Class Quiz 7 Flashcards

Which of the following is not a function of smooth muscle tissue?

forcing urine out of the urinary tract

altering the diameter of the respiratory passageways

elevating hairs on the arm

forcing blood from the heart into the major arteries

moving food materials along the digestive tract

Which of the following surrounds the individual muscle cell?

perimysium

endomysium

epimysium

fasicle

When a muscle is unable to respond to stimuli temporarily, it is in which of
the following periods?

relaxation period

refractory period

latent period

fatigue period

The functional role of T-tubules is to?

stabilize the G and F actin

relay the action potential to the interior of the muscle fiber.

hold cross bridges in place in a resting muscle

synthesize ATP to provide energy for muscle contraction

Calcium ions bind to the ________ molecule in skeletal muscle cells.

actin

tropomyosin

troponin

myosin

The complex known as the triad consists of:

actin, myosin and tropomyosin

transverse tubules and terminal cisternae

myofilaments, myofibirils and sarcomeres

A band, H band, and I bands

actin, myosin, and sarcomeres

The sliding filament model of contraction involves:

actin and myosin sliding past each other but not shortening

the shortening of thick filaments so that thin filaments slide past

actin and myosin shortening but not sliding past each other

the Z discs sliding over the myofilaments

Myoglobin:

holds a reserve supply of oxygen in muscle cells

breaks down glycogen

is a protein involved in the direct phosphorylation of ADP

produces the end plate potential

The following is a list of the events that occur during a muscle contraction.

1. Myosin cross-bridges bind to the actin.
2. The free myosin head splits ATP.
3. Calcium ion is released from the sarcoplasmic reticulum.
4. The myosin head pivots toward the center of the sarcomere.
5. Calcium ion binds to troponin.
6. The myosin head binds an ATP molecule and detaches from the actin.
The correct sequence of these events is

1, 4, 6, 2, 3, 5.

3, 5, 1, 4, 6, 2.

3, 5, 1, 2, 4, 6.

1, 3, 5, 4, 6, 2.

5, 1, 4, 6, 2, 3.

Because skeletal muscle contractions demand large quantities of ATP,
skeletal muscles have

a rich nerve supply.

a rich blood supply.

abundant mitochondria.

A, B, and C

both B and C

During anaerobic glycolysis

oxygen is not consumed.

pyruvic acid is produced.

ATP is produced.

all of the above

B and C only

The types of muscle tissue include all of the following, except

skeletal muscle.

smooth muscle.

cardiac muscle.

striated muscle.

none of the above

An excitatory neurotransmitter secreted by motor neurons innervating
skeletal muscle is:

acetylcholine

gamma aminobutyric acid

cholinesterase

norepinephrine

The major function of the sarcoplaslmic reticulum in muscle contraction is
to:

make and store phosphocreatine

synthesis actin and myosin myofilaments

provide a source of myosin for the contraction process

regulate intracellular calcium concentration

At rest, active sites on the actin are blocked by:

myosin molecules

troponin molecules

tropomyosin molecules

calcium molecules

ATP molecules

Creatine phosphate functions in the cell by:

forming a temporary chemical compound with myosin

forming a chemical compound with actin

inducing a conformational change in the myofilaments

storing energy that will be transferred to ADP to resynthesize ATP as needed

Of the following muscle types, which has only one nucleus, sarcomeres, and
gap junctions?

visceral smooth muscle

multiunit smooth muscle

cardiac muscle

skeletal muscle

Which of these would lead to increased oxygen consumption?

increased heat production

increased muscle activity

increased aerobic respiration by muscle cells

increased conversion of lactic acid to glucose

all of the above

An anaerobic metabolic pathway that results in the production of two net
ATP per glucose plus two pyruvic acid molecules is:

the citric acid cycle

glycolysis

hydrolysis

the electron transport system

The functional unit of skeletal muscle is the:

sarcolemma

sarcomere

sarcoplasmic reticulum

myofibril

myofilament