Term | Definition |
Excitability | muscle to respond to a stimulus |
Extensibility | ability to be stretched |
Elasticity | ability to recoil their original shape |
Contractility | muscle to shorten with force |
Epimysium | skeletal muscle is surrounded by a connective tissue |
Fascia | connective tissue located outside the epimysium |
Endomysium | each fiber is surrounded by a connective tissue sheath |
Myofibrils | threadlike structure that extends from one end of the fiber to the other |
Actin Myofilaments | thin myofilaments |
Myosin Myofilaments | thick myofilaments |
sarcomeres | joined end to end to form the myofibril |
A Band | extends the length of the myosin |
Resting Membrane Potential | the charge diffrence across the membrane |
Action potential | The breif reversal back of charge |
Motor Neurons | nerve cells that carry action potential to the skeletal muscle fibers |
Neuromusclar junction | forms each branch that connects to the muscle |
Synapse | near the center of the cell |
Motor Unit | a single motor neuron and all skeletal muscle fibers |
Presynaptic terminal | the enlarged nerve terminal |
Synaptic cleft | space between the presynaptic terminal and the muscle cell |
Postsynaptic terminal | the muscle fiber |
Synaptic vesicles | Presynaptic terminal contains |
Acetylcholine | secretes a neurootransmitter |
Sliding filament mechanism | the sliding of actin myofilaments past myosin myofilaments during contgraction |
Thresold | A muscle fiber will not respond to stimulus until that stimulus reaches that level |
All-or-None Response | A Phenomenon |
Lag phase | the time between application of a stimulus to a motor neuron and beginning of a contraction |
Contraction phase | the time of contraction |
Relaxation Phase | the time during which the muscle relaxes |
Tetany | where the muscle remains contracted without relaxing |
Recruitment | the increase in number of motor units being activated |
Creatine Phosphate | high energy molecule |
Anaerobic Respiration | without oxygen |
Aerobic Respiration | with oxygen |
Oxygen Debt | the amount of oxygen needed in chemical reactions to convert lactic acid to glucose |
Muscle Fatigue | result when ATP is used during muscle contraction faster than it can be produced |
Isometric | equal distance |
Isotonic | equal tension |
Muscle tone | muscle tone refers to constant tension produced by muscles of the body for long periods of time |
Fast twitch fibers | contract quickly and fatigue quickly |
slow twitch fibers | contract more slowly and more resistant to fatigue |
Origin | the most stationary end of the muscle |
Insertion | is the end of the muscle undergoing the greatest movement |
Belly | the portion of the muscle between the origin and insertion |
Synergist | muscle that works together to accomplish specific movement |
Antagonist | muscles that work in opposition to one another |
Prime mover | one muscle playing the major role in accomplishing the desired movement |
Occipitofrontalis | raises the eyebrows |
Orbicularis oculi | closes the eyelids and causes wrinkles in the skin at lateral corners of the eye |
Orbicularis oris | puckers the lips |
Buccinator | flattens the cheeks. |
Zygomaticus | smiling muscle |
Levator labii superioris | sneering |
Depressor anguli oris | frowning |
Mastication | chewing |
Intrinsic tongue muscle | change the shape of the tongue |
Extrinsic tongue muscle | moves the tongue |
Thoracic muscle | muscle that moves the thorax |
Trapezius | rotates scapula |
Serratus anterior | pulls scapula anteriorly |
Pectoralis major | adducts and flexes the arm |
Deltoid | attaches the humerus to the scapula and clavicle |
Triceps brachii | extends the forearm |
Biceps brachii | flexes the forearm occupies the anterior compartment of the arm |
Brachialis | flexes the forearm |
Brachioradialis | flexes and supinates the forearm |
Flexor carpi | flexes the wrist |
Extensor carpi | extends the wrist |
Flexor digitorum | flexes the finger |
Extensor digitorum | extends fingers |
Gluteus maximas | buttocks |
Quadriceps femoris | extends the leg and anterior thigh muscle |
Sartorius | flexes the thigh |
Hamstring | posterior thigh muscle flexes the leg and extends thigh |
Gastrocnemius | forms the calf muscle |