Question | Answer |
The ability of skeletal muscle to shorten with force | Contractility |
The capacity of skeletal muscle to respond to a stimulus | Excitability |
The ability to be stretched | Extensibility |
Skeletal muscle is surrounded by this connective tissue sheath | Epimysium |
Another connective tissue located outside the epimysium | Fascia |
Loose connective tissue that surrounds the fascicle | Perimysium |
The fasciculi are composed of single muscle cells called this | Fibers |
Each fiber is surrounded by this connective tissue sheath | Endomysium |
The cytoplasm of each fiber is filled with this | Myofibrils |
Thin myofilaments | Actin Myofilaments |
Thick myofilaments | Myosin Myofilaments |
Actin and myosin myofilaments form highly ordered units called this | Sarcomeres |
The charge difference across the membrane is called this | Resting Membrane Potential |
The brief reversal back of the charge is called this | Action Potential |
Nerve cells that carry action potentials to skeletal muscle fibers | Motor neurons |
Each branch that connects to the muscle | Synapse |
A single motor neuron and all the skeletal muscle fibers it innervates | Motor Unit |
The enlarged nerve terminal | Presynaptic Terminal |
The space between the presynaptic terminal and the muscle cell | Synaptic Cleft |
The muscle fiber | Postsynaptic Terminal |
Each presynaptic terminal contains synaptic vesicles that secrete this neurotransmitter | Acetylcholine |
The acetylcholine released into the synaptic cleft between the neuron and muscle cell is rapidly broken down by this enzyme | Acetylcholinesterase |
The sliding of actin myofilaments past myosin myofilaments during contraction is called this | Sliding Filament Mechanism |
Contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers | Muscle twitch |
A muscle fiber will not respond to stimulus until that stimulus reaches a level called this | Threshold |
The time between application of a stimulus to a motor neuron and the beginning of a contraction | Lag Phase |
The time of contraction | Contraction Phase |
The time during which the muscle relaxes | Relaxation Phase |
Muscle remains contracted without relaxing | Tetany |
The increase in number of motor units being activated | Recruitment |
Needed for energy for muscle contraction and is produced in the mitochondria | ATP(adenosine triphosphate) |
ATP reduces to this stable compound | ADP (adenosine diphosphate) |
Can store another high-energy molecule | Creatine Phosphate |
Without oxygen | Anaerobic Respiration |
With oxygen (more efficient) | Aerobic Respiration |
The increased respiration provides the oxygen to pay back the oxygen debt | Oxygen Debt |
Results when ATP is used during muscle contraction faster than it can be produced in the muscle cells | Muscle Fatigue |
The length of the muscle does not change, but the amount of tension increases | Isometric |
The amount of tension produced by the muscle is constant, but the length of the muscle changes | Isotonic |
Refers to constant tension produced by muscles of the body for long periods of time | Muscle Tone |
Contract quickly and fatigue quickly | Fast-twitch Fibers |
Contract more slowly and are more resistant to fatigue | Slow-twitch Fibers |
The most stationary end of the muscle | Origin |
The end of the muscle undergoing the greatest movement | Insertion |
The portion of the muscle between the origin and the insertion | Belly |
Muscles that work together to accomplish specific movements | Synergists |
Muscles that work in opposition to one another | Antagonists |
In a group of synergists, if this muscle plays the major role in accomplishing the desired movement | Prime Mover |
Raises the eyebrows | Occipitofrontalis |
Closes the eyelids and causes “crows feet” wrinkles in the skin at the lateral corners of the eye | Orbicularis oculi |
Puckers the lips | Orbicularis oris |
Flattens the cheeks | Buccinator |
Smiling muscle | Zygomaticus |
Sneering | Levator Labii Superioris |
Frowning | Depressor Anguli Oris |
Chewing | Mastication |
Change the shape of the tongue | Intrinsic Tongue Muscles |
Move the tongue | Extrinsic Tongue Muscles |
lateral neck muscle and prime mover; rotates and abducts the head | Sternocleidomastoid |
group of muscles on each side of the back; responsible for keeping the back straight and the body erect | Erector Spinae |
Muscles that move the thorax | Thoracic Muscles |
Elevate the ribs during inspiration | External Intercostals |
Contract during forced expiration | Internal Intercostals |
Accomplishes quiet breathing | Diaphragm |
The muscles of the anterior abdominal wall flex and rotate the vertebral column | Abdominal Wall Muscles |
Tendinous area of the abdominal wall | Linea Alba |
On each side of the linea alba | Rectus Abdominis |
Cross the rectus abdominis at three or more locations | Tendinous Inscriptions |
Rotates the scapula | Trapezius |
Pulls scapula anteriorly | Serratus Anterior |
Adducts and flexes the arm | Pectoralis Major |
Medially rotates, adducts, and powerfully extends the arm | Latissimus Dorsi |
Attaches the humerus to the scapula and clavicle | Deltoid |
Extends the forearm | Triceps Brachii |
Flexes the forearm | Biceps Brachii |
Flexes forearm | Brachialis |