Chapter 17-1

Treppe

• Also known as the staircase phenomenon.

Motor Units

• Some motor neurons stimulate only a few dozen muscle fibers.
• The more muscle fibers stimulated by a motor neuron, the more precise the movements of that muscle can be is not true.

Muscle Size

• A decrease in muscle size is termed atrophy.

Muscle Cell Characteristic

• Contractility is the characteristic of the muscle cell that causes movement.

Sarcomere

• A sarcomere is a segment of myofibril between two successive Z-lines.

Skeletal Muscle Cell Striations

• The striations seen in skeletal muscle cells under the microscope are part of the A-bands.

Myofilaments

• Actin can be described as a globular protein strung together like beads to form two intertwined strands.
• Myosin can be described as bundled golf clubs with their heads sticking out from the bundle.

Sarcoplasmic Reticulum

• After calcium is released from the sarcoplasmic reticulum, the calcium combines with troponin.

Glucose Storage

• Glucose can be stored in the muscle as glycogen.

Myoglobin Molecule

• The substance that attracts oxygen in the myoglobin molecule is iron.

Anaerobic Respiration

• The lactate produced by anaerobic respiration is converted back to glucose in the liver.

Muscle Contraction

• Calcium tends to accumulate in the sarcoplasm, is not a factor in why a warm muscle contracts more forcefully than a cool muscle.
• Muscle contractions will continue as long as calcium ions are attached to the troponin.

ATP Breakdown

• All of the above are end-products of the breakdown of ATP, an inorganic phosphate, energy that can be used in muscle contraction, and ADP.

T-Tubules

• Smooth muscle does not have T-tubules.

Calcium Ion Storage

• The structure that functions to temporarily store calcium ions is the sarcoplasmic reticulum.

Peristalsis

• Single-unit smooth muscle is responsible for peristalsis.

Muscle Cell Names

• A sarcocyte is not a name for a muscle cell.

Neuromuscular Junction

• T-tubules are not a part of the neuromuscular junction.

Heat Production

• Body temperature functions on a negative-feedback mechanism is not a statement regarding heat production.

Muscle Tone

• Muscles with less than normal muscle tone are referred to as spastic is not a correct statement regarding muscle tone.

Cardiac Muscle

• Cardiac muscle requires nervous stimulation to contract is an incorrect statement about cardiac muscle.
• Cardiac muscle forms an electrically coupled mass called a syncytium is an incorrect statement about cardiac muscle.

Isometric Contraction

• Static tension describes an isometric contraction.

Satellite Cell

• A satellite cell in a muscle can become active after an injury to a muscle.

Myofibrils

• The myofibrils contain about 15,000 sarcomeres

Motor End Plate

• The motor end plate makes up part of the neuromuscular junction.

Sarcomere Contraction

• The A-band stays almost the same size during contraction.

Muscle Contraction Length

• Muscles usually contract to about 80% of their length.