Muscular Practice Exam Part 3 - A & P Zoo 172 For Exam 1

The zygomaticus is indeed a facial muscle. It is responsible for raising the corners of the mouth when a person smiles. This muscle connects the zygomatic bone (cheekbone) to the corner of the mouth and plays a crucial role in facial expressions.

The buccinator is a facial muscle that is responsible for compressing the cheeks inward. It helps with actions such as blowing, whistling, and sucking. It also plays a role in mastication (chewing) by keeping food between the teeth.

The soleus is a muscle located on the back of the lower leg. It is one of the calf muscles and works together with the gastrocnemius to help flex the foot and stabilize the ankle joint. The location of the soleus on the back of the lower leg is important for its function in providing strength and support during activities such as walking, running, and jumping.

The correct answer is trapezius. The trapezius muscle is a large triangular muscle that extends over the upper back and shoulders. It is responsible for movements such as shrugging the shoulders, pulling the shoulder blades together, and tilting the head and neck. The latissimus dorsi is a large muscle in the lower back, the rhomboideus major is a muscle located between the shoulder blades, and the platysma is a thin sheet of muscle in the neck and lower face.

The correct answer is rectus abdominis. The rectus abdominis is a paired muscle that runs vertically along the anterior wall of the abdomen. It is commonly referred to as the "six pack" because when well-developed, it creates visible abdominal muscles in the form of six distinct segments. The internal oblique is another muscle in the abdominal wall, but it is not specifically associated with the "six pack" appearance. The buccinator is a muscle in the cheek, and the rectus femoris is a muscle in the thigh.

Pronation is the correct answer because it refers to the movement of the palm down. This movement involves the rotation of the forearm in such a way that the palm faces downwards or towards the ground. It is commonly observed when turning the hand to place the palm on a flat surface or when facing the palm downwards while performing certain exercises or movements. Supination, on the other hand, refers to the movement of the palm up or facing upwards.

Z lines are the shared zig zag connections between adjacent sarcomeres. They are made up of proteins called actin and connect the thin filaments of one sarcomere to the thin filaments of the next sarcomere. Z lines play a crucial role in maintaining the structural integrity of the sarcomere and in coordinating the contraction of muscle fibers.

Acetylcholine is the correct answer because it is the neurotransmitter responsible for transmitting signals from motor neurons to skeletal muscles. When acetylcholine is released at the neuromuscular junction, it binds to receptors on the muscle fibers, triggering a series of events that ultimately lead to muscle contraction. This neurotransmitter plays a crucial role in controlling skeletal muscle movement and is essential for proper muscle function.

Myofibrils are composed of the proteins myosin and actin. Actin is a protein that is responsible for the contraction of muscles. It forms thin filaments that interact with thick filaments made of myosin. The interaction between actin and myosin allows muscles to contract and generate force. Therefore, actin is an essential component of myofibrils and plays a crucial role in muscle function.

The statement is true because the insertion point of a muscle is where it attaches to the bone that it moves. When the muscle contracts, it pulls on the bone, causing movement towards the origin point of the muscle. Therefore, the insertion point does indeed move the associated bone towards the origin.

The pectoralis major is a muscle that is primarily responsible for moving and stabilizing the arm and shoulder joint, not the head and vertebral column. It is a large muscle that is located in the chest area and is involved in movements such as pushing and pulling. Therefore, the statement that the pectoralis major moves the head and vertebral column is false.

The quadriceps femoris group consists of the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius muscles. The rectus thighongus is not a muscle that is part of this group.

Antagonists are muscles that act in an opposite manner to the agonist. They work to relax and lengthen while the agonist contracts, allowing for smooth and controlled movement. This opposing action helps to stabilize joints and prevent excessive or uncontrolled movements.

The biceps brachii muscle is responsible for flexion of the arm at the elbow joint. When the biceps brachii contracts, it shortens and pulls the forearm towards the upper arm, causing flexion. This movement is commonly seen when performing bicep curls or lifting objects towards the body. Therefore, the correct answer is flexion.

Myosin myofibrils are the thick filaments that provide the active process in contraction. These filaments are responsible for generating force during muscle contraction. They contain the protein myosin, which interacts with the thin filaments (actin) to produce the sliding movement that shortens the muscle fibers. The thick filaments are composed of multiple myosin molecules, which have a unique structure that allows them to bind to actin and generate the necessary force for muscle contraction.

The head of the femur is a ball-and-socket joint. This type of joint allows for a wide range of motion in multiple directions, including flexion, extension, abduction, adduction, and rotation. The head of the femur (ball) fits into the acetabulum of the pelvis (socket), creating a stable joint that is able to withstand weight-bearing activities and provide stability and mobility to the hip joint.

Supination is the correct answer because it refers to the movement of the palm facing upward. This movement involves the rotation of the forearm so that the palm faces upward or forward. It is the opposite of pronation, which is the movement of the palm facing downward or backward.

Actin myofibrils are the thin filaments that provide an anchor against which the myosin pulls. These thin filaments are composed of actin proteins and are responsible for the sliding movement of the myofibrils during muscle contraction. The myosin filaments grab onto the actin filaments and pull them closer together, causing the muscle to contract. Therefore, the correct answer is "thin".

The correct answer is "orbicularis occuli." The orbicularis occuli is a muscle that surrounds the eye and is responsible for blinking. It helps to close the eyelids and protect the eye from foreign objects or excessive light.

Prime movers are muscles that are responsible for the principal activity of a particular movement. They are the main muscles that generate the force needed to perform the movement. Synergists are muscles that assist the prime movers in performing the movement, while antagonists are muscles that oppose or inhibit the action of the prime movers. Therefore, the correct answer is prime movers.

The deltoid muscle is the main muscle of the shoulder. It is a large, triangular muscle that covers the shoulder joint and is responsible for various movements of the arm, including abduction, flexion, and extension. It is the primary muscle involved in lifting and rotating the arm. The biceps brachii is a muscle located in the upper arm, the trapezius is a muscle in the upper back and neck area, and the digastric is a muscle in the lower jaw.

A synovial joint is a type of joint that allows for free movement between the bones. These joints are surrounded by a synovial membrane that produces synovial fluid, which lubricates the joint and reduces friction. Examples of synovial joints include the knee, shoulder, and hip joints. Therefore, the statement that a synovial joint is a freely movable joint is true.

When muscle contraction occurs, myosin needs to attach to the binding site on the actin filament. However, this binding site is initially blocked by tropomyosin. In order for myosin to attach, tropomyosin needs to be pulled off of the binding site. This is where troponin comes in. Troponin is a globular protein that is associated with tropomyosin on the actin filament. When calcium ions are released during muscle contraction, they bind to troponin, causing a conformational change. This change in troponin position allows tropomyosin to move away from the binding site, making it available for myosin to attach and initiate muscle contraction.

The elbow is an example of a hinge joint because it allows movement in only one plane, similar to the movement of a hinge on a door. The elbow joint allows for flexion and extension, but does not allow for rotation or side-to-side movement. This type of joint is found in the body where stability and movement in one direction is required, such as in the knees and fingers.

The sarcomere is the section of the muscle fiber that extends from one Z line to the next. It is the basic functional unit of a muscle and is responsible for muscle contraction. The sarcomere contains the contractile proteins actin and myosin, which slide past each other during contraction. The Z lines mark the boundaries of the sarcomere and anchor the actin filaments. The sarcomere shortens during muscle contraction, resulting in overall muscle shortening and movement. The sarcolemma is the cell membrane of a muscle fiber, sarcoplasm is the cytoplasm of a muscle fiber, and a fascicle is a bundle of muscle fibers.

When an action potential (AP) travels through the sarcolemma and reaches the T-tubules, it triggers the release of calcium ions (Ca++) from the cisternae into the sarcoplasm. This release of calcium ions is a crucial step in muscle contraction. Calcium ions bind to the protein troponin, causing a conformational change that allows the myosin heads to bind to actin and initiate the sliding filament mechanism. This ultimately leads to muscle contraction.

After Ca++ combines with troponin on the actin filaments, the troponin changes shape causing tropomyosin to be pulled from the binding sites on the actin filaments. This exposes the binding sites on the actin filaments, allowing myosin cross-bridges to attach and initiate muscle contraction.

When myosin cross-bridges bind with the actin binding sites, they undergo a power stroke where they flex and pull the actin filaments towards the center of the sarcomere. This movement causes the filaments to slide past each other, resulting in the shortening of the sarcomere.

During intense exercise, the cardiovascular system may not be able to deliver enough oxygen to the muscles, resulting in oxygen debt. This leads to anaerobic glycolysis, a process in which glucose is broken down without the presence of oxygen. As a byproduct of anaerobic glycolysis, lactic acid is formed. Therefore, the correct answer is lactic acid.

ATP (adenosine triphosphate) is the primary source of energy for muscle contraction. It is required for the myosin heads to bind to actin filaments and generate force, leading to muscle contraction. Additionally, ATP is also needed for the relaxation of muscles after contraction. It is used to pump calcium ions back into the sarcoplasmic reticulum, allowing the muscle to relax. Therefore, ATP is necessary for both muscle contraction and relaxation, making the statement true.

Intercalated discs are specialized structures found in cardiac muscle. These discs play a crucial role in connecting individual cardiac muscle cells, allowing them to synchronize their contractions and function as a coordinated unit. This unique feature is not present in smooth or strong muscle, making cardiac muscle the correct answer.

The biceps femoris is located on the back of the upper leg. It is one of the hamstring muscles and is responsible for flexing the knee and extending the hip.

The levator scapulae is a muscle that elevates the scapula. It is located on the side and back of the neck, connecting the upper cervical vertebrae to the scapula. When this muscle contracts, it pulls the scapula upward, helping to raise the shoulder.

The semitendinosus muscle is responsible for flexing and rotating the leg medially, but it does not extend the thigh. Therefore, the correct answer is "Extends." This means that the semitendinosus muscle does not contribute to extending the thigh.

The triceps brachii are responsible for extension of the arm at the elbow joint. When the triceps contract, they straighten the arm by extending it. Flexion refers to bending the arm, pronation refers to turning the palm downwards, and supination refers to turning the palm upwards. Therefore, the correct answer is extension, as the triceps brachii are used in extending the arm.

The adductor longus is located on the medial thigh. This means that it is positioned towards the midline of the body, closer to the center of the body rather than the outer side.

The gracilis muscle is responsible for adducting the thigh. Adduction refers to the movement of bringing a body part closer to the midline of the body. In the case of the thigh, adduction involves bringing the leg back towards the center of the body. Therefore, the gracilis muscle plays a role in this movement by contracting and pulling the thigh towards the midline.

During an action potential (AP), Ca++ is released into the sarcoplasm. This influx of Ca++ ions causes troponin to bind to the actin filament, causing a conformational change that pulls tropomyosin away from the actin binding sites. This allows myosin to bind to actin and initiate muscle contraction.

Isometric contractions refer to a type of muscle contraction where the length of the muscle stays the same while the force exerted by the muscle changes. This means that there is no movement or change in joint angle during the contraction. Isometric contractions are commonly used in exercises like planks or wall sits, where the muscles are engaged and holding a static position without any movement.

The origin of a muscle is the immovable end of the muscle and in most cases, it does not have a tendon. The origin is the point of attachment of the muscle to a bone that remains fixed during muscle contraction. This is in contrast to the insertion, which is the movable end of the muscle that attaches to the bone that moves during muscle contraction. Ligaments are fibrous connective tissues that connect bones to other bones, while tendons connect muscles to bones.

The deltoid muscle is a large muscle located in the shoulder. It is responsible for the abduction and flexion of the arm. The deltoid tuberosity is the correct answer because it is the point of insertion for the deltoid muscle. The tuberosity is a bony prominence located on the lateral side of the humerus, the bone of the upper arm. When the deltoid muscle contracts, it pulls on the tuberosity, allowing for movement and stability in the shoulder joint.

Intervertebral discs are an example of a fibrocartilage plate or disc called a symphysis. These discs are located between the vertebrae in the spine and act as shock absorbers, providing cushioning and allowing for flexibility and movement in the spine. They are made up of a tough outer layer called the annulus fibrosus and a gel-like center called the nucleus pulposus. The fibrocartilage composition of intervertebral discs allows them to withstand compression and tension forces, making them well-suited for their role in the spine.

The statement is true because there are indeed two types of tetany: fused and unfused. Fused tetany refers to sustained muscle contractions that do not have any relaxation periods in between, while unfused tetany refers to muscle contractions that have intermittent relaxation periods. These two types of tetany can occur due to various factors such as electrolyte imbalances, hyperventilation, or certain medical conditions.

The sternocleidomastoid muscle is not responsible for moving the pectoral girdle. It is actually responsible for the rotation and flexion of the head and neck. The pectoral girdle is primarily moved by muscles such as the trapezius, deltoid, and pectoralis major. Therefore, the statement is false.

Synergists are muscles that work together with the agonist to assist, stabilize, guide, or coordinate movements. They help to enhance the action of the agonist and ensure smooth and efficient movement. Unlike prime movers, which are primarily responsible for generating movement, synergists provide additional support and control. Antagonists, on the other hand, oppose or inhibit the action of the agonist. Therefore, the correct answer for this question is synergists.

The masseter is a muscle that elevates the mandible, or lower jaw. It is one of the main muscles involved in chewing and biting. When the masseter contracts, it pulls the mandible upward, allowing for the closing of the mouth and the exertion of force during chewing.

The correct answer is flexors. Flexors are a group of muscles that cause flexion, or bending, of the joints. They generally have their origin on the medial epicondyle of the humerus, which is a bony prominence on the inner side of the elbow. These muscles are responsible for movements such as closing the hand into a fist or bending the fingers. Extensors, on the other hand, are a group of muscles that cause extension, or straightening, of the joints. They have their origin on the lateral epicondyle of the humerus.

The orbicularis oris muscle is responsible for allowing you to pucker your lips and perform actions such as kissing. This muscle encircles the mouth and is involved in various facial expressions and movements related to the lips, including closing and opening the mouth, as well as shaping the lips for different activities like speaking, eating, and yes, kissing.

The pectoralis major is a large muscle located in the chest region. It is primarily responsible for movements of the arm, specifically flexion, adduction, and medial rotation. These actions involve bringing the arm closer to the body, as well as rotating it towards the midline. Therefore, it is correct to say that the pectoralis major is an arm mover.

A bands are dark colored and are located in the central part of the sarcomere. The A band is composed of thick filaments made of myosin, which are responsible for muscle contraction. These filaments overlap with thin filaments made of actin in the region called the H zone, creating the dark appearance of the A band. The A band is an important structural component of the sarcomere and plays a crucial role in muscle contraction.