Question | Answer |
Contractility | The ability of skeletal muscle to shorten with force. |
Excitability | The capacity of skeletal muscle to respond to a stimulus. |
Extensibility | The ability to be stretched. |
Elasticity | The ability to recoil to their original resting length after they have been stretched. |
Epimysium | Connective tissue that surrounds each skeletal muscle. |
Fascia | Connected tissue located outside the epimysium. |
Fasicle (fasciculi) | Numerous visible bundles of muscle. |
Perimysium | Connective tissue that surrounds fasciculi. |
Muscle cells | Muscle fibers. |
Endomysium | Surrounds muscle fibers. |
Myofibrils | A threadlike structure that extends from one end of the fiber to the other. |
Actin myofilaments | Thin myofilaments. |
Myosin myofilaments | Thick myofilaments. |
Sarcomere | Form the myofibril / Basic structural and functional unity of the muscle. |
Resting Membrane Potential | The charge difference across the membrane. |
Action Potential | The brief reversal back of the charge. |
Motor Neurons | Nerve cells that carry action potentials to skeletal muscle fibers. |
Neuromuscular | Synapse. |
Motor Unit | A single motor neuron and all the skeletal muscle fibers it innervates. |
Presynaptic Terminal | The enlarged nerve terminal. |
Synaptic Cleft | The space between the presynaptic terminal and the muscle cell. |
Postsynaptic Terminal | The muscle fiber. |
Synaptic Vesicles | Secretes a neurotransmitter called acetylcholine. |
Acetylcholine | Neurotransmitter secreted by the synaptic vesicles |
Mastication | Chewing |
Occipitofrontalis | Raises eyebrows |
Orbicularis Oculi | Closes eyelids |
Orbicularis Oris | Puckers Lips |
Buccinator | Flattens the cheeks |
Zygomaticus | Smiling muscle |
Levator Labii Superoris | Sneering |
Depressor Anguli Oris | Frowning |
Intrinsic Tongue Muscles | Change the shape of the tongue |
Extrinsic Tongue Muscles | Move the tongue |
Sternocleidomastoid | Lateral neck muscles and prime mover |
Erector Spinae | Group of muscles on each side of the back |
Thoracic Muscles | Muscles that move the thorax |
External Intercostals | Elevate the ribs during inspiration |
Internal Intercostals | Contract during forced expiration |
Diaphragm | Accomplishes quiet breathing |
Trapezius | Rotates scapula |
Serratus Anterior | Pulls scapula anteriorly |
Pectoralis Major | Adducts and flexes the arm |
Lattissimus Dorsi | Medially rotates, adducts, and powerfully extends the arm |
Deltoid | Attaches the humerus to the scapula and clavicle |
Triceps Brachii | Extends the forearm |
Biceps Brachii | Flexes the forearm |
Brachialis | Flexes forearm |
Brachioradialis | Flexes and supinates the forearm |
Flexor Carpi | Flexes the wrist |
Extensor Carpi | Extends the wrist |
Flexor Digitorum | Flexes the fingers |
Extensor Digitoum | Extends the fingers |
Gluteus Maximus | Buttocks |
Quadriceps Femoris | Extends the leg |
Sartorius | Flexes the thigh |
Hamstring | Posterior thigh muscles |
Gastocnemius | 1/2 the Calf muscle |
Soleus | 1/2 the Calf muscle |
Calcaneal Tendon | Achilles Tendon |
Number of Muscles Located in the Foot | 20 |
Muscle Twitch | A contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers. |
Threshold | The point in which the muscle fiber will contract maximally |
Lag Phase | The time between application of a stimulus to a motor neuron and the beginning of a contraction |
Contraction Phase | The time of contraction |
Relaxation Phase | The time in which the muscle relaxes |
Tetany | Where the muscle remains contracted without relaxing |
Recruitment | The increase in number of motor units being activated |
Muscle Tone | The constant tension produced by muscles of the body for a long period of time. |
Fast-twitch Fibers | Contract quickly and fatigue quickly |
Slow-twitch Fibers | Contract slowly and are more resistant to fatigue |
Origin | The most stationary part of the muscle |
Insertion | The end of a muscle that undergoes the most movement |
Belly | Lies between the origin and the insertion |
Prime Mover | One muscle that plays a key role in movement. |