Human Morp & Funch Ch 11

Describe axial muscles.

• origins and insertions on axial skeleton

• Support and move the head and vertebral column

• Function in facial expression, breathing, chewing, and swallowing

• Support and protect abdominal and pelvic organs

Describe appendicular muscles.

• Control movements of upper and lower limbs

• Control movements of pectoral and pelvic girdles

• Organized into groups based on locations

What is the difference between superior and inferior attachments in axial skeleton?

superior = more moveable

What is the difference between proximal and distal attachments in appendicular skeleton?

proximal = less moveable

Where are distal attachment of biceps brachii located?

on radius

What does contraction do to the forearm?

pulls radius toward scapula, flexing the elbow

What are fascicles?

bundles of muscle fibers

How are fascicles classified?

circular, parallel, convergent, pennate

Describe circular fascicles.

concentrically arranged fascicles to create a sphincter; control material passage through an opening

Describe parallel fascicles.

fascicles run parallel to muscle's long axis

• Sometimes have an expanded central belly; high

endurance

Describe convergent fascicles.

fascicles merge toward a common attachment site

• Can pull in varying directions, but not as hard as parallel muscles

Describe pennant fascicles.

fascicles organized as if part of a large feather in which fbers pull at an angle to the tendon to generate more tension but don't pull their tendons as far as parallel muscles

- unipennate, bipennate, multipennate

Describe unipennate muscle fascicles.

fascicles on same side of tendon

Describe bipennate muscle fascicles.

fascicles on both sides of tendon; most common

Describe multipennate muscle fascicles.

branches of tendon within muscle, and fascicles arranged around both sides of each tendon branch

What criteria is used to name muscles?

- muscle action

- body regions

- muscle attachments

- orientation of muscle fibers

- muscle shape

- muscle size

- # of muscle heads at point of attachment

Describe muscle action in terms of naming muscles.

indicates muscle's primary action

ex: flexor digitorum longus flexes digits

Describe specific body regions in terms of naming muscles.

indicates muscle location

ex: rectus femoris is near the femur

Describe muscle attachment in terms of naming muscles.

indicates origins and/or insertions

ex: sternocleidomastoid originates on the sternum and clavicle and inserts on the mastoid process

Describe orientation of muscle fibers in terms of naming muscles.

indicates organization of muscle fascicles

ex: rectus abdominis is composed of fibers running in vertically straight ("rectus") orientation

Describe muscle shape in terms of naming muscles.

Indicates shape of muscle

• E.g., deltoid is shaped like a triangular delta symbol

• E.g., abuctor pollicis longus is a long muscle

Describe muscle size in terms of naming muscles.

Indicates size of muscle

E.g., gluteus maximus is the largest of the buttocks muscle

Describe the number of muscle heads at point of attachment in relation to naming muscles.

indicates number of muscle bellies or heads each contains at the superior or proximal attachment site

• E.g., triceps brachii has three heads

Muscles of facial expression generally attach where?

to subcutaneous layer deep to skin

What nerve control facial expression?

facial nerve CN VII

What are the muscles of facial expression?

- front belly

- orbicularis oculi

- zygomaticus major + minor

- depressor angus oris

- platysma

- orbicularis oris

What are Extrinsic eye muscles?

extraocular = insert onto outer surface of the eye and move it

- • Six muscles: four rectus and two oblique

Where does Rectus eye muscles originate from?

common tendinous ring

What does the process of respiration involve?

inspiration and expiration

Describe inspiration.

inhalation: Several muscles contract to increase the size of the thoracic cavity, allowing lungs to fill with air

Describe expiration.

exhalation: Some respiratory muscles contract and others relax, decreasing the size of the thoracic cavity and forcing air out of lungs

Describe the Diaphragm.

involved in respiration, internally placed dome-shaped muscle that partitions thoracic and abdominal cavities

Where do muscle fibers converge on the diaphragm?

toward fibrous central tendon

Describe diaphragm involvement in breathing.

contracts during inspiration as central tendon pulled inferiorly, increasing dimension of thoracic cavity

What is the function of External intercostal?

Elevate ribs during inspiration, expanding cavity

Describe Internal intercostals.

Deep to external intercostals, has fibers at right angles to external intercostals that depress ribs during forced expiration

Describe function of Transversus thoracis.

Depresses ribs during forced expiration

What are Scalene muscles?

Help elevate first and second ribs during forced inspiration

What is the purpose of Serratus posterior superior?

elevates ribs during forced inspiration and increases lateral dimensions of thorax