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Ch 9 A&P Text
| Question | Answer |
|---|---|
| is packaged into skeletal muscles: organs that are attached to bones and skin. Key words for ___: skeletal, striated, and voluntary | Skeletal muscle tissue |
| are longest of all muscle and have striations (stripes) | Skeletal muscle fibers |
| is found only in heart. Makes up bulk of heart walls . Key words for ___: Cardiac, striated, and involuntary | Cardiac muscle tissue |
| found in walls of hollow organs. Examples: stomach, urinary bladder, and airways. Key words: non-striated, involuntary | Smooth muscle tissue |
| ability to receive and respond to stimuli | Excitability |
| ability to shorten forcibly when stimulated | Contractility |
| ability to be stretched | Extensibility |
| ability to recoil to resting length | Elasticity |
| Produce ____: responsible for all locomotion and manipulation. Example: walking, digesting, pumping blood | Movement (Four important functions) |
| Maintain ___ and body position. | Posture (four important functions) |
| _____ joints | Stabilize joints (four important functions) |
| ____ ___ as they contract | Generate heat (four important functions) |
| nerve and blood supply, connective tissue sheaths, and attachments | Skeletal muscle is an organ made up of different tissues with three features |
| Each _____ muscle receives a nerve, artery, and veins. Consciously controlled skeletal muscle has nerves supplying every fiber to control activity. | Skeletal muscle |
| dense irregular connective tissue surrounding entire muscle; may blend with fascia | Epimysum (outer) |
| fibrous connective tissue surrounding fascicles (groups of muscle fibers) | Perimysium |
| fine areolar connective tissue surrounding each muscle fiber | Endomysium |
| epimysium fused to periosteum of bone or perichondrium (the outer bone) of cartilage | Direct (fleshy) |
| connective tissue wrappings extend beyond muscle as ropelike tendon or sheetlike aponeurosis (is most common bc of druability) | Indirect |
| muscle fiber plasma membrane | Sarcolemma (emmy builds walls- plasma membrane is a wall) |
| muscle fiber cytoplasm. Contains many glycosomes for glycogen storage, as well as myoglobin for O2 storage. | Sarcoplasm |
| ___ are densely packed, rodlike elements . Single muscle fiber can contain 1000s. Accounts for ~80% of muscle cell volume. | Myofibrils |
| stripes formed from repeating series of dark and light bands along length of each myofibril | Striations (part of myofibril) |
| Dark regions. Each ___ has a lighter section in its midsection called H zone.Each H zone is bisected vertically by M line- a dark line of proteins (myosesins) | A Bands |
| Lighter regions. Has a midline interruption called z disc: coin-shaped sheet of proteins on midline of light I band. | I Bands: |
| Smallest contractile unit (functional unit) of muscle fiber | Sarcomere |
| Orderly arrangement of actin and myosin myofilaments within sarcomere. has thick and thin filaments | Myofilaments |
| Thin filaments. Extend across I band and partway in A band Anchored to Z discs | Actin Myofilaments |
| thick filaments. Extend length of A band. Connected at M line. | Myosin myofilaments |
| composed of protein myosin that contains 2heavy and 4light polypeptide chains. Heavy chains intertwine to form myosin tail. Light chains form myosin globular head. During contraction, heads link thick and thin filaments together, forming cross bridges. | Thick filaments (moleculare composition of myofilaments) |
| composed of fibrous protein actin (or G Actin- it bears active sites for myosin head attachment during contraction). ___ filaments also contain *tropomyosin and troponin*: regulatory proteins bound to actin | Thin filaments |
| composed of protein titin. Holds thick filaments in place; helps recoil after stretch; resists excessive stretching. | Elastic Filament (other proteins help form the struct of myofibril) |
| network of smooth endoplasmic reticulum tubules surrounding each myofibril (like sleeves of a crocheted sweater around ur arms). Stores and releases CA2+. | Sarcoplasmic reticulum |
| Tube formed by protrusion of sarcolemma deep into cell interior. Allow electrical nerve transmissions to reach deep into interior of each muscle fiber. | T Tubules |
| the activation of cross bridges to generate force | Contraction |
| ___ ___ when cross bridges become inactive | Contraction ends |
| In the relaxed state, thin and thick filaments overlap only slightly at ends of A band. ____ states that during contraction, thin filaments slide past thick filaments, causing actin and myosin to overlap more | Sliding filament model of contraction |
| Neither thick nor thin filaments change length, just ___ more | overlap |
| Z discs are pulled toward M line . I bands shorten. Z discs become closer H zones disappear. A bands move closer to each other | As muscle cell shortens all of the following occurs |
| 1)Nerve stimulation 2)Action potential, an electrical current, must be generated in sarcolemma. 3) Action potential must be propagated along sarcolemma 4) Intracellular Ca2+ levels must rise briefly | Four steps must occur for skeletal muscle to contract |
| Axon (long threadlike extensions of motor neurons) branches end on muscle fiber, forming | Neuromuscular junction or motor end plate |
| Region where motor neuron comes into close contact with skeletal muscle | Neuromuscular junction/ motor end plate |
| _____ and muscle fiber are separated by gel-filled space called synaptic cleft | Axon Terminal (end of axon) |
| Stored within axon terminals are membrane-bound ___ which contain neurotransmitter acetylcholine (ACh) | Synaptic vesicles |
| ACh is quickly broken down by enzyme ____ which stops contractions | acetylcholinesterase, |
| Resting sarcolemma is ____, meaning a voltage exists across membrane. Aka Inside of cell is negative compared to outside | Polarized |
| ____ is caused by changes in electrical charges Occurs in three steps End plate potential Depolarization Repolarization | Action potential |
| ACh binds to ACh receptors. Causes chemically gated ion channels on sarcolemma to open. Na+ diffuses in less K+ diffuses out. Causes interior of sarcolemma becomes less negative.Results in local depolarization called ___ | End plate potential |
Created by:
cshelly