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EVERYTHING ELMHURST > Anatomy: Skeletal Muscles (Locations & Functions) > Flashcards

Anatomy: Skeletal Muscles (Locations & Functions) Flashcards

1
Q

Sarcolemma

A

Function: Encloses the muscle fiber and conducts action potentials.
Origin: Derived from the plasma membrane of muscle cells.
Location: Surrounds each muscle fiber (cell).

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2
Q

Sarcoplasm

A

Function: Site of metabolic processes and contains organelles and myofibrils.
Origin: The cytoplasm of muscle cells.
Location: Inside the muscle fiber.

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3
Q

Mitochondrion

A

Function: Produces ATP through aerobic respiration.
Origin: Organelle found in eukaryotic cells.
Location: Scattered throughout the sarcoplasm of muscle fibers.

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4
Q

Sarcoplasmic Reticulum

A

Function: Stores and releases calcium ions (Ca²⁺) during muscle contraction.
Origin: Specialized form of endoplasmic reticulum in muscle cells.
Location: Surrounds myofibrils within the muscle fiber.

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5
Q

Myofibril

A

Function: Contains the contractile elements (sarcomeres) responsible for muscle contraction.
Origin: Composed of myofilaments (actin and myosin).
Location: Runs parallel within the muscle fiber.

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6
Q

Nucleus

A

Function: Contains genetic material and regulates cellular activities, including protein synthesis.
Origin: Found in all eukaryotic cells.
Location: Typically located at the periphery of the muscle fiber.

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7
Q

Striation

A

Function: Indicates the organized arrangement of muscle fibers and contractile proteins.
Origin: Result of alternating thick (myosin) and thin (actin) filaments.
Location: Visible across myofibrils and muscle fibers under a microscope.

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8
Q

Triad

A

Function: Facilitates rapid transmission of action potentials and calcium release.
Origin: Formed by two terminal cisternae and one transverse tubule.
Location: At the junction of the A and I bands in the myofibrils.

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9
Q

Terminal Cisternae

A

Function: Stores calcium ions and releases them during muscle contraction.
Origin: Extensions of the sarcoplasmic reticulum.
Location: Flank the T-tubules in the triad structure.

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10
Q

Transverse Tubule (T-tubule)

A

Function: Transmits action potentials deep into the muscle fiber.
Origin: Extensions of the sarcolemma.
Location: Penetrates into the muscle fiber at the junction of the A and I bands.

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11
Q

Endomysium

A

Function: Surrounds and supports individual muscle fibers.
Origin: Layer of connective tissue.
Location: Within a muscle, surrounding each muscle fiber.

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12
Q

Perimysium

A

Function: Surrounds and organizes bundles of muscle fibers (fascicles).
Origin: Connective tissue layer.
Location: Between individual fascicles within a muscle.

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13
Q

Epimysium

A

Function: Surrounds the entire muscle, providing support and protection.
Origin: Outer layer of connective tissue.
Location: Envelops the entire muscle.

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14
Q

Fascicle

A

Function: A bundle of muscle fibers that allows for organized structure and efficient force generation.
Origin: Group of muscle fibers surrounded by perimysium.
Location: Found within a muscle, grouped together to form the muscle.

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15
Q

Synergist

A

Function/Action: Assists the prime mover (agonist) by providing additional force or by reducing undesirable movements.
Definition: A muscle that works together with another muscle to enhance its effect.
Example: The brachialis acts as a synergist to the biceps brachii during elbow flexion.

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16
Q

Fixator

A

Function/Action: Stabilizes the origin of the agonist so that it can act more efficiently.
Definition: A muscle that prevents unwanted movement at a joint.
Example: The rotator cuff muscles stabilize the shoulder during arm movements.

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17
Q

Antagonist

A

Function/Action: Opposes or reverses a particular movement of the agonist.
Definition: A muscle that acts in opposition to the agonist.
Example: The triceps brachii is an antagonist to the biceps brachii during elbow flexion

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18
Q

Agonist (Prime Mover)

A

Function/Action: The main muscle responsible for a specific movement.
Definition: A muscle that is primarily responsible for movement.
Example: The biceps brachii is the agonist during elbow flexion.

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19
Q

Epicranius (Occipitofrontalis)

A

Function/Action: Raises eyebrows and wrinkles the forehead.

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20
Q

Temporalis

A

Function/Action: Elevates and retracts the mandible (closes the jaw).
Origin: Temporal fossa.
Insertion: Coronoid process of the mandible.

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21
Q

Masseter

A

Function/Action: Elevates the mandible (primary muscle for jaw closure).
Origin: Zygomatic arch and maxilla.
Insertion: Angle and ramus of the mandible.

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22
Q

Frontalis (Frontal Belly of the epicranius)

A

Action: Elevates eyebrows, pullls scalp forward
Origin: Top of the forehead or forehead area. (cranial aponeurosis).
Insertion: Skin of eyebrows and root of the nose.

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23
Q

Orbicularis Oculi

A

Function/Action: Closes eyelids; enables blinking and squinting.
Origin: Frontal and maxillary bones.
Insertion: Skin of the eyelid.

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24
Q

Occipitalis (Occipital Belly)

A

Function: Pulls scalp backwards (raises eyebrows)
Origin: Occipital bone
Insertion: epicranial neurosis

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25
Orbicularis Oris
Function/Action: Closes and protrudes lips (kissing muscle). Origin: Indirectly from maxilla and mandible. Insertion: Encircles mouth; inserts into the muscle and skin at the angles of the mouth.
25
Zygomaticus
Function/Action: Raises lateral corners of the mouth (smiling). Origin: Zygomatic bone. Insertion: Skin and muscle at the corner of the mouth.
26
Levator Anguli Oris
Function/Action: Elevates the angle of the mouth (smiling). Origin: Maxilla. Insertion: Lips
27
Buccinator
Function/Action: Compresses the cheek (as in whistling or sucking). Origin: Molar region of maxilla and mandible. Insertion: Cheeks
28
Risorius
Function/Action: Draws the corner of the lip laterally. Origin: Fascia of masseter muscle. Insertion: Skin at the corner of the mouth.
29
Depressor Labii Inferioris
Function/Action: Lowers the lower lip. Origin: Mandible. Insertion: Skin of lower lip.
30
Depressor Anguli Oris
Function/Action: Draws the corners of the mouth downward (frowning). Origin: Mandible. Insertion: Skin and muscle at the angle of the mouth.
31
Mentalis
Function/Action: Protrudes the lower lip and wrinkles the chin. Origin: Mandible. Insertion: Skin of the chin.
32
Thyrohyoid
Function/Action: Swallowing Origin: Thyroid cartilage of the larynx. Insertion: Hyoid bone.
32
Mylohyoid
Function/Action: Aids in swallowing, elevates the tongue, speech Origin: Mylohyoid line of the mandible. Insertion: Hyoid bone.
33
Sternohyoid
Function/Action: Depresses the hyoid bone after it has been elevated (RESETS the hyoid bone after swallowing or speech to prepare for next action). Origin: Manubrium of the sternum Insertion: Hyoid bone.
34
Splenius Capitis
Function/Action: Extends or hyperextends the head; rotates and bends the head to the same side (helps in LOOKING up) Origin: Spinous process of cervical vertebrae Insertion: Mastoid process of occipital bone.
35
Sternocleidomastoid
Function/Action: Flexes the neck Origin: Manubrium of the sternum and medial portion of the clavicle. Insertion: mastoid process of temporal bone
36
Scalenes
Function/Action: Flexes and rotates the neck. Origin: Transverse processes of cervical vertebrae (C2-C7). Insertion: First two ribs.
37
Levator Scapulae
Function/Action: Elevates the scapula Origin: Transverse processes of C1-C4. Insertion: Superior Angle of Scapula
38
Pectoralis Minor
Function/Action: Protract the scapula, raises the ribs Origin: Anterior surfaces of ribs 3-5. Insertion: Coracoid process of the scapula.
39
Pectoralis Major
Function/Action: Flexes and rotates the humerus Origin: Clavicle, sternum Insertion: greater tubercle
40
Serratus Anterior
Function/Action: Protracts scapula Origin: ribs 1-9. Insertion: medial border of the scapula.
41
Intercostalis (Intercostal Muscles)
Function/Action: External intercostals elevate the ribs during inspiration; internal intercostals depress the ribs during forced expiration. Origin: Inferior/Lower border of the rib above (for both external and internal intercostals). Insertion: Superior border of the rib below.
42
Rectus Abdominis
Function/Action: Flexes the vertebrae. Origin: Pubic bones Insertion: Costal Cartilage of inferior ribs
43
Internal Oblique
Function/Action: Compresses abdominal contents, flexes and rotates the trunk. Origin: Iliac Crest Insertion: pubic bone, Inferior/last 3 ribs
44
Transversus Abdominis
Function/Action: stabilizes the vertebrae and abdomin Origin: Illiac crest Insertion: Pubic Bone
45
External Oblique
Function/Action: Compresses abdominal cavity, aids in trunk rotation and lateral flexion. Origin: Inferior 8 ribs Insertion: Illiac crest, pubic bone
46
Infraspinatus
Function/Action: Rotates the humerus laterally; stabilizes the shoulder joint. Origin: Infraspinous fossa Insertion: Greater tubercle of the humerus.
46
Trapezius
Function/Action: Elevates, retracts, rotates, and stabilizes the scapula; extends the neck. Origin: Cervical Vertebrae Insertion: Spine of the scapula
47
Supraspinatus
Function/Action: Abducts the arm; stabilizes the shoulder joint. Origin: Supraspinous fossa of the scapula. Insertion: Greater tubercle of the humerus.
48
Subscapularis
Function/Action: Medially rotates the humerus. Origin: Subscapular fossa of the scapula. Insertion: Lesser tubercle of the humerus.
49
Teres Major
Function/Action: Extends, adducts, and medially rotates the humerus. Origin: Posterior inferior scapula Insertion: Intertubercular sulcus of the humerus.
50
Rhomboid Major
Function/Action: Retracts the scapula Origin: Spinous processes of T2-T5. Insertion: Medial border of the scapula.
51
Latissimus Dorsi
Function/Action: Extends, adducts, and medially rotates the humerus. Origin: Inferior Thoracic vertabrae & Lumbar Vertabrae Insertion: Bicipital groove of the humerus.
52
Deltoid
Function/Action: Abducts, flexes, and extends the arm. Origin: Lateral clavicle, and scapula Insertion: Deltoid tuberosity of the humerus.
53
Triceps Brachii
Function/Action: Extends the forearm; the long head also aids in adducting the shoulder. Origin: Posterior shaft of humerus Insertion: Olecranon process
54
Biceps Brachii
Function/Action: Flexes the forearm and supinates the forearm. Origin: Short head - coracoid process of the scapula; long head - supraglenoid tubercle of the scapula. Insertion: Radial tuberosity
55
Pronator Teres
Function/Action: Pronates the forearm and assists in flexion of the elbow. Origin: Medial epicondyle of the humerus and coronoid process of the ulna. Insertion: Lateral radius
55
Brachialis
Function/Action: Primary flexor of the forearm. Origin: Diaphysis of humerus Insertion: Coronoid process of the ulna.
56
Supinator
Function/Action: Supinates the forearm. Origin: Lateral epicondyle of the humerus and proximal ulna. Insertion: Proximal end of the radius.
57
Brachioradialis
Function/Action: Flexes the forearm, especially in a mid-pronated position. Origin: distal humerus Insertion: Distal radius.
58
Flexor Carpi Radialis
Function/Action: Flexes wrist and hand Origin: Medial epicondyle of the humerus. Insertion: Metacarpals 2 & 3
59
Flexor Carpi Ulnaris
Function/Action: Flexes and ADDUCTS the wrist/hand. Origin: Medial epicondyle of the humerus Insertion: 5th metacarpal
60
Palmaris Longus
Function/Action: Flexes the wrist and tenses the palm. Origin: Medial epicondyle of the humerus. Insertion: Connective tissue in palm of hand
61
Extensor Carpi Radialis Longus
Function/Action: Extends and abducts the wrist/hand. Origin: lateral lower diaphysis of humerus Insertion: Base of the second metacarpal.
61
Flexor Digitorum Superficialis
Function/Action: flexes digits and hand Origin: Medial epicondyle of the humerus Insertion: Middle phalanges of fingers 2-5.
61
Extensor Carpi Ulnaris
Function/Action: Extends and adducts the wrist. Origin: Lateral epicondyle of the humerus Insertion: Base of the fifth metacarpal.
62
Extensor Digitorum
Function/Action: extends digits and hand Origin: Lateral epicondyle of the humerus. Insertion: phalanges 2-5
63
Piriformis
Function/Action: Laterally rotates and abducts the thigh. Origin: Anterior surface of the sacrum. Insertion: Greater trochanter of the femur.
64
Tensor Fascia Lata
Function/Action: Abducts, flexes, and medially rotates the thigh; tenses the iliotibial band, stabilizing the knee. Origin: Iliac crest Insertion: (IT band).
65
Gluteus Maximus
Function/Action: Extends and laterally rotates the thigh; assists in thigh abduction. Origin: Dorsal ilium, sacrum, and coccyx. Insertion: Gluteal tuberosity of the femur and iliotibial tract.
66
Biceps Femoris (Hamstrings)
Function/Action: Extends the thigh, flexes the knee, and laterally rotates the leg when the knee is flexed. Origin: distal half of femur Insertion: Head of the fibula
67
Semitendinosus
Function/Action: Extends the thigh, flexes the knee, and medially rotates the leg when the knee is flexed. Origin: Ischial tuberosity. Insertion: Medial surface of the proximal tibia.
68
Adductor Longus
Function/Action: Adducts, flexes, and medially rotates the thigh. Origin: body of pubis Insertion: Linea aspera of the femur.
68
Semimembranosus
Function/Action: Extends the thigh, flexes the knee, and medially rotates the leg when the knee is flexed. Origin: Ischial tuberosity. Insertion: Medial condyle of the tibia.
68
Pectineus
Function/Action: Adducts and flexes the thigh; assists in medial rotation. Origin: Superior ramus of the pubis. Insertion: posterior femur
69
Gracilis
Function/Action: Adducts the thigh, flexes, and medially rotates the leg. Origin: Inferior ramus and body of the pubis. Insertion: Medial surface of the tibia just below the condyle.
69
Sartorius
Function/Action: Flexes, abducts, and laterally rotates the thigh; flexes the knee. Origin: Anterior superior iliac spine. Insertion: Medial aspect of the proximal tibia.
70
Rectus Femoris
Function/Action: Extends the knee and flexes the thigh at the hip. Origin: Anterior inferior iliac spine and superior margin of the acetabulum. Insertion: Patella and tibial tuberosity via the patellar ligament.
71
Vastus Intermedius
Function/Action: Extends the knee. Origin: Anterior and lateral surfaces of the proximal femur shaft. Insertion: Patella and tibial tuberosity via the patellar ligament.
71
Fibularis Longus (Peroneus Longus)
Function/Action: Everts and plantarflexes the foot. Origin: Head and upper lateral fibula. Insertion: Base of the first metatarsal and medial cuneiform.
71
Vastus Medialis
Function/Action: Extends the knee. Origin: Linea aspera, intertrochanteric line, and medial supracondylar line of the femur. Insertion: Patella and tibial tuberosity via the patellar ligament.
71
Vastus Lateralis
Function/Action: Extends the knee. Origin: Greater trochanter, intertrochanteric line, and linea aspera of the femur. Insertion: Patella and tibial tuberosity via the patellar ligament.
72
Tibialis Anterior
Function/Action: Dorsiflexes and inverts the foot. Origin: Lateral condyle and upper shaft of the tibia. Insertion: First metatarsal and medial cuneiform.
72
Extensor Digitorum Longus
Function/Action: Extends toes 2-5 and dorsiflexes the foot. Origin: Lateral condyle of the tibia Insertion: Phalanges 2-5
73
Gastrocnemius
Function/Action: Plantarflexes the foot and flexes the knee. Origin: Lateral and medial condyles of the femur. Insertion: calcaneous

EVERYTHING ELMHURST (43 decks)

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