Chapter 10: Muscle Tissue and Physiology

Question 1

muscular system

Answer 1

the body system that consists of the skeletal muscles & associated connective tissue

Question 2

muscle tension

Answer 2

generated force that….
creates movement
maintains posture
generates heat
stabilizes joints
regulates material flow through hollow organs

Question 3

endomysium

Answer 3

the surrounding extracellular matrix of muscle cells
* it holds muscle cells together within muscle tissue
* transmits tension to neighboring cells.

Question 4

muscle fibers

Answer 4

alternating name for a skeletal muscle cell

Question 5

intercalated discs

Answer 5

• unites cardiac muscle cells
• permits them to coordinate contraction so that the heart contracts as a unit

Question 6

3 types of muscle tissue

Answer 6

skeletal, cardiac, smooth

Question 7

describe skeletal muscle tissue structure

Answer 7

• long, cylindrical striated fibers
• multinucleated
• voluntary
• function: produces movement of the body

Question 8

describe cardiac muscle tissue structure

Answer 8

• short, wide, branching striated cells w/ intercalated discs
• single nucleus or 2 nuclei
• involuntary
  function: produces beating of the heart

Question 9

describe smooth muscle tissue structure

Answer 9

• long and flattened cells (oval-shaped)
• joined by gap junctions
• single nucleus
• found in walls of hollow organs, skin, and eyes
• involuntary

Question 10

contractility

Answer 10

the ability of cells to contract (proteins within cell draw together)

Question 11

excitability

Answer 11

cells responsiveness in the presence of stimuli

Question 12

conductivity

Answer 12

Ability of electrical changes across a cell’s membrane to be conducted along the entire length of the plasma membrane.

Question 13

distensibility

Answer 13

A cell’s ability to stretch without damage or rupturing

Question 14

elasticity

Answer 14

A cell’s ability to return to their original shape after being stretched

Question 15

sarcoplasm

Answer 15

the cytoplasm of a muscle fiber

Question 16

sarcolemma

Answer 16

the plasma membrane of a muscle fiber

Question 17

myofibrils

Answer 17

bundles of specialized proteins, including those involved in muscle contraction.

Question 18

sarcoplasmic reticulum

Answer 18

modified endoplasmic reticulum of muscle fibers;
STORES CALCIUM IONS

Question 19

transverse tubules

Answer 19

hollow inward extensions of sarcolemma which surround myofibrils; filled with ECF

Question 20

terminal cisternae

Answer 20

enlarged regions of sarcoplasmic reticulum where it contacts t-tubules

Question 21

contractile proteins

Answer 21

proteins that produce tension

Question 22

regulatory proteins

Answer 22

controls when the muscle fiber can contract

Question 23

structural proteins

Answer 23

hold myofilaments in place and ensures stability of myofibril and muscle fiber

Question 24

thick filaments

Answer 24

a myofilament composed of many molecules of the protein myosin

Question 25

thin filament

Answer 25

myofilament composed of molecules of the proteins actin, troponin, & tropomyosin

Question 26

elastic filaments

Answer 26

myofilament consisting of structural protein titin

Question 27

sliding filament mechanism

Answer 27

the mechanism of contraction of a muscle cell in which thin & thick filaments slide past one another

Question 28

leak channels

Answer 28

ion channels that are always open - continually allow ions to follow gradients into/out of cell

Question 29

gated channels

Answer 29

ion channels that are closed at rest, and open only in response to certain stimuli

Question 30

ligand-gated channels

Answer 30

ion channel that opens in response to certain chemical binding to the channel (or to an associated receptor)

Question 31

voltage-gated channels

Answer 31

open or close in response to changes in voltage across the membrane.

Question 32

Na+/ K+ ion pump

Answer 32

maintains concentration gradients of sodium and potassium ions across the sarcolemma, using ATP

Question 33

action potential

Answer 33

quick, temporary change in the membrane potential in a single region of the plasma membrane

Question 34

depolarization stage

Answer 34

temporary increase in cell membrane potential - Less negative (ex: from -90 to 30)

Question 35

repolarization stage

Answer 35

sarcolemma returns to its negative resting membrane potential - it goes back to a polarized state

Question 36

motor neuron

Answer 36

neuron that transmits motor impulses from the CNS to a muscle or gland cell

Question 37

synapse

Answer 37

location where presynaptic neuron communicated with its target cell

Question 38

neuromuscular junction

Answer 38

where a neuron communicates with a muscle fiber

Question 39

glycolytic catabolism

Answer 39

- ATP-producing reaction - glucose is broken down to make 2 molecules of pyruvate - does not require oxygen

Question 40

oxidative catabolism

Answer 40

- a reaction that occurs in mitochondria - oxygen IS required to make ATP - produces MORE ATP than glycolysis.

Question 41

muscle twitch

Answer 41

a single cycle of contraction of a muscle fiber generated by a single action potential

Question 42

twitch contraction: Latent period

Answer 42

the time that it takes for the action potential to spread through the sarcolemma

Question 43

twitch contraction: contraction period

Answer 43

a rapid increase in tension as crossbridge cycles occur repeatedly.

Question 44

twitch contraction: relaxation period

Answer 44

tension decreases due to the decreasing calcium ion concentration in the cytosol. Muscle fiber eventually relaxes fully.

Question 45

refractory period

Answer 45

period during which muscle fiber cannot respond to another stimulus.

Question 46

unfused tetanus

Answer 46

- type of wave summation - muscle fiber is stimulated rapidly and can only partially relax b/w contractions

Question 47

fused tetanus

Answer 47

type of wave summation - muscle fiber is stimulated rapidly and fiber is NOT allowed to relax b/x contractions

Question 48

type 1 fibers

Answer 48

* slow-twitch fibers that are small-intermediate in diameter * contract slowly/less forcefully than other fibers * requires large ATP amounts via oxidative catabolism * a large amount of myoglobin, mitochondria, & blood supply

Question 49

type 2 fibers

Answer 49

fast-twitch fibers ... often larger in diameter & contract more rapidly than type I fibers * quickly fatigued * rely on glycolytic energy * less myoglobin, less mitochondria, less blood supply

Question 50

motor unit

Answer 50

the group of muscle fibers innervated by a single motor neuron

Question 51

muscle tone

Answer 51

Even when a muscle is at rest, it still has some degree of tension - tone is due to involuntary activation of motor units by the brain and spinal cord