Chapter 10 Flashcards
Muscle tissue is one of the four major tissue types.
A) True
B) False
A) True
Explanation: Muscle tissue is indeed one of the four major tissue types, alongside epithelial, connective, and nervous tissues.
The plasma membrane of a muscle cell is called the sarcoplasmic reticulum.
A) True
B) False
B) False
Explanation: The plasma membrane of a muscle cell is called the sarcolemma. The sarcoplasmic reticulum is a specialized type of smooth endoplasmic reticulum that stores and releases calcium ions.
Another name for a muscle cell is a muscle fiber.
A) True
B) False
A) True
Explanation: Muscle cells are also known as muscle fibers due to their elongated shape.
Skeletal muscle requires nervous system stimulation to contract.
A) True
B) False
A) True
Explanation: Skeletal muscles are under voluntary control and require stimulation from the nervous system to initiate contraction.
The epimysium is the connective tissue covering the exterior of a muscle.
A) True
B) False
A) True
Explanation: The epimysium is a dense layer of connective tissue that surrounds the entire muscle, providing structural support and protection.
Which of the following statements about the microscopic structure of muscle fibers is not correct:
A) The sarcoplasmic reticulum surrounds each myofibril in a muscle fiber.
B) At each A band-I band junction, the sarcolemma dives deep into the cells interior forming an elongated tube called the T tubule.
C) The T tubule is integrated with two terminal cisterns of the sarcoplasmic reticulum to form triads.
D) At the triad, T tubule proteins act as voltage sensors and change shape in response to voltage changes.
E) All are true statements
E) All are true statements
During repolarization, Sodium (Na+) channels close and voltage-gated Potassium (K+) channels open – the K+ efflux rapidly restores negatively charged conditions inside cell.
A) True
B) False
A) True
Explanation: During repolarization, the closing of Sodium (Na+) channels and the opening of Potassium (K+) channels result in the efflux of K+ ions, which restores the negative membrane potential.
In a relaxed state, the thick and thin filaments overlap only in the I band.
A) True
B) False
B) False
Explanation: In a relaxed state, the thick and thin filaments overlap in the A band. The I band contains only thin filaments and is where the filaments do not overlap.
Once an AP is initiated, it is unstoppable and leads to a muscle fiber contraction.
A) True
B) False
A) True
Explanation: Once an action potential (AP) is initiated, it propagates along the muscle fiber and triggers contraction, making it an all-or-nothing event.
Each muscle fiber is individually innervated by its own axon terminal.
A) True
B) False
A) True
Explanation: Each muscle fiber is connected to a single motor neuron at the neuromuscular junction, where it receives signals to contract.
During repolarization Sodium (Na+) channels close and Potassium (K+) channels open.
A) True
B) False
A) True
Explanation: During repolarization, voltage-gated Na+ channels close, and K+ channels open to restore the resting membrane potential by allowing K+ to exit the cell.
Which of the following statements about the generation and propagation of action potentials initiated at the neuromuscular junction is not true:
A) The binding of neurotransmitters to receptors at the neuromuscular junction (NMJ) opens chemically (ligand) gated ion channels.
B) The opening of ligand gated channels at the NMJ allows the simultaneous diffusion of Sodium (Na+) inward and Potassium (K+) outward causing interior of cell to becomes less negative (a local depolarization).
C) Local depolarization spreads to adjacent membrane areas and causes additional voltage-gated Na+ channels to open.
D) Increasing Na+ influx further decreases membrane voltage toward critical voltage called threshold.
E) All are true statements.
E) All are true statements.
Which is the correct sequence of events for the generation of an action potential?
A)
1. Neurotransmitters are received at the neuromuscular junction
2. Neurotransmitter binding opens Sodium (Na+)/Potassium (K+) channels
3. Na+ influx causes local depolarization of the cell membrane causing an end-plate potential
4. The end-plate potential spreads to adjacent membrane areas causing additional voltage gated Na+ channels to open
5. Action potential is generated
B)
1. Neurotransmitters are received at the neuromuscular junction
2. Neurotransmitter binding opens Na+/K+ channels
3. Na+ influx causes local depolarization of the cell membrane causing an end-plate potential
4. Action potential is generated
5. The end-plate potential spreads to adjacent membrane areas causing additional voltage gated Na+ channels to open
C)
1. Neurotransmitters are received at the neuromuscular junction
2. Action potential is generated
3. Neurotransmitter binding opens Na+/K+ channels
4. The end-plate potential spreads to adjacent membrane areas causing additional voltage gated Na+ channels to open
5. Na+ influx causes local depolarization of the cell membrane causing an end-plate potential
A)
1. Neurotransmitters are received at the neuromuscular junction
2. Neurotransmitter binding opens Na+/K+ channels
3. Na+ influx causes local depolarization of the cell membrane causing an end-plate potential
4. The end-plate potential spreads to adjacent membrane areas causing additional voltage gated Na+ channels to open
5. Action potential is generated
What is the correct sequence of events that occur at the neuromuscular junction?
A)
1. An action potential arrives at the axon terminal of a motor neuron.
2. Ach binding opens ions channels allowing Na+ in and K+ out of the muscle fiber.
3. Ach diffuses across the synaptic cleft and binds to receptors on the sarcolemma.
4. Voltage-gated Ca++ channels in the axon terminal open and Ca++ moves in
5. Ca++ entry causes the neurotransmitter acetylcholine (Ach) to be released by exocytosis.
B)
1. An action potential arrives at the axon terminal of a motor neuron.
2. Voltage-gated Ca++ channels in the axon terminal open and Ca++ moves in
3. Ca++ entry causes the neurotransmitter acetylcholine (Ach) to be released by exocytosis.
4. Ach diffuses across the synaptic cleft and binds to receptors on the sarcolemma.
5. Ach binding opens ions channels allowing Na+ in and K+ out of the muscle fiber.
C)
1. An action potential arrives at the axon terminal of a motor neuron.
2. Ca++ entry causes the neurotransmitter acetylcholine (Ach) to be released by exocytosis.
3. Ach diffuses across the synaptic cleft and binds to receptors on the sarcolemma.
4. Voltage-gated Ca++ channels in the axon terminal open and Ca++ moves in.
5. Ach binding opens ions channels allowing Na+ in and K+ out of the muscle fiber.
B)
1. An action potential arrives at the axon terminal of a motor neuron.
2. Voltage-gated Ca++ channels in the axon terminal open and Ca++ moves in
3. Ca++ entry causes the neurotransmitter acetylcholine (Ach) to be released by exocytosis.
4. Ach diffuses across the synaptic cleft and binds to receptors on the sarcolemma.
5. Ach binding opens ions channels allowing Na+ in and K+ out of the muscle fiber.
Which of the following statements about resting membrane potential is not correct:
A) The resting sarcolemma is polarized; that is the inside of the plasma membrane is negative relative to the outside.
B) There is more Potassium (K+) inside the cell than outside the cell.
C) There is more Sodium (Na+) outside the cell than inside the cell.
D) The presence of negatively charged proteins inside the cell contribute to the negative charge inside the cell.
E) All are true statements.
E) All are true statements.
What are the three types of muscle tissue in the body?
A) Skeletal, Nervous, Cardiac
B) Cardiac, Skeletal, Smooth
C) Smooth, Connective, Cardiac
D) Nervous, Connective, Skeletal
B) Cardiac, Skeletal, Smooth
Explanation: The body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle. Each type has distinct properties and functions within the body.
All muscle tissues exhibit excitability.
A) True
B) False
A) True
Explanation: All three muscle tissues exhibit excitability as their plasma membranes can change their electrical states and send an action potential along the entire length of the membrane.
Fill in the blank: Skeletal muscle completely depends on signaling from the ______ to work properly.
Nervous system
Explanation: Skeletal muscle completely depends on signaling from the nervous system to work properly, unlike cardiac and smooth muscle which can respond to other stimuli such as hormones and local stimuli.
What quality allows muscle tissue to stretch or extend?
A) Contractility
B) Excitability
C) Extensibility
D) Elasticity
C) Extensibility
Explanation: Extensibility allows muscle tissue to stretch or extend. This is an important quality that enables muscles to lengthen in response to stretching.
Which muscle type has a striated appearance and is multinucleated?
A) Cardiac muscle
B) Skeletal muscle
C) Smooth muscle
D) All of the above
B) Skeletal muscle
Explanation: Skeletal muscle fibers are multinucleated and have a striated appearance due to the regular arrangement of actin and myosin proteins.
Cardiac muscle fibers are connected to each other so that the entire heart contracts as one unit.
A) True
B) False
A) True
Cardiac muscle fibers are physically and electrically connected to each other so that the entire heart contracts as a single unit, known as a syncytium.
Fill in the blank: ______ muscle regulates blood pressure necessary to push blood through the circulatory system.
Smooth
Explanation: Smooth muscle in the walls of arteries is crucial for regulating the blood pressure necessary to push blood through the circulatory system.
What feature is absent in smooth muscle but present in skeletal and cardiac muscles?
A) Actin and Myosin
B) Striations
C) Nuclei
D) Elasticity
B) Striations
Explanation: Smooth muscle lacks the striated appearance seen in skeletal and cardiac muscles because its actin and myosin are not arranged in a regular pattern.
All muscles require adenosine triphosphate (ATP) to contract.
A) True
B) False
A) True
Explanation: All muscles require adenosine triphosphate (ATP) to continue the process of contracting and relaxing.