Muscle Tissues Flashcards
An entire skeletal muscle is surrounded by _________.
epimysium
A motor neuron and all the muscle fibers it supplies is called a(n) _________.
motor unit
What does not occur during skeletal muscle contraction?
Calcium binds to myosin heads.
What is the ion released from the terminal cisternae that combines with troponin and removes the blocking action of tropomyosin, resulting in the formation of cross bridges?
Ca^(2+)
Each skeletal muscle fiber is controlled by a neuron at a single________.
Neuromuscular junction
Description of the composition of the structure known as a triad in a skeletal muscle fiber
terminal cisterna, transverse tubule, and terminal cistern.
In the sliding filament model of muscle contraction, the myofilaments slide over each other, resulting in the overlapping of actin and _______.
myosin
The dense layer of collagen fibers that surround an entire skeletal muscle is the ________.
epimysium
The functional unit of contraction in a skeletal muscle fiber is the ______.
sarcomere
The space between the neuron and the muscle is the _______.
synaptic cleft
The term that means a continued mild or partial contraction of a muscle that keeps it healthy and ready to respond is muscle _________.
tone
The type of muscle contraction in which the muscle fibers produce increased tension, but the muscle neither shortens nor lengthens, is called __________.
isometric
What do you know about the fibers in smooth muscle tissue?
fibers are small and spindle-shaped
What substance increases in quantity during repetitive muscle contraction during oxygen deficit?
lactic acid
The sequence of electrical changes that occurs along the sarcolemma when a muscle fiber is stimulated is known as the _______.
action potential
What binds calcium ions in a smooth muscle, causing contractions?
calmodulin
Elasticity refers to the ability of a muscle fiber to _________.
recoil and resume its resting length after being stretched
What muscle in the arm is voluntary?
The muscle that extends the arm at the elbow
A sarcomere is part of a(n)________.
myofibril
“cross bridges” that link between the thick and thin filaments are formed by the __________.
globular head of thick filaments
The alternating contraction and relaxation of opposing layers of smooth muscle is referred to as ________.
peristalsis
What characteristic is unique to smooth muscle?
the absence of striations
T or F
Cardiac muscle control is voluntary
False
T or F
Communication between neurons and skeletal muscle fibers occurs at specialized junctions called neuromuscular junctions.
True
T or F
Cross bridges are formed by the actin molecules.
False
T or F
During the recovery period after exercise, the body’s need for oxygen is increased.
True
T or F
In isotonic contractions, the muscle changes in length and the tension remains constant through most of the contractile period.
True
T or F
Lactic acid is an end product of anaerobic fermentation that contributes to muscle fatigue.
True
T or F
Muscles that exert very fine control (such as the muscles controlling movements of the fingers and eyes) have large motor units.
False
T or F
One of the functions of the smooth muscle tissue is to force blood from the heart into the major arteries.
False
T or F
The area of the sarcomere that contains only thin and elastic filaments is the I band.
True
T or F
The neurotransmitter that stimulates skeletal muscle is acetylcholine.
True
T or F
The sequence of events that forms the link between electrical activity in the sarcolemma and the initiation of a contraction is called excitation-contraction coupling.
True
T or F
The skeletal muscle complex known as the triad consists of the transverse tubule and the terminal cisternae.
True
T or F
The space between the neuron and the muscle is the axon terminal.
False
T or F
The type of muscle fiber that is most resistant to fatigue is the fast fiber.
False
T or F
Thick filaments consist mainly of the protein actin.
False
T or F
Cross bridges occur when myosin heads combine with the binding sites on actin.
True
T or F
Cross bridge attachment to actin requires K+.
False
T or F
In the initial stages of repolarization, the ionic conditions are restored, returning the membrane to its resting potential.
False
T or F
Ca++ is essential for skeletal muscle contraction.
True
T or F
Subthreshold stimuli result in only a small amount of muscle response movement.
False
T or F
At maximal stimulus, the muscle is contracting at full strength and all motor units are recruited.
True
