Muscular System

Question 0

Tendon

Answer 0

The end of the muscle that attaches to the bone periosteum.

Question 1

Epimysium

Answer 1

Fibrous connective tissue

Question 2

Bone periosteum

Answer 2

A specialized connective tissue covering all bones.

Question 3

Proximal

Answer 3

Closer to trunk

Question 4

Distal

Answer 4

Farther from the trunk

Question 5

Superior

Answer 5

Closer to head

Question 6

Inferior

Answer 6

Closer to feet

Question 7

Origin of the muscle

Answer 7

Defined as it’s proximal attachment

Question 8

Insertion of the muscle

Answer 8

Defined as it’s distal attachment

Question 9

Muscle fibers

Answer 9

Long cylindrical cells 50 to 100 µm in diameter. These fibers have many nuclei situated on the periphery of the cell and have a striated appearance under low magnification

Question 10

Fasciculi

Answer 10

Bundles of muscle fibers under the epimysium

Question 11

Perimysium

Answer 11

The connective tissue that surrounds the fasciculi

Question 12

Endomysium

Answer 12

Connective tissue that surrounds the individual muscle fiber

Question 13

Sarcolemma

Answer 13

The membrane that encircles and is continuous within the muscle fiber

Question 14

Motor neuron

Answer 14

Nerve cell

Question 15

Neuromuscular junction

Answer 15

Where the motor neuron and the muscle fiber it innervates connect

Question 16

Motor unit

Answer 16

A motor neuron and the muscle fibers it innervates

Question 17

Sarcoplasm

Answer 17

The cytoplasm of muscle fiber- contains contractile components

Question 18

Myofibrils

Answer 18

Contain the apparatus that contract the muscles, which consist primarily of two types of myofilament: myosin and actin.

Question 19

Myofilament

Answer 19

Ultra microscopic threadlike structures composed of Myofibrils of striated muscle fiber. Thick, myosin. Thin, actin.

Question 20

Myosin

Answer 20

Thick filaments that contain up to 200 myosin molecules. Globular heads called cross-bridges protrude away from the filament at regular intervals

Question 21

Actin

Answer 21

Thin filaments that consist of two strands arranged in a double helix

Question 22

Sarcomere

Answer 22

The small contractile unit of the skeletal muscle that contains the actin and myosin

Question 23

Z-line

Answer 23

The middle of the I-band and appears as a thin dark line running longitudinally through the I-band

Question 24

A-band

Answer 24

Corresponds with the alignment of myosin filaments

Question 25

I-band

Answer 25

Corresponds with areas in the two adjacent sarcomeres that contain only actin filaments

Question 26

H-zone

Answer 26

The area in the center of the sarcomere where only myosin filaments are present

Question 27

Sarcoplasmic reticulum

Answer 27

And intricate system of tubules that run parallel to and surround each myofibril. They terminate at vesicles in the vicinity of the Z-lines.

Question 28

Vesicles

Answer 28

Storage for calcium in the muscles

Question 29

T-tubules

Answer 29

Aka transverse tubules, run perpendicular to the sarcoplasmic reticulum and terminate in the vicinity of the Z-line between two vesicles.

Question 30

Triad

Answer 30

The pattern of a t-tubule spaced between and perpendicular to two sarcoplasmic reticular vesicles.

Question 31

Action potential

Answer 31

The electrical nerve impulse

Question 32

Sliding-filament theory

Answer 32

The actin filaments at each end of the sarcomere slide inward on the myosin filaments, pulling the z-lines toward the center of the sarcomere and thus shortening the muscle fiber.

Question 33

Troponin

Answer 33

A protein that is situated at regular intervals along actin filaments and has a high affinity for calcium ions

Question 34

Tropomyosin

Answer 34

A protein molecule that runs on the length of the actin filament in the groove of the double helix