Muscle 3

Question 1

T/F Cardiac muscle has a single nucleus at the end of the muscle fiber.

Answer 1

False. At the MIDDLE of the muscle fibers

Question 2

where are intercalated discs

Answer 2

at the connections between cells

Question 3

Desmosomes

Answer 3

mechanical connections

Question 4

Gap junctions

Answer 4

eletrical connections

Question 5

Cardiac muscle works as a __.

Answer 5

functional syncytium

Question 6

T/F Cardiac muscle tissue contracts with neural stimulation.

Answer 6

FALSE. without

Question 7

Timing of contractions in cardiac muscle tissue are determined by these type of cells.

Answer 7

Pacemaker cells

Question 8

The Autonomic nervous system can do what do that cardiac muscle (2)

Answer 8

1) alter the rhythmicity established by the pacemaker

2) adjust the contractility of the cardiac muscle

Question 9

cardiac muscle cell contraction last how much longer than do those of skeletal muscle fibers.

Answer 9

10 times

Question 10

What type of muscle is under control of ANS

Answer 10

Smooth

Question 11

T/F Smooth muscle cells are longer than cardiac muscle cells.

Answer 11

TRUE

Question 12

T/F Cells contain sarcomeres.

Answer 12

FALSE

Question 13

What type of muscle is present in hollow organs and tube structures

Answer 13

Smooth

Question 14

Are smooth muscle cells have a direct connection with neurons?

Answer 14

Not exactly. There are places where the plasma membrane is close enough to nerve endings that it can still receive the neurotransmitter and bind to change the activation site

Question 15

What muscle types behave as a functional syncytium?

Answer 15

unitary smooth muscle and cardiac muscle

Question 16

Cell-to-cell communication occurs through what, as with cardiac muscle?

Answer 16

Gap-junction

Question 17

Where does calcium availability for smooth muscle come almost entirely from?

Answer 17

extracellular calcium

Question 18

Smooth muscle is MYOSIN/ACTIN regulated.

Answer 18

MYOSIN

Question 19

You need MORE/LESS ATP contraction for smooth muscle to occur?

Answer 19

LESS

Question 20

What in smooth muscle allows for sustained contractions without much energy consumption?

Answer 20

Latch bridges

Question 21

When does relaxation take place in smooth muscle?

Answer 21

when Ca++ is taken back up from the cytoplasm and phosphate enzyme inactivates the myosin molecule

Question 22

What activates the myosin light chain kinase?

Answer 22

when Ca++ binds to calmodulin

Question 23

What activates the catalytic form of myosin to interact with actin and perform crossbridge cycling? What is needed to keep the cycling occuring?

Answer 23

Phosphorylation of myosin light chain kinase;ATP

Question 24

Phasic muscle contraction

Answer 24

smooth muscle: twitch like contraction in response to single stimuli or brief bursts of stimuli (occurs in the muscles that propel contents of the organ)

Question 25

What are phasic muscle contractions associated with? (2)

Answer 25

1) action potentials

2) slow waves are associated with periodic depolarization and generation of action potentials

Question 26

Tonic muscle contraction

Answer 26

smooth muscle: sustained contractions over time

Question 27

Where do tonic muscle contractions occur?

Answer 27

In sphincters and blood vessels

Question 28

Why are tonic muscle contractions dissociated with action potentials?

Answer 28

Contraction is modulated by external stimuli that modulate membrane potential and calcium availability.

Question 29

T/F Mechanical activity of smooth muscle is constantly modulated by load or length.

Answer 29

FALSE. it is not modulated by this, allowing the metabolic demand to be relatively constant.