Chapter 8 - Muscular System

Question 1

abduction

Answer 1

The movement of a limb away from the midline of the body

Question 2

acetylcholine

Answer 2

an organic chemical that functions in the brain and body of many types of animals as a neurotransmitter—a chemical message released by nerve cells to send signals to other cells

Question 3

actin

Answer 3

a protein that forms (together with myosin) the contractile filaments of muscle cells, and is also involved in motion in other types of cell

Question 4

action potential

Answer 4

the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell

Question 5

adduction

Answer 5

the movement of a body part toward the body’s midline

Question 6

adductor muscle

Answer 6

a muscle whose contraction moves a limb or other part of the body toward the midline of the body or toward another part

Question 7

agonist muscle

Answer 7

Also called prime movers since they produce most of the force, and control of an action. Agonists cause a movement to occur through their own activation.

Question 8

biceps brachii

Answer 8

a large muscle that lies on the front of the upper arm between the shoulder and the elbow

Question 9

biomechanical engineering

Answer 9

the combined use of mechanical engineering principals and biological knowledge to better understand how these areas intersect and how they can be used together to potentially improve peoples’ quality of life

Question 10

carpal tunnel syndrome

Answer 10

A common condition that causes pain, numbness, and tingling in the hand and arm. The condition occurs when one of the major nerves to the hand — the median nerve — is squeezed or compressed as it travels through the wrist.

Question 11

circumduction

Answer 11

movement of a limb or extremity so that the distal end describes a circle while the proximal end remains fixed

Question 12

concentric contraction

Answer 12

A type of muscle activation that causes tension on your muscle as it shortens. As your muscle shortens, it generates enough force to move an object. This is the most popular type of muscle contraction. In weight training, a bicep curl is an easy-to-recognize concentric movement.

Question 13

condyle

Answer 13

the round prominence at the end of a bone, most often part of a joint

Question 14

deltoid

Answer 14

a large triangular muscle that covers the shoulder joint and serves to raise the arm laterally

Question 15

dorsiflexion

Answer 15

flexion in a dorsal direction; especially: flexion of the foot in an upward direction

Question 16

eccentric contraction

Answer 16

the motion of an active muscle while it is lengthening under load

Question 17

electric potential

Answer 17

The energy that is needed to move a charge against an electric field. You need more energy to move a charge further in the electric field, but also more energy to move it through a stronger electric field.

Question 18

ergonomics

Answer 18

the study of people’s efficiency in their working environment

Question 19

eversion

Answer 19

(1) the act of turning inside out : the state of being turned inside out
(2) the condition (as of the foot) of being turned or rotated outward

Question 20

external oblique

Answer 20

a diagonally arranged abdominal muscle on either side of the torso

Question 21

fibularis group

Answer 21

also called peroneus muscles; a group of muscles in the lower leg (shin area); they are: peroneus longus, peroneus brevis, peroneus tertius

Question 22

flexion

Answer 22

the act of bending a limb

Question 23

gastrocnemius

Answer 23

the largest muscle in the back part of the lower leg, the action of which extends the foot, raises the heel, and assists in bending the knee

Question 24

gluteus maximus

Answer 24

A muscle that is located in the buttocks. It is connected to the coccyx, or tailbone, as well as other surrounding bones. The gluteus maximus muscle is responsible for movement of the hip and thigh.

Question 25

hamstring muscles

Answer 25

the group of three muscles that run along the back of your thigh; those three muscles are: semitendinosus semimembranosus biceps femoris

Question 26

iliopsoas

Answer 26

a muscle consisting of the iliacus and psoas major muscles

Question 27

"in concert"

Answer 27

acting jointly

Question 28

innervate

Answer 28

(transitive verb) to supply with nerves

Question 29

intercalated disk

Answer 29

Unique structural formations found between the myocardial cells of the heart. They play vital roles in bonding cardiac muscle cells together and in transmitting signals between cells.

Question 30

intercostal muscle

Answer 30

The muscles between your ribs. They allow your ribcage to expand and contract so you can breathe.

Question 31

internal oblique

Answer 31

an abdominal muscle located beneath the external abdominal oblique

Question 32

isometric contraction

Answer 32

A muscle contraction without motion. Isometric contractions are used to stabilize a joint, such as when a weight is held at waist level neither raising nor lowering it.

Question 33

isotonic contraction

Answer 33

a muscle contraction that occurs when the force or tension in the muscle remains constant while the length of the muscle changes; there are two types: eccentric contraction and concentric contraction

Question 34

latissimus dorsi

Answer 34

a broad flat superficial muscle chiefly of the middle and lower back that extends, adducts, and rotates the arm medially and draws the shoulder downward and backward

Question 35

masseter

Answer 35

a large muscle that raises the lower jaw and assists in mastication

Question 36

mastication

Answer 36

(1) to grind or crush (food) with or as if with the teeth | (2) to soften or reduce to pulp by crushing or kneading

Question 37

mastoid process

Answer 37

A conical protuberance of the posterior portion of the temporal bone that is situated behind the ear and serves as a site of muscle attachment

Question 38

motor neuron

Answer 38

a neuron that passes from the central nervous system or a ganglion toward a muscle and conducts an impulse that causes movement

Question 39

muscle strength

Answer 39

the muscle’s ability to contract and create force in response to resistance

Question 40

muscle tone

Answer 40

the tension in a muscle at rest

Question 41

myoglobin

Answer 41

an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost all mammals

Question 42

myosin

Answer 42

a fibrous protein that forms (together with actin) the contractile filaments of muscle cells and is also involved in motion in other types of cells

Question 43

neuromuscular junction (NMJ)

Answer 43

a highly specialized synapse between a motor neuron nerve terminal and its muscle fiber that are responsible for converting electrical impulses generated by the motor neuron into electrical activity in the muscle fibers

Question 44

occipital bone

Answer 44

the bone that forms the back and base of the skull, and through which the spinal cord passes

Question 45

orbicularis oris

Answer 45

a complex of muscles in the lips that encircles the mouth

Question 46

oxygen debt

Answer 46

the body's oxygen deficiency resulting from strenuous physical activity.

Question 47

pectoralis major

Answer 47

any of the muscles that connect the front walls of the chest with the bones of the upper arm and shoulder

Question 48

plantar flexion

Answer 48

a movement in which the top of your foot points away from your leg; you use plantar flexion whenever you stand on the tip of your toes or point your toes.

Question 49

pronation

Answer 49

(1) rotation of the hand and forearm so that the palm faces backwards or downwards (2) rotation of the medial bones in the midtarsal region of the foot inward and downward so that in walking the foot tends to come down on its inner margin

Question 50

psoas major

Answer 50

a muscle that originates at the spine around the bottom of the rib cage and runs down to the thigh bone (the femur)

Question 51

quadriceps femoris

Answer 51

``` A large muscle group that includes the four prevailing muscles on the front of the thigh. It is the great extensor muscle of the knee, forming a large fleshy mass which covers the front and sides of the femur. The four muscles it is made up of are: rectus femoris vastus lateralis vastus medialis vastus intermedius ```

Question 52

rectus abdominis

Answer 52

also known as the "abdominal muscle", is a paired muscle running vertically on each side of the anterior wall of the human abdomen, as well as that of some other mammals; it is between the obliques

Question 53

sphincter

Answer 53

a circular muscle that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning; sphincters relax at death, often releasing fluids and feces

Question 54

sternocleidomastoid

Answer 54

a thick superficial muscle on each side of the neck that arises by one head from the first segment of the sternum and by a second from the inner part of the clavicle, that inserts into the mastoid process and occipital bone, and that acts especially to bend, rotate, flex, and extend the head

Question 55

supination

Answer 55

(1) rotation of the forearm and hand so that the palm faces forward or upward (2) a corresponding movement of the foot and leg in which the foot rolls outward with an elevated arch

Question 56

synergist muscles

Answer 56

muscles that act around a moveable joint to produce motion similar to or in concert with agonist muscles. They often act to reduce excessive force generated by the agonist muscle and are referred to as neutralizers

Question 57

temporal bone

Answer 57

two major bones in the skull, or cranium. They help form the sides and base of the skull, where they protect the temporal lobe of the brain and surround the ear canal

Question 58

tenosynovitis

Answer 58

inflammation of the lining of the sheath that surrounds a tendon (the cord that joins muscle to bone)

Question 59

tetanic contraction

Answer 59

a sustained muscle contraction evoked when the motor nerve that innervates a skeletal muscle emits action potentials at a very high rate

Question 60

threshold stimulus

Answer 60

the lowest point at which a particular stimulus will cause a response in an organism

Question 61

tibialis anterior

Answer 61

a muscle arising chiefly from the lateral condyle of the tibia and part of the shaft of the tibia; it is on the lower part of the leg

Question 62

tonic contraction

Answer 62

the sustained contraction of different groups of fibers within a muscle to maintain continual muscular tension

Question 63

transversus abdominis

Answer 63

one of the flat muscles that form the anterior abdominal wall; it is deep to (layered below) the internal oblique muscle

Question 64

trapezius

Answer 64

either of a pair of large triangular muscles extending over the back of the neck and shoulders and moving the head and shoulder blade

Question 65

triceps brachii

Answer 65

the large muscle at the back of the upper arm; it consists of 3 parts: the medial head, lateral head, and long head

Question 66

zygomatic bone

Answer 66

also called cheekbone, or malar bone, diamond-shaped bone below and lateral to the orbit, or eye socket, at the widest part of the cheek

Question 67

zygomaticus

Answer 67

a slender band of muscle on each side of the face that arises from the zygomatic bone, inserts into the orbicularis oris and skin at the corner of the mouth, and acts to pull the corner of the mouth upward and backward when smiling or laughing

Question 68

origin (anatomy)

Answer 68

the place where a muscle attaches to a more stationary part of the bone

Question 69

insertion (anatomy)

Answer 69

the place where a muscle attaches to the more movable part of the bone

Question 70

sliding filament model

Answer 70

An explanation of how a skeletal muscle contracts. According to this model, during contraction, the thick and thin myofilaments in a muscle fiber first attach to one another by forming crossbridges that then act as levers to ratchet or pull the myofilaments past each other.

Question 71

myofilaments

Answer 71

The two protein filaments of myofibrils in muscle cells. The two proteins are myosin and actin and are the contractile proteins involved in muscle contraction. The two filaments are a thick one composed mostly of myosin, and a thin one composed mostly of actin.

Question 72

crossbridge

Answer 72

the globular head of a myosin molecule that projects from a myosin filament in muscle and in the sliding filament hypothesis of muscle contraction is held to attach temporarily to an adjacent actin filament and draw it into the A band of a sarcomere between the myosin filaments

Question 73

myofibril

Answer 73

any of the longitudinal parallel contractile elements of a muscle cell that are composed of myosin and actin

Question 74

ratchet (verb)

Answer 74

to cause to move by steps or degrees —usually used with up or down

Question 75

posture

Answer 75

the position of a body while standing or sitting

Question 76

antagonist muscles

Answer 76

muscles that produce a movement opposite to that of the prime movers (agonist muscles) and their synergist muscles

Question 77

three basic skeletal muscle fiber types

Answer 77

slow, fast, and intermediate fibers

Question 78

slow fibers

Answer 78

Slow fibers are also called “red fibers” because they have a high content of oxygen-storing myoglobin (a red pigment similar to hemoglobin). Slow fibers are best suited to endurance activities such as long-distance running because they do not fatigue easily. Muscles that maintain body position—posture—have a proportion of slow fibers.

Question 79

fast fibers

Answer 79

Fast fibers are also called “white fibers” because they have a low red myoglobin content. Fast fibers are best suited for quick, powerful contractions because even though they fatigue quickly, they can produce a great amount of ATP very quickly. Fast fibers are well suited to sprinting and weight-lifting events. Muscles that move the fingers have a high proportion of fast fibers—a big help when playing computer games or musical instruments.

Question 80

intermediate fibers

Answer 80

Intermediate fibers have characteristics between the extremes of slow and fast fibers. This muscle type is found in muscles such as the calf muscle (gastrocnemius), which is used both for posture and occasional brief, powerful contractions such as jumping.

Question 81

excess post-exercise oxygen consumption (EPOC)

Answer 81

informally called afterburn; a measurably increased rate of oxygen intake following strenuous activity

Question 82

twitch

Answer 82

A quick, jerky response to a stimulus. Twitch contractions can be seen in isolated muscles during research, but they play a minimal role in normal muscle activity

Question 83

extension (anatomy)

Answer 83

the act of stretching out a limb

Question 84

rotation (anatomy)

Answer 84

movement around a longitudinal axis, as in rotating the neck

Question 85

inversion (anatomy)

Answer 85

the condition (as of the foot) of being turned or rotated inward