14. Each of the following statements concerning striated myofibrils is true, EXCEPT:
A
– I band contains only thin filaments; B – thin filaments anchor at Z line; C – A band
contains both thin and thick filaments in 6 to 1 ratio; D
– M line is formed by the midpoints
of thick filaments; E
– H zone contains only thin filaments.
Directions
: one or more of the given statements or completions is/are correct. Choose the
answer: A
– if only 1,2, and 3 are correct; B – if only 1 and 3 are correct; C – if only 2 and
4 are correct; D
– if only 4 is correct; E – if all are correct.
15. The characteristics of the skeletal muscle as an organ are true:
(1) is formed of striated fibres (2) contains the endomisium (3) contains the perimysium (4)
contains the epymysium
16. The following statements regarding a sarcomere are true:
(1) is a distance between two successive Z lines (2) is a functional unit of striated
myofibrils (3) is similarly arranged in skeletal tissue and cardiac muscle (4) includes 0.5 of
I band + A band + 0.5 of I band
17. The cross striation of muscle fibres is due to:
(1) cross disposition of myofibrils (2) the presence of dark and light bands (3) the presence
of many nuclei (4) alternation of dark and light bands
18. The following statements regarding the atypical cardiac muscle cells are true:
(1) contain few myofibrils (2) contain many glycogen granules (3) contain few mitochondria
(4) make up the heart impulse-generating system
19. The following statements regarding the repair of skeletal muscle fibres are true:
(1) satellite cells divide (2) myoblasts arise from satellite cells (3) myoblasts fuse to form
myotubes (4) myotubes differentiate to muscle fibres
20. The following statements regarding the satellite cells of the skeletal muscle
tissue are true:
(1) are stem cells (2) exist in G
0
phase (3) take part in muscle repair (4) are located
between the basement membrane and the muscle fibre plasmalemma
21. The following statements regarding the T tubules of striated muscle fibres are
true:
(1) are plasmalemma invaginations (2) take part in the release of calcium ions (3) are
located between adjacent terminal cisterns (4) take part in the diad formation
22. The intercalated disks of the cardiac muscle cells have the following
specializations:
(1) sites of myofibril attachment (2) desmosomes (3) interdigitations (4) gap junctions
23. The following statements regarding the smooth muscle cells are true:
(1) are fusiform (2) contact by gap junctions (3) produce reticular fibrils (4) lack
sarcolemmal vesicles
24. The following statements regarding the cytoplasmic and peripheral densities of
the smooth muscle cells are true:
(1) are analogous to Z lines (2) contain
α-actinin (3) function as myofilament attachment
sites (4) facilitate the spread of excitation
25. The following statements regarding the sarcolemmal vesicles (caveolae) of the
smooth muscle cells are true:
(1) are present along the periphery of the cell cytoplasm (2) are associated with sER (3)
are associated with the cell membrane (4) function to take up and release calcium ions
26. The following statements regarding the smooth muscle tissue regeneration are
true:
(1) smooth muscle cells can divide (2) minor wounds heal by new smooth muscle cells (3)
large defects are closed by connective tissue (4) regeneration is not possible at all.
27. The following statements regarding the cardiac muscle tissue regeneration are
true: