A&P Quiz 5

Recall that a synovial membrane lines the cavity of a freely movable joint (as you in saw Chapter 4: The Tissue Level of Organization). The synovial fluid it secretes lubricates the joint and permits smooth movement. What kind of cells secrete the synovial fluid?

fibroblasts **Synovial fluid is produced by fibroblasts in the connective tissue of the synovial membrane.

Glycolysis

is an anaerobic process

Why do individual muscle twitches have to be added together, as in summation or tetanus?

Multiple twitches add up to an increase in muscle fiber tension, which increases the strength of the muscle.

Which statement regarding skeletal muscle is true?

Skeletal muscles contain blood vessels.

As a skeletal muscle contraction is initiated, acetylcholine binding alters the motor end plate membrane's permeability to

sodium ions

The region of a sarcomere containing myosin, going from one end of the myosin molecules to the other end of the myosin molecules, is the

A band

The stiffness that occurs at death, when actin and myosin molecules stay linked to each other in a contracted state, is due to a lack of

ATP

Any condition that interferes with the generation of an action potential in the sarcolemma will cause muscular paralysis. Two examples worth noting are Botulism and Myasthenia Gravis. Botulism is a disease that results from the consumption of foods contaminated with a bacterial toxin that prevents the release of ACh at the axon terminals, leading to a severe, potentially fatal, muscular paralysis. The progressive muscular paralysis seen in the autoimmune disease myasthenia gravis results from the loss of ACh receptors at the motor end plate. What is the name of the enzyme that normally breaks down Ach in the neuromuscular junction?

Acetylcholinesterase **Acetylcholinesterase or AChE quickly breaks down the ACh on the motor end plate and in the synaptic cleft, thus inactivating the ACh receptors.

Which of the following is ranked from smallest to largest?

H-band, sarcomere, myofibril, muscle fiber, fascicle, muscle

During moderate activity, which of the following is true regarding muscle metabolism?

Glucose and fatty acids are catabolized.

Upon the nerve impulse arriving at the axon terminal,

acetylcholine is released.

As you unsuccessfully attempt to lift the 300-pound weights off the ground, you are demonstrating ________.

isometric contraction

A primary function of the skeletal system is

maintaining the normal concentrations of calcium and phosphate ions in body fluids.