Chapter 10 - Muscle Tissue & Physiology

Question 1

Six functions of skeletal muscle

Answer 1

Produce skeletal movement, maintain posture and position, support soft tissues, guard entrances and exits, maintain body temperature, and store nutrients

Question 2

Skeletal muscle

Answer 2

Organs composed mainly of skeletal muscle tissue also containing connective tissues, nerves, and blood vessels

Question 3

Muscle fiber

Answer 3

Cell in skeletal muscle tissue

Question 4

Intercalated discs

Answer 4

Regions where adjacent cardiocytes interlock and where gap junctions permit electrical couping between the cells

Question 5

Gap junctions

Answer 5

Connections between cells that permit electrical coupling

Question 6

Sarcolemma

Answer 6

Plasma membrane of a muscle fiber

Question 7

Sarcoplasm

Answer 7

Cytoplasm of the muscle fiber

Question 8

Transverse tubules

Answer 8

T tubules, narrow tubes whose surfaces are continuous with the sarcolemma and extend deep into the sarcoplasm, conducting electrical impulses throughout the cell interior

Question 9

Myofibrils

Answer 9

Cylindrical structures, the active shortening of which is responsible for skeletal muscle fiber contractions

Question 10

Myofilament

Answer 10

Protein filaments arranged into bundles that make up myofibrils

Question 11

Thin filament

Answer 11

A cytoskeletal filament in a skeletal or cardiac muscle cell; consists of actin, troponin, nebulin, and tropomyosin

Question 12

Actin

Answer 12

The protein component of microfilaments that forms thin filaments in skeletal muscles and produces contractions of all muscles through interaction with thick filaments (myosin)

Question 13

Thick filament

Answer 13

A cytoskeletal filament in a skeletal or cardiac muscle cell; composed of myosin, with a core of titin

Question 14

Myosin

Answer 14

Ptrotein component of thick filaments

Question 15

Triad

Answer 15

Combination of a pair of terminal cisternae plus a T tubule

Question 16

Sarcoplasmic reticulum

Answer 16

Membrane complex that forms a tubular network around each individual myofibril, stores calcium

Question 17

Terminal cisternae

Answer 17

Expanded chambers where tubules of the SR elarge and fuse on either side of a T tubule

Question 18

I band

Answer 18

Light band of the sarcomere, primarily thin filaments

Question 19

A band

Answer 19

Dark band of the sarcomere, containing overlapping thick and thin filaments with thick filaments at the center of each sarcomere

Question 20

Z lines

Answer 20

Bisect the I bands and mark the boundary between adjacent sarcomeres

Question 21

M line

Answer 21

Center of the A band, center of the sarcomere

Question 22

Sarcomere

Answer 22

Smallest functional unit of muscle fiber

Question 23

Active site

Answer 23

Location on actic where myosin can bind to produce muscle contraction

Question 24

Troponin

Answer 24

Molecule consisting of three globular subunits - when Ca2+ binds to troponin, it causes the tropomysin to change shape, exposing the active site and allowing muscle contraction

Question 25

Tropomyosin

Answer 25

Covers active sites and prevents actin-myosin interaction; moved by troponin

Question 26

Cross-bridge

Answer 26

When myosin heads interact with thin filaments during a contraction

Question 27

Sliding filament theory

Answer 27

Where thin filaments are sliding toward the center of each sarcomere alongside the thick filaments

Question 28

Polarized

Answer 28

Unequal charge distribution, with the sarcoplasm having a negative charge and the outer surface having apositive

Question 29

Depolarization

Answer 29

A change in membrane potential from a negative value toward 0 mV

Question 30

Repolarization

Answer 30

The movement of the membrane potential away from a postitive value and toward the resting potential

Question 31

Hyperpolarization

Answer 31

Result of movenemt of potassium ions out of a cell; membrane potential becomes more negative

Question 32

Neuromuscular junction

Answer 32

Synapse between two skeletal muscle fibers

Question 33

Synapse

Answer 33

Location where communication between aneuron and another cell occurs

Question 34

Axon terminal

Answer 34

Synaptic terminal of a neuron, the cytoplasm of which contains vesicles filled with acetylcholine (AC h), a neurotransmitter

Question 35

Motor end plate

Answer 35

Specialized region of the sarcolemma which receives communication from axon terminal

Question 36

Synaptic cleft

Answer 36

Narrow space between axon terminal and motor end plate

Question 37

Excitation-contraction coupling

Answer 37

Link between the generation of an action potential in the sarcolemma and the start of a muscle contraction