Chapter 12: The Muscular System Flashcards

A comprehensive vocabulary flashcard set covering 250 concepts from Chapter 12: The Muscular System.

Origin

The point of muscle attachment that does not move during contraction.

Insertion

The point of muscle attachment that moves during contraction.

Prime Mover

The principal muscle involved in accomplishing a specific action; also known as the agonist.

Synergist

A muscle that assists the prime mover in accomplishing a movement.

Fixator

A muscle that stabilizes insertion points or origins during a movement.

Antagonist

A muscle that produces the opposite movement of an agonist.

Fascicle

A bundled group of skeletal muscle fibers surrounded by perimysium.

Perimysium

The connective tissue sheath that surrounds each individual muscle fascicle.

Parallel Fascicle Arrangement

Fascicle organization where fascicles are arranged in the same direction as the long axis of the muscle.

Fusiform Fascicle Arrangement

Parallel fascicle arrangement with a large muscle belly in the middle and narrowing ends.

Circular Fascicle Arrangement

Fascicle organization where muscle fibers wrap in a circular pattern around an opening.

Convergent Fascicle Arrangement

Fascicle organization where broad fascicles unite on a singular, narrow insertion point.

Pennate Fascicle Arrangement

Fascicle organization where fascicles blend obliquely into a central tendon.

Unipennate Fascicle Arrangement

Pennate arrangement where fascicles are located on only one side of the tendon.

Bipennate Fascicle Arrangement

Pennate arrangement where fascicles are located on both sides of a central tendon.

Multipennate Fascicle Arrangement

Pennate arrangement where the tendon branches within the muscle, resembling many feathers arranged together.

Muscle Belly

The central, expanded portion of a muscle that enlarges when fusiform muscles contract.

Tendon Function

Attaches muscle to bone and pulls on the periosteum causing bone movement.

Prime Mover for Elbow Flexion

Biceps brachii.

Synergists for Elbow Flexion

Brachioradialis and brachialis.

Antagonist to Biceps Brachii

Triceps brachii.

Fascicle Arrangement Influence

Determines the range of motion and force generated by a skeletal muscle.

Prime Mover and Synergists Diagram

Illustrates biceps brachii acting as prime mover and brachialis/brachioradialis acting as synergists.

Agonist and Antagonist Pairs Diagram

Demonstrates biceps brachii as agonist/flexor and triceps brachii as antagonist/extensor.

Patterns of Fascicle Organization Diagram

Displays fusiform, parallel, circular, convergent, unipennate, bipennate, and multipennate fiber layouts.

Roots of Muscle Names

Derived from Greek and Latin words based on observable physical characteristics.

Characteristics Used to Name Muscles

Shape, size comparison, fiber orientation, number of origins, action, attachment location, and muscle group.

Maximus

Latin/Greek size term meaning the largest of a group.

Medius

Latin/Greek size term meaning medium-sized in a group.

Minimus

Latin/Greek size term meaning the smallest of a group.

Brevis

Latin/Greek size term meaning short.

Longus

Latin/Greek size term meaning long.

Major

Latin/Greek size term meaning the larger of two.

Minor

Latin/Greek size term meaning the smaller of two.

Longissimus

Latin/Greek size term meaning the longest.

Rhomboid Muscle Shape

Named for its physical resemblance to a rhombus geometric shape.

Deltoid Muscle Shape

Named for its resemblance to an upside-down Greek letter delta.

Uni-

Numerical prefix meaning one.

Bi- / Di-

Numerical prefix meaning two.

Tri-

Numerical prefix meaning three.

Quad-

Numerical prefix meaning four.

Multi-

Numerical prefix meaning many.

Biceps Brachii Etymology

Named for structure ('bi' = two, 'ceps' = head) and location (brachium region).

Flexor Carpi Ulnaris Etymology

Named for action (flexes), wrist location ('carpi'), and bone location along the ulna ('ulnaris').

Predictable Muscle Action: Lateral Side of Joint

Causes abduction of limbs or lateral flexion of trunk/neck.

Predictable Muscle Action: Medial Side of Joint

Causes adduction of limbs.

Predictable Muscle Action: Anterior Portion of Joint

Causes flexion.

Predictable Muscle Action: Posterior Portion of Joint

Causes extension.

Facial Muscle Insertion Point

Facial expression muscles originate on skull bones and insert directly into the skin.

Orbicularis Oris Description

Circular muscle surrounding the mouth.

Orbicularis Oris Action

Puckers the lips.

Orbicularis Oris Origin & Insertion

Origin: Medial aspects of maxilla and mandible. Insertion: Skin and mucous membrane of lips.

Orbicularis Oculi Description

Circular muscle surrounding the eye.

Orbicularis Oculi Action

Opens and closes the eye.

Orbicularis Oculi Origin & Insertion

Origin: Nasal part of frontal bone, maxilla, and lacrimal. Insertion: Skin of orbital region.

Occipitofrontalis Description

Muscle with two bellies (frontal and occipital) spanning the top and back of the head.

Occipitofrontalis Action

Moves the scalp and the eyebrows.

Occipitofrontalis Origin & Insertion

Origin: Skin of eyebrow, forehead muscles, and superior nuchal line. Insertion: Epicranial aponeurosis.

Buccinator Description

Makes up the cheeks and contributes to facial expression.

Buccinator Action

Compresses the cheek (e.g., whistling or sucking cheeks).

Buccinator Origin & Insertion

Origin: Maxilla, mandible, and temporomandibular joint. Insertion: Fibers of orbicularis oris.

Zygomaticus Major Description

One of the main facial expression muscles attaching at corners of mouth, responsible for smiling.

Zygomaticus Major Action

Raises the corners of the mouth.

Zygomaticus Major Origin & Insertion

Origin: Anterior lateral surface of zygomatic bone. Insertion: Muscles of upper lip.

Zygomaticus Minor Description

Facial muscle attaching at corners of mouth, assisting in smiling.

Zygomaticus Minor Action

Raises the corners of the mouth.

Zygomaticus Minor Origin & Insertion

Origin: Posterior lateral surface of zygomatic bone. Insertion: Muscles of upper lip.

Platysma Description

Very superficial muscle of the neck.

Platysma Action

Tenses the skin of the neck.

Platysma Origin & Insertion

Origin: Fascia over upper, lateral chest. Insertion: Skin, fascia, and muscles of mandible.

Nerve Supply for Facial Expression Muscles

Cranial nerve VII (Facial nerve).

Medial Rectus Action

Moves the eye medially.

Lateral Rectus Action

Moves the eye straight to the (lateral) side.

Inferior Rectus Action

Moves the eye medially and inferiorly (toward the tip of the nose).

Superior Rectus Action

Moves the eye upward and medially.

Inferior Oblique Action

Moves the eye downward and laterally.

Superior Oblique Action

Moves the eye upward and laterally.

Eye Movement Coordinated Straight Up

Occurs when superior rectus and inferior oblique contract together.

Eye Movement Coordinated Straight Down

Occurs when inferior rectus and inferior oblique contract together.

Cranial Nerve III Eye Muscles

Innervates medial rectus, inferior rectus, superior rectus, and inferior oblique.

Cranial Nerve VI Eye Muscles

Innervates lateral rectus and superior oblique.

Extrinsic Eye Muscle Origins

All rectus muscles originate on the common tendinous ring; inferior oblique originates on maxilla; superior oblique originates on sphenoid bone.

Eye Movements Diagram

Shows direction vectors for rectus and oblique muscles acting on the left eye.

Mastication Definition

The physiological process of chewing food.

Masseter Description & Action

Lateral jaw muscle that elevates mandible; main muscle responsible for chewing.

Masseter Origin & Insertion

Origin: Zygomatic arch. Insertion: Angle and ramus of mandible.

Temporalis Description & Action

Spans lateral skull above jaw; retracts the mandible.

Temporalis Origin & Insertion

Origin: Frontal, parietal, and temporal bones. Insertion: Coronoid process of mandible.

Medial Pterygoid Description & Action

Deep facial muscle; prime mover for side-to-side jaw movement, opening and closing mouth.

Medial Pterygoid Origin & Insertion

Origin: Pterygoid plate of sphenoid bone. Insertion: Medial surface of ramus and angle of mandible.

Lateral Pterygoid Description & Action

Deep facial muscle; prime mover for side-to-side jaw movement, opening and closing mouth.

Lateral Pterygoid Origin & Insertion

Origin: Pterygoid plate of sphenoid bone. Insertion: Joint capsule of TMJ and condyloid process of mandible.

Nerve Supply for Mastication Muscles

Cranial nerve V (Trigeminal nerve).

Extrinsic Tongue Muscles Definition

Tongue muscles that originate outside the tongue and insert into it.

Intrinsic Tongue Muscles Definition

Tongue muscles that originate and insert entirely within the tongue.

Genioglossus Description & Action

Fan-shaped extrinsic tongue muscle that depresses and protracts the tongue.

Genioglossus Origin & Insertion

Origin: Mandible bone. Insertion: Tongue and body of hyoid.

Styloglossus Description & Action

Smallest extrinsic tongue muscle; elevates and retracts the tongue.

Styloglossus Origin & Insertion

Origin: Styloid bone. Insertion: Merges with hyoglossus and inferior longitudinal muscle.

Palatoglossus Description & Action

Extrinsic tongue muscle in lateral pharyngeal wall; elevates back of tongue.