Unit 3: Lecture 10 - Axial Muscles

Classification of skeletal muscles

• attached to bones

• Voluntary

• Striated

Organization of Skeletal Muscles

• Muscle

• Fascicle

• Muscle Fiber (cell)

• Myofibril

• Sarcomere

• Myofilaments

What is a bundle of muscle fibers called

fascicle

Individual muscle fibers contain

Myofibrils

Myofibrils are composed of

myofilaments

What is the thin filament of a skeletal muscle

actin

What is the thick filament of a skeletal muscle

myosin

What does the epimysium wrap around

the muscle

What does the perimysium surround

each fascicle

What surrounds each muscle fiber and electrolytically isolates cells from neighbors

Endomysium

What is the sarcolemma

the cell membrane

What is the function of a t-tubule

transport electro signals deep into the muscle

What excites skeletal muscle fibers

axons of somatic motor neurons

What is a motor unit

a single motor neuron and the muscle fibers it innervates

What initiates a contraction in muscles

a motor neuron impulse

Where does the motor neuron communicate with the muscle fibers

neuromuscular junction

Classification of Cardiac muscle

• Found only in the heart

• involuntary

• striated

What connects the short bifurcated cardiac cells in the heart

intercalated discs

what allows the heart cells to function together at the same time

the intercalated discs are coupled

Classification of smooth

• In walls of organs in guts and blood vessels

• Involuntary

• Non-striated

What are the four patterns of fascicle arrangements in skeletal muscle

• circular

• parallel

• Convergent (triangular/fan-shaped)

• Pennate (feather)

What are the three subclasses of pennate

• unipennate

• bipennate

• multipennate

What determines an axial muscle

both attachments are on the axial skeleton

What are the functions of the axial muscles

• support the head and spinal column

• facial expression, chewing, and swallowing

• aid in breathing

  • support and protect abdominal and pelvic organs

Attachments of the masseter

zygomatic and mandible

What are the actions of the masseter

elevate and protract the mandible

Attachments of the temporalis

temporal line and coronoid process (mandible)

what are the actions of the temporalis muscle

elevates and retracts the mandible

attachments of the glenioglossus muscle

mental spines of mandible and inferior region of the tongue

what are the actions of the glenioglossus

protracts tongue

What are the attachments of the styloglossus

styloid process of the temporal bone and sides and inferior aspect of tongue

Attachments of the sternocleidomastoid

mastoid process of the temporal bone, manubrium, and clavicle

Actions of the sternocleidomastoid

flex head/neck (bilateral) and rotation of head to opposite side (unilateral)

Attachments of the scalene muscles

transverse process of cervical vertebrae and superior surface of 1st and 2nd ribs

WHat are the actions of the scalene muscles

flex the neck, and elevate 1st and 2nd ribs when neck is fixed

attachments of the splenius capitis

occipital bone and ligamentum nuchae

Action of the splenius capitis

extends the head/neck (bilateral) and rotation of head to the same side (unilateral)