Module 4

Question 1

acetylcholine (ACh)

Answer 1

neurotransmitter that binds at a motor end-plate to trigger depolarization

Question 2

actin

Answer 2

protein that makes up most of the thin myofilaments in a sarcomere muscle fiber

Question 3

action potential

Answer 3

change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibres

Question 4

cardiac muscle

Answer 4

heart muscle, under involuntary control, composed of striated cells that attach to form fibers, each cell contains a single nucleus, contracts autonomously

Question 5

connective tissue

Answer 5

type of tissue that serves to hold in place, connect, and integrate the body’s organs and systems

Question 6

contractility

Answer 6

ability to shorten/contract forcibly

Question 7

depolarize

Answer 7

to reduce the voltage difference between the inside and outside of a cell’s plasma membrane (the sarcolemma for a muscle fiber), making the inside less negative than at rest

Question 8

elasticity

Answer 8

ability to stretch and rebound

Question 9

elastic fiber

Answer 9

fibrous protein within connective tissue that contains a high percentage of the protein elastin that allows the fibers to stretch and return to original size

Question 10

epimysium

Answer 10

outer layer of connective tissue around a skeletal muscle

Question 11

excitability

Answer 11

ability to undergo neural stimulation

Question 12

excitation-contraction coupling

Answer 12

sequence of events from motor neuron signaling to a skeletal muscle fiber to contraction of the fiber’s sarcomeres

Question 13

extensibility

Answer 13

ability to lengthen/extend

Question 14

histology

Answer 14

microscopic study of tissue architecture, organization, and function

Question 15

motor end-plate

Answer 15

sarcolemma of muscle fiber at the neuromuscular junction, with receptors for the neurotransmitter acetylcholine

Question 16

muscle tissue

Answer 16

type of tissue that is capable of contracting and generating tension in response to stimulation; produces movement

Question 17

myoblast

Answer 17

muscle-forming stem cell

Question 18

myofibril

Answer 18

long, cylindrical organelle that runs parallel within the muscle fiber and contains the sarcomeres

Question 19

myosin

Answer 19

protein that makes up most of the think cylindrical myofilament within a sarcomere muscle fiber

Question 20

nervous tissue

Answer 20

type of tissue that is capable of sending and receiving impulses through electrochemical signals

Question 21

neuromuscular junction (NMJ)

Answer 21

synapse between the axon terminal of a motor neuron and the section of the membrane of a muscle fiber with receptors for the acetylcholine released by the terminal

Question 22

neurotransmitter

Answer 22

signaling chemical released by nerve terminals that bind to and activate receptors on target cells

Question 23

perimysium

Answer 23

connective tissue that bundles skeletal muscle fibers into fascicles within a skeletal muscle

Question 24

power stroke

Answer 24

action of myosin pulling actin inward (toward the M line)

Question 25

projection

Answer 25

bone markings where part of the surface sticks out above the rest of the surface, where tendons and ligaments attach

Question 26

sarcolemma

Answer 26

plasma membrane of a skeletal muscle fiber

Question 27

sarcomere

Answer 27

longitudinally repeating functional unit of skeletal muscle, with all of the contractile and associated proteins involved in contraction

Question 28

sarcoplasm

Answer 28

cytoplasm of a muscle cell

Question 29

sarcoplasmic reticulum (SR)

Answer 29

specialized smooth endoplasmic reticulum, which stores, releases, and retrieves Ca++

Question 30

skeletal muscle

Answer 30

usually attached to bone, under voluntary control, each cell is a fiber that is multinucleated and striated

Question 31

smooth muscle

Answer 31

under involuntary control, moves internal organs, cells contain a single nucleus, are spindle-shaped, do not appear striated; each cell is a fiber

Question 32

striation

Answer 32

alignment of parallel actin and myosin filaments which form a banded pattern

Question 33

supportive connective tissue

Answer 33

type of connective tissue that provides strength to the body and protects soft tissue

Question 34

synaptic cleft

Answer 34

space between a nerve terminal (axon) and a motor end-plate

Question 35

T-tubule

Answer 35

projection of the sarcolemma into the interior of the cell

Question 36

thick filament

Answer 36

the thick myosin strands and their multiple heads projecting from the center of the sarcomere toward, but not all the way to, the Z-discs

Question 37

thin filament

Answer 37

thin strands of actin and its troponin-tropomyosin complex projecting from the Z-discs toward the center of the sarcomere

Question 38

tissue

Answer 38

group of cells that are similar in form and perform related functions

Question 39

tropomyosin

Answer 39

regulatory protein that covers myosin-binding sites to prevent actin from binding to myosin

Question 40

troponin

Answer 40

regulatory protein that binds to actin, tropomyosin, and calcium

Question 41

voltage-gated sodium channels

Answer 41

membrane proteins that open sodium channels in response to a sufficient voltage change, and initiate and transmit the action potential as Na+ enters through the channel