Chapter 10 - Muscle Tissue: BIOL 2301
An action potential for a muscle cell is propagated along the...
Sarcolemma
The muscle cell membrane is called the...
Sarcolemma
The area between two Z discs is termed a...
Sarcomere
Calcium ions released from the sarcoplasmic reticulum enter the...
Sarcoplasm
The neurotransmitter at the neuromuscular junction is...
Acetylcholine
(T/F) The I-band of a sarcomere is widest when a muscle is relaxed.
True Explanation: The I-band is widest when a muscle is relaxed.
Increased calcium ion permeability of the presynaptic terminal cell membrane is caused by an...
Action potential
A bundle of muscle fibers is known as a...
Answer:
Which region of the sarcomere does not change length between muscle relaxation and muscle contraction?
A band Explanation: The A band of the sarcomere is constant in length.
The actin-myosin bond is broken by the attachment of...
ATP
Uncovering binding sites for myosin on actin myofilaments involves troponin binding to...
Calcium ions Explanation: Troponin binds with calcium ions to cause tropomyosin to move and uncover myosin binding sites.
Movement of sodium ions into the muscle cell at the neuromuscular junction causes...
Depolarization of the muscle cell membrane Explanation: Sodium ions entering the muscle cell causes depolarization of the muscle cell membrane.
In a fully contracted sarcomere, the H zone...
Disappears
Which connective tissue wrapping separates individual muscle fibers?
Endomysium Explanation: Endomysium (endo is Greek for "within") surrounds each muscle fiber.
(T/F) A short rest period after a muscle fiber experiences fatigue will allow that muscle fiber to contract again equally as long as it did before the fatigue
False
(T/F) ATP is continually consumed by a resting muscle fiber.
False
(T/F) In fully contracted muscles, the actin filaments lie side-by-side
False
(T/F) Multiunit smooth muscle is characterized by the use of gap junctions between cell membranes
False
(T/F) A skeletal muscle fiber (cell) contains a single nucleus.
False Explanation: A single skeletal muscle fiber contains multiple nuclei (smooth muscle cells contain a single nucleus, cardiac muscle contains one or two nuclei)
Cross bridges form between binding sites on actin myofilaments and...
Myosin heads
Energy produced when ATP is converted to ADP and phosphate is stored in...
Myosin heads
In a fully contracted sarcomere, the actin myofilaments...
Overlap
What is released when myosin heads attach to actin filaments?
Phosphate
Choline formed from the breakdown of acetylcholine in the synaptic cleft is resorbed by the...
Presynaptic terminal membrane Explanation: Choline is resorbed through the presynaptic terminal membrane for re-use.
The neurotransmitter at the neuromuscular junction increases permeability of the muscle cell membrane to...
Sodium ions Explanation: Acetylcholine increases the muscle cell membrane permeability to sodium ions.
An action potential enters a muscle cell at the...
T-tubule
During muscle contraction, binding sites for myosin are uncovered by the movement of...
Tropomyosin
During muscle contraction, calcium ions bind to...
Troponin
(T/F) Myofibrils are composed of protein filaments called actin and myosin.
True
