Anatomy and Physiology Exam 3 Questions And Answers

Sarcolemma - ANS muscle plasma membrane Sarcoplasm - ANS cytoplasm of a muscle cell Muscle cells respond to neural, stretch, or other signals by changing their _______. - ANS sarcolemma electrical potential (voltage) The electrical potential change is coupled to intracellular changes that result in ______. - ANS force generation (contraction) Contractility - ANS active shortening of muscle cell and generation of tension (force) Extensibility - ANS passive stretching of muscle cells Elasticity - ANS return of muscle cells to original resting length after being stretched Which muscle tissue(s) has cells w/ obvious stripes called striations - ANS skeletal, cardiac Which muscle tissue is voluntary and which is involuntary? - ANS voluntary-skeletal......involuntary-cardiac,smooth What muscle tissue contracts rapidly but tires easily? - ANS skeletal Cardiac muscle contracts at a rate set by the heart's ________. - ANS pacemaker Which muscle tissue is primarily found in the walls of hollow visceral organs? - ANS smooth Which muscle tissue forces food and other substances through internal body cavities? - ANS smooth What are the three connective tissue sheaths? - ANS endomysium, perimysium, epimysium What is a fine sheath of connective tissue composed of reticular fibers surrounding each muscle fiber? - ANS endomysium What is fibrous connective tissue that surrounds groups of muscle fibers called fascicles? - ANS perimysium What is an overcoat of dense regular connective tissue that surrounds the entire muscle? - ANS epimysium each muscle is served by ________. - ANS one nerve(bundle of nerve fibers), an atery, and one or more veins when muscles contract... - ANS the movable bone (insertion) moves toward the immovable bone (origin) How does a muscle attach to a bone directly? - ANS epimysium of the muscle is fused to the periosteum of a bone (less common) How does a muscle attach to a bone indirectly? - ANS connective tissue wrappings extend beyond the muscle as a tendon or aponeurosis that attaches to a bone (more common) What is a single muscle cell called? - ANS a myocyte or muscle fiber Myocyte size - ANS 10 to 100 micrometers in diamter and many 10s of cm long Each mature myocyte is created by fusion of multiple precursor cells called _________. - ANS myoblasts Sarcoplasm has numerous ________ and an oxygen-binding protein called _________. - ANS glycosomes, myoglobin Myocytes contain the usual organelles, as well as.... - ANS myofibrils, sarcoplasmic reticulum, T-tubules Densly packed rodlike contractile elements are called ________. - ANS myofibrils What is the smallest contractile unit of a muscle called? - ANS a sarcomere What is the region of a myofibril b/w two succesive Z-discs? - ANS a sarcomere What is a sarcomere composed of? - ANS thick and thin myofilaments made up of contractile proteins How long does a thick filament of a myofilament extend? A thin filament? - ANS thick: the entire length of an A-band thin:across the I band and part way into the A band What is a coin-shaped sheet of proteins (connectins) that anchors the thin filaments and connects myofibrils? - ANS Z-disc Where do elastic filaments stretch and what are they made of? - ANS from Z-disc through the thick filament to the M-line. a huge protein called titin. What are thick filaments composed of? - ANS 200-500 myosin protein molecules What protein has a rod-like tail and two golbular heads? - ANS myosin What is the primary contractice protein in thin filaments and what is it made out of? - ANS F-actin each F-actin strand is a double helical polymer of individual globular subunits called G-actin Each G-actin subunit contains an active site to which _______ attaches to during contraction. - ANS a myosin head