Muscle Tissue

Question 1

can shorten with force and pull on attachment points

Answer 1

contractility

Question 2

can stretch or extend

Answer 2

extensibility

Question 3

can generate electricity

Answer 3

excitability

Question 4

can recoil back to original position

Answer 4

elasticity

Question 5

The functional unit of skeletal muscle is called a

Answer 5

sarcomere

Question 6

Human muscles are powered by _____________, which is generated in the body through _______________.

Answer 6

ATP; cellular respiration

Question 7

______________ muscle is a voluntary muscle that usually connects two bones, _____________ muscle is an involuntary, fatigue-resistant muscle found exclusively in the heart, and ______________ muscle is an involuntary muscle found in viscera (internal organs).

Answer 7

skeletal; cardiac; smooth

Question 8

Which of the following is NOT a function of muscles in the human body?

movement
posture
balance
generating heat

Answer 8

all of the above are functions of muscles in the human body

Question 9

In order for actin and myosin to be able to carry out their function, ______________ must first rush into the cell to remove the molecule that normally blocks them from grabbing and sliding across each other.

Answer 9

calcium

Question 10

The specific neurotransmitter that sends the signal from a motor neuron to muscles is

Answer 10

acetylcholine

Question 11

The generic name for a protein that transmits a neuron’s signal from one neuron to another, or from a neuron to a muscle fiber (muscle cell) is called

Answer 11

a neurotransmitter

Question 12

The ion that depolarizes (flips the electric charge) of a muscle cell is _____, and the ion that repolarizes (resets the electric charge) is _____.

Answer 12

Na+; K+

Question 13

A bundle of muscle fibers (muscle cells) is called a ________________.

Answer 13

fascicle

Question 14

The neurons that carry the signals from the brain to effectors, such as muscles, to carry out their effects, such as movement, are called ______________

Answer 14

motor neurons

Question 15

The site at which the nerve and muscle come together is called the

Answer 15

neuromuscular junction

Question 16

Muscle contractions in which a muscle is flexed without moving (like when holding a textbook straight out in front of you) are called _____________ contractions.

Answer 16

isometric

Question 17

Activating more and more motor units in a muscle to reach the required strength for a given task is called

Answer 17

recruitment

Question 18

Isotonic muscle contractions in which the muscle is lengthening while contracting (like when slowly extending your arm to put something down gently) are called ______________ contractions.

Answer 18

eccentric

Question 19

A group of muscle fibers innervated by the same motor neuron are called a

Answer 19

motor unit

Question 20

In order for a muscle to have optimal contraction when needed, the sarcomeres should be _____________ at rest.

Answer 20

at their optimal length

Question 21

_______________ is the constant state of partial muscle contraction maintained by the central nervous system. _______________ is when the muscles are more flaccid and weak than they should be and ______________ is when they are too rigid, spastic, and overactive.

Answer 21

muscle tone; hypotonia; hypertonia

Question 22

Which of the following performance enhancing substances is NOT correctly paired with its effect?

Answer 22

creatine: increases muscle mass and endurance

Question 23

Burst activities, like sprinting, use anaerobic _____________ fibers, while high endurance activities like marathons or posture use aerobic _____________ fibers, and the ____________ fibers fall in between for activities like walking.

Answer 23

fast glycolytic; slow oxidative; fast oxidative (intermediate)

Question 24

Endurance exercise triggers all of the following EXCEPT:

angiogenesis (new blood vessel formation)
more mitochondria in the muscle cells
the formation of more muscle cells (hyperplasia)
more myogloben in the muscle cells

Answer 24

the formation of more muscle cells (hyperplasia)

Question 25

Resistance (strength) training triggers all of the following EXCEPT: formation of more muscle cells (hyperplasia) increase in tendon strength increase in bone density increase in muscle cell size (hypertrophy)

Answer 25

the formation of more muscle cells (hyperplasia)

Question 26

Which of the following is NOT true regarding cardiac muscle cells? They are autorhythmic, meaning they can initiate contractions without outside influence They have multiple nuclei due to multiple stem cells fusing during their formation They are highly fatigue resistant due to a high number of mitochondria and myoglobin They have intercalated discs with gap junctions that allow large sections of muscles to contract together as one

Answer 26

They have multiple nuclei due to multiple stem cells fusing during their formation

Question 27

Skeletal and cardiac muscle heal through

Answer 27

scarring and fibrosis

Question 28

In cardiac muscle, the desmosomes function to

Answer 28

prevent the cells from pulling apart

Question 29

Smooth muscle heals through

Answer 29

hyperplasia new cell formation regeneration via stem cells called pericytes all of the above

Question 30

Which of the following is NOT true regarding smooth muscle cells? They are present in internal organs, such as blood vessels, the intestines, the eyes, and the bladder They do not have a neuromuscular junction They are composed of functional units called sarcomeres They can increase in size due to an increase in the number or cells or size of the cells.

Answer 30

They are composed of functional units called sarcomeres

Question 31

Smooth muscle contractions can be stimulated by

Answer 31

the autonomic (automatic/involuntary) nervous system hormone stimulation (ligands) stretching (mechanoreceptors) built-in pacesetter cells all of the above

Question 32

Identify the two types of myrofilaments

Answer 32

actin and myosin

Question 33

Identify the 2 molecules that Ca2+ moves out of the way to expose the binding sites on actin:

Answer 33

troponin and tropomyosin

Question 34

The ___________ is defined as the region between two z-lines

Answer 34

sarcomere

Question 35

Identify 3 sources of ATP for muscle contraction:

Answer 35

creatine phosphate, glycolysis aerobic, respiration

Question 36

Identify 2 possible causes of muscle fatigue

Answer 36

Lack of ATP; Lactic acid buildup affecting pH and enzymes; Na+ and K+ imbalances from repeated use; sarcoplasmic reticulum and/or sarcolemma damage affecting Ca2+ regulation