muscles

Question 1

syncytium

Answer 1

contains many nuclei in a common cytoplasm; skeletal muscle cell

Question 2

what are contractile proteins synthesized into in cytosol

Answer 2

myosin thick and actin thin filaments

Question 3

what is muscle fiber made of?

Answer 3

myofibrils

Question 4

what is muscle fiber further organized into?

Answer 4

fascicles, and into anatomically identifiable muscles

Question 5

myofiber

Answer 5

each muscle cell, made up of myofibrils

Question 6

sarcomere I band

Answer 6

only actin

Question 7

sarcomere H band

Answer 7

only myosin

Question 8

M line

Answer 8

bisects H and A bands

Question 9

Z line

Answer 9

bisects the I band (*made of alpha actinin)

Question 10

titin

Answer 10

large thick filament associated protein

Question 11

nebulin

Answer 11

thin filament associated protein

Question 12

desmin

Answer 12

intermediate filament protein

Question 13

calsequestrin

Answer 13

calcium binding protein

Question 14

neuromuscular junction

Answer 14

where myofiber and axon terminus meet

Question 15

primary synaptic cleft

Answer 15

shallow trough in which the axon terminal lies

Question 16

secondary synaptic clefts, or junctional folds

Answer 16

sarcolemma invaginations to increase surface area at site of junction

Question 17

how is muscle stabilized

Answer 17

basal lamina and reticular fiber

Question 18

how does dystrophin work?

Answer 18

anchors the cortical actin network ot the extracellular matrix through the interaction of its N-terminus with F0actin, and the interaction of its C termninus with a transmembrane complex of dystrophin-associated proteins and dystrophin-associated glycoproteins.

Question 19

dystrophin-transmembrane protein/ glycoprotein complex

Answer 19

stabilizes association between myofibrillar proteins inside the muscle cell and the extracellular basal lamina. protects physical integritiy of the muscle.

Question 20

three types of connective tissue that organize myofibers

Answer 20

endomysium, perimysium, epipysium

Question 21

endomysium

Answer 21

surrounds each myofiber

Question 22

perimysium

Answer 22

bundles several myofibers into groups called fascicles

Question 23

epimysium

Answer 23

dense CT sheath that finds fascicles together to form the muscle body

Question 24

role of mytendinous junction

Answer 24

attaches skeletal muscle to bone via tendon

Question 25

muscle spindle

Answer 25

encapsulated, lymph filled, fusiform structures that lie parallel to the skeletal myofibers in connective tissue bet. bundles of myofibers.

Question 26

intrafusal fibers

Answer 26

contained by muscle spindle. modified muscle fiber. has a central nonstriated area where nuclei are concentrated.

Question 27

two types of intrafusal fibers

Answer 27

nuclear bag fibers | nuclear chain fibers

Question 28

two types of sensory fiber receptors associated with intrafusal fibers

Answer 28

annulospiral endings | flower-spray endings

Question 29

what happens when muscle is stretched

Answer 29

sensory fiber receptors are distorted and stimulated, and the relay of this info leads to contraction

Question 30

satellite cells

Answer 30

stem cells in adult muscle. proliferate after injury to generate new myoblasts. reside underneath the basal lamina.

Question 31

where are cardiac muscle cells found

Answer 31

myocardium of heart and in the walls of the large veins at their junction with the heart. mononucleated

Question 32

organization of cardiac muscle includes

Answer 32

myofibrils in sarcomers, intercalated disks, abundant mitochondria

Question 33

role of intercalated disks

Answer 33

organize several specialized junctions for stable adhesion and communication

Question 34

what kind of junctions in intercalated disks

Answer 34

desmosomes, fascia adheres, gap junctions

Question 35

what does desmin do in cardiac muscle cells?

Answer 35

the intermediate filament protein associated with desmosomes

Question 36

diads

Answer 36

formed between SR and T tubules in cardiac myocytes. Present at the Z lines.

Question 37

cardiac T tubules

Answer 37

are thicker

Question 38

SR in cardiac myocytes

Answer 38

less extensive; uses extracellular calcium

Question 39

delicate CT endomysium

Answer 39

surrounds individual cardiac myofibers.

Question 40

where is a rich capillary network present

Answer 40

cardiac myocyte

Question 41

role of perimysium in cardiac myocytes

Answer 41

myofibers are bundled into groups. collagenous fibers are coarser than those of endomysium

Question 42

Purinje fibers

Answer 42

modified cardiac myocytes. conduct impulses from AV node through ventricular septum into the ventricles. these cells have few poorly organized myofibrils. no t tubules.

Question 43

myofilaments in smooth muscle contain mostly

Answer 43

actin; not arranged in sarcomeres or myofibrils

Question 44

dense bodies

Answer 44

in sarcoplasm. contain alpha-actinin and are analogous to Z lines of striated myofibers. serve as anchoring sites for actin myofilaments

Question 45

attachment plaques

Answer 45

anchoring site for actin myofilament

Question 46

what role does desmin play in smooth muscle?

Answer 46

intermediate filaments associated with attachment plaques

Question 47

what happens during smooth muscle contraction?

Answer 47

their nuclei coil up

Question 48

does smooth muscle have SR?

Answer 48

yes, but it is poorly elaborated

Question 49

two types of smooth muscle tissue

Answer 49

unitary (visceral); multi-unit

Question 50

visceral (unitary) smooth muscle

Answer 50

found in walls of many hollow organs. exhibit sustained contractions or waves of contraction. few are innervated. connected by gap junctions. spontaneous depolarization.

Question 51

multi unit smooth muscle

Answer 51

rely upon neural stimulation of contraction. cells receive individual innervation. undergo relatively rapid, precisely graded contraction. sphincter pupillae of eye and arrector pili muscles of skin