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40 terms

Chapter 10: Muscular System

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Myology
the study of muscle
Endomysium
Thin sleeve of loose connective tissue surrounding each muscle fiber
Allows room for capillaries and nerve fibers to reach each muscle fiber
Provides extracellular chemical environment for the muscle fiber and its associated nerve ending
Perimysium
Slightly thicker layer of connective tissue
Fascicles: bundles of muscle fibers wrapped in perimysium
Carry larger nerves and blood vessels, and stretch receptors
Epimysium
Fibrous sheath surrounding the entire muscle
Outer surface grades into the fascia
Inner surface sends projections between fascicles to form perimysium
Fascia
Sheet of connective tissue that separates neighboring muscles or muscle groups from each other and the subcutaneous tissue
Tendon
bridge the gap between muscle ends and bony attachment
Aponeurosis
tendon is a broad, flat sheet (eg: palmar aponeurosis)
Retinaculum
connective tissue band that tendons from separate muscles pass under
Origin
bony attachment at stationary end of muscle
Belly
thicker, middle region of muscle between origin and insertion
Insertion
bony attachment to mobile end of muscle
Action
the effects produced by a muscle; to produce or prevent movement
Prime Mover (agonist)
Muscle that produces most of force during a joint action
Synergist
muscle that aids the prime mover; stabilizes the nearby joint; modifies the direction of movement
Antagonist
opposes the prime mover; relaxes to give prime mover control over an action
Antagonistic Pairs
muscles that act on opposite sides of a joint
Fixator
muscle that prevents movement of bone
Intrinsic Muscles
entirely contained within a region, such as the hand
Extrinsic Muscles
act on a designated region, but has its origin elsewhere
Innervation of a muscle
refers to the identity of the nerve that stimulates it; Enables the diagnosis of nerve, spinal cord, and brainstem injuries from their effects on muscle function
Plexus
weblike network of spinal nerves adjacent to the vertebral column
Spinal Nerves
arise from the spinal cord; Emerge through intervertebral foramina; Immediately branch into a posterior and anterior ramus; Innervate muscles below the neck
Cranial Nerves
arise from the base of the brain; Emerge through skull foramina; Innervate the muscles of the head and neck; Numbered CN I to CN XII
Digastric muscle
opens mouth widely
Geniohyoid
depresses mandible
Mylohyoid
elevates floor of mouth at the beginning of swallowing
Stylohyoid
elevates hyloid
Omohyoid
depresses hyoid after elevation
Sternohyoid
depresses hyoid after elevation
Thyrohyoid
depresses hyoid and elevates larynx
Sternothyroid
depresses larynx after elevation
Carpal Tunnel Syndrome
Repetitive motions cause inflammation and pressure on median nerve
Pharyngeal Constrictors
Encircle pharynx forming a muscular funnel
During swallowing, drive food into the esophagus
Hyoid Muscles- Infrahyoid Group
Fix hyoid bone from below, allowing suprahyoid muscles to open mouth
Hyoid Muscles- Suprahoid Group
Aspects of chewing, swallowing, and vocalizing
Eight pairs of hyoid muscles associated with hyoid bone
Fascicles
bundles of muscle fibers wrapped in perimysium
Glycemic Control
Regulation of blood glucose concentrations within its normal range
Sphincters
internal muscular rings that control the movement of food, bile, blood, and other materials within the body
Antigravity Muscles
resist pull of gravity and prevent us from falling or slumping over
Intermuscular Septa
separate one muscle compartment from another