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reposition : movement of the thumb from opposition back to the anatomical position (next to index finger)
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
retraction : posterior motion of the scapula or mandible
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
rotation : movement of a bone around a central axis (atlantoaxial joint) or around its long axis (proximal radioulnar joint; shoulder or hip joint); twisting of the vertebral column resulting from the summation of small motions between adjacent vertebrae
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
rotator cuff : strong connective tissue structure formed by the fusion of four rotator cuff muscle tendons to the articular capsule of the shoulder joint; surrounds and supports superior, anterior, lateral, and posterior sides of the humeral head
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
saddle joint : synovial joint in which the articulating ends of both bones are convex and concave in shape, such as at the first carpometacarpal joint at the base of the thumb; functionally classified as a biaxial joint
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
subacromial bursa : bursa that protects the supraspinatus muscle tendon and superior end of the humerus from rubbing against the acromion of the scapula
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
subcutaneous bursa : bursa that prevents friction between skin and an underlying bone
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
submuscular bursa : bursa that prevents friction between bone and a muscle or between adjacent muscles
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
subscapular bursa : bursa that prevents rubbing of the subscapularis muscle tendon against the scapula
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
subtalar joint : articulation between the talus and calcaneus bones of the foot; allows motions that contribute to inversion/eversion of the foot
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
subtendinous bursa : bursa that prevents friction between bone and a muscle tendon
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
superior rotation : movement of the scapula during upper limb abduction in which the glenoid cavity of the scapula moves in an upward direction as the medial end of the scapular spine moves in a downward direction
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
supinated position : forearm position in which the palm faces anteriorly (anatomical position)
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
supination : forearm motion that moves the palm of the hand from the palm backward to the palm forward position
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
suture : fibrous joint that connects the bones of the skull (except the mandible); an immobile joint (synarthrosis)
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
symphysis : type of cartilaginous joint where the bones are joined by fibrocartilage
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
synarthrosis : immobile or nearly immobile joint
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
synchondrosis : type of cartilaginous joint where the bones are joined by hyaline cartilage
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
syndesmosis : type of fibrous joint in which two separated, parallel bones are connected by an interosseous membrane
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
synostosis : site at which adjacent bones or bony components have fused together
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
synovial fluid : thick, lubricating fluid that fills the interior of a synovial joint
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
synovial joint : joint at which the articulating surfaces of the bones are located within a joint cavity formed by an articular capsule
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
synovial membrane : thin layer that lines the inner surface of the joint cavity at a synovial joint; produces the synovial fluid
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
talocrural joint : ankle joint; articulation between the talus bone of the foot and medial malleolus of the tibia, distal tibia, and lateral malleolus of the fibula; a uniaxial hinge joint that allows only for dorsiflexion and plantar flexion of the foot
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
temporomandibular joint (TMJ) : articulation between the condyle of the mandible and the mandibular fossa and articular tubercle of the temporal bone of the skull; allows for depression/elevation (opening/closing of mouth), protraction/retraction, and side-to-side motions of the mandible
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
tendon : dense connective tissue structure that anchors a muscle to bone
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
tendon sheath : connective tissue that surrounds a tendon at places where the tendon crosses a joint; contains a lubricating fluid to prevent friction and allow smooth movements of the tendon
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
tibial collateral ligament : extrinsic ligament of knee joint that spans from the medial epicondyle of the femur to the medial tibia; resists hyperextension and rotation of extended knee
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
ulnar collateral ligament : intrinsic ligament on the medial side of the elbow joint; spans from the medial epicondyle of the humerus to the medial ulna
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
uniaxial joint : type of diarthrosis; joint that allows for motion within only one plane (one axis)
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
zygapophysial joints : facet joints; plane joints between the superior and inferior articular processes of adjacent vertebrae that provide for only limited motions between the vertebrae
https://openstax.org/books/anatomy-and-physiology-2e/pages/9-key-terms
Muscle is the tissue in animals that allows for active movement of the body or materials within the body. There are three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle. Most of the body’s skeletal muscle produces movement by acting on the skeleton. Cardiac muscle is found in the wall of t...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
Smooth muscle is found in the skin, where it is associated with hair follicles; it also is found in the walls of internal organs, blood vessels, and internal passageways, where it assists in moving materials.
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
Skeletal muscles contain connective tissue, blood vessels, and nerves. There are three layers of connective tissue: epimysium, perimysium, and endomysium. Skeletal muscle fibers are organized into groups called fascicles. Blood vessels and nerves enter the connective tissue and branch in the cell. Muscles attach to bon...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
Skeletal muscle fibers are long, multinucleated cells. The membrane of the cell is the sarcolemma; the cytoplasm of the cell is the sarcoplasm. The sarcoplasmic reticulum (SR) is a form of endoplasmic reticulum. Muscle fibers are composed of myofibrils. The striations are created by the organization of actin and myosin...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
A sarcomere is the smallest contractile portion of a muscle. Myofibrils are composed of thick and thin filaments. Thick filaments are composed of the protein myosin; thin filaments are composed of the protein actin. Troponin and tropomyosin are regulatory proteins.
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
Muscle contraction is described by the sliding filament model of contraction. ACh is the neurotransmitter that binds at the neuromuscular junction (NMJ) to trigger depolarization, and an action potential travels along the sarcolemma to trigger calcium release from SR. The actin sites are exposed after Ca++enters the sa...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
The number of cross-bridges formed between actin and myosin determines the amount of tension produced by a muscle. The length of a sarcomere is optimal when the zone of overlap between thin and thick filaments is greatest. Muscles that are stretched or compressed too greatly do not produce maximal amounts of power. A m...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
ATP provides the energy for muscle contraction. The three mechanisms for ATP regeneration are creatine phosphate, anaerobic glycolysis, and aerobic metabolism. Creatine phosphate provides about the first 15 seconds of ATP at the beginning of muscle contraction. Anaerobic glycolysis produces small amounts of ATP in the ...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
Hypertrophy is an increase in muscle mass due to the addition of structural proteins. The opposite of hypertrophy is atrophy, the loss of muscle mass due to the breakdown of structural proteins. Endurance exercise causes an increase in cellular mitochondria, myoglobin, and capillary networks in SO fibers. Endurance ath...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
Cardiac muscle is striated muscle that is present only in the heart. Cardiac muscle fibers have a single nucleus, are branched, and joined to one another by intercalated discs that contain gap junctions for depolarization between cells and desmosomes to hold the fibers together when the heart contracts. Contraction in ...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
Smooth muscle is found throughout the body around various organs and tracts. Smooth muscle cells have a single nucleus, and are spindle-shaped. Smooth muscle cells can undergo hyperplasia, mitotically dividing to produce new cells. The smooth cells are nonstriated, but their sarcoplasm is filled with actin and myosin, ...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
Muscle tissue arises from embryonic mesoderm. Somites give rise to myoblasts and fuse to form a myotube. The nucleus of each contributing myoblast remains intact in the mature skeletal muscle cell, resulting in a mature, multinucleate cell. Satellite cells help to repair skeletal muscle cells. Smooth muscle tissue can ...
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-chapter-review
acetylcholine (ACh) : neurotransmitter that binds at a motor end-plate to trigger depolarization
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
actin : protein that makes up most of the thin myofilaments in a sarcomere muscle fiber
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
action potential : change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
aerobic respiration : production of ATP in the presence of oxygen
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
angiogenesis : formation of blood capillary networks
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
aponeurosis : broad, tendon-like sheet of connective tissue that attaches a skeletal muscle to another skeletal muscle or to a bone
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
ATPase : enzyme that hydrolyzes ATP to ADP
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
atrophy : loss of structural proteins from muscle fibers
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
autorhythmicity : heart’s ability to control its own contractions
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
calmodulin : regulatory protein that facilitates contraction in smooth muscles
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
cardiac muscle : striated muscle found in the heart; joined to one another at intercalated discs and under the regulation of pacemaker cells, which contract as one unit to pump blood through the circulatory system. Cardiac muscle is under involuntary control.
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
concentric contraction : muscle contraction that shortens the muscle to move a load
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
contractility : ability to shorten (contract) forcibly
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
contraction phase : twitch contraction phase when tension increases
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
creatine phosphate : phosphagen used to store energy from ATP and transfer it to muscle
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
dense body : sarcoplasmic structure that attaches to the sarcolemma and shortens the muscle as thin filaments slide past thick filaments
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
depolarize : to reduce the voltage difference between the inside and outside of a cell’s plasma membrane (the sarcolemma for a muscle fiber), making the inside less negative than at rest
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
desmosome : cell structure that anchors the ends of cardiac muscle fibers to allow contraction to occur
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
eccentric contraction : muscle contraction that lengthens the muscle as the tension is diminished
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
elasticity : ability to stretch and rebound
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
endomysium : loose, and well-hydrated connective tissue covering each muscle fiber in a skeletal muscle
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
epimysium : outer layer of connective tissue around a skeletal muscle
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
excitability : ability to undergo neural stimulation
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
excitation-contraction coupling : sequence of events from motor neuron signaling to a skeletal muscle fiber to contraction of the fiber’s sarcomeres
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
extensibility : ability to lengthen (extend)
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
fascicle : bundle of muscle fibers within a skeletal muscle
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
fast glycolytic (FG) : muscle fiber that primarily uses anaerobic glycolysis
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
fast oxidative (FO) : intermediate muscle fiber that is between slow oxidative and fast glycolytic fibers
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
fibrosis : replacement of muscle fibers by scar tissue
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
glycolysis : anaerobic breakdown of glucose to ATP
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
graded muscle response : modification of contraction strength
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
hyperplasia : process in which one cell splits to produce new cells
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
hypertonia : abnormally high muscle tone
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
hypertrophy : addition of structural proteins to muscle fibers
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
hypotonia : abnormally low muscle tone caused by the absence of low-level contractions
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
intercalated disc : part of the sarcolemma that connects cardiac tissue, and contains gap junctions and desmosomes
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
isometric contraction : muscle contraction that occurs with no change in muscle length
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
isotonic contraction : muscle contraction that involves changes in muscle length
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
lactic acid : product of anaerobic glycolysis
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
latch-bridges : subset of a cross-bridge in which actin and myosin remain locked together
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
latent period : the time when a twitch does not produce contraction
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
motor end-plate : sarcolemma of muscle fiber at the neuromuscular junction, with receptors for the neurotransmitter acetylcholine
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
motor unit : motor neuron and the group of muscle fibers it innervates
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
muscle tension : force generated by the contraction of the muscle; tension generated during isotonic contractions and isometric contractions
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
muscle tone : low levels of muscle contraction that occur when a muscle is not producing movement
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
myoblast : muscle-forming stem cell
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
myofibril : long, cylindrical organelle that runs parallel within the muscle fiber and contains the sarcomeres
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
myogram : instrument used to measure twitch tension
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
myosin : protein that makes up most of the thick cylindrical myofilament within a sarcomere muscle fiber
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
myotube : fusion of many myoblast cells
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
neuromuscular junction (NMJ) : synapse between the axon terminal of a motor neuron and the section of the membrane of a muscle fiber with receptors for the acetylcholine released by the terminal
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
neurotransmitter : signaling chemical released by nerve terminals that bind to and activate receptors on target cells
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
oxygen debt : amount of oxygen needed to compensate for ATP produced without oxygen during muscle contraction
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
pacesetter cell : cell that triggers action potentials in smooth muscle
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
pericyte : stem cell that regenerates smooth muscle cells
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
perimysium : connective tissue that bundles skeletal muscle fibers into fascicles within a skeletal muscle
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms
power stroke : action of myosin pulling actin inward (toward the M line)
https://openstax.org/books/anatomy-and-physiology-2e/pages/10-key-terms