chapter 7-muscle
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35 terms
Terms | Definitions |
|---|---|
 3 types of muscle | 1-smooth 2-cardiac 3-skeletal |
| muscle fibers | the elongated contractile cells of muscle tissues |
| myology | study of muscle, 600+ skeletal muscles |
| 3 principal movements of muscle | 1-movement (by contracting and generating force) 2-heat production 3-posture and body support |
| smooth muscle | located in the walls of hollow internal organs and blood vessels, involuntary contraction that moves materials thru organs, regulates blood flow, fibers are narrow, tapered rod-shaped and is uninucleated, does not fatigue easily, cells arranged in parallel lines forming sheets |
| cardiac muscle | forms the heart wall, fibers are uninucleated, striated, tubular, and branched which allows the fibers to interlock at INTERCALATED DISKS, fibers relax completely between contractions to prevent fatigue, contraction is rhythmical and occur without outside nervous stimulation (involuntary) |
| uninucleated | fibers that has one nucleus |
| intercalated disks | (in cardiac muscle)...contain gap junctions which permit contractions to spread quickly throughout the heart |
| skeletal muscle | tubular, multinucleated, striated fibers that run the length of a muscle, VOLUNTARY movement bc contraction is always stimulated and controlled by nervous system |
| What are muscles? | organs! but contain nervous tissue, blood vessels, and connective tissue |
| connective tissue | *essential to organization of fibers within muscle |
| FIBERS 101 | 1-endomysium 2-fascicles 3-perimysium 4-epimysium 5-fascia 6-tendon |
| endomysium | a thin layer of areolar (loose) connective tissue...surrounds each fiber... blood capillaries and nerve fibers reach each muscle by this |
| fascicles | muscle fiber bundles, have a sheath of connective tissue called perimysium |
| epimysium | a connective tissue that covers the muscle (made of collagen?) |
| fascia | part of the epimysium, a layer of fibrous tissue that separates muscles from each other (deep fascia) and from the skin (superficial fascia) |
| tendon | strong fibrous material that attaches muscle to bone, comes from a continuation of collagen fibers from epimysium |
| What do skeletal muscles do? | 1-support body 2-make bones and other body parts move 3-help maintain a constant body temperature 4-assist movement in cardiovascular and lymphatic vessels by contraction 5-protect bones and internal organs, stabilize joints |
| sarcolemma | plasma membrane |
| sarcoplasm | cytoplasm |
| sarcoplastmic reticulum | same as endoplasmic reticulum |
| T (transverse) tubules | formed from the sarcolemma...penetrate into the cell so that they come into contact (but don't fuse) with expanded portions of the sarcoplasmic reticulum |
| myofibrils | cylindrical in shape, run the length of the muscle fibers, composed of sarcomeres (each myofibril is a single freight train, sarcomeres are cars...both shorten during muscle contraction) |
| Z lines | 2 dark, vertical lines that each sarcomere extends between... |
| 2 kinds of protein myofilaments found in sarcomeres | 1- thick filaments (made of single protein called myosin) 2-thin filaments (made of 3 proteins...1-actin (globular) 2-tropomyosin 3-troponin |
| thick filaments | composed of several hundred molecules of protein myosin |
| sarcomere | the "boxcar" of myofibril train...contains A and I bands, and H zone |
| thin filaments | consists of two strands of globular protein actin, twisted around eachother...double strands of tropomyosin coil over each actin strand |
| sliding filaments | when muscles are activated by motor nerves, impulses travel down T tubules and calcium is released from the sarcoplasmic reticulum...movement of actin filaments in relationto myosis filaments |
| neuromuscular junction | entire region where muscle contraction from axon occurs |
| synaptic cleft | small gap that separates the axon terminal from the sarcolemma |
| acetylcholine | (ACh) a neurotransmitter that can be found in axon terminal's synaptic vesicles |
| power stroke | pulls the thin filaments toward the middle of sarcomere...occurs from ADP and P being released and causing the cross-bridges to bend sharply |
| dense bodies | smooth muscle...thin filaments in smooth muscle are anchored directly to the sarcolemma or to protien muscles called dense bodies...t |
| creatine phosphate | high energy compound built up when a muscle is resting, cannot participate directly in muscle contraction, but regenerates ATP by transferring its phosphate to ADP*speediest way to make ATP available to muscles (but only makes 8 seconds of activity) |
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