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A & P MS2 MOD 3
Muscle System
Question | Answer |
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Muscular System | all of the muscles of the body considered as an interrelated structural group |
Functions of the muscular system | Assists in body movements; assists in the movement of materials to the body; produces heat and energy; assists in maintaining posture and balance; helps to protect the internal organs |
Skeletal muscle tissue | voluntary;striated,consisting of long,slender,striped cells;attached to the skeleton moves the skeleton’s moving parts,acting in opposing groups with some muscles relaxing and some contracting;contracts quickly in response to stimulation of nerve impulses |
Voluntary | functioning under the conscious control of the organism |
Involuntary | functioning without the conscious control of the organism |
Striated | consisting of narrow bands or rows |
Visceral muscle tissue | is voluntary; is non striated, consisting of spindle shaped cells; is found in the viscera, especially the stomach, intestines, urinary ducts, and blood vessels; contracts slowly in response to stimulation to nerve impulses |
Viscera | the internal organs in the abdominal cavity |
Cardiac muscle tissue | Is involuntary; is partially striated; found only in the heart; contracts moderately fast in response to stimulation to nerve impulses |
Origin | the less movable end of a skeletal muscle attachment that is closer to the midline of the trunk of the body and is attached to the less movable end of the bone |
Insertion | the end of a skeletal muscle attachment that is attached to the more movable bone |
Body | the largest or the main part of a skeletal muscle |
Skeletal muscles are | enclosed in the epimysium, which is continuous with the fibrous structures that attach the muscles to bones and other structures |
Epimysium | a fibrous sheath that enfolds a skeletal muscle and extends over the origin and insertion and between bundles of muscle fibers |
Skeletal muscles are | firmly attached to the structures on which they pull during contraction |
Skeletal muscles | may be attached directly to the periostium of a bone or may be attached by tendons or aponeuroses |
Periostium | a fibrous, vascular membrane covering the bones, except at their extremities |
Tendon | a structure in which the epimysium extends from the muscles as a broad, flat sheet of connective tissue that attaches to an adjacent structure; one of many white, glistening fibrous bands of tissue that attach muscle to bone |
Aponeurosis | –structure which the epimysium extends from the muscle a strong,tough cord of connective tissue is continuous with the periostium of the bone;strong sheet of fibrous connective tissue serves as a tendon 2 attach muscles 2 bone or fascia 2 bind muscle |
Muscles contract in response | to electrical impulses, either the natural stimulus of a motor nerve Impulse or an artificial stimulus such as electrical shock |
Muscles that move | a body part usually lie proximal to the part that they move |
Locomotion of the body | is caused by muscles pulling on bones |
Body movements | result from coordinated actions in pairs of muscles |
The coordinated actions of a pair of muscles | generally mean that one muscle contracts while the other relaxes |
Normal movements of body parts | are the result of the coordinated motion of several pairs of muscles |
The energy to produce movement | in muscles is released from simple sugars through metabolism |
Irritability | the ability to respond to stimuli |
Conductivity | the ability to transmit impulses |
Extensibility | the ability to stretch and remain stretched |
Elasticity | the ability to return to a former length when the stretching force is removed |
Contractility | the ability to contract or shorten |
Tone | the slight tension that is present in muscles even when they are at rest so that they can respond more easily and quickly when needed |
Abductor | performs abduction, moving away from a part or midline |
Adductor | performs adduction, moving toward a part or toward a midline |
Levator | performs elevation, lifting a part |
Depressor | performs depression, lowering a part |
Flexor | performs flexion, bending a part at a joint |
Extensor | performs extension, straightening a part at a joint |
Rotator | performs medial rotation, revolving a part on its axis, or lateral |
Protractor | performs protraction, moving a part forward |
Retractor | performs retraction, moving a part back |
Invertor | performs inversion, turning a part upside down or inside out |
Evertor – performs eversion, turning or rotating a part outward | |
Supinator – performs supination, turning a part upward | |
Pronator – performs pronation, turning a part downward | |
Sphincter – performs constriction, closing a body opening | |
Tensor – performs tension, making a part more rigid | |
Prime mover – a muscle that generates the majority of force to accomplish a movement | |
Agonist – a muscle or group of muscles that create a specific movement by flexing | |
Antagonist – a muscle or group of muscles that when flexed directly oppose prime mover muscles | |
Synergist – a muscle or group of muscles that assist in the movement produced by prime mover muscles | |
Fixator – a muscle or group of muscles that stabilize a joint, helping to maintain posture and balance during the action of prime mover muscles | |
Head and face muscles – control talking, chewing, swallowing, facial expressions, and blinking | |
Neck muscles – move the head from side to side, from back to front, and in rotation | |
Back muscles – allow the body to bend, turn, and stand erect | |
Chest muscles – assist in respiration and movements of the neck, arms, and trunk | |
Abdominal muscles – support the internal organs, assist in respiration, and assist in eliminating waste from the large intestines and bladder | |
Perineal muscles – assist in defecation and urination and form the floor of the pelvic cavity | |
Frontalis – wrinkles the forehead horizontally | |
Temporalis – closes the mandible | |
Orbicularis oculi – closes the eyelids | |
Orbicularis oris – draws the lips together as in kissing | |
Buccinator – moves the lips for blowing, wistling, and smiling | |
Masseter – closes the jaws as in chewing | |
Trapezius – moves the shoulders by raising, assists in moving the head to one side or the other, hyperextends the head when the occiput acts as insertion, and helps hold the head erect | |
Sternocleidomastoid – rotates the head from side to side, flexes the upper vertebral column and head as in bowing the head, and helps hold the head erect | |
Platysma – acts to wrinkle the skin in the neck and depresses the mandible | |
Hyperextend – to extend to its fullest range of motion or beyond | |
Occiput – the back of the head | |
Clavicle – the collarbone | |
Scapula – the shoulder bone | |
Sternum – the breast bone | |
Mastoid process – the process of the temporal bone behind the ear | |
Mandible – the lower jaw bone | |
Deltoid – moves the upper arm at the point of the shoulder | |
Pectoralis major – flexes the upper arm, adducts the upper arm anteriorly, and draws the arm across the chest | |
Serratus anterior – rotates the scapula and raises the shoulder, as in full flexion and abduction of the arm | |
Intercostals – elevate and depress the ribs | |
Latissimus dorsi – brings the arms down forcefully | |
Diaphragm – conracts and relaxes to cause inhalation and exhalation | |
External oblique – compresses the abdomen and rotates the trunk laterally | |
Internal oblique – compresses the abdomen and rotates the trunk laterally | |
Transverse abdominis – compresses the abdomen and rotates the trunk laterally | |
Rectus abdominus – compresses the abdomen and rotates the trunk laterally and flexes the trunk laterally | |
Levator ani – forms the floor of the pelvic cavity and supports the organs | |
Deep transverse perinei – forms the floor of the pelvic cavity | |
Biceps brachii – flexes the supinated forearm | |
Triceps brachii – extends the lower arm | |
Brachialis – flexes the pronated forearm | |
Brachioradialis – flexes the forearm | |
Carpi muscles – control hand movements | |
Digitorum muscles – control finger movements | |
Pollicis muscles – control thumb movements | |
Gluteas maximus – helps maintain an erect posture and extends and rotates the thigh | |
Gluteas medius – abducts the thigh, rotates the thigh outward, and stabilizes the pelvis on the femur | |
Gluteas minimus – abducts the thigh, rotates the thigh outward, stabilizes the pelvis on the femur, and extends the thigh | |
Sartorious – adducts and flexes the leg | |
Quadricepts fomoris – extends the leg | |
Adductor – presses the thigh together | |
Hamstring – flexes the lower leg | |
Gastrocnemius – extends the foot | |
Tibialis anterior – flexes the foot and inverts the ankle | |
Peroneus longus – everts the ankle | |
Soleus – inverts the ankle | |
Flexor digitorum – flexes the toes | |
Extensor digitorum – extends the toes | |
Tenosynovitis – an inflammation of the tendon sheath often caused by repetitive motion | |
Atrophy – a condition of weakness in a muscle due to lack of use | |
Cramps – painful, involuntary twitches of a muscle | |
Convulsions – abnormal, uncoordinated contractions of muscles | |
Fibrillation – an asynchronous contraction of individual tissue fibers with in a muscle | |
Asynchronous contraction – the flexing of the muscles at unexpected or undesired times | |
Strain – a condition in which the muscle fibers have been overstretched or torn | |
Myositis – an inflammation of muscle tissue | |
Fibromyosis – an inflammation of a tendon | |
Contusion – localized internal bleeding within a muscle | |
Myalgia – muscle pain | |
Muscular dystrophy – a group of genetic diseases that lead to atrophy | |
Myasthenia gravis – an autoimmune disease in which the immune system attacks muscle cells at the neuromuscular junction | |
Hernia – a protrusion of an abdominal organ, such as the small intestine, due to weakness in the abdominal muscles | |
Tetanus – the inability of the muscles to relax due to the presence of a toxin | |
Botulism – an infection by an organism that releases a toxin that prevents muscle contraction |