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chapter 6 muscles
Question | Answer |
---|---|
contractility | the ability of skeletal muscle to shorten with force |
elasticity | ability to recoil to their original resting length after they have been stretched |
extensibility | the ability to be stretched |
excitability | the capacity of skeletal muscle to respond to a stimulus |
What does an I band consist of? | actin |
tetany | where the muscle remains contracted without relaxing |
Where is ATP produced? | mitochondria |
Fast-twitch fibers... | contract quickly and fatigue quickly |
Slow-twitch fibers... | contract more slowly and are more resistant to fatigue |
Muscles that work together to accomplish specific movements are called... | synergists |
Muscles that work in opposition to one another are called... | antagonists |
Flexor carpi | flexes the wrist |
Extensor carpi | extends the wrist |
Flexor digitorum | flexes the fingers |
Extensor digitorum | extends the fingers |
Triceps brachii | extends the forearm; occupies the posterior component of the arm |
Biceps brachii | flexes the forearm; occupies the anterior component of the arm |
Brachialis | flexes forearm |
Brachioradialis | flexes and supinates the forearm |
Trapezius | rotates scapula |
Serratus anterior | pulls scapula anteriorly |
Pectoralis major | adducts and flexes the arm |
Lastissimus dorsi | medially rotates, adducts, and powerfully extends the arm. "swimmer muscles" |
Deltoid | attaches the humerus to the scapula and clavicle, and is the major abductor of the upper limb |
Occipitofrontalis | raises the eyebrows |
Orbicularis oculi | closes the eyelids and causes "crows feet" wrinkles in the skin at the lateral corners of the eye |
Orbicularis oris | puckers the lips |
Buccinator | flattens the cheeks; trumpeter's muscles |
Zygomaticus | smiling muscle |
Levator labii superioris | sneering |
Depressor anguli oris | frowning |
Mastication | chewing |
Each skeletal muscle is surrounded by a connective tissue sheath called the... | epimysium |
What is another connective tissue located outside the epimysium that surrounds and separates muscles? | fascia |
A muscle is composed of numerous visible bundles called what? | muscle fasciculi (fascicle) |
Muscle fasciculi are surrounded by loose connective tissue called the what ? | perimysium |
The fasciculi are composed of single muscle cells called what? | Muscle fibers |
Each fiber is surrounded by a connective tissue sheath called the what? | endomysium |
The cytoplasm of each muscle fiber is filled with what? | myofibrils |
What are myofibrils? | a threadlike structure that extends from one end of the fiber to the other |
2 major kinds of protein fibers | actin and myosin |
gluteus maximus | buttocks |
quadriceps femoris | extends the leg; anterior thigh muscles |
sartorius | "tailors muscle"; flexes the thigh |
hamstring muscles | posterior thigh muscles; flexes the leg and extends the thigh |
intrinsic foot muscles | 20 muscles that flex, extend, abduct, and adduct the toes |
peroneus | lateral muscles of the leg; everters of the foot and aid in plantar flexion |
gastrocnemius and soleus | form the calf muscle; form the calcaneal tendon, flex the foot and toes |
retinaculum | strong band of fibrous connective tissue that covers the flexor and extensor tendons and holds them in place around the wrist so that they do not “bowstring” during muscle contraction |
intrinsic hand muscles | 19 hand muscles |
interossi muscles | located between the metacarpals, are responsible for the abduction and adduction of the fingers |
gluteus medius | hip muscle and common injection site |
diaphragm | accomplishes quiet breathing, dome-shaped muscle |
erector spinae | group of muscles on each side of the back, responsible for keeping the back straight and the body erect |
sternocleidomastoid | lateral neck muscle and prime mover, rotates and abducts the head |
thoracic muscles | muscles that move the thorax |
external intercostals | elevate the ribs during inspiration |
internal intercostals | contract during forced expiration |
linea alba | a vertical linear indentation is visible, extending from the sternum, through the navel to the pubis; consists of white connective tissue rather than muscle |
rectus abdominis | muscles on each side of the linea alba |
tendinous inscriptions | cross the rectus abdominis at three or more locations, causing the abdominal wall of a well-muscled person to appear segmented |
The time of contraction is the... | contraction phase |
The time during which the muscle relaxes is the... | relaxation phase |
The increase in number of motor units being activated is called... | recruitment |
Anaerobic respiration | without oxygen |
Aerobic respiration | with oxygen |
Origin | the most stationary end of the muscle |
The portion of the muscle between the origin and the insertion is... | belly |
Among a group of synergists, if one muscle plays the major role in accomplishing the desired movement, it is the... | prime mover |
The end of the muscle undergoing the greatest muscle is... | insertion |
isometric | the length of the muscle does not change, but the amount of tension increases during the contraction process |
isotonic | the amount of tension produced by the muscle is constant during contraction, but the length of the muscle changes |
oxygen debt | the amount of oxygen needed in chemical reactions to convert lactic acid to glucose and to replenish the depleted stores of creatine phosphate stores in muscle cells |
The time between application of a stimulus to a motor neuron and the beginning of a contraction is the... | lag phase |
A muscle fiber will not respond to stimulus until that stimulus reaches a level called... | threshold |
The sliding of actin myofilaments past myosin myofilaments during contraction is called the... | sliding filament mechanism |