Anat Exam 3

Epimysium

separates muscles from surrounding tissues and organs

Perimysium

divides muscle into internal compartments

Fascicle

bundle of muscle fibers

Endomysium

surrounds muscle fiber, binds muscle fiber to neighbor, and supports capillaries

Aponeuroses

tendons that form thick, flattened sheets

How do nerves attach to muscle fibers

they enter through the epimysium, branch through perimysium, and enters endomysium to attach

Where do chemical communications between neuron and skeletal muscle fiber occur

neuromuscular junction

Where do the axon of motor neuron establish a synaptic contact with a skeletal muscle fiber

motor end plate

Sarcolemma

plasma membrane of skeletal muscle cell

Sarcoplasm

cytoplasm in muscle cell

What structures conduct action potentials to stimulate muscle fiber contraction

sarcolemma and T tubules

What is responsible for muscle fiber contraction

myofibrils shortening

Actin

forms thin filament and produces contraction of all muscle by interacting with thick filament

Myosin

protein of thick filament

Sarcoplasmic Reticulum

release site of calcium

Triad

combo of a pair of terminal cisternae and T tubule

Sarcomere

smallest functional unit of muscle fiber

Where is the M Band

goes straight down the middle of the sarcomere

What is unique about A Bands

they never change site during a contraction and the width stays the same

What do Z lines do during contraction

moves closer together

Troponin

holds tropomyosin strands in place

What covers myosin binding sites on actin molecules

troponin-tropomyosin complex

How do you get myosin binding heads to bind to myosin binding sites on actin

you get calcium and troponin-tropomyosin to expose the sites

Where is calcium released from

terminal cisternae

Where is terminal cisternae located

in the zone of overlap

How does contraction begin

calcium ion binds to troponin → troponin-tropomyosin complex switches sizes → active sites on actin molecule are exposed

How does contraction end

sarcoplasmic reticulum recaptures calcium → troponin-tropomyosin covers active sites → cessation of contraction

Downstream effect

release of calcium from terminal cisternae

How is calcium released

Acetylcholine binds to molecules → binds to presynaptic terminal → diffuses across synaptic cleft → Ach receptor sites present → downstream effect

Motor unit

one neuron and all the muscle fibers it innervates

Motor recruitment

more recruited muscle fibers → more motor units involved → more potential

Muscle tone

some motor units are always contracting and providing a resting tension

Muscle Hypertrophy

gets bigger

Muscle atrophy

gets smaller

Slow fibers

dark in color, fatigue resistant, contains myoglobin, uses aerobic metabolism, takes longer to contract

Fast fibers

pale color, easily fatigued, has densely packed myofibrils, gets tired easily

Which fiber is connected to sprinting

Fast

Which fiber is connected to long distance running

Slow

Which stays stationary

origin

Which one moves

insertion

Prime mover

does movement especially well

Synergist

helps prime mover

Antagonist

actions oppose that of prime movers

Origin= alveolar process of maxilla & mandible opposite molar teeth, Insertion= fibers of obicularis oris

buccinator

Origin= incisive fossa of mandible, Insertion= skin of chin

mentalis

Origin= maxilla and mandible, Insertion= lips

obicularis oris

Origin= fascia surrounding parotid salivary gland, Insertion= angle of mouth

risorius

Origin= zygomatic bone near zygomaticotemporal suture, Insertion= angle of mouth

zygomaticus major

Origin= zygomatic bone posterior to zygomaticomaxillary suture, Insertion= upper lip

zygomaticus minor

Origin= epicranial aponeuroses, Insertion= skin of eyebrow and bridge of nose

epicranium frontal belly

Origin= superior nuchal line and adjacent region of mastoid portion of temporal bone, Insertion= epicranial aponeuroses

epicranium occipital belly

Origin= fascia of superior thorax between cartilage of 2nd rib and acromion of scapula, Insertion= mandible and skin of cheek

platysma

Origin= zygomatic arch, Insertion= lateral surface and angle of mandibular ramus

masseter

Origin= temporal lines of skull, Insertion= coronoid process of mandible

temporalis

Origin= inferior surface of mandible at chin, Insertion= hyoid bone

digastric anterior belly

Origin= mastoid region of temporal bone, Insertion= hyoid bone

digastric posterior belly

Origin= superior border of scapula near scapular notch, Insertion= hyoid bone

omohyoid

Origin= clavicle and manubrium, Insertion= hyoid bone

sternohyoid

Origin= dorsal surface of manubrium and 1st costal cartilage, Insertion= thyroid cartilage of larynx

sternothyroid

Origin= clavicular head attaches to sternal end of clavicle and sternal head attaches to manubrium, Insertion= mastoid region of skull and lateral portion of superior nuchal line

sternocleidomastoid

Origin= spinous process and ligaments connecting inferior cervical and superior thoracic vertebrae, Insertion= mastoid process, occipital bone, superior cervical vertebrae

splenius

Origin= inferior portion of ligamentum nuchae and spinous process of C7, Insertion= spinous process of axis

spinalis cervicis

Origin= spinous process of inferior thoracic and superior lumbar vertebrae, Insertion= spinous process of superior thoracic vertebrae

spinalis thoracis

Origin= transverse processes of inferior cervical and superior thoracic vertebrae, Insertion= mastoid process of temporal bone

longissimus capitis

Origin= transverse processes of superior thoracic vertebrae, Insertion= transverse processes of middle and superior cervical vertebrae

longissimus cervicis

Origin= broad aponeurosis and transverse processes of inferior thoracic and superior lumbar vertebrae, Insertion- transverse processes of superior thoracic and lumbar vertebrae and inferior surfaces of lower 10 ribs

longissimus thoracis

Origin= superior borders of vertebrosternal ribs near the angles, Insertion= transverse processes of middle and inferior cervical vertebrae

iliocostalis cervicis

Origin= superior borders of ribs 6-12 medial to the angles, Insertion= superior ribs and transverse processes of last cervical vertebrae

iliocostalis thoracis

Origin= iliac crest, sacral crests, and lumbar spinous processes, Insertion= inferior surfaces of ribs 6-12 near their angles

iliocostalis lumborum

Origin= transverse and costal processes of cervical vertebrae C2-C7, Insertion= superior surfaces of first 2 ribs

scalenes

Origin= inferior border of each rib, Insertion= superior border of more inferior rib

external intercostal

Origin= superior border of each rib, Insertion= inferior border of the more superior rib

internal intercostal

Origin= lateral surfaces of the first 8-9 ribs, Insertion= costal surface of medial border of scapula

serratus anterior

Origin= external and inferior borders of ribs 5-12, Insertion= external oblique aponeuroses extending to linea alba and iliac crest

external oblique

Origin= thoracolumbar fascia and iliac crest, Insertion= inferior surfaces of ribs 9-12, costal cartilages 8-10, linea alba, and pubis

internal oblique

Origin= cartilages of ribs 6-12, iliac crest, and thoracolumbar fascia, Insertion= linea alba and pubis

transverse abdominis

Origin= superior surface of pubis around symphysis, Insertion= inferior surfaces of cartilages and xiphoid process of sternum

rectus abdominis

What structures are part of the superficial urogenital triangle

bulbospongiosus, ischiocavenosus, and superficial transverse perineal

What structures are part of the deep urogenital triangle

deep transverse perineal and external urethral sphincter

Action of buccinator

compresses cheeks

Action of mentalis

pouting

Action of obicularis oris

purses lips

Action of risorius

draws corners of mouth to the side

Action of zygomaticus major

retracts and elevates corner of mouth

Action of zygomaticus minor

retracts and elevates upper lip

Action of epicranium frontal belly

raises eyebrows and wrinkles forehead

Action of epicranium occipital belly

tenses and retracts scalp

Action of platysma

tenses skin of neck and depresses mandible

Action of masseter

elevates mandible and closes jaw

Action of temporalis

elevates mandible and closes jaw

Action of digastric

depresses mandible, opens mouth, and/or elevates larynx

Action of omohyoid

depresses hyoid bone and larynx

Action of sternohyoid

depresses hyoid and elevates larynx

Action of sternothyroid

depresses hyoid and elevates larynx

Action of sternocleidomastoid

together they flex the neck, alone one side bends neck toward shoulder and turns face to opposite side

Action of splenius

together they extend neck, alone they rotate and laterally flexes neck to that side

Action of spinalis cervicis

extends neck

Action of spinalis thoracis

extends vertebral column

Action of longissimus capitis

together they extend neck, alone they rotate and laterally flexes neck to that side

Action of longissimus cervicis

together they extend the neck, alone rotates and laterally flexes neck to that side