BOI 201 Chapter 9 Flashcards

What does A represent?

The tissue that binds muscles into functional groups.
Connective tissue covering the exterior of a muscle organ.

What does B represent?

Within the muscle.
Connective tissue sheath surrounding individual muscle fibers.

What does C represent?

Individual muscle fiber.
Skeletal and smooth muscle cells (but not cardiac muscle cells) are elongated and called___.

What does D represent?

Bundles.
Bundles of muscle cells surrounded by a perimysium

What does E represent?

Around the fascicles.
Connective tissue surrounding muscle fiber bundles.

What does A represent?

A sarcomere is defined as the segment between two neighboring Z-lines. In electron micrographs of cross-striated muscle, the ___.

What does B represent?

Within the A-band is a polar region called the ___.

What does C represent?

Surrounding the Z-line is the region of the ___.

What does D represent?

Following the I-band is the ___.

What does E represent?

Inside the H-zone is a thin ___.

Depends on oxygen delivery and aerobic mechanisms.

Have very fast-acting myosin ATPases and depend upon anaerobic metabolism during contraction.

Red fibers, the smallest of the fiber types.

Contain abundant amounts of glycogen.

Abundant in muscles used to maintain posture.

A relatively high percentage are found in successful marathon runners.

The strongest stimulus that produces increased contractile force.

The stimulus above which no stronger contraction can be elicited, because all motor units are firing in the muscle.

All skeletal muscle is maintained in a constant, slightly contracted state, spinal reflexes activate groups of motor units alternately

Determined by alternating motor units of a muscle organ even when the muscle is at rest.

A state of continuous muscular contraction, especially when induced artificially by rapidly repeated stimuli.

Continued sustained smooth contraction due to rapid stimulation.

The situation in which contractions become stronger due to stimulation before complete relaxation occurs.

Temporal aka _____________, occurs because the second contraction occurs before the muscle has completely relaxed.

How a smooth increase in muscle force is produced.

The force of contraction is controlled more precisely by recruitment also called __________________.

A sacromere is the distance between two ___.

The ___ contains only the actin filaments.

The thicker filaments are the ___ filaments.

Both actin and myosin are found in the ___.

The myosin filaments are located in the ___.

Serves as the actual "trigger" for muscle contraction by removing the inhibition of the troponin molecules.

A neurotransmitter released at motor end plates by the axon terminals.

Diffusion across the cell membrane results in depolarization.

Activate synaptic vesicles in axon terminals.

Used to convert ADP to ATP by trnsfer of high-energy phosphate group. A reserve high-energy compound.

Destroys ACh.

An enzyme located in the synaptic cleft.

Once a motor neuron has fired, all the muscle fibers in a muscle contract.
True / False

The thin filaments (actin) contain a polypeptide subunit G actin that bears active sites for myosin attachment.
True / False

The thin filaments (actin) contain a polypeptide sub-unit G actin that bears active sites for myosin attachment.
True / False

The force of muscle contraction is controlled by multiple motor unit summation or recruitment.
True / False

Eccentric contractions are more forceful than concentric contractions.
True / False

A motor neuron and all the muscle cells that it stimulates are referred to as a motor end plate.
True / False

Peristalsis is characteristic of smooth muscle.
True / False

A contraction in which the muscle does not shorten but its tension increases is called isometric.
True / False

During isotonic contraction, the heavier the load, the faster the velocity of contraction.
True / False

During isometric contraction, the energy used appears as movement.
True / False

One of the important functions of skeletal muscle contraction is a production of heat.
True / False

An increase in the calcium ion level in the sarcoplasm starts the sliding of the thin filaments. When the level of calcium ions declines, sliding stops.
True / False

Muscle contraction will always promote movement of body parts regardless of how they are attached.
True / False

Although there are "no" sacromeres, smooth muscle still possesses thick and thin filaments.
True / False

Muscle tone is the small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units.
True / False

Cells of unitary (single-unit) smooth muscle are found in the longitudnal and circular muscle layers of the intestine.
True / False

A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell.
True / False

The effect of a neurotransmitter on the muscle cell membrane is to modify its ion permeability properties temporarily.
True / False

When a muscle fiber contracts, the I bands diminish in size, the H zones disappear, and the A bands move closer together but do not diminish in length.
True / False

Contractures are a result of a total "lack" of ATP.
True / False

Smooth muscles relax when intercellular Ca2+ (calcium ion) levels drop but may not cease contractions.
True / False

Which muscle cells have the greatest ability to regenerate?

Most skeletal muscle contain ___.

Fatigued muscle cells that recover rapidly are the products of ___.

The strongest muscle contractions are normally achieved by ___.

Myoglobin ___.

What structure in skeletal muscle cells functions in calcium storage?

Immediately following the arival of the stimulus at a skeletal muscle cell there is a short period called the ___ period during which the events of excitation-contraction coupling occur.

Marathons

25 Meter Swim

Weight Lifting

A smooth, sustained contraction from rapid stimulation is called ____.

Only ____ muscle cells commonly branch.

Only ______ muscle cells are always multinucleated.

The end of the muscle that typically moves when a muscle contracts is called the _____.

In the synaptic cleft of a neuromuscular junction, and enzyme called _____ is always present.

The time in which cross bridges are active is called the period of ____.