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Megan Williams
Anatomy
| Question | Answer |
|---|---|
| Muscle Cells | Muscle Fibers |
| Muscle responsible for smiling? | zygomaticus |
| What is contractility? | Ability of muscle to shorten with force |
| What is excitability? | Capacity of muscle to respond to a stimulus |
| What is extensibility? | Ability to be stretched |
| What is elasticity? | Ability to recoil after they have been stretched |
| Each skeletal muscle is surrounded by a connective tissue sheath called | epimysium |
| Connective tissue located outside the epimysium that surrounds and separates muscles | fascia |
| Loose connective tissue surrounding muscle fasciculi | perimysium |
| Single muscle cells | fibers |
| Connective tissue sheath surrounding each fiber | endomysium |
| Threadlike structure that extends from one end of the fiber to the other | myofibrils |
| Thin myofilaments | actin myofilaments |
| Thick myofilaments | myosin myofilaments |
| Actin and myosin myofilaments form highly ordered units called | sarcomeres |
| The charge difference across the membrane is called | resting membrane potential |
| The brief reversal back of the charge | action potential |
| Nerve cells that carry action potentials to skeletal muscle fibers | Motor neurons |
| Branches of neurons that connect to muscle form what? | neuromuscular junction or synapse |
| A single motor neuron and all the skeletal muscle fibers it innervates | motor unit |
| Enlarged nerve terminal | presynaptic terminal |
| Space between the presynaptic teriminal and the muscle cell | synaptic cleft |
| Each presynaptic terminal contains? | synaptic vesicles |
| Synaptic vesicles secrete? | acetylcholine |
| Sliding of actin myofilaments past myosin myofilaments during contaction | sliding filament mechanism |
| Contraction of entire muscle | Muscle twitch |
| Time of contraction | contraction phase |
| Time of relaxation | relaxation phase |
| Muscle remains contracted without relaxing | tetany |
| Increase in number of motor units being activated | recruitment |
| Anaerobic respiration | without oxygen |
| Aerobic respiration | with oxygen |
| ATP is used during muscle contraction faster than it can be produced | muscle fatigue |
| Muscle fibers that fatigue quickly | Fast-twitch |
| Muscle fibers that are resistant to fatigue | Slow-twitch |
| Most stationary end of the muscle | origin |
| Portion between the origin and insertion | belly |
| Muscles that work opposite of each other | antagonists |
| The end of the muscle attached to the bones undergoing the greatest movement | insertion |
| Muscles that work together | synergists |
| Action of a flexor? | flexes muscle |
| Occipitofrontalis | raises the eyebrows |
| Orbicularis oculi | closes the eyelids |
| Orbicularis oris | puckers the mouth |
| Buccinator | flattens the cheek |
| Zygomaticus | smiling |
| Levator labii superioris | sneering |
| Depressor anguli oris | frowning |
| Muscle that changes tongue's shape | intrinsic tongue muscles |
| Muscle that moves the tongue | Extrinsic tongue muscles |
| Movement of triceps brachii? | extends forearm |
| Movement of biceps brachii? | flexes or suppinates forearm |
| Movement of flexor carpi | flexes wrist |
| Movement of extensor carpi | extends wrist |