lect 7- muscle tissue 2 Flashcards

1
Q

how are cardiac muscle fibers attached

A

end to end by intercalated discs

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2
Q

how many nuclei are in cardiac muscle and where are they located

A

located centrally (one or occasionally 2)

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3
Q

compare T tubules of skeletal muscle vs cardiac

A

cardiac T tubules are larger

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4
Q

where are T tubules located in cardiac muscle

A

Z lines

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5
Q

where to mitochondria lie in cardiac muscle

A

parallel to I bands

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6
Q

what is the source of ANF

A

atrial granules

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7
Q

what specializations make up the transverse portion of the intercalated discs

A

fascia adherens and desmosomes

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8
Q

what does the longitudinal portions of the intercalated discs contain

A

gap junctions

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9
Q

_______ are specialized conducting cells of the AV bundle

A

purkinje fibers

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10
Q

where are the few myofibrils of purkinje fibers located

A

peripherally

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11
Q

what are smooth muscle cells surrounded by

A

reticular fiber network

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12
Q

explain the shape and nuclei of smooth muscle

A

are fusiform in shape with a single centrally placed nucleus

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13
Q

what do dense bodies contain and what do they function as

A

contain alpha-actinic and function as myofilament attachment sites

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14
Q

what are the intermediate filaments in nonvascular smooth muscle cells

A

desmin

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15
Q

what are the intermediate filaments in vascular smooth muscle

A

vimentin

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16
Q

what do gap junctions facilitate

A

the spread of excitation

17
Q

what are sarcolemmal vesicles/caveolae similar to

A

smooth ER

18
Q

what is the innervation of smooth muscle provided by

A

sympathetic and parasympathetic nerves of the ANS

19
Q

where are nerve terminals of smooth muscle observed

A

close to the muscle within the endomysium

20
Q

what is vascular smooth muscle contraction usually initiated by

A

nerve impulse

21
Q

describe visceral smooth muscle contraction

A

it is myogenic (stretch) and the signal spreads from cell to cell via gap junctions

22
Q

what are smooth muscle cells most responsive to (hormone)

A

epinephrine

23
Q

what does dystrophin do

A

links the actin cytoskeleton of muscle to the external lamina

24
Q

what occurs if dystrophin is absent

A

abnormal muscle fiber fragility