lect 6- muscle tissue I

Question 1

what is the activity of skeletal muscle

Answer 1

strong, quick, discontinuous voluntary contraction

Question 2

what is the activity of cardiac muscle

Answer 2

strong, quick and continue involuntary contractions

Question 3

what is the activity of smooth muscle

Answer 3

weak, slow involuntary contraction

Question 4

what is the sarcolemma equivalent to

Answer 4

cell membrane

Question 5

what is the sarcoplasm

Answer 5

cytoplasm of muscle cells

Question 6

________ surrounds the entire muscle cell

Answer 6

epimysium

Question 7

________ invests each fascicle

Answer 7

perimysium

Question 8

______ envelopes each fiber (muscle cell)

Answer 8

endomysium

Question 9

how many types of fibers/cells is skeletal muscle made up of

Answer 9

three

Question 10

what type of fibers red fibers

Answer 10

slow fibers

Question 11

what type of fibers are white fibers

Answer 11

fast

Question 12

what type of cytochemical staining do red fibers show for ATPase

Answer 12

weak

Question 13

what type of cytochemical staining do white fibers show for ATPase

Answer 13

marketable

Question 14

what are white fibers rich in

Answer 14

phosphorylases

Question 15

how does the A band appear with light microscopy

Answer 15

bright when examined with polarized light (although it is darkly stained with ordinary histological dyes)

Question 16

describe the I band with light microscopy

Answer 16

it is isotropic and appears dark when exampled with polarized light, but it is lightly stained in routine histological preparations

Question 17

define the Z disc/line

Answer 17

dense area that bisects the I band

Question 18

define the H band

Answer 18

it transects the A band and has a dark M line in its center

Question 19

what is the distance between 2 successive Z lines called

Answer 19

sarcomere

Question 20

what is the functional unit of contraction in striated muscle

Answer 20

sarcomere

Question 21

what is the plasma membrane that envelopes skeletal muscle fibers called

Answer 21

sarcolemma

Question 22

where are the nuclei located in skeletal muscle

Answer 22

in peripheral location just beneath the sarcolemma

Question 23

what is the cytoplasm of the muscle fiber called

Answer 23

sarcoplasm

Question 24

what does the sarcoplasmic reticulum surround

Answer 24

surrounds myofilaments and forms a meshwork around each myofibril

Question 25

what does the sarcoplasmic reticulum sequester

Answer 25

calcium ions

Question 26

where are triads of skeletal muscle located

Answer 26

at the A-I junction

Question 27

what type of filaments does the I band have

Answer 27

thin filaments which anchor at the dense Z line

Question 28

what type of filaments does the A band consist of

Answer 28

both thick and thin filaments (making it anisotropic)

Question 29

what is the M line formed by

Answer 29

cross connections at the midpoints of the thick filaments

Question 30

what type of filaments does the H band have

Answer 30

thick filaments

Question 31

what occurs at the heads of myosin filaments of thick myofilaments

Answer 31

ATP hydrolysis as well as the location for the actin-binding site

Question 32

what type of actin do thin myofilaments primary have

Answer 32

F actin (which is formed by polymerization of G actin monomers)

Question 33

describe the 3 subunits of troponin

Answer 33

TnC binds to calcium ions, TnT binds to tropomyosin, and TnI prevents the interaction between actin and myosin

Question 34

when is contraction of skeletal muscle fibers initiated

Answer 34

when calcium binds to the TnC unit of troponin