Chapter 9 Part 8 (true or false) Flashcards Preview

Organic Chemistry ACS > Chapter 9 Part 8 (true or false) > Flashcards

Flashcards in Chapter 9 Part 8 (true or false) Deck (20):
1

Once a motor neuron has fired, all the muscle fibers in a muscle contract.
(true or false)

false

2

The thin filaments (actin) contain a polypeptide subunit G actin that bears active sites for myosin attachment.
(true or false)

true

3

The force of muscle contraction is controlled by multiple motor unit summation or recruitment.
(true or false)

true

4

Eccentric contractions are more forceful than concentric contractions.
(true or false)

true

5

A motor neuron and all the muscle cells that it stimulates are referred to as a motor end plate.
(true or false)

false

6

Peristalsis is characteristic of smooth muscle.
(true or false)

true

7

A contraction in which the muscle does not shorten but its tension increases is called isometric contraction.
(true or false)

true

8

Muscle cells store more creatine phosphate than ATP resulting in the muscle having a reserve source of energy.
(true or false)

true

9

During isometric contraction, the energy used appears as movement.
(true or false)

false

10

One of the functions of skeletal muscle contraction is production of heat.
(true or false)

true

11

An increase in the calcium ion level in the sarcoplasm starts the sliding of the thin filaments. When the level of calcium ions declines, sliding stops.
(true or false)

true

12

Muscle contraction will always promote movement of body parts regardless of how they are attached.
(true or false)

false

13

Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments.
(true or false)

true

14

Muscle tone is the small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units.
(true or false)

true

15

Cells of unitary smooth muscle are found in the longitudinal and circular muscle layers of the intestine.
(true or false)

true

16

A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell.
(true or false)

true

17

The effect of a neurotransmitter on the muscle cell membrane is to modify its ion permeability properties temporarily.
(true or false)

true

18

When a muscle fiber contracts,the I bands diminish in size, the H zones disappear, and the A bands do not diminish in length.
(true or false)

true

19

Cardiac muscle has a limited regenerative capacity.
(true or false)

true

20

Smooth muscles relax when intracellular Ca2+ levels drop but may not cease contractions.
(true or false)

true