: laterally flexes head and neck to the same side; together: elevate first two ribs during forceful inhalation
Nerve supply: Cervical spinal nerves
Quadratus lumborum
Origin: Illiac crest
Insertion: upper lumbar vertebrae and twelfth (12th) rib
Action: Extends lumbar region of vertebral column
Nerve supply: thoracic and lumbar spinal nerves
Erector spinae (divides into three groups)
Iliocostalis (lateral) group: luborum, thoracis, cervicis
Longissimus (intermediate) group: thoracic, cervicis, capitis
Spinalis (medial) group: thoracic & cervicis
Iliocostalis lumborum
Origin: iliac crest
Insertion: lower six ribs
Action: extends lumbar region of vertebral column
Nerve supply: lumbar spinal nerve
Iliocostalis thoracis
Origin: lower six ribs
Insertion: upper six ribs
Action: hold spine erect
Nerve supply: thoracic spinal nerves
Iliocostalis cervicis
Origin: upper six ribs
Insertion: fourth through sixth cervical vertebrae
Action: extends cervical region of vertebral column
Nerve supply: cervical spinal nerves
Longuissimus thoracis
Origin: lumbar vertebrae
Insertion: thoracic and upper lumbar vertebrae and ribs 9 & 10
Action: extends thoracic region of vertebral column
Nerve supply: spinal nerves
Lonhissimus cervicis
Origin: fourth and fifth (4-5)thoracic vertebrae
Insertion: second through sixth (2-6) cervical vertebrae
Action: extends cervical region of vertebral column
Nerve supply: spinal nerves
Longissimus capitis
Origin: upper thoracic and lower cervical vertebrae
Insertion: mastoid process of temporal bone
Action: extends and rotates head
Nerve supply: cervical spinal nerves
Spinalis thoracis
Origin: Upper lumbar and lower thoracic vertebrae
Insertion: upper thoracic vertebrae
Action: extends vertebral column
Nerve supply: spinal nerves
Spinalis cervicis
Origin: ligamentum nuchae and seventh (7th) cervical vertebrae
Insertion: axis (1st cervical vertebrae)
Action: extends vertebral column
Nerve supply: spinal nerves
Muscles that move the pectoral girdle
Trapezius, rhomboid major, rhomboid minor, levator scapulae, serratus anterior, pectoralis minor
Trapezius
Origin: Occipital bone, ligamentum nuchae, and spinous processes of seventh cervical and all thoracic vertebrae
Insertion: Clavicle, spine, and acromion process of scapula
Action: Rotates and retracts scapula Superior portion elevates scapula, Inferior portion depresses scapula
Nerve supply: Accessory nerve
Rhomboid major
Origin: Spinous processes of upper thoracic vertebrae
Insertion: Medial boarder of scapula
Action: Retracts, elevates, and rotates scapula
Nerve supply: Dorsal scapular nerve
Rhomboid minor
Origin: Spinous processes of lower cervical vertebrae
Insertion: medial border of scapula
Action: retracts and elevates scapula
Nerve supply: Dorsal scapular cervical nerves
Levator scapulae
Origin: transverse process of cervical vertebrae
Insertion: medial border of scapula
Action: elevates scapulae
Nerve supply: dorsal scapular and cervical nerves
Serratus anterior
Origin: anterior surfaces of upper ribs
Insertion medial boarder of scapula
Action: protracts and rotates scapula
Nerve supply: long thoracic nerve
Pectoralis minor
Origin: anterior surface of ribs 3 to 5
Insertion: coracoid process of scapula
Action: depresses and protracts scapula, elevates ribs during forceful inhalation
Nerve supply: pectoral nerve
Coracobrachialis
Origin: Coracoid process of scapula
Insertion: Medial mid-shaft of humerus
Action: flexes shoulder and adducts arm
Nerve supply: musculocutaneus nerve
Pectoralis major
Origin: Clavicle, sternum, and costal cartilages of upper ribs
Insertion: Intertubercular sulcus of humerus
Action: Flexes shoulder, adducts, and rotates arm medially
Nerve supply: pectorla nerve
Teres major
Origin: lateral border of scapula
Insertion: Intertubercular sulcus of humerus
Action: Extends shoulder, adducts, and rotates arm medially
Nerve supply: Lower subscapular nerve
Latissimus dorsi
Origin: Spines of sacral, lumbar, and lower thoracic vertebrae, iliac crest, and lower ribs
Insertion: Intertubercular sulcus of humerus
Action: Extends shoulder, adducts, and rotates arm medially, or depresses and retracts shoulder
Nerve supply: Thoracodorsal nerve
Supraspinatus
Origin: Supraspinous fossa of scapula
Insertion: Greater tubercle of humerus
Action: abducts arm
Nerve supply: Suprascapular nerve
Deltoid
Origin: Acromion process, spine of the scapula, and the clavicle
Insertion: Deltoid tuberosity of humerus
Action: Lateral portion: abducts arm; Anterior portion flexes shoulder; Posterior portion: extends shoulder
Nerve supply: axillary nerve
Subscapularis
Origin: Anterior surface of scapula
Insertion: Lesser tubercle of humerus
Action: rotates arm medially
Nerve supply: Subscapular nerve
Infraspinatus
Origin: Infraspinous fossa of scapula
Insertion: Greater tubercle of humerus
Action: Rotates arm laterally
Nerve supply: Upper and lower suprascapular nerves
Teres minor
Origin: Lateral border of scapula
Insertion: Greater tubercle of humerus
Action: Rotates arm laterally
Nerve supply: Axillary nerve
Muscle that move the forearm
Biceps brachii, Brachialis, Brachioradialis, Triceps brachii, Supinator, Pronator teres, Pronator quadratus
Biceps brachii
Origin: Coracoid process and tubercle above glenoid cavity of scapula
Insertion: Radial tuberosity
Action: Flexes elbow and supinates forearm and hand
Nerve supply: Musculocutaneous nerve
Brachialis
Origin: Anterior surface of humerus
Insertion: Coronoid process of ulna
Action: Flexes elbow
Nerve supply: Musculocutaneous, median, and radial nerves
Brachioradialis
Origin: Distal lateral end of humerus
Insertion: N/A
Action: Flexes elbow
Nerve supply: Radial nerve
Triceps Brachii
Origin: Tubercle below glenoid cavity and lateral and posterior surfaces of humerus
Insertion: Lateral surface of radius above styloid process
Action: Extends elbow
Nerve supply: Radial nerve
Supinator
Origin: Lateral epicondyle of humerus and proximal ulna, just distal to radial notch
Insertion: Anterior and lateral surface of radius
Action: Rotates forearm laterally; supinates forearm and hand
Nerve Supply: Radial nerve
Pronator teres
Origin: Medial epicondyle of humerus and coronoid process of ulna
Insertion: Lateral surface of proximal 1/3 of radius
Action: Rotates forearm medially; pronates forearm and hand
Nerve Supply: Median nerve
Pronator quadaratus
Origin: Anterior distal end of ulna
Insertion: Anterior distal end of radius
Action: Rotates forearm medially; pronates forearm and hand
Nerve Supply: Median nerve
Muscles That Move the Hand
flexor carpi radialis, flexor carpi ulnaris, palmaris longus, flexor digitorum profundus, flexor digitorum superficialis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, extensor digitorum
Flexor carpi radialis
Origin: Medial epicondyle of humerus
Insertion: Base of second and third metacarpals
Action: Flexes wrist and abducts hand
Nerve Supply: Median nerve
Flexor carpi ulnaris
Origin: Medial epicondyle of humerus and olecranon process of ulna
Insertion: Carpal and metacarpal bones
Action: Flexes wrist and adducts hand
Nerve Supply: Ulnar nerve
Palmaris longus
Origin: Medial epicondyle of humerus
Insertion: Fascia of palm
Action: Flexes wrist
Nerve Supply: Median nerve
Flexor digitorum superficialis
Origin: Medial epicondyle of humerus, coronoid process of ulna, and radius
Insertion: Tendons of fingers
Action: Flexes wrist and joints of fingers
Nerve Supply: Median nerve
Extensor carpi radialis longus
Origin: Lateral end of humerus
Insertion: Base of second metacarpal
Action: Extends wrist and abducts hand
Nerve Supply: Radial nerve
Extensor carpi radialis brevis
Origin: Lateral epicondyle of humerus
Insertion: Base of third (3rd) metacarpal
Action: Extends wrist and abducts hand
Nerve Supply: Radial nerve
Extensor carpi ulnaris
Origin: Lateral epicondyle of humerus and proximal, posterior ulna
Insertion: Base of fifth (5th) metacarpal
Action: Extends wrist an adducts hand
Nerve Supply: Radial nerve
Extensor digitorum
Origin: Lateral epicondyle of humerus
Insertion: Posterior surface phalanges in fingers 2 to 5
Action: Extends joints of finger
Nerve Supply: Radial nerve
Muscles of the Abdominal Wall
External oblique, internal oblique, transversus abdominis, rectus abdominis
External oblique
Origin: Outer surfaces of lower 8 ribs
Insertion: Outer lip of iliac crest and linea alba
Action: Compresses abdomen, flexes and rotates vertebral column
Nerve Supply: Intercostal nerves 7 to 12
Internal oblique
Origin: Iliac crest and inguinal ligament
Insertion: Lower 3 to 4 ribs, linea alba, and crest of pubis
Action: Compresses abdomen, flexes and rotates vertebral column
Nerve Supply: Intercostal nerves 7 to 12
Transversus abdominis
Origin: Costal cartilages of lower 6 ribs, processes of lumbar vertebrae, lip of iliac crest, and inguinal ligament
Insertion: Linea alba and crest of pubis
Action: Compresses abdomen, flexes and rotates vertebral column
Nerve Supply: Intercostal nerves 7 to 12
Rectus abdominis
Origin: Crest of pubis and pubic symphysis
Insertion: Xiphoid process of sternum and ribs 5 to 7
Action: Compresses abdomen, flexes vertebral column
Nerve Supply: Intercostal nerves 7 to 12
Levator ani
Origin: Pubis and ischial spine
Insertion: Coccyx
Action: Supports pelvic viscera and compresses anal canal
Nerve Supply: Pudendal nerve
Coccygenus
Origin: Ischial spine
Insertion: Sacrum and coccyx
Action: Supports pelvic viscera and provides sphincter-like action in anal canal and vagina
Nerve Supply: S4 and S5 nerves
Pelvic diaphragm
Levator ani & Coccygeus
Urogenital disphragm
Superficial transversus perinei, Bulbospongiosus, Ischiocavernosus, External urethral sphincter, External anal sphincter
Levator ani
Origin: Pubis ischial spine
Insertion: Sacrum and coccyx
Action: Supports pelvic viscera and provides sphincter-like action in anal canal and vagina
Nerve Supply: S4 and S5 nerves
Superficial transversus perinei
Origin: Ischial tuberosity
Insertion: Central tendon
Action: Supports pelvic viscera
Nerve supply: Pudendal nerve
Bulbospongiosus
Origin: Central tendon
Insertion: Males: Corpus cavernosa of penis; Females: Corpus cavernosa of clitoris
Action: Males: Assists emptying of urethra and assists in erection of penis; Females: Constricts vagina and assists in erection of clitoris
Nerve Supply: Pudendal nerve
Ischiocavernosus
Origin: Ischial tuberosity
Insertion: Males: Corpus cavernosa of penis; Females: Corpus cavernosa of clitoris
Action: Males: Contributes to erection of the penis; Females: Contributes to erection of the clitoris
Nerve Supply: Pudendal nerve
External urethral sphincter
Origin: Margins of pubis and ischium
Insertion: Fibers of each unite with those from other side and encircle urethra
Action: Closes urethra
Nerve Supply: Pudendal nerve
External anal sphincter
Origin: Coccyx and central tendon
Insertion: Some circular fibers as well as some fibers from each side unite with those from the other side and encircle anal canal
Action: Closes anal canal
Nerve supply: Pudendal nerve
Muscles that move the thigh
Psoas major, Iliacus, Gluteus maximus, Gluteus medius, Gluteus minimus, Piriformis, Tensor fasciae latae, Pectineus, Adductor brevis, Adductor longus, Adductor magnus, Gracilis
Psoas major
Origin: Bodies and transverse processes of lumbar vertebrae
Insertion: Lesser trochanter of femur
Action: flexes hip
Nerve Supply: Branches of L1-3 nerves
Illiacus
Origin: Iliac fossa of ilium
Insertion: Lesser trochanter of femur
Action: Flexes hip
Nerve Supply: Femoral nerve
Gluteus maximus
Origin: Sacrum, coccyx, and posterior surface of ilium
Insertion: Posterior surface of femur and fascia of thigh
Action: Extends hip
Nerve supply: Inferior gluteal nerve
Gluteus minimus
Origin: Lateral surface of ilium
Insertion: Greater trochanter of femur
Action: Abducts and rotates thigh medially
Nerve Supply: Superior gluteal nerve
Piriformis
Origin: Anterior surface of sacrum
Insertion: Greater trochanter of femur
Action: Abducts and rotates thigh laterally
Nerve Supply: L5, S1, and S2 nerves
Tensor fasciae latae
Origin: Anterior iliac crest
Insertion: Iliotibial tract (fascia of thigh)
Action: Abducts thigh, flexes hip, and rotates thigh medially
Nerve Supply: Super gluteal nerve
Pectineus
Origin: Spin of pubis
Insertion: Femur distal to lesser trochanter
Action: Flexes hip and adducts thigh
Nerve Supply: Obturator and femoral nerves
Adductor brevis
Origin: Pubic bone
Insertion: Posterior surface of femur
Action: Adducts thigh and flexes hip
Nerve Supply: Obturator nerve
Adductor longus
Origin: Pubic bone near pubic symphysis
Insertion: Posterior surface of femur
Action: Adducts thigh and flexes hip
Nerve Supply: Obturator nerve
Adductor magnus
Origin: Ischial tuberosity
Insertion: Posterior surface of femur
Action: Adducts thigh, posterior portion extends and anterior portion flexes hip
Nerve Supply: Obturator and branch of sciatic nerves
Gracilis
Origin: Lower edge of pubic symphysis
Insertion: Proximal, medial surface of tibia
Action: Adducts thigh and flexes knee
Nerve Supply: Obturator nerve
Muscles that move the leg
Hamstring group (Biceps femoris, Semitendinosus, Semimembranosus), Sartorius, Quadriceps Femoris Group (Rectus femoris, Vastus lateralis, Vastus medialis, Vastus intermedius)
Hamstring group
Biceps femoris, Semitendinosus, Semimembranosus
Quadriceps Femoris Group
Rectus femoris, Vastus lateralis, Vastus medialis, Vastus intermedius
Biceps femoris
Origin: Ischial tuberosity and linea aspera of femur
Insertion: Head of fibular
Action: Flexes knee, rotates leg laterally, and extends hip
Nerve Supply: Tibial nerve
Note
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