Ch.11 Flashcards
Arrangement of Fascicles in Muscles
- Skeletal muscles consist of fascicles
- Fascicles are bundles of muscle fibers
- Fascicles are arranged in different patterns
- Fascicle arrangement determines action of a muscle
Circular Arrangement of Fascicles in Muscles
•Fascicles arranged in concentric rings
•Surround external body openings
•Sphincter—general name for circular muscle
•Examples
–Orbicularis oris around mouth
–Orbicularis oculi around eye orbitConvergentArrangement of Fascicles in Muscles
- Convergent
- Origin of the muscle is broad
- Fascicles converge toward the tendon of insertion
- Example is pectoralis major
Fusiform Arrangement of Fascicles in Muscles
•Fusiform—fascicles run parallel to the long axis of the muscle and have an expanded central belly e.g., biceps brachii
Parallel Arrangement of Fascicles in Muscles
- Parallel—fascicles run parallel to the long axis of the muscle
- Strap-like—sartorius
- Strap-like—sternocleidomastoid
Pennate Arrangement of Fascicles in Muscles
•Unipennate—fascicles insert into one side of the tendon (e.g. extensor digitorum longus)•Bipennate—fascicles insert into the tendon from both sides (rectus femoris)•Multipennate—fascicles insert into one large tendon from more than two sides (deltoid)
Muscle groups based on location & function
- Non-cardiac visceral organ muscles, glands and blood vessels: smooth muscle
- Cardiac muscle: cardiac muscle
- Head and Neck muscles: skeletal muscles of head & neck
- Axial/Trunk muscles: skeletal muscles of the thorax, abdomen, and pelvis
- Limb muscles: skeletal muscles of upper and lower extremities
Muscles ofFacial Expression
- Face: obicularis oculi, orbicularis oris
- Scalp: epicranius with frontal belly, occipetal belly and galea aponeurotica
- Neck: platysma
- Thin and variable in shape
- Often insert in skin—not on bones
- Innervated by CN VII—the facial nerve
Four main pairs of muscles of mastication
- Prime movers of jaw closure and biting: masseter &temporalis
- Side-to-side movement of jaw: pterygoid muscles
- Compression of cheeks: buccinator muscles fo rwhistling, sucking (e.g., breast feeding)
- Innervated by mandibular division of the trigeminal nerve (CN V)
Extrinsic muscles of tongueTongue Movement
- Genioglossus: attached to mandible
- Hyoglossus: attached to hyoid bone and depresses tongue
- Styloglossus: attached to styloid process
- Move tongue–Laterally–Anteriorly –Posteriorly
- All innervated by CN XII—the hypoglossal nerve
The Hyoid Bone
- Associated with skull but not directly in contact with any other bone
- Lies inferior to the mandible in anterior neck
- The only bone with no direct articulation with any other bone•Acts as a movable base for the tongue
Anterior and posterior triangles of the neck
•Neck is divided into anterior & posterior triangles by the sternocleidomastoid muscle
Muscles of the Anterior Neck and Throat within Anterior Triangle of Neck—Swallowing Muscles
MAKE SURE TO KNOW THIS SLIDE
- As food in the mouth is chewed and squeezed posteriorly toward pharynx, the suprahyoid muscles(above the hyoid bone) aid in closing air passage in larynx by lifting the larynx superiorly and anteriorly
- Pharyngeal constrictor muscles constrict pharynx during swallowing and squeeze food into the esophagus
- After food is squeezed into esophagus, infrahyoid muscles (below the hyoid bone) bring the larynx inferiorly back into its normal position for breathing
Suprahyoid muscles above hyoid bone close larynx air passage with swallowing
- Digastric
- Mylohyoid
- Stylohyoid
Pharyngeal constrictor musclessqueeze food into esophagus
- Superior
- Middle
- Inferior
