6.3 lecture - muscle EMs, cytoskeleton, & embryology Flashcards Preview

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Flashcards in 6.3 lecture - muscle EMs, cytoskeleton, & embryology Deck (38)
1

in smooth muscle, calcium is

start

2

the sarcoplasmic reticulum ends in tubular structures called

terminal cisternae

3

VGCa++ channels in t-tubules

DHP dihydropyridine receptors

4

T/F in all types of muscle, calcium is shuttled into the cell via caveolae and sequestered in the SR until an electrical signal is received

true

5

in addation to actin, dense bodies bind to intermediate filaments, which are typically __ in visceral muscle and __ in vascular muscle

desmin in visceral smooth muscle
vimentin in vascular smooth muscle

6

what are the intermediate filaments in:
-visceral smooth muscle
-vascular smooth muscle

-desmin
-vimentin

7

this intermediate filament connects Z-lines of myofibrils with each other

desmin

8

muscular dystrophy is due to a problem with this protein

dystrophin
part of costamere complex that anchors Z lines to sarcolemma

9

muscular dystrophy is due to a lack of this protein

dystrophin
part of costamere complex that anchors Z lines to sarcolemma

10

myotube

early formation with central nuclei and a few peripheral myofibers that will eventually grow into myofibers of adult skeletal muscle

11

T/F adult myofibers can increase in number

false
can only change in size by addition or subtraction of myofibrils

12

how are muscle external membrane, nerve external membrane, and basement membrane functionally similar?

serves as scaffolding for tissue repair
-disruption makes regeneration response more difficult

13

T/F intermediate filaments seem to have little importance in skeletal muscle

true

14

T/F cardiac and skeletal muscle contain intermediate filaments

true
connecting Z-lines and anchoring z-lines to costameres

15

why is the occasional cardiac myocyte binucleated?

failure of division
(not a combination to form a functional syncytium as with skeletal muscle)

16

T/F cardiac cells can have multiple nuclei within sarcolemma

true
occasionally a failure of division results in binucleated cardiac myocytes

17

what 3 junctions does an intercalated disk consist of?

fascia adherens (actin + catenin)
desmosomes (intermediate filament + catenin)
gap junctions

18

other than myocytes, other specialized cardiac cells include

cardiac endocrine cell (mostly atrial)
cardiac conducting cell (in myocardial layer)

19

which layer of heart wall has major blood vessels?

epicardium

20

how would a type I red muscle fiber compare to a type IIb white muscle fiber on H&E?

*not going to be able to tell the difference, need PAS stain
BUT if really pressed to try:
white probably larger
red probably more darkly eosinophilic (more mitochondria)

21

how would a type I red muscle fiber compare to a type IIb white muscle fiber on H&E?

white probably larger
red probably more darkly eosinophilic (more mitochondria)

22

chief materials of:
lamina lucida
lamina densa
lamina retucularis

lucida - glycoproteins (laminin, fibronectin)
densa - type IV collagen
reticularis - type IV collagen; type VII collagen

23

chief materials of:
lamina lucida
lamina densa
lamina retucularis

lucida - glycoproteins (laminin, fibronectin)
densa - type IV collagen
reticularis - type IV collagen; type VII collagen

24

T/F satellite cells are within external membrane of muscle fiber but outside sarcolemma

true
but will never be able to make this out on LM

25

quiescent precursors that become activated to divide and differentiate in response to the needs of muscle growth and damage

satellite cells
(quiescent but actively monitoring and moving along surface)

26

T/F external membrane is a barrier to neurotransmitter and therefore does not exist in neuromuscular junciton

false
not a barrier to NT
exists in NMJ same as everywhere else

27

T/F external membrane is a barrier to neurotransmitter and therefore does not exist in neuromuscular junciton

false
not a barrier to NT
exists in NMJ same as everywhere else

28

T/F adipocytes have an external membrane

true
muscle cells
nervous cells
adipocytes

29

T/F smooth muscle motor end plates have junctional folds

false
at least not as significantly as skeletal muscle

30

T/F smooth muscle motor end plates have junctional folds

false
at least not as significantly as skeletal muscle

31

why do muscle spindle and golgi tendon organ include small muscle fibers in addition to nerves?

muscle fiber contracts and stretches proportionally to the other fibers so that nerves can sense length in the case of the muscle spindle and force exerted in the case of the golgi tendon organ

32

why do muscle spindle and golgi tendon organ include small muscle fibers in addition to nerves?

muscle fiber contracts and stretches proportionally to the other fibers so that nerves can sense length in the case of the muscle spindle and force exerted in the case of the golgi tendon organ

33

muscle spindle is encapsulated by ...

perimysium (kind of a perineurium too)

34

musculotendinous junction

actin filaments directly anchored to cell membrane in structure similar to fascia adherens

35

musculotendinous junction

actin filaments directly anchored to cell membrane in structure similar to fascia adherens

36

what does an muscle external membrane directly surround?

plasmalemma bound units, including:
-skeletal muscle fibers
-cardiac myocytes
-smooth muscle cells
NOT skeletal muscle fascicles (not directly)
NOT smooth muscle bundles (not directly)
NOT skeletal muscle fibrils (not directly)

37

what does an muscle external membrane directly surround?

plasmalemma bound units, including:
-skeletal muscle fibers
-cardiac myocytes
-smooth muscle cells
NOT skeletal muscle fascicles (not directly)
NOT smooth muscle bundles (not directly)
NOT skeletal muscle fibrils (not directly)

38

what will break first, plasmalemma or external membrane?

plasmalemma
(external membrane is very tough)
-can have broken plasma membrane but intact external membrane