Openstax Anatomy and Physiology: Chapter 10 Muscle Tissue

Slow fibers have a small network of _______.

Capillaries

Muscle relaxation occurs when ________.

calcium ions are actively transported into the sarcoplasmic reticulum

Drug X blocks ATP regeneration from ADP and phosphate. How will muscle cells respond to this drug?

none of the above

Muscle fatigue is caused by ________.

exhaustion of energy reserves and buildup of lactic acid levels

Which element is important in directly triggering contraction?

calcium (Ca++)

From which embryonic cell type does muscle tissue develop?

myoblast cells

The muscles of a professional sprinter are most likely to have ________.

80 percent fast-twitch muscle fibers and 20 percent slow-twitch muscle fibers

A sprinter would experience muscle fatigue sooner than a marathon runner due to ________.

anaerobic metabolism in the muscles of the sprinter

The muscles of a professional marathon runner are most likely to have ________.

20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers

During muscle contraction, the cross-bridge detaches when ________.

calcium ions bind to troponin

If cardiac muscle cells were prevented from undergoing aerobic metabolism, they ultimately would ________.

stop contracting

What is common to all three muscle tissues?

excitability, the need for ATP and elasticity

Which cell type helps to repair injured muscle fibers?

satellite cells

In relaxed muscle, the myosin-binding site on actin is blocked by ________.

tropomyosin

What aspect of creatine phosphate allows it to supply energy to muscles?

phosphate bonds

According to the sliding filament model, binding sites on actin open when ________.

calcium ion levels rise

During which phase of a twitch in a muscle fiber is tension the greatest?

contraction phase

What fibers have large glycogen reserves.

Fast

Thin and thick filaments are organized into functional units called ________.

sarcomeres

Depolarization of the sarcolemma means ________.

the inside of the membrane has become less negative as sodium ions accumulate

Muscle that has a striped appearance is described as being ________.

striated

The correct order for the smallest to the largest unit of organization in muscle tissue is ________.

filament, myofibril, muscle fiber, fascicle

Smooth muscles differ from skeletal and cardiac muscles in that they ________.

lack myofibrils

Describes smooth muscle cells

They are resistant to fatigue.

The cell membrane of a muscle fiber is called ________.

sarcolemma

Cardiac muscles differ from skeletal muscles in that they ________.

contain intercalated discs