Muscles

Question 1

sarcolemma

Answer 1

cytosol of a muscle cell

Question 2

sacroplasm

Answer 2

cytoplasm of a muscle cell

Question 3

sarcomere

Answer 3

gives striation to the muscle cell
made up of thick and thin filaments
fundamental to muscle contraction

Question 4

motor unit

Answer 4

= 1 motor neuron + all the muscle fibers the neuron innervates
those with fewer muscle fibers are better for precise movement

Question 5

characteristics of muscle fibers

Answer 5

excitability
contractibility
extendability
elasticity

Question 6

parts of a sarcomere

Answer 6

A-band 
I-band 
H-zone 
M-line
Z-line

Question 7

A-band

Answer 7

myosin filaments

Question 8

I-band

Answer 8

actin filaments and Z-line

Question 9

H-zone

Answer 9

area of myosin that DOESN’T overlap

Question 10

M-line

Answer 10

middle of myosin filament

Question 11

Z-line

Answer 11

anchored actin filament

Question 12

what changes in the sarcomere when a muscle contracts?

Answer 12

z-lines move closer together
I-band shortens
H-zone disappears

Question 13

what are thin filaments mostly made of?

Answer 13

actin filaments

Question 14

what are thick filaments mostly made of?

Answer 14

myosin

Question 15

anatomy of myosin

Answer 15

head: binds actin

neck and tail: have variable lengths

Question 16

which myosin type is present in muscles?

Answer 16

myosin II

Question 17

myosin II

Answer 17

aka muscle myosin

has very long tail region that gives the structure of thick filaments

Question 18

myosin I

Answer 18

acts as an anchor between the cell membrane and the cytoskeleton

Question 19

myosin V

Answer 19

transports various cargo molecules

one of the main transport molecules

Question 20

proteins involved in regulating access to myosin binding sites

Answer 20

troponin

tropomyosin

Question 21

tropomyosin

Answer 21

binds and obscures myosin binding sites

Question 22

troponin

Answer 22

respond to calcium ions

Question 23

troponin subunits

Answer 23

TnC: binds to calcium ions
TnI: interacts with actin and obscures the binding site
TnT: interacts with tropomyosin

Question 24

proteins responsible for changes in intracellular calcium ion concentration

Answer 24

ATPase 
SERCA
sodium/calcium reversible exchanger
L-type calcium channel
RyR

Question 25

ATPase

Answer 25

actively transports calcium ions outside the cell

Question 26

SERCA

Answer 26

actively transports calcium ions from the sarcoplasm into the sarcoplasmic reticulum (SR)

Question 27

sodium/calcium reversible exchanger

Answer 27

moves sodium and calcium either inside or outside the cell

Question 28

L-type calcium channel

Answer 28

first responder to voltage changes across the sarcolemma

Question 29

RyR

Answer 29

calcium channel that allows calcium to rapidly exit the SR

is where most of the intracellular calcium comes from

Question 30

factors that determine the force of muscle action

Answer 30

the length of the muscle fiber before stimulation
the number of recruited motor units
the frequency of neuronal stimulation

Question 31

summation

Answer 31

stimuli of increasing frequency that result in combining individual twitches

Question 32

which type of muscle is NOT striated?

Answer 32

smooth (visceral) muscle

Question 33

fast twitch muscle

Answer 33

reaches depolarization faster because of the number and the properties of the present sodium and calcium channels

Question 34

slow twitch muscle

Answer 34

has slower depolarization and a longer contraction cycle

Question 35

cardiac muscle

Answer 35

contraction is similar to slow twitch muscles, but differs in repolarization

Question 36

what stimulates contraction of cardiac muscle?

Answer 36

pacemaker cells

Question 37

what forms connections between the cytoplasms of two cardiac muscle cells?

Answer 37

desmosomes

gap junctions

Question 38

which type of muscle has NO organized sarcomeres?

Answer 38

smooth (visceral muscle)