Chapter 6: The Muscular System Flashcards


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1

Muscle Fibers

Skeletal & smooth muscle cells are elongated, not cardiac muscle cells.

2

Skeletal Muscle Fibers

Packaged into the organs & attach to the body's skeleton.

3

Striated Muscle

Also skeletal muscle, its fibers have obvious stripes.

4

Voluntary Muscle

The only muscle type subject to conscious control.

5

Endomysium

A delicate connective tissue sheath

6

Perimysium

A coarser fibrous membrane.

7

Epimysium

A tougher "overcoat" of connective tissue fibers.

8

Tendons

Cord of dense fibrous tissues attaching muscle to bone.

9

Aponeuroses

Attach muscles indirectly to bone, cartilages, or connective tissue coverings.

10

Smooth Muscle

Has no striations & is involuntary, cannot consciously be controlled. Found mainly within the walls of the stomach, urinary bladder & respiratory passages.

11

Cardiac Muscle

Found in ONLY one place within the body, in the heart.

12

Sarcolemma

Plasma membrane in muscle cells

13

Myofibrils

Long ribbon like organelles.

14

Myofilaments

Filaments composing the myofibrils. 2 types: Myosin & Actin

15

Thin Filaments

Composed of contractile protein called actin.

16

Sarcoplasmic Reticulum (SR)

A specialized smooth ER.

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Motor Unit

1 neuron & all the skeletal muscle cells it stimulates.

18

Axon

A long threadlike extension of neurons, AKA nerve fibers

19

Action Potential

When an "upset" generates an electrical current.

20

Neuromuscular Junctions

Contain vesicles filled with a chemical called neurotransmitter

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Neurotransmitter

Chemical released by neurons that may stimulate or inhibit them.

22

Graded response

A response that varies directly with the strength of the stimulus.

-Produced 2 ways:

  • by changing the frequency of muscle stimulation
  • by changing the # of muscle cells being stimulated at 1 time
23

Muscle Twitch

Single, brief, jerky contraction; sometimes result from certain nervous system problems, NOT the way muscles normally operate.

24

Fused

When the muscle is stimulated so rapidly that no evidence of relaxation is seen & the contractions are completely smooth & sustained.

25

Lactic Acid

The product of anaerobic metabolism, especially in muscle.

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Muscle Fatigue

When we exercise our muscles strenuously for a long time, when a muscle is no longer able to contract.

27

Oxygen Deficit

Occurs when a person is not able to take in oxygen fast enough to keep the muscles supplied with all the oxygen needed when working vigorously.

28

Isotonic Contractions

Myofilaments are successful in their sliding movements, the muscle shortens, movement occurs.

Ex: bending the knee, rotating the arms & smiling.

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Isometric Contractions

Contractions in which the muscles do not shorten

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Muscle Tone

Sustained partial contraction of a muscle in response to stretch receptor inputs; keeps the muscle healthy and ready to react.

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Origin

Is attached to the immovable or less moveable bone.

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Insertion

Is attached to the moveable bone & when the muscle contracts it moves toward the origin.

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Flexion

Movement, generally in the sagittal plane, that decrease the angle of the joint & brings 2 bones closer together.

Ex: bending the knee or elbow, or bending forward at the hip.

34

Extension

Opposite of flexion; movement that increases the angle or distance between 2 bones or parts of the body.

Ex: straightening the knee or elbow.

35

Rotation

Movement of a bone around its longitudinal axis.

Ex: shaking your head "no"

36

Abduction

Moving a limb away (generally on the frontal plane) from the midline or median plane of the body.

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Adduction

Opposite of abduction: moving the limb toward the body midline.

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Circumduction

Combination of flexion, extension. abduction and adduction commonly seen in ball-and-socket joints such as the shoulder.

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Dorsiflexion

Lifting the foot so the it superior surface approaches the shin.

Ex: Standing on you heels.

40

Plantar Flexion

Depressing the foot.

Ex: pointing the toes.

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Inversion

Turn the sole medially.

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Eversion

Turn the sole laterally.

43

Supination

Occurs when the forearm rotates laterally so that the palm faces anteriorly & the radius & ulna are parallel, "turning backward"

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Pronation

Occurs when the forearm rotates medially so that the palm faces posteriorly, bring the radius across the ulna forming a X. "turning forward"

45

Opposition

Action which you move your thumb to touch the tips of the other fingers on the same hand.

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Prime Mover

Muscle that has the major responsibility for causing a particular movement.

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Antagonists

Muscles that oppose or reverse a movement.

48

Synergists

Help prime movers by producing the same movement or by reducing undesirable movements.

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Fixators

Specialized synergists, had a bone still or stabilize the origin of a prime mover so all the tension can be used to mover the insertion bone.

50

Direction of Muscle Fibers

rectus (straight), its fibers run parallel to that imaginary line; oblique (at a slant), muscle fibers run at a slant to the imaginary line.

51

Relative Size if the Muscle

Maximus (largest), Minimis ( smallest), and longus (long).

Ex: gluteus Maximus (largest muscle of the gluteus group).

52

Location of the Muscles

Named for bone which they are associated.

Ex: temporalis & Frontalis muscles overlie the temporal & frontal bones of the skull.

53

Number of Origin

When the pre-fix bi- (2), tri- (3), & quad- (4) form part of a muscle name you can assume that muscle has 2,3,4 origins

Ex: Bicep has 2 heads or origin.

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Location of Muscle's Origin & Insertion

Muscles are named for their attachment site.

Ex: Sternum (sterno) and Clavicle (cleido) & inserts on the mastoid process of the temporal bone.

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Shape of the muscle

Muscles have a distinctive shape that helps identify them.

Ex: Deltoid is triangular (deltoid means triangular)

56

Action of the Muscle

When muscles are named for their action, the terms flexor, extensor, and adductor appear.

57

Circular

when fascicles are arranged in rings.

Ex: the orbicularis muscles surrounding the eyes and mouth.

58

Convergent

Fascicles converge toward a single insertion.

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Parallel

Length of fascicles run parallel to the long axis of the muscle.

60

Fusiform

(modification of parallel) Result in spindle-shaped muscle with an expanded belly (midsection)

61

Frontails

Covers the frontal bone, runs from the cranial aponeurosis to the skin of the eyebrows, when it inserts. Allows you to raise your eyebrow & wrinkle your forehead.

62

Occipitails

Covers the posterior aspect if the skull and pulls the scalp posteriorly.

63

Orbicularis Oculi

Has fibers that run in circles around the eyes. Allows you to close you eyes, blink, squint, & wink.

64

Orbicularis Oris

Is the circular muscle of the lips "kissing muscle"

65

Buccinator

Muscle runs horizontally across the cheek and inserts into the Orbicularis Oris. Also a chewing muscle because It compresses the cheek to hold food between the teeth while chewing.

66

Zygomaticus

Extends form the corner of the mouth to the cheekbone, "smiling muscle"

67

Masseter

Covers the angle if the lower jaw. Closes the jaw by elevating the mandible.

68

Temporalis

Fan-shaped muscle overlying the temporal bone, inserts into the mandible and acts as a synergist of the masseter in closing the jaw.

69

Platysma

A single sheet like muscle that covers the anterolateral neck.

70

Sternocleidomastoid

Muscles are 2-headed, one found on each side of the neck. Heads fuse before inserting into the mastoid process of the temporal bone. "Prayer Muscles"

71

Pectoralis Major

Is a large fan-shaped muscle covering the upper part of the chest.

72

Intercostal Muscles

Deep muscles found between the ribs

73

Rectus Abdominis

Run from the pubis to the rib cage, enclosed in an aponeurosis, main function is to flex the vertebral column.

74

External Oblique

Are paired superficial muscles that make up the lateral wall if the abdomen, their fibers run downward & medially from the last 8 ribs & insert into the ilium

75

Internal Oblique

Paired muscles deep to the external oblique, fibers run at right angles to those of external obliques.

76

Tranversus abdominis

The deepest muscle of the abdominal wall & has fibers that run horizontally across the abdomen.

77

Trapezius

The most superficial muscles of the posterior neck & upper trunk, form a diamond or kite-shaped muscle mass.

78

Latissimus Dorsi

Muscles are 2 large flat muscles that cover the lower back.

79

Erector Spinae

Group is the prime mover of back extension, these paired muscles are deep muscles of the back.

80

Quadratus Lumborm

Muscles form part of the posterior abdominal wall, acting separately each muscle of the pair flexes the spine laterally.

81

Deltoid

Are fleshy, triangle-shaped muscles that form the rounded shape of your shoulders

82

Biceps Brachii

Muscle of the arm that bulges when the elbow is flexed

83

Brachialis

Lies deep to the bicep muscle & is as important as the biceps in elbow flexion.

84

Brachioradialis

A fairly week muscle that arises on the humerus & inserts into the distal forearm.

85

Triceps Brachii

The ONLY muscle fleshing out the posterior humerus.

86

Gluteus Maximus

Is a superficial muscle of the hip that forms most of the flesh of the buttock. Most important muscle when extending the hip when power is needed.

87

Gluteus Medius

Runs from the ilium to the femur, beneath the gluteus maximus for most of its length.

88

Iliopsoas

is a fused muscle composed of muscles, the iliacus and the psoas major.

89

Adductor Muscles

From the muscle mass at the medial side of each thigh

90

Hamstring group

The muscles forming the muscle mass of the posterior thigh.

  • Biceps femoris
  • semimembranosus
  • semitendinosus
91

Sartorius

Thin, strap like muscle is not too important, but it is the most superficial muscle of the thigh and is rather hard to miss.

92

Quadriceps Group

Consists of 4 muscles that flesh out the anterior thigh.

  • The rectus femoris
  • 3 Vastus Muscles
93

Tibialis Anterior

Is a superficial muscle on the anterior leg, arises from the upper tibia & then parallels the anterior crest as it runs to the tarsal bones, where it inserts by a long tendon.

94

Extensor Digitorum Longus

Lateral to the tibialis anterior, arises from the lateral tibial condyle &proximal 3/4 of the fibula & inserts into phalanges of toes 2-5.

95

Fibularis Muscles

3 muscles are found on the lateral part of the leg- longus, brevis, & tertius, arise from the fibula & insert into the metatarsal bones.

96

Gastrocnemius muscle

is 2-bellied muscle that forms the curved calf of the posterior leg, arises by 2 heads, 1 from each side of the distal femur, & inserts through the large calcaneal (Achilles) tendon into the heel.

97

Soleus

Deep to the gastrocnemius muscle, arises on the tibia & fibula (rather than the femus) it DOES NOT affect the knee movement and inserts into the calcaneal tendon & is strong plantar flexor of the foot.