Term | Definition |
Contractibility | skeletal muscles shorten with force |
Excitability | skeletal muscle responds to stimulus |
Extensibility | skeletal muscles stretches |
Elasticity | skeletal mucles recoilt ooriginal length after being stretched |
Epimysium | connective tissue that surrounds skeletal muscle |
Fascia | connective tissue located outside of the epimysium |
Fascicle | bundles the compose a muscle |
Perimysium | loose connective tissue that surrounds the fascicle |
Myofibrils | a structure that extends from one end of a fiber to the other |
Actin Myofilaments | THIN myofilaments that resemble 2 strands of pearls twisted together |
Myosin Myofilaments | THICK myfilaments that resemble bundles of golf club |
Sarcomeres | formed by both actin a myosin myofilaments |
Sarcomeres | are joined end to end to form the myofibril |
Sarcomeres | are the basic structural and funtional unit of the muscle |
Resting Membrane Potential | the difference across the membrane |
Action Potential | the reversal back of the charge |
Motor Neurons | nerve cells that carry action potentials to muscle fibers |
Neuromusclular Junction | formed by each branch the connect to the muscle |
Synapse | Neuromusclular Junction |
Neuromusclular Junction | formed near the center of a cell |
Motor Unit | composed of a single motor neuron and the skeletal muscle fibers it innervates |
Motor Unit | formed a single muscle |
Presynaptic Terminal | the enlarged nerve terminal |
Synaptic Cleft | the space between the presynaptic terminal and the muscle cell |
Postsynaptic Terminal | the muslce fiber |
Synaptic Vesicles | secrete a neurotransmitter called Acetylcholine |
Acetylcholine | diffuses across the synaptic cleft and binds to the postsynaptic terminal |
Acetylcholine | causes a change in the postsynaptin cell |
Acetylcholinesterase | rapidly break down the synaptic cleft |
Sliding Filament Mechanism | the sliding of actin myofilaments past myosin myofilaments during contraction |
Muscle Twitch | the contraction of an entire muscle in response to a stimulus |
Muscle Twitch | causes the action potential in one or more muscle fibers |
Threshold | point at which the muscle fiber will contract maximally |
All-or-None Response | the action of the muscle fiber contracting maximally |
Lag Phase | the time between application of a stimulus to a motor neuron |
Lag Phase | the beginning of a contraction |
Contraction Phase | the time of contraction |
Relaxation Phase | time during which the muscle relaxes |
Tetany | when the muscle remains contracted without relaxing |
Recruitment | increase in number of motor units being activated |
ATP | adenosine triphosphate |
Adenosine Triphosphate | needed for energy for muscle contraction |
Adenosine Triphosphate | produced in the mitochondria |
ATP | short-lived and unstable |
ADP | adenosine diphosphate |
Adenosine Diphosphate | more stable than ATP |
Creatine Phosphate | a high energy molecule |
Occipitofrontalis | raises eyebrows |
Orbicularis Oculi | closes eyelids |
Orbicularis Oris | puckers lips |
Buccinator | smiling |
Kissing Muscles | orbicularis oris and buccinator |
Zygomaticus | responsible for smiling |
Levator Labii Superioris | sneering |
Depressor Anguli Oris | frowning |
Tongue Muscles | intrinsic and extrinsic |
Extrinsic Tongue Muscle | moves the tongue |
Intrinsic Tongue Muscle | changes shape of the tongue |
Masticating | another name for chewing |
Masticating Muscles | Masseter, Temporalis, Pteragoids |
Sternocleidomastoid | located in the neck |
Pectoralis Major | located in the upper limb of the body |
Trunk Muscles | erector spinal |
Erector Spinal | found on each side of the back |
Erector Spinal | responsible for erect posture |
Thoracic Muscles | External Intercostal, Internal Intercostal, Diaphragm |
External Intercostal | contract during inspiration |
Internal Intercostal | contract during forced expiration |
Diaphragm | dome shaped muscles responsible for quiet breaths |
Abdominals | Rectus Abdominis, Linea Alba, Tendinous Inscriptions, External Abdominal Obliques |
Rectus Abdominus | abs |
Linea Alba | white line of connective tissue that extends from the sternum to the pubis |
Tendinous Inscriptions | cross the rectus abdominis in 3 places & form a segmented look in the abs |
External Abdominal Obliques | internal and transverse |
Origin | most stationary end of the muscle |
Insertion | the end of the muscle undergoing the greatest amount of movement |
Belly | the portion of the muscle between the origin and the insertion |
Synergists | muscles that work together to accomplish specific movements |
Antagonists | muscles that work in opposition to one another |
Prime Mover | the muscle in a group of synergists that plays the major role in accomplishing the desired movement |