Muscular System Test 2017

Muscle #21 is the semimembranosus muscle.

The correct answer is "soleus" because the question states "Muscle #3 is [Blank]" and the answer provided is "soleus". This suggests that the muscle being referred to as "Muscle #3" is the soleus muscle.

Muscle #10 is the vastus medialis.

Muscle cramps are indeed prolonged muscle spasms that can occur due to various reasons, including overuse and electrolyte imbalance. Overuse of muscles can lead to fatigue and muscle cramps, especially if proper rest and recovery are not taken. Additionally, an electrolyte imbalance, such as low levels of potassium, calcium, or magnesium, can disrupt the normal functioning of muscles and contribute to cramping. Therefore, the statement "Muscle cramps are prolonged muscle spasms that may be due to overuse and electrolyte imbalance" is accurate and true.

Oxygen debt refers to the amount of oxygen that the body needs to restore after intense physical activity. During exercise, the body's demand for oxygen increases, and if the oxygen supply is insufficient, the body accumulates a debt. This debt needs to be repaid in order for the tissues to function properly. Breathing heavily after exercise is a way for the body to take in more oxygen and repay the oxygen debt. Therefore, the statement that oxygen debt must be repaid and you will breathe heavily until your tissues have the proper amount of oxygen is true.

The attachment of a muscle's tendon to the stationary bone is called the origin, while the attachment of the muscle's other tendon to the movable bone is called the insertion.

A flaccid muscle refers to a muscle that lacks muscle tone, meaning it is weak and has reduced strength and firmness. This can result from various factors such as nerve damage or prolonged inactivity. When a muscle is flaccid, it is more prone to atrophy, which is the wasting away or shrinking of the muscle due to disuse. Therefore, it is accurate to say that a flaccid muscle can lead to atrophy.

Muscle #2 is the sartorius muscle.

Muscle #25 is the gluteus medius.

The correct answer is tibialis anterior because it is the muscle located in the front of the lower leg. It is responsible for dorsiflexion of the foot and inversion of the ankle. The tibialis anterior helps to lift the foot and control the movement of the ankle joint.

When sarcomeres get shorter, it means that the actin and myosin filaments within the muscle fibers are sliding past each other. This sliding action causes the sarcomeres to contract, resulting in muscle movement. Therefore, the correct answer is that sarcomeres get shorter in order to create movement.

Muscle #1 is called "gracilis".

Muscle tone refers to the natural tension and readiness of muscles to contract. It plays a crucial role in joint stabilization as it helps to keep the joints in their proper alignment and prevent excessive movement or instability. When muscles have adequate tone, they provide support and protect the joints from injury or damage. Therefore, it is true that muscle tone is important for joint stabilization.

Muscles can only generate force by contracting, which results in pulling on the bones they are attached to. Muscles cannot actively push or extend themselves. When a muscle contracts, it pulls on the tendons, which in turn pull on the bones, causing movement. This is why it is correct to say that muscles only pull and do not push.

Anaerobic respiration is a process that occurs in the absence of oxygen and is used by some organisms to produce energy. One of the byproducts of anaerobic respiration is lactic acid. This is because during anaerobic respiration, glucose is broken down into pyruvate, which is then converted into lactic acid. Therefore, the statement that anaerobic respiration produces lactic acid as a byproduct is true.

The muscle mentioned in the question is the rectus femoris.

Muscle #8 is the psoas major.

The correct answer is biceps femoris because muscle #28 refers to a specific muscle in the human body, and the biceps femoris is one of the muscles located in the posterior thigh. It is responsible for flexing the knee joint and extending the hip joint.

A quick, jerky response to a stimulus is known as a twitch. This refers to a sudden and involuntary movement or contraction of a muscle in response to a stimulus. Twitches are often brief and can occur in various parts of the body. They are typically caused by nerve impulses that result in the contraction of muscle fibers.

Muscles are always slightly contracted even when they are not being actively used. This is known as muscle tone, which helps to maintain posture and stability. The constant low-level contraction of muscles ensures that they are ready to respond quickly when needed. Therefore, the statement is true.

The muscle described in the question is most likely the quadriceps muscle group, which includes the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. These muscles originate from the femur and insert on the tibia via the patellar tendon. When these muscles contract, they cause extension of the knee joint, which involves the tibia moving towards the femur. Therefore, the correct answer is "The tibia moves towards the femur."

Skeletal muscles are responsible for movement, heat production, and maintaining posture. However, stimulus is not a function of skeletal muscles. Stimulus refers to a signal or trigger that causes a response in an organism. While skeletal muscles respond to stimuli, they do not generate or produce stimuli themselves.

An aponeurosis is a broad flat tendon that connects muscles to bones or other muscles. It is different from other types of tendons, such as those that are referred to as perimysium or endomysium, which are not broad and flat. Deep fascia refers to a layer of connective tissue that surrounds muscles, but it is not specifically related to tendons. A fascicle, on the other hand, is a bundle of muscle fibers within a muscle, and it is not the same as a tendon. Therefore, the correct answer is an aponeurosis.

The sarcoplasmic reticulum is a specialized organelle found in muscle cells. It is responsible for storing and releasing calcium ions (Ca2+). During muscle contraction, calcium ions are released from the sarcoplasmic reticulum into the muscle fibers, which triggers the contraction process. Therefore, the correct answer is Ca2+.

Regular endurance exercise can increase the number of mitochondria in muscle cells. Mitochondria are the powerhouse of cells, responsible for producing energy. During endurance exercise, the demand for energy increases, leading to an upregulation of mitochondrial biogenesis. This means that the body produces more mitochondria to meet the increased energy needs. As a result, regular endurance exercise can enhance the capacity for aerobic energy production in muscle cells, improving endurance and overall physical performance.

Creatine phosphate functions in the muscle cells by storing energy that will be used to transform ADP into ATP. When the muscle cells need energy for contraction, creatine phosphate donates a phosphate group to ADP, converting it back into ATP. This process is crucial for providing the necessary energy for muscle contraction, allowing the muscles to perform work.

Muscles do not begin to atrophy by age 30. While it is true that muscle mass tends to decrease with age, this process is not inevitable or solely determined by age. Regular exercise, particularly strength training, can help to maintain and even increase muscle mass as we age. Protein supplements can also support muscle growth and repair. Therefore, it is incorrect to say that no amount of exercise or protein supplements can slow, halt, or reverse the trend of muscle atrophy after age 30.

The main reason why skeletal muscles generate heat is because the energy transfer from chemical (ATP) to kinetic energy is inefficient. This means that not all of the energy produced during muscle contractions is converted into movement, and some of it is instead released as heat.

Muscles are attached to bones via tendons, allowing them to generate movement at the joints. Joints are the points where two or more bones come together, and muscles work in conjunction with these joints to create movement. Therefore, it is correct to say that muscles cross at least one joint.

A muscle fiber refers to a single muscle cell. It is the basic structural and functional unit of a muscle. Each muscle fiber contains specialized proteins, such as actin and myosin, that allow it to contract and generate force. Multiple muscle fibers work together to form a muscle, which enables coordinated movement and control.

Isotonic contractions produce movement because the muscle changes length while generating force. This type of contraction occurs when the tension in the muscle remains constant as the muscle shortens or lengthens. Isotonic contractions are commonly seen in activities such as weightlifting or running, where the muscle contracts and moves a load. In contrast, isometric contractions do not produce movement as the muscle generates force without changing length.

Long distance runners primarily rely on aerobic respiration as their main energy pathway. This is because aerobic respiration utilizes oxygen to break down carbohydrates and fats, producing ATP (adenosine triphosphate) as a source of energy. As long distance running requires sustained energy over a prolonged period of time, aerobic respiration is the most efficient way to generate ATP. Anaerobic respiration and direct phosphorylation are not as sustainable for long distances, as they rely on limited ATP stores and do not utilize oxygen efficiently.

A fixator muscle is responsible for stabilizing the origin of a prime mover muscle. It helps to hold the bone in place, providing a stable base for the prime mover to work more efficiently. By preventing unnecessary movement at the origin, the fixator allows the prime mover to focus on its main function without wasting energy on stabilizing the joint. Therefore, a fixator muscle plays a crucial role in enhancing the efficiency of the prime mover.

The correct answer is skeletal muscle tissue, blood vessels, connective tissue, and nerves. Skeletal muscle organs like the biceps femoris are composed of skeletal muscle tissue, which is responsible for voluntary movement. Blood vessels are also present in skeletal muscle organs to supply oxygen and nutrients to the muscle fibers. Connective tissue provides support and structure to the muscle. Nerves innervate the muscle, allowing for communication between the brain and the muscle fibers.

T-tubules conduct signal for muscle fiber to contract (action potential)

T-tubules extend into sarcoplasm (perpendicular to cell surface)

All muscle fibers are indeed present at birth. Muscle fibers are formed during fetal development and do not increase in number after birth. However, muscle fibers can grow in size and strength through exercise and physical activity.

The epimysium is a band of connective tissue that surrounds whole muscles. It provides support and protection to the muscle fibers, as well as helps to transmit force generated by the muscle. It is the outermost layer of connective tissue in the muscle and separates the muscle from surrounding tissues. The epimysium also connects to tendons, which attach the muscle to bones, allowing for movement and stability.

Muscle hypertrophy refers to an increase in the size of muscle cells, not the number of fibers. During hypertrophy, the existing muscle fibers become larger and stronger due to increased protein synthesis. This results in an overall increase in muscle size and strength. However, the number of muscle fibers remains relatively constant. Therefore, the statement that muscles mostly increase in the number of fibers when they hypertrophy is false.

Muscle tone is not caused by voluntary control. Muscle tone refers to the continuous and partial contraction of muscles, even when at rest. It is regulated by the central nervous system and is not under voluntary control. Therefore, the correct answer is false.

The explanation for the answer "False" is that the bulk of the muscle usually lies proximal to the joint crossed, not distal. This means that the majority of the muscle mass is located closer to the point of attachment or origin of the muscle, rather than towards the end or insertion point.

This statement is true because individual motor units are composed of muscle fibers that are either slow twitch or fast twitch. Slow twitch fibers are responsible for endurance activities and have a slower contraction speed, while fast twitch fibers are responsible for quick and powerful movements and have a faster contraction speed. Therefore, individual motor units can only have one type of fiber, either slow or fast twitch, but not both.

2 terminal cisternae on either side of 1 T-tubule = triad

Both the I band and A band contain thin filaments. The I band is the region of the sarcomere where only thin filaments are present, while the A band contains both thick and thin filaments. The thin filaments in the A band overlap with the thick filaments, creating the dark appearance of the A band. Therefore, both the I band and A band contribute to the presence of thin filaments in the sarcomere.

A muscle twitch is not a muscle spasm that recurs. A muscle twitch is a brief, involuntary contraction of a small number of muscle fibers. It is usually harmless and can be caused by various factors such as stress, fatigue, or caffeine. On the other hand, a muscle spasm is a more prolonged and intense contraction of a muscle or group of muscles, often causing pain and discomfort. Therefore, the statement that a muscle twitch is a muscle spasm that recurs is false.

Achilles Tendon Rupture is a condition where the Achilles tendon, which connects the calf muscles (gastrocnemius and soleus) to the heel bone (calcaneus), tears or completely severs. As a result of the rupture, the gastrocnemius and soleus muscles will not work properly. This injury often occurs in young sprinters due to the high forces placed on the Achilles tendon during explosive movements. The rupture typically happens suddenly, often during activities such as running or jumping. In this condition, the calcaneal tendon is completely severed.

Muscle fibers are:
- long
- cylindrical
- striated
- multinucleate

The pectineus, adductor longus, and gracilis muscles are all responsible for adducting the thigh. Adduction refers to the movement of bringing the thigh towards the midline of the body. These muscles work together to bring the thigh back to the midline after it has been abducted (moved away from the midline). The sartorius muscle, on the other hand, is responsible for flexing, abducting, and laterally rotating the thigh, but not adducting it.