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Ch 6 Muscles
Muscles
| Question | Answer |
|---|---|
| 4 Major Functional Characteristics | Contractility Excitability Extensibility Elasticity |
| Ability of skeletal muscle to shorten with force | Contractility |
| Capacity of skeletal muscle to respond to a stimulus | Excitability |
| Ability to be stretched | Extensibility |
| Ability to recoil to their original resting length after they have been stretched | Elasticity |
| Connective tissue sheath that surrounds the skeletal muscle | Epimysium |
| Superficial to the epimysium | Fascia |
| Fascia | Surrounds and separates the muscles |
| Fascicle | Composes a muscle |
| Loose connective tissue that surrounds the fascicle | Perimysium |
| Muscle cells | Muscle fibers |
| Connective tissue sheath that surrounds the fiber | Endomysium |
| Myofibrils | 2 major kinds of protein fibers |
| Actin myofilament | Thin: 2 strands of pearls twisted |
| Myosin myofilaments | Thick: bundles of golf clubs |
| Sarcomere | Basic structural unit and function unity of the muscle |
| Stretches from one Z line to the next | Sarcomere |
| I band | Light area composed of actin |
| A band | Dark composed of myosin |
| M line | Line found in-between the A bands composed of myosin |
| H zone | Space between A bands composed of myosin |
| Outside of the cell membranes | Positively charged |
| Inside of the cell membranes | Negatively charged |
| Charge difference across the membrane | Resting membrane potential |
| Action potential | When a muscle cell is stimulated the membrane characteristics change briefly. This is the brief reversal back |
| Nerve cells that carry action potentials to skeletal muscle fibers | Motor neurons |
| Each branch that connects to the muscle forms a... near the center of the cell | Neuromuscular junction; synapse |
| A single motor neuron and all the skeletal muscle fibers it innervates | Motor unit |
| Neuromuscular junction | Formed by an enlarged nerve terminal resting in an indentation of the muscle membrane |
| Enlarged nerve terminal | Presynaptic terminal |
| Space between the presynaptic terminal and the muscle cell | Synaptic cleft |
| Postsynaptic terminal | Muscle fiber |
| Each presynaptic terminal contains | Synaptic vesicles |
| Synaptic vesicles | Secrete a neurotransmitter caller acetylcholine |
| Acetylcholine | Diffuses across the synaptic cleft and binds to the postsynaptic terminal Causing a change in the postsynaptic cell |
| Acetycholinesterase | An enzyme that rapidly breaks down acetylcholine which is released into the synaptic cleft between the neuron and muscle cell |
| Sliding filament mechanism | The sliding of actin myofilaments slide past myosin myofilaments during contraction |
| During a contraction, what bands shorten and what band does not change in length | H and I bands shorten. A does not change |
| Muscle Twitch | A contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers |
| A muscle fiber will not respond to stimuli until that stimulus reaches a level called | Thresh hold |
| All-or-none response | Refers to the threshold thing |
| Lag phase | Time between application of a stimulus to a motor neuron and the beginning of a contraction |
| Contraction phase | Time of contraction |
| Relaxation phase | Time during which the muscle relaxes |
| Tetany | Where the muscle remains contracted without relaxing |
| The increase in number of motor units being activated is called | recruitment |
| ATP | Adenosine triphosphate |
| Needed for energy for muscle contraction | ATP |
| ATP is produced by | Mitochondria |
| ADP | Adenosine diphosphate |
| Creatine phosphate | Stored in place of ATP and is used for energy |
| Anaerobic | Without oxygen |
| Aerobic | With oxygen (more efficient) |
| Muscle fatigue | Results when ATP is used during muscle contraction faster than it can be produced in the muscle cells |
| The amount of oxygen needed in chemical reactions to convert lactic acid to glucose and to replenish the depleted stores of creatine phosphate stores in muscle cells. | Oxygen debt |
| 2 types of muscle contractions | Isotonic and Isometric |
| Isotonic | (equal tension) The amount of tension produced by the muscle is constant while the distance of the muscle changes (bowling) |
| Isometric | (equal distance) The distance of the muscle stays the same while the tension of the muscle changes |
| Muscle Tone | Muscle tone refers to constant tension produced by muscles of the body for long periods of time. Keeps head up and back straight. |
| Fast-Twitch fibers | Contract quickly and fatigue quickly. Well adapted to perform anaerobic metabolism (chicken breast// white meat) |
| Slow-Twitch fibers | Contract more slowly and are more resistant to fatigue. Better suited for aerobic metabolism (chicken legs// dark meat) |
| 4 pairs of mastication muscles | 2 pairs of pterygoids, temporalis, and masseter |
| Zygomaticus | Smiling muscles |
| Intrinsic Tongue Muscle | Change the shape of the tongue |
| Orbicularis Oris | Puckers the lips |
| Levator Labii Superious | Sneering |
| Depressor Anguli Oris | Frowning |
| Antagonists | Muscles that work in opposition to one another |
| Extrinsic Tongue Muscle | Move the tongue |
| Buccinator | Flattens the cheeks. Trumpeter's muscle |
| Which 2 muscles or involved in kissing | Orbicularis oris and the buccinator |
| Sternocleidomastoid | Lateral neck muscle and prime mover. Rotates and abducts the head |
| Synergists | Muscles that work together to accomplish specific movements |
| Insertion | The end of the muscle undergoing the greatest movement |
| Mastication | Chewing |
| Occipitofrontalis | Raises the eyebrows |
| Prime mover | Among a group of synergists, the muscle that plays the major role in accomplishing the designed movement |
| Orbicularis Oculi | Closes the eyelids and causes "crow's feet" wrinkles in the skin at the lateral corners of the eye |
| Belly | Portion of muscle between the origin and the insertion |
| Origin | (head) most stationary end of the muscle |
Created by:
erharpe2
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