Unit 3 - A & P Module - Introduction to Cardiac and Smooth Muscle

Question 1

What triggers contraction in smooth muscle?

Answer 1

Calcium binds to calmodulin.

Question 2

Put the following in order of largest to smallest:
a. myofibril
b. muscle fiber
c. fascicle
d. thick filament

Answer 2

c, b, a, d

Question 3

In what way(s) is cardiac muscle similar to smooth muscle

Answer 3

It contains gap junctions, it possesses pacemaker cells, and it is innervated by autonomic neurons.

Question 4

Which is the fastest way that a skeletal muscle cell can generate ATP to power muscle contraction?

Answer 4

The high-energy phosphate on the creatine phosphate (phosphocreatine) is transferred to ADP creating more ATP.

Question 5

Which of the following statements is true about smooth muscle?

Answer 5

Actin and myosin generate force through the crossbridge cycle.

Question 6

Which of the following have a large muscle fiber diameter and a high force-generating capacity?

Answer 6

White, fast glycolytic fibers

Question 7

Which of the following statements is true?

Answer 7

The thin and thick filaments in smooth muscle have an oblique arrangement.

Question 8

During skeletal muscle contraction, thick and thin filaments bind together forming __________.

Answer 8

crossbridges

Question 9

Molecules common to both skeletal and smooth muscle crossbridge cycling include __________.

Answer 9

actin

Question 10

In smooth muscle, the release of calcium from the sarcoplasmic reticulum is regulated by __________.

Answer 10

all answers are incorrect

Question 11

The generation of a smooth, steady, maximum tension contraction by a muscle fiber, with no evidence of relaxation, due to a very rapid stimulation of the muscle fiber is known as __________.

Answer 11

complete (fused) tetanus

Question 12

The burning sensation that is felt in muscles during exercise is due to the buildup of __________.

Answer 12

lactic acid

Question 13

Smooth muscle is similar to skeletal muscle in which of the following ways?

Answer 13

Both possess actin and myosin

Question 14

When a muscle is stimulated at a high frequency such that the twitches build on each other, __________ is observed.

Answer 14

summation

Question 15

Which of the following statements is true?

Answer 15

Eccentric contractions perform a lengthening action.

Question 16

In which type of muscle is the function of gap junctions of the greatest importance in maintaining life?

Answer 16

Cardiac

Question 17

An increase in the force generated by a muscle is achieved by the __________ of more motor units.

Answer 17

recruitment

Question 18

Which of these statements about smooth muscle is true?

Answer 18

There are two types: multi-unit, which lacks gap junctions, but has dense innervation; single-unit, which does have gap junctions, but sparse innervation.

Question 19

What terminates smooth muscle contraction?

Answer 19

Dephosphorylation of myosin by a phosphatase

Question 20

The amount of force a muscle can generate depends on __________.

Answer 20

the number of sarcomeres in parallel, the length of individual sarcomeres, and the cross-sectional diameter of the muscle fibe

Question 21

Which type of muscle is subject to the greatest diversity of hormonal control?

Answer 21

Smooth muscle

Question 22

Which muscle fiber type experiences slow-wave potentials?

Answer 22

Smooth muscle

Question 23

Thick and thin filaments overlap within the __________.

Answer 23

A band

Question 24

There is a high degree of overlap between the action potential and the contractile response in cardiac fibers. Why?

Answer 24

The overlap prevents summation of cardiac muscle contractions; it is critical that the heart have time to relax and fill with blood before the next contraction.

Question 25

Which of the following statements comparing smooth muscles to skeletal muscles is false?

Answer 25

Smooth muscles have more sarcoplasmic reticulum than skeletal muscles.

Question 26

In which types of muscle does myosin have an ATPase activity?

Answer 26

Smooth, cardiac, and skeletal